1 Mind and Brain, Chaos and Quantum Mechanics.
1.1 Paradigms in Scientific Discovery and The Enigma of Consciousness
The twentieth century has seen the unification of the microscopic
and cosmic realms of physics in theories such as inflation, in
which symmetry-breaking of the fundamental forces is linked to
cosmic expansion. Molecular biology has had equally epoch-making
successes unravelling the intricate molecular mechanisms underlying
living systems, from the genetic code through to developmental
structures such as homeotic genes. Despite these conceptual advances,
the principles by which the brain generates mind remain mysterious.
The intractability of this central unresolved problem in science
suggests its principles run deeper than the conventional biochemical
description, requiring novel biophysical principles. This paper
develops such a model based on linkage between the fractal aspect
of chaotic neurodynamics and quantum non-locality, giving brain
science a cosmological status at the foundations of physical
description.
1.2 Chaos and Quantum Mechanics : Unpredictability as a Basis
for Mind Although mechanists tolerate mind as a passive shadow
representation of physical causality in such theories as epiphenomenalism
and brain-mind identity, free-will conjures up the spectre of
active causal interference. To quote Sir John Eccles :'It is
a psychological fact that we believe we have the ability to control
and modify our actions by the exercise of "will", and
in practical life all sane men will assume they have this ability'.
Nevertheless free will has a very unpopular history in science
because of the paradox of mind acting on a supposedly deterministic
physical system. The controversiality of consciousness and free-will
in science stems from their supposed inconsistency with causal
scientific description - but is this so? Chaotic dynamical systems
and quantum mechanics both share attributes which are more consistent
with these two features than biochemical reductionism would suggest:
1.2.1 Chaotic dynamics possess both sensitivity to initial conditions
and computational unpredictability, fig 1(a) (Schuster 1986,
Stewart 1989) because exponential spreading of adjacent trajectories
with increasing time occurs with a positive Liapunov exponent
L > 1 fig 1(a). Similar considerations apply to complex systems
in transition in and out of chaotic regimes, where L crosses
1 . Arbitrarily small fluctuations are thus inflated into global
instabilities by the "butterfly effect", in which a
perturbation such as a butterfly can become the source of a subsequent
tropical cyclone. A chaotic system is arbitrarily sensitive to
perturbation and hence responsive. Sensitivity also prevents
a chaotic system from being precisely modelled. It is thus unpredictable,
though it may be deterministic. Such systems behave in a way
which makes it impossible for an observer outside the system
to describe it precisely enough to determine its outcome and
hence test its causal nature.
1.2.2 Quanta possess a global internal model of their environment
in the form of the wave function and violate causality through
uncertainty during reduction of the wave packet. These attributes,
although somewhat different in nature from sensitivity and unpredictability,
cap off the causality of chaotic physical systems at the microscopic
level and have parallels to consciousness and free-will. Although
a quantum behaves like a particle in terms of its emission and
absorption, its wave function extends throughout space-time,
forming a global representation of its environment. Subsequent
absorption of the particle appears to collapse the wave function
into only one of its superposition of possible states. Thus although
averaged ensembles of events conform to the probability distribution
of the wave, the absorption foci of individual quanta cannot
be predicted. The stochastic nature of the theory makes it possible
in effect for each quantum to both be conscious of the universe
through the extended wave function and to exercise free-will
in its demise in wave packet reduction, while conforming to the
principles of quantum mechanics.
1.2.3 Fractal linkage. These two levels of physics have a natural
link of scale through the fractal nature of chaotic dynamics.
Many chaotic systems display conserved sets such as attractors
and basins which are fractal in the sense that they are replicatively
self-similar on descending microscopic scales, resulting in a
non-integer dimensionality (Peitgen & Richter 1986). In fig
1(b) the Koch flake illustrates a simple geometrical fractal
in which each side is repeatedly replaced by 4 sides of 1/3 the
length l. The number of units thus scales as l -log4/log3, giving
a fractal dimension D = log4/log3. The correlation dimension
is a similar measure (Grassberger & Procaccia 1983).
The term quantum chaos has been used to describe a variety of
quantum systems which have analogous dynamics to classically
chaotic systems. Electrons, atoms and small molecules traversing
a molecular milieu, have dynamics well approximated by a chaotic
system. Complementing this frontier is the link between quantum
uncertainty and sensitive dependence. In a chaotic physical system,
quantum fluctuations will become amplified into global instabilities
by the butterfly effect - quantum inflation. The fractal nature
of chaotic dynamics results in a disseminated set of increasingly
unstable regimes which can serve as nuclei for global fluctuation
(King 1991). Complex systems in the chaotic transition region
may also enter a state of self-organized criticality in which
a local perturbation leads to global bifurcation.
Although our sensory experiences, particularly visual representations
of the physical world, have obvious stability properties, the
necessity of sensitive dependence on the external world guarantees
that the internal model must include unstable dynamics, as is
confirmed by study of optical illusions, hallucinations and dreams.
Recent studies of the chaotic dynamics of a variety of neurophysiological
processes support such attractor-bifurcation models at both the
cellular and neurosystems level.
1.2.4 The Mind of the Uncertain Brain Such a linkage could be
used by the brain to allows mind states to critically perturb
brain states through quantum non-locality. Such an interaction
is possible only if the time evolution of the brain is formally
unpredictable when observed externally as a physical system.
This unpredictability must also be advantageous in evolutionary
terms, and hence must assist the brain in the computationally
intractable task of survival in the open environment. In this
sense, mind may be an extra-physical dual aspect of reality,
corresponding to unpredictabilities and uncertainties in a physical
brain. Such an interpretation is a dual model of reality in which
mental and physical are fundamental components of the universe.
The physical world is manifest only indirectly as a set of stability
properties of mind. From the physical perspective the same mental
experiences correspond to stability structures in an internal
model of reality.
2 Conceptual Problems in the Mind-Brain Relationship
2.1 Defining Mind and Consciousness
2.1.1 Mind and Consciousness remain so different from the usual
objects of scientific inquiry that it is unclear they conform
to the objective criteria usually applied to scientific description.
The terms are the subject of such ambiguity that it is essential
to review their semantic variations:
Mind is often referred to as the sum of our intellectual faculties,
our capacity to think or reason, the rational mind, as distinct
from sensation. Being out of one's mind in a complementary way
suggests escape from rational controls into insanity. Mindless
activity similarly implies unreflecting action. Minding carries
different emphases of attending - "Mind that step!"
or caring - "I don't mind if I do!". Being mindful
again implies attentiveness. Having something on one's mind that
of preoccupied thought. Making up one's mind that of deciding.
Being of one mind having the same opinion or intent. Nevertheless,
mind as the dual of body embraces the diversity of subjective
experience. To avoid such semantic confusion, I will inclusively
define mind as: the envelope of all subjective manifestations
of brain-related activity, including sensation, thought, feeling
and states such as dreaming. The essential feature of the mental
is its fundamentality, the fact that all our access to the physical
world occurs via the conduit of subjective experience, the one
undeniable reality of existence.
Two scientifically controversial attributes of mind are likely
to be pivotal to a successful description :
2.1.1.1 Consciousness : subjective manifestation of attentive
brain function.
2.1.1.2 Free-will : mental action upon brain function, violating
physical determinism.
At a primary level, our conscious experiences are our only access
to the nature of physical reality. Although we become firmly
convinced of the existence of the real world, our access to this
world is only by inference from our subjective, conscious experience
as observers. The physical universe is manifest entirely as structural
stabilities of conscious experience, or as conceptual descriptions
we develop from analysis of other forms of conscious observation,
such as particle tracks, spectrographs etc. The physical world
is thus accessed indirectly as an inferential structure linking
our own conscious experiences and those of others into a single
stable description. Thus despite believing in the primacy of
the world we live in, all of us derive all our knowledge of the
universe from our subjective representations of reality (Eccles
1966, Blakemore & Greenfield, 1987, Rose 1973, Margenau 1984).
Without the direct avenue of subjective awareness, it is unclear
that a physical universe would even exist.
This basic and undeniable manifestation of subjective consciousness
has again a backdrop of other more restrictive concepts. One
can refer to another person as conscious or unconscious depending
on whether they appear to be responding to stimuli, or in a state
of coma. One can also compare the conscious with the subconscious
or the collective unconscious of Jung, allowing for some attributes
of mind to pass subliminally into existence or represent archetypes
lying below the level of attentive awareness. Cognitive scientists
may dismiss many peripheral aspects of brain processing as being
pre-conscious, leaving only the major orienting focus of attention
as reaching the conscious level. Finally consciousness is viewed
as a reflective type of attention process, exemplified by self-consciousness
in which a person in addition to perceiving is aware of themselves
as a subject. As described by Rosenthal (1986) "a conscious
state is one which has a higher-order accompanying thought which
is about the state in question". Ironically such self-consciousness
has been claimed by Jaynes (1976) to be a very recent and culture-born
imposition, however to the contrary, it may be an evolutionary
feature of mammalian or even metazoan brains, because distinction
of self from world is the fundamental distinction for survival.
A central feature of consciousness research is how perception
and attention combine to result in action in the brain (and mind).
I will thus inclusively define consciousness as: the envelope
of capacities of the brain to form subjective representations
of reality. In this sense, the brain is conscious of mind. This
is consistent with one of the most popular modern conceptions
of the mind as an internal model of reality constructed by the
brain, a view consistent with a variety of lines of evidence
spanning normal cognition, the nature of optical illusions, dreaming
and many pathological states of the brain. Free-will on the other
hand is the reciprocal action of mind on brain.
2.1.2 The Menagerie of the Mind The scope of subjective experience
can be outlined through a combination of introspection and study
of traditional concepts in language. The most undeniable mental
experiences are our sensory experiences of the world around us,
and physical sensations in our bodies from touch and pain through
to the manifestations of emotions such as fear and anger. Along
with these come less clearly defined inner images provided by
memorization, imagination and thought. While these are less rich
than direct sensory experience in usual waking life, probably
as a result of competition with direct sensory stimuli accessing
the same processing modules, in states of relaxation, sensory-deprival,
dreaming, or meditation, internal imagery becomes clearer and
less distinguishable in intensity from sensory experience, and
may take on a life of its own. Study of the properties of such
alternative states has immense potential for consciousness research,
because the properties of consciousness are not sensorily tied
to the physical world description, thus providing a unique opportunity
to test its internal dynamical qualities.
Many mental features, being processes rather than states, cannot
be subjected to stable scrutiny without changing their characteristics.
While it is easy to understand the meaning of this sentence,
it is vastly more difficult to simultaneously perceive the details
of how you are able to understand its meaning, and more difficult
still to decide to what extent the semantic background of the
words is consciously perceived or merely subconsciously controlling
the conceptual process. Nevertheless it is accepted English usage
that we can choose to think and that thinking is a structured
conscious process, in which a sequence of semantic concepts emerge
as a product of directed voluntary attention, a sequential process
with semantic direction, which may take the form of narrative,
rehearsal or have sensory or abstract properties. To imagine
is again a voluntary process but dealing with imagery generation.
By contrast, to have an idea is a spontaneous and possibly novel
product of the thought process. Such terminology is consistent
with a dynamical model in which the attention process generates
structural bifurcations, some of which spontaneously generate
novel features or concepts. The difficulty of attending to two
things at once and the singularity of the stream of consciousness
suggests that it represents a global dynamic in the brain. It
may be more accurately described as a bundle of related awarenesses,
dynamically coupled, but capable of further bifurcation.
Central to our subjective consciousness is the notion of an observer,
or self, witnessing a theatre of conscious experience through
the attention process, having the capacity by an act of will,
or intent, to alter the circumstances occurring in the perceived
world. Dennet (1991), based on the dictates of a parallel processing
model, and various perceptual illusions, asserts that such a
"Cartesian Theatre" is non-existent. "What would
make this sequence the stream of consciousness? There is no one
inside , looking at the wide screen show displayed all over the
cortex, even if such a show is discernible by outside observers".
Nevertheless the construction of the physical world model is
derived from our conscious experiences. While there may not be
a localized and distinct representation of the stream of consciousness
in the brain, and consciousness, including time-perception, may
present as an internal model of reality, the self and its intentional
relation to the stream of consciousness remains our fundamental
arena of experiential reality.
2.1.3 Observer Problems in Consciousness Several features make
consciousness uniquely difficult to observe:
2.1.3.1 Mental observation [introspection] involves a whole-systems
observer problem in which the system being observed is also the
system doing the observing. "Introspection is one of the
many forms consciousness itself can assume, so that it represents
a significant part of what we are trying to explain" (Miller
1992). The attempt to examine conscious states thus globally
alters their phenomenology.
2.1.3.2 Mental constructs do not satisfy the criteria of objectivity
possessed by physical objects and processes, so most aspects
objective observation are rendered invalid. "Although consciousness
exists by virtue of some physical property of the brain, just
as bioluminescence exists by virtue of some chemical property
of specialized cells, it is not as bioluminescence is an observable
property of living matter. Nor is it an invisible property...
It is detectible to anyone who has it. The difficulty is the
method by which consciousness is detected is logically different
from ... bioluminescence" (Miller 1992). Thus qualia such
as redness remain ill-defined.
2.1.3.3 As William James originally pointed out "consciousness
is not a thing, but a process". Conscious features may thus
be rapidly transformed by the very act of observation, leaving
only the sensoria as stable observables. Thought is an example
of such dynamically unstable observation, because the act of
thinking results in an evolution of the experience. An idea is
an unstable bifurcation to a novel thought state.
2.1.3.4 The boundary between subconscious processing and conscious
experience is ill-defined. Consciousness may thus be incomplete
as a process. The hidden background of conscious experience,
which Dreyfus and Searle call "intrinsic intentionality"
may contain some of the highest computations.
2.1.3.5 Crick & Koch (1992) note that the problem of consciousness
is ill posed, because it is a constructive process, requiring
further constraints to provide a unique solution.
2.1.3.6 The subjective experience of free-will is inconsistent
with causal description.
2.2 Concepts of the Brain-Mind Relationship
A diverse variety of views of the mind-brain relationship have
been advanced, providing pointers to the basis of mind in brain
function, while confirming the unresolved state of understanding
in this area.
2.2.1 Complexity : Consciousness as a property of complex computational
systems. One common idea about the emergence of mind is that
it is somehow a product of the very complexity of the brain.
However neither computer circuits nor artificial neural nets
are ascribed to possess the attribute of mind in addition to
their functioning at any given level of numerical complexity.
John Searle (1980) invented the Chinese room, in which [conscious]
operators translate Chinese by symbolic constructs without the
system being conscious of the meaning of the translation, to
point out that strong AI cannot by itself explain consciousness.
Dennett (1991) utters the 'systems reply' against this by saying
that the brain is complex and is conscious so it is possible
in principle for a parallel virtual machine to become conscious
through it's many parallel interactions - "this little bit
of brain activity doesn't understand Chinese, and neither does
this bigger bit of which it is a part ... even the activity of
the whole brain is insufficient to account for understanding
Chinese"... of course the dualists would say "it takes
an immaterial soul to pull off the miracle of understanding".
Dennet's critical untested assumption is that the brain is simply
a classical virtual machine.
Measures of complexity based only on neural net architecture
neglect non-trivial properties of the individual neuron. The
coelenterate Hydra, fig 2, displays complex behaviour involving
a greater variety of locomotion types than the sea snail Aplysia
and coordinated feeding, despite having an undifferentiated nerve
net, which can withstand migratory reintegrations of the ectoderm
and endoderm if the organism is turned inside out.
Certain non-linear systems near the chaotic boundary L ~ 1 or
in chaotic transition do however display complex bifurcations
and the development of novel structure within the system, and
for this reason are termed complex systems by the Santa Fe school
(Jen 1990). These form good models for neurophysiology, and have
the potential when given an adequate quantum foundation also
to explain consciousness.
2.2.2 Emergence: The idea that new properties emerge from
the interaction of subsystems, not predicted by the subsystem
architecture. In this sense emergence, which is a property of
many digital and non-linear systems including molecular assemblies,
applies to virtually every system with global feedback, from
machines and organisms to the weather, all of which share system
attributes which are disrupted by partitioning. Thus while the
basis of mind is doubtless also emergent, this does not in itself
explain how it 'emerges' from the brain. It is thus necessary
to look in detail at the underlying mechanisms of mind for a
substantive explanation.
2.2.3 An internal model of reality constructed by the brain.
The idea of the mind as an internal model of reality has widespread
support, both in the modular structures of sensory detectors
which respond to features such as line orientation, thus synthesizing
a model out of a combined set of features, and in various visual
illusions in which these features lead to incomplete or contradictory
results. The internal model is also consistent with a role for
the mind as a monitoring system for attention. However the precise
nature of the model and how the brain uses it to generate mind
remain to be elucidated.
On a physiological level, research into modular sensory processing
(see 3.3) and the distributed chaos models of Freeman's group
(see 4.1.1) illustrate internal models of brain function which
share distributed processing features. At an opposite extreme
Blackmore's (1988) internal model unites a variety of modes of
mental experience surrounding dreaming into a common description.
Somewhere in between stand the purely structural models of artificial
intelligence (AI) and cognitive psychology, which draw from the
studies of distributed processing in modern physiology (see 3.1)
to present parallel cybernetic models which, although they have
powerful features, explain consciousness away as an elaborate
form of parallel computational control of the organism. Dennet's
(1991) multiple drafts model is an example which denies our subjective
view of a theatre of conscious experience with an attentive observer.
"There is no single definitive "Stream of Consciousness"
because there is no Central Headquarters, no Cartesian Theatre
where "it all comes together", for the perusal of the
Central Meaner. Instead of such a single stream (however wide),
there are multiple channels in which specialist circuits try,
in parallel pandemoniums, to do their various things, creating
Multiple Drafts as they go. Most of these fragmentary drafts
of "narrative" play short-lived roles in the modulation
of current activity but some get promoted to further functional
roles, in swift succession, by the activity of a virtual machine
in the brain. The seriality of this machine (its 'von Neumanesque'
character) is not a hard-wired design feature, but rather the
upshot of a succession of coalitions of these specialists",
(see also Marcel & Bisiach 1988, Baars 1988).
The multiple drafts model makes some physiological sense because
an asynchronous parallel architecture allows the brain to make
optimally rapid, but arbitrarily complex calculations. Such an
architecture is consistent with cortical design in which the
incoming afferents are associatively connected with the outgoing
efferents with no intervening structures, leading to very short
computational delays, while the timing delays across the cortex
are non-zero. It is also consistent with the attractor dynamical
model advanced in this paper in which multiple bifurcations can
induce parallel structures in the same dynamic. The general nature
of such a distributed internal model also has very interesting
time properties (see 8.2), and allows for constructive filling
in [blind spot and fig 5(c)], editing, and for gaps in the description,
such as those caused by visual saccades to be smoothed out (Dennett
1991) . "Nothing can seem jerky except what is represented
as jerky" - Minsky.
However Dennett's description clearly leaves mind a role equivalent
only to an abstract computational process. "The neuroscientists
are right to insist that you don't really have a good model of
consciousness until you solve the problem of where it fits in
the brain, but the cognitive scientists, (the AIers ad the cognitive
psychologists, for instance) are right to insist that you don't
really have a good model of consciousness until you solve the
problem of what functions it performs and how it performs them
- mechanically, without the benefit of Mind. ... Anyone or anything
that has such a virtual machine as its control system is conscious
in the fullest sense and conscious because it has such a virtual
machine" (Dennett 1991). "Any scientific theory of
mind has to treat it as an automaton" (Johnson-Laird 1983).
These statements lose the subjective nature of mind completely.
This difficulty arises from dependence on abstract computational
ideas as the basis for the models, reducing the functional implementation,
and particularly its neurophysiological basis to subordinate
roles as in Marr's (1982) three-level analysis of mental phenomena.
If the brain uses unusual physical principles in its neurophysiology,
such models will fail by the classical trap. Repeated objections
have also been mounted on philosophical grounds. "No connectionist
computer could exhibit real mentality" (Searle 1990a,b).
"The subjective features of conscious mental processes -
as opposed to their physical causes and effects - cannot be captured
by the purified form of thought suitable for dealing with the
physical world that underlies the appearances" (Nagel 1986).
The current paper addresses this problem by presenting a model
in which the biophysical principles are paramount and the computational
features are a product of the biophysics.
2.2.4 Duality : Mind as a dual phenomenon to physical reality.
The very great difference between mind and the diversity of physical
phenomena suggests that although in a sense paralleling the physical
brain, mind may not be a physical attribute as such but a complementary
principle, making mind and universe dual aspects of totality.
Descartes' homunculus in the pineal and his "cogito ergo
sum" illustrate two aspects of his dualism, expressed very
eloquently in the following passage: "While I could pretend
that I had no body, that there was no world ... I could not pretend
that I was not ... from the fact that I thought of doubting the
truth of other things ... it followed I existed ... from this
I recognised that I was a substance whose whole essence or nature
is to think and whose being requires no place and depends on
no material things" - Descartes Discourse on Method 1637.
Dualism has been the subject of attack and counter-attack during
the 20th century. Gilbert Ryle (1949) made a classic critique
of dualism, describing it as the "ghost in the machine",
and branding many aspects of mental description as category mistakes,
promoting Koestler (1967) to mount a rebuttal by the same title.
An outstanding feature of many of Ryle's descriptions, such as
the lemon on the desk, is that they derive from everyday experiences
in which the stable physical world model dominates other aspects
of conscious perception.
Several researchers have proposed dualistic philosophies or even
three-aspect brain-mind-knowledge models. Sir John Eccles wrote
"we are a combination of two things or entities : our brains
on the one hand; and our conscious selves on the other."
The brain is a precious "instrument" a "lifelong
servant and companion" providing "lines of communication
from and to the material world," but we are not it. An act
of will, as Eccles sees it is an everyday case of psychokinesis
of mind moving bits of matter (Hooper & Teresi 1986). He
has even gone as far as to propose structured entities psychons
corresponding to ideas which interact with dendrons possibly
in the pyramidal tracts. Vendler (1972, 1984) has also made a
defence of dualism. Epiphenomenalism constitutes a weak one-sided
form of duality in which world effects mind but not vice versa.
Critics of the artificial intelligence and cognitive psychology
schools such as Dennet (1991) describe dualism as forlorn because
it undermines the agenda of materialist or operationalist description
of both the brain and mind in abstract computational terms ...
"If mind and body are distinct things or substances, they
nevertheless must interact; the bodily sense organs via the brain
must inform the mind, ... and then the mind, having thought things
over must direct the body in appropriate action. ... Cartesian
interactionism". "How can mind stuff both elude all
physical measurement and control the body?". Such criticisms
depend on outmoded classical reasoning ... "It is [the]
principle of conservation of energy that accounts for the physical
impossibility of perpetual motion machines, and the same principle
is apparently violated by dualism. This confrontation between
quite standard physics and dualism has been endlessly discussed
since Descartes's own day, and is widely regarded as the inescapable
and fatal flaw of dualism". This statement displays a startling
lack of understanding of a variety of physical processes from
the weather to the behaviour of quanta, in which instability
and uncertainty fragment classical causality and provide room
for a logical loop connecting mind and brain - a central theme
of the current paper.
2.2.5 Sensitive instability. The internal model is non-linear,
dynamically unstable and undergoes transitions to and from chaos.
While some aspects of mind, such as visual processing, have structural
stability in their representation of most objects, optical illusions
and a variety of mental phenomena from hallucinations to the
bizarre subjective realities of dreaming sleep demonstrate that
the mind is capable of unstable self-generative behavior. Dynamical
arguments dictate that a nervous system which is optimally responsive
to sensory conditions must undergo transitions into chaos to
provide arbitrary sensitivity and ensure it does not become locked
in any stability state or periodic oscillation. Thus while philosophers
such as Gilbert Ryle, who rely on stable mental representations
of objects, may conclude that mind is not even a well formulated
concept, the unstable aspects may be essential to the internal
model of reality.
Sensitive dependence is consistent both with representation of
the mind as an internal model and with a dualistic interpretation
of reality. The form of stability sets such as attractors and
their evolution through bifurcation provides the basis for an
internal model. The unpredictability of the chaotic regime and
its ramifications in terms of quantum uncertainty provide a causal
loophole within which to discuss principles complementary to
physical processes occurring above the quantum level, which would
support the dualistic perspective without contradiction.
3 The Neurophysiological Basis of Mind
It is obvious that the manifestation of consciousness in the
forms we are used to experiencing requires interactive dynamics
of the sensitively dependent active brain. What remains more
elusive, like the engram of memory, is the neurophysiological
basis for conscious states.
3.1 Local versus distributed generation of mind.
The hypothesis that mind is a consequence of the nature of distributed
brain processing has a variety of support, based on the modular
architecture of the cortex, modal arousal of the ascending distributed
pathways and the impact of limbic circuits which we will investigate
below. As all these systems are required for conscious attentiveness,
the conclusion that consciousness is a global manifestation of
attentive brain function is strongly supported.
An alternative strategy for the brain to generate the mind would
be to have specialized areas dedicated to the generation of the
internal model of reality. Sir John Eccles suggested that the
mind is generated by the supplementary motor cortex, which is
almost universally active (Popper & Eccles 1977). However
damage to a variety of cortical areas reveals only "graceful
degradation" of both function and subjective awareness,
rather than 'mind loss' (Blakemore 1991).
Disagreement over the source of major oscillations in the brain
such as the alpha and theta rhythms has led to ideas that specific
sub-cortical structures such as the thalamus may play a principal
role in generating mind, acting as a gating mechanism between
the cortex and subcortical sensory centres (Crick 1984, Taylor
1992). It has topographical representations of many cortical
modalities and forms an intermediate position between the cortex
and the sensoria, thus having the potential to act as a filter
releasing only the most relevant stimuli into conscious attention,
coinciding with Huxley's (1954) filter theory of consciousness.
These roles remain to be proven because the thalamus is difficult
to access and the evidence from accidental lesions in humans
is not clear. Similarly the ascending pathways of the basal brain
are essential to maintain active consciousness, but this appears
to be by diffusely activating the entire cortex.
Consciousness could nevertheless involve only a subset of cortical
neurons. "Consciousness corresponds to coalitions of cortical
neurons dynamically modulated by attention and higher-level expectations
... We would expect that only some of the cells in the cortex
would be expressing what we see, while others are carrying out
unconscious computations, but which cells correspond to consciousness?"
(Crick & Koch 1992). At an extreme, identifying mind with
distributed processing becomes mind-brain identity in which all
mental states are considered the subjective equivalent of particular
brain states. Mind-brain identity has two difficulties. Firstly
the structural basis of mind is eliminated rather than explained
by identity. Any responsive physical system, such as a computer
could equally possess mind by the identity principle. Secondly
identity prevents any causal link between the mind and brain,
reducing consciousness and free-will to the status of delusions
of the internal model, eliminating any role for the subjective
aspect of reality in evolution and hence the need for an 'identity'
mind.
3.2 Ascending distributed pathways. A very important contribution
to the modal nature of conscious activity comes from the distributed
pathways ascending from the midbrain centres, fig 3(a) responsible
for general arousal in the reticular activating system [RES],
and in regulating the major modality shifts of consciousness,
light and dreaming sleep. Two pathways lead from the Raphe Nuclei
and the Locus Coeruleus to diverse cortical areas and involve
the modulating neurotransmitters, serotonin and nor-epinephrine,
fig 11. The onset of dreaming sleep is heralded by activity of
cells in the Pons and silencing of cells in the Raphe Nuclei
and Locus Coeruleus (Bloom et. al. 1986). The latter also show
bursts during orientation to novel stimuli. Similar dopamine
paths spread out from the Substantia Nigra selectively into the
frontal lobes and motor centres. The ascending pathways have
been implicated in mental illness, addiction and motor syndromes
such as Parkinson's disease (Gilling & Brightwell 1982).
Dopamine is sometimes associated with pleasure and nor-adrenaline
with anxiety.
Dreaming or REM sleep is both one of the most singular phases
of conscious activity in which feedback appears to be accentuated
at the expense of external input, generating complete subjective
realities or 'worlds within'. The nature and function of dreaming
consciousness and its wealth of detail remains obscure. The principal
hallucinogens are also serotonin and catecholamine analogues,
fig 11. In addition to cerebral arousal and sleep loss, their
action probably triggers fractal waves of cortical excitation
through the diffuse connections into interleaved cortical layers
shown in fig 3(a) inset. Such connectivity gives the hallucinogens
the capacity to modulate reflex modular excitability across the
entire cortex, giving rise to patterned visions and cross-sensory
synesthesias. They have earned a controversial reputation by
provoking, alongside dreaming, some of the most remarkable changes
in the nature of consciousness discovered by man. For the same
reason they represent a key tool for consciousness research.
3.3 Cortical modularity. A variety of experiments support the
modular (Fodor 1983, Mountcastle 1978) involvement of cortical
centres, both in various sensory-cognitive tasks and their correlates
in mental activity. These illustrate how modular cortical processing
can be associated with different aspects of conscious experience.
Visual processing is clearly modular, with parallel processing
of colour and movement in distinct areas (Zeki 1992). The primary
visual area V1 has 'discrete and segregated' connections through
more structured sensors in V2 to V3, V4 and V5 responsible for
dynamic form, colour form and motion. These areas are each associated
with their own lesion syndromes such as achromatopsia [no colour],
akinetopsia [no movement]. Zeki's studies raise fascinating questions
concerning how subjective visual awareness is generated from
these modular aspects. Although they have direct reciprocal connections
and diffuse connections back to V2 and V1, there is no central
arena where their output is sent, suggesting visual awareness
is generated either by their modulation back on V1, or somehow
by the entire distributed dynamic. Face and mood recognition,
written and spoken speech, and music, are all modular features.
The PET scans in fig 4(a) illustrate the correspondence between
different conscious activities and the activation of specific
modular regions of the cortex, including well-known areas such
as Wernicke's and Broca's areas of linguistic interpretation
and articulation and the supplementary motor cortex, as well
as highlighting less well understood areas in the frontal lobes.
Listening to ambiguous structured signals [time reversed recordings]
can activate just about the entire cortex (Friberg 1992) suggesting
that activation is at least partially a product of chaotic instabilities
in the process of forming a stable representation. Dreaming states
provide interesting PET scans in which the cortex is perceptually
activated in a manner consistent with the similar EEG to the
waking state, fig 4(b,c), and the intensity of dream experiences.
One feature different in dreams is the lower activity of the
inferior frontal cortex, which may reflect the uncontrolled nature
of dreams (Madsen et.al. 1991).
Such studies support a modular distributed internal model, which
may also be holographic in its use of distributed phase fronts
and wave transforms. The holographic aspect, popularized by Pribram,
arises naturally from the many to many nature of synaptic connections,
the simultaneity of Hebbian synaptic response and from the decomposition
of sensoria into features such as line orientation and ocular
dominance, forming a parallel representation in which each memory
or experience is registered across the cortex as in terms of
its attributes. What is less clear is how attributes such as
colour motion, edges and filled regions coordinate with the primary
sensory areas to resynthesize the complete conscious view.
3.4 The Split-brain and sex. Study of split-brain patients reveals
how difficult it is to pinpoint the structures supporting sentient
consciousness. When the left and right cerebral hemispheres are
severed by cutting the corpus callosum, replies to experimental
questions centre around the content of the dominant hemisphere,
because it is uniquely able to articulate verbal responses. If
a composite image is shown separately to the left and right half
eye fields of the split-brain subject, they will describe the
image their dominant hemisphere sees, and will be unable to refer
descriptively to stimuli presented exclusively to their recessive
hemisphere, unless it also retains linguistic ability. For example
a nude in the left field will elicit a laugh and the indirect
comment "That funny machine". The person thus behaves
verbally, but not emotionally, as if the experiences of the non-dominant
hemisphere are unavailable. However if asked merely to point
to the picture seen, the recessive hemisphere, which is specialized
at non-verbal pattern recognition, can assume control. The subject
appears to retain an integrated personality and displays only
minor conflicts of behavior, because the midbrain structures
involving emotion and arousal are still intact, although the
hemispheres appear a little like Siamese twin minds which can
express distinct desires and aims. One patient's hemispheres
for instance had the distinct aims of being draftsman and racing
driver (Gazzaniga in Bloom et. al. 1985). Consciousness, even
in the intact brain, may be a bundle of coupled awarenesses (Gazzaniga
1985, Parfitt 1987, Dennett 1991) rather than a single dynamical
entity.
Sexual differences in the brain provide a further intriguing
dimension of variation in human consciousness (Kimura 1992).
At least three types of difference have been noted, enlargement
of a specific hypothalamic nucleus in men, and differences both
in lateralization and relative function of frontal and parietal
areas. Women appear to have less linguistic lateralization, despite
displaying superior verbal abilities (McGlone in Bloom et. al.
1985), and are several times more likely to have aphasia or apraxia
from frontal than parietal strokes. Men have corresponding parietal
and lateral dominance, leading to the possibility that male and
female brains have global differences of organization similar
to the plasticity seen in sensory processing.
3.5 Attention and Memory : The Limbic System and Frontal Areas.
The limbic system fig 3(e), (Mishkin et.al.1988, Alkon 1989)
also forms a particularly interesting set of looping pathways
combining sensoria, emotional states and episodic long-term memory,
(c,d). The hippocampus, which has an older three-layered structure
than the six-layer neocortex has a pivotal role in establishing
long-term memory, possibly by transferring experiences into associative
memory over a matter of weeks. It has projections from diverse
sensory areas via the entorhinal cortex and feeds back into the
thalamus and subsequently to cortical areas including prefrontal,
cingulate gyrus, and basal forebrain. The amygdala has similar
looping circuits linking diverse sense modes and connecting to
the thalamus and deeper emotional centres in the hypothalamus.
Phase decoherence occurs in the hippocampus during orientation
to unfamiliar stimuli. The limbic system thus forms a bridge
between emotion, memory and a distributed representation of time
action and self in the frontal lobes. This is consistent with
the emotional and motivational side-effects of frontal lobotomy
and with studies on time-delayed learning in damaged hippocampi.
It also gives a graphic portrayal of the link between extremes
of emotional experience from fear to exaltation, the central
themes of survival, attention, and the establishment of long-term
memory.
The limbic system may also be linked to both the ascending pathways
and the cortex in processing waking memories in the REM phase
of sleep (Winsen 1990). In several mammalian species, theta rhythms,
which are generated in the brain stem and pass both to the Septum
in the forebrain and to synchronous generators in the hippocampus,
can act as phase locking signals for long-term potentiation,
in association with orientation to key survival activities. Spatially
selective CA1 cells, which signal an animal's location in the
waking state, are selectively active in subsequent REM phases,
suggesting REM functions in memory processing in the sleep cycle.
The role of emotion in the limbic system as a monitor of and
driving force for survival, may thus underlie the archetypal
intensity of dream content. However, because we dream about past
experiences, it is also likely that hippocampal cells will revisit
locationary states. Notably, we can also remember our dreams.
It is difficult to see how this is possible at the same time
as memory reconsolidation.
A second active type of short-term memory often called working
memory (Goldman-Rakic 1992) complements [long-term] associative
memory by providing short-term storage of symbolic information
as well as permitting the manipulation of that information. It
appears to be centred on the prefrontal cortex with reciprocal
connections with both the parietal cortex and the limbic system.
Prefrontal damage effects use of knowledge to guide behaviour
in everyday situations, including predictive tracking e.g. of
projectile movements. When a monkey is trained to look at where
a target has disappeared after a delay selected cells in the
prefrontal cortex fire, on target disappearing, others fire during
the delay and others on the motor act. Such eye movement also
involves feedback loops to the basal brain [from pyramidal cells
to the striatum, the substantia nigra, mediodorsal thalamus and
back to pyramidal cells]. Prefrontal action is modular with spatial
and compound attributes active in different loci. A model linking
the frontal and limbic structures in a representation of space-time
is developed in 8.2.
3.6 Global Dynamics : Mind States and Brain states.
Examination of the contributions to consciousness by the major
dynamical structures of the brain confirms that consciousness
is a collective product of the ascending pathways, the cortex
and limbic system. The dynamical activation of the cortex by
ascending distributed pathways appears essential for consciousness,
while all sensory areas and most of the associative areas of
the cortex can be seen to contribute in a modular manner to the
envelope of conscious experience, dynamically modified by the
looping circuits of the limbic system.
Conscious experience is thus subject to much of the global dynamical
variation for which the brain is capable, from anaesthesia, through
waking, resting, dreaming, and hallucination. Only in deep sleep,
seizure and coma when the global dynamics are profoundly altered
do we see a loss of conscious function. In fig 5(a) the close
correspondence between conscious recognition and brain states
is illustrated. In (b) two optical illusions illustrate the way
in which perception displays both oscillatory compensations in
the presence of ambiguous 3-D information, and attractor-like
constructs which complete partial visual information with perceived
lines and regions. This can be seen as a possible example of
linkages between edge detectors in V2 and higher areas and is
also consistent with an attractor-bifurcation basis for the internal
model of reality.
Crick and Koch (1990,1992) have explored a variety of hypotheses
as to where and how consciousness might be generated in the cortex.
One structured hypothesis is that it is associated with a specific
frequency mode. "We have suggested that one of the functions
of consciousness is to present the result of various underlying
computations and that this involves an attentional mechanism
that temporarily binds the relevant neurons together by synchronising
their spikes in 40Hz [35-70Hz] oscillations". They point
out that distinct images could excite the same modules without
confusion if they had synchronous oscillations. This would explain,
for example, how you can briefly imagine something while looking
at the world around you. They also speculate that the top layers
of the cortex could be unconscious and layers 5 & 6 which
output to other areas might be conscious. A minimum processing
time of 60-70ms for a conscious percept can be deduced from the
display of rapid images [20ms red + 20ms green = yellow] or tones.
4 Non-linear Dynamics in the Central Nervous System
Physical evidence for attractor dynamics in a variety of aspects
of central nervous system function and development has become
abundant in recent years. Chaotic regimes have been demonstrated,
both at the neurosystems level and in the dynamics of single
excitable cells, and fractal dynamics has been proposed for ion
channels (King 1991).
4.1 Electrodynamics.
4.1.1 Neurosystems Dynamics: At the neurosystems level, experimental
evidence has accumulated for chaos in the EEG's of at least some
phases of cortical activity, including sleep, resting wakefulness
and pathological states such as epilepsy (Babloyantz 1985, 1989,
Basar 1990). The low correlation dimensions of several of these
states is consistent with collective chaotic dynamics in neuron
populations, rather than stochastic or independently programmed
behaviour. Evoked potentials also show desynchronizations during
orientation, consistent with phase relations being pivotal in
recognition and orientation (Basar et.al. 1989, Hoke 1989), supporting
a holographic model. The model of burst dynamics in the olfactory
bulb advanced by Walter Freeman fig 6(e,f) combines these two
aspects into a model with bifurcations of spatially distributed
waves into chaotic temporal temporal dynamics which both follow
the neurophysiology and also permit real tests of pattern discrimination
of neural nets displaying comparable dynamics (Freeman &
Baird 1987, Skarda & Freeman 1987, Freeman 1991, Yao et.al.
1991).
In this model, low level chaos is lifted into a higher energy
state by olfactory input. Chaos in this state enables the system
to explore its phase space, falling into an existing attractor
in the case of a recognised odour, but bifurcating to form a
new attractor in the case of a newly learned stimulus. The transition
into chaos thus provides sensitive dependence on input, ergodic
'randomizing' phase space exploration, parametric bifurcation
to form new symbols, and possible quantum amplification. Return
from chaos in turn fixes stability structures from the fractal
dynamics.
4.1.2 Single Cell Dynamics: Similar experimental evidence
has accumulated for chaos in a variety of excitable cell types,
supported by the chaotic models of Chay and Rinzel (1985), fig
7(a,b,c). These extend the Hodgkin-Huxley equations (1952) to
take account of calcium ion pumping, thus displaying a variety
of dynamical features, including period doubling bifurcations,
chaotic regimes and period three oscillations characteristic
of the chaotic regime. These dynamics model well the chaotic
excitations of Nitella pancreas cells, and similar models have
been advanced for excitations in neurons and heart pacemaker
cells. The irregular behaviour of controlling cells in small
ganglia such as in Aplysia studies is also consistent with sensitive
dependence and chaos, by contrast with the more regular beating
of subordinate neurons.
4.1.3 Fractal Ion-Channel Kinetics : A Markov model is commonly
used for ion channel kinetics, in which an open state is linked
to one or more closed states. However the likelihood that a closed
channel will open behaves fractally with increasing time scales
according to fig 7(d) (Liebovitch et. al. 1987a,b, 1991). This
is consistent with bio-molecular structures behaving fractally,
not only in a geometrical sense, but also dynamically as shown
for myoglobin in (e) (Ansari et. al. 1985). The dynamics of many
important biological molecules may be fractal in this way, which
involves the linkage between a variety of quantum excitations
of differing energies, and feedback between tertiary structures
and active sites.
4.2 Long-term adaption. Many aspects of the long-term structure
of sensory areas of the cortex are consistent with their inheriting
an attractor structure derived from particular sensory innervation
and stimulation patterns. On a short time scale are the reported
spatial distributions corresponding to olfactory stimuli, fig
6(e) which on a longer time scale adopt new forms on relearning
the same stimulus a second time, and phase desynchronization
of cortical evoked potentials. On a longer time scale plasticity
of sensory structure fig 7 from the somatosensory barrels of
the rodent (b), through to visual ocular dominance and orientation
patterns induced by training regimes (a) indicate major sensory
structures arise as a dynamical system induced through bifurcation.
4.3 Neurogenesis. The raw numbers game of neurogenesis suggests
attractor dynamics may form an essential bridge between central
nervous genotype and phenotype. The 5 x 10^4 genes governing
central nervous system development [around 60% of human genes]
cannot informationally specify the connections for 10^11 neurons
and 10^15 synapses. Generalizing principles are thus required
to complement the informational specificity of developmental
genes such as the homeotic genes, thus providing both genetic
efficiency and plasticity. The form of early embryogenesis is
a series of bifurcations induced by morphogen gradients leading
to the differentiation of major brain structures, fig 9(a). Further
general principles playing a dynamical role in central nervous
organization include cell surface interactions enabling migration
up the glial scaffold (b), selection of tissue layer, or target
cell synapse type, and parallel growth (Blakemore 1991). The
neurogenic picture is thus consistent with genetic selection
up to target cell type but the development of specific synaptic
connections and the organization of thalamic and cortical layers,
ocular dominance columns, barrels etc. through dynamical excitation
driven by the afferent sense organs, culminating in the sensory
experiences of the newborn (Kalil 1989). This is consistent with
the plasticity of sensory structures already described, with
tissue culture experiments (c), and with the waves of excitation
seen on the prenatal retina [1/10-1/100 action potential speed],
which stop just before the onset of visual activity. These waves
appear to result in both geniculate layering and subsequent organization
in the visual cortex (Shats 1992), by competitive input, in which
synchronous inputs cause Hebbian enhancement, while asynchronous
inputs from distinct eyes cause synaptic separation, consistent
with the sequential organization of (1) the retina via early
firing in ganglion cells, (2) subsequent layering of the geniculate
after retinal wave input, and finally (3) organization of ocular
dominance and other features in the visual cortex.
5 The Fractal Link between Chaos and Quantum Mechanics.
5.1 The Scale Link between Neurosystems and Cellular Dynamics.
The occurrence of chaos in neurosystem dynamics suggests that
the brain may also utilize the fractal aspect of chaos as an
intrinsic aspect of its processing, in combination with the natural
scale transformations from organism to cell to molecule. The
architecture of the central nervous system includes specific
linkages between the level of whole neurosystems and the single
cell. One is illustrated in fig 3(d) where a single hippocampal
CA1 pyramidal cell has inputs from distinct brain regions, the
sensoria and the reticular activating system via distinct neurotransmitters
and distinct anatomical regions of the cell.
Such architecture permits a two-way relation between large-scale
neurosystems dynamics and that of single cells, which both enables
large-scale bifurcations to alter the stability of single cells
and for single cells to precipitate bifurcations at the neurosystems
level. The utilization of instability to provide responsiveness
pinpoints the unstable aspects of the dynamics at the centre
of processing demands, because these are the unresolved aspects
of the internal model. The occurrence of either chaotic sensitivity
or self-organized criticality at the neurosystems level could
then enable a small subpopulation or even a single critical cell
to precipitate global bifurcation.
The brain may utilize sensitive instability to deal with computationally
difficult situations by mapping parallel representations on a
fractal basis similar to Penrose's (1989) fractal algorithms
for parallel computation (Dewdney 1989), with the added feature
that continuous dynamical instability is used in addition to
resolve ambiguous situations which remain intractable digitally.
5.2 The Complexity of Form of the Eucaryote Excitable Cell. Such
reasoning places an additional emphasis on the neuron (Stevens
1989) as an integrated field processing unit, thus replacing
the trivial formal neurons of McCulloch-Pitts, or optimizing
analogue models such as the Hopfield net (Tank & Hopfield
1987) with a sophisticated integrated unit capable of chaos and
unstable bifurcations. This is supported by the obvious complexity
of typical central nervous neurons, with up to 100,000 synaptic
junctions having a variety of anatomical forms fig 10(c), unstable
bifurcations across threshold, and other non-linear features,
(a). On a descending series of scales, the cell is itself a physical
fractal both structurally and functionally in terms of its dendritic
and axonic trees, (b) and in terms of subcellular processing
both across dendrites (d) and synapto-synaptic junctions (e).
Despite the approximate conformity to linearity of neuronal conduction
over a restricted range above threshold (a), the neuron also
has pivotal features of self-organized criticality in the form
of tuning to its threshold, sigmoid limit-cycle bifurcation at
threshold, and chaotic dynamics as depicted by the Chay-Rinzel
model. The sensitivity of sensory modules such as pressure organelles
also displays non-linear [quadratic] dynamics.
The fractal nature of dendritic and axonal trees provides the
neuron with its second outstanding complex systems feature, which
is that of a fractal integral transform. The capacity of the
neuron to use its fractal structure to form many-to-many synaptic
contacts lies at the foundation of its traditional role as a
summation module. When organized in layers this permits a global
integral transform, leading to the formation of complex fields
from simple ones in sensory processing. The combination of this
architecture with oscillatory signals could generate a Fourier-type
invertible transform which would permit the retrieval of previous
structures in a form comparable to a hologram, consistent with
phase decoherence dynamics in experimental studies of the cortex
and hippocampus.
Two characteristics of the neuron pivotal to a reassessment of
its function are thus:
* 5.2.1 chaos and threshold self-organized criticality in
non-linear dynamics.
* 5.2.2 the fractal integral transform.
Fig 9: Morphogenic and contact fields and bifurcations: (a)
impact of position within primary morphogenic tissue bifurcations
on the development of brain regions, (b) cell-adhesion properties
of proteins such as CAMs enable migration of specific neuron
types, both along the glial scaffold and to specific cell layers
or target types, (c) Specificity of ascending optic fibres may
be limited to a general affinity for cortex suggesting the form
of cortical sensory architecture may be organized by input from
sense organs and stimulation in early life, rather than genetic
specificity alone (Blakemore 1991).
5.3 The Non-linear Synapse. The fractal geometry of the neuron
leads to an examination of the way cell organelles can provide
a similar bridge between cellular and molecular dynamics. A variety
of cell organelles provide a non-linear basis for sub-cellular
dynamics. The concentration dynamics of the synapse fig 10(e)
involves a rich diversity of feedbacks with non-linear characteristics.
Concentration dynamics is linear only for single molecule interactions,
but critical ion channels such as the acetyl-choline channel
require two molecules for activation, thus having quadratic dynamics.
Synapto-synaptic junctions display bilinear dynamics. Both of
these can lead to chaos. Membrane dynamics also involve piezo-electric
interactions. Microtubules have also been proposed as functional
cellular automata (Hameroff 1987).
Such non-linearities make it possible for unstable fluctuation
at the synaptic vesicle or ion channel level, within a critically
poised neuron, to precipitate cellular instability and subsequent
global neurosystem bifurcation. In cortical synapses, there is
no need for the large number of vesicles seen in the neuro-muscular
junction, and it has been proposed that in some synapses, the
release of contents of a single vesicle is sufficient to traverse
the threshold and elicit a post-synaptic response. A single vesicle,
releases around 10,000 acetyl-choline molecules, activating 2000
ion channels, causing discrete micro-potentials even at the neuro-muscular
junction, which depolarize the membrane by about 1 mV, sufficient
to result in an action potential if a cell is already at threshold.
Eddington (1935) and Eccles (1970) discussed the possibility
of quantum-mechanical action of the vesicle and pointed out that
the uncertainty of position of a vesicle of 400 oA diameter and
mass 3 x 10^-17g is about 30oA, comparable with the thickness
of the membrane. Because of this, the vesicle can be regarded
as a quantum object, which is at the same time capable of triggering
cellular and hence global instability. The topological closure
of the vesicle membrane results in the amplification of quantal
instabilities from the level of the molecule to the larger level
of the vesicle. The kinetics of vesicle association with the
pre-synaptic membrane is determined by binding to one, or a few
proteins, making vesicle release a function of the kinetics of
one or a few molecules. The precise mechanism of vesicle exocytosis
is not yet elucidated, but may involve the vesicle membrane protein
synapsin I.
5.4 The Molecular Level. Activation of a single ion channel requires
one or two neurotransmitter molecules. While the ion flux resulting
from a single open ion channel will not generally elicit an action
potential, if the channel happens to command a critical site
on the two-dimensional dendritic surface, for example close to
the cell body where the action potential begins, and the cell
is at or near threshold, then the single quantal encounter of
a neurotransmitter binding to an ion channel could be capable
of evoking an action potential. The fractal nature of ion channel
kinetics finally allows for the interaction of molecular quantum
excitations on a variety of fractal scales, constituting the
quantum chaotic level of expression. Long-term potentiation associated
with a receptor-kinase-membrane feedback (Alkon 1989, Winson
1990) is another kinetic process at the molecular level which
permits a molecular change to trigger a distinct global history,
however the determinate nature of memory makes it one of the
less likely aspects of brain function to be subject to quantum
instability.
The four levels of instability link in stages, making it possible
for the fractal aspect of chaotic dynamics at the global, cellular,
synaptic and molecular levels to combine to provide a fractal
model in which global and quantum instabilities are linked by
mutual interactions of scale. Global instabilities in brain dynamics
may be dynamically-linked to fluctuation of a critical neuron.
Threshold instability similarly makes the neuron a potentially
unstable dynamical system which is open to synaptic perturbations.
Quantization at the level of the synaptic vesicle allows for
amplification of quantum fluctuations in binding proteins into
vesicle rupture that is capable of eliciting micropotentials
at the neuronal level. Sensitive dependence and quantum amplification
thus give the brain the capacity to detect fluctuation at the
quantum level. This is consistent with the sensitivity of sensory
apparati which are all capable of detections at or close to the
level of single quanta [see 7.1].
Fig 10: Non-linear and fractal aspects of the neuron. (a)
Non-linearities occur in formation of a limit cycle and excitation
threshold (ii), despite approximate linear relation between depolarization
current and firing rate in a limited range (i). Sigmoid transmission
curve (iii) and mechanoreceptive bulbs also have a non-linear
response. (b) Fractal structures of dendrites of two cell types
and their electrodynamics (Schierwagen 1986). (c) The anatomical
complexity of the neuron is illustrated by the structural variety
of synaptic junctions, which also utilize distinct neurotransmitters.
(d) Dendritic microcircuits and synapto-synaptic junctions (e)
place the level of net organization one or two levels below the
neuron. Synaptic conduction involves many feedbacks (e), some
of which, including the two-molecule activation of the acetyl-choline
ion channel have quadratic rather than linear concentration dynamics.
6 The Evolutionary Origins of Fractal Processing
It is one thing to establish the possibility that fluctuations
at the quantum level could in principle become amplified into
global instabilities in the brain, but quite another thing to
explain why the brain should find it advantageous to allow such
disordered processes to intervene in its functioning. Normally
noise in a system is regarded as the anathema of computational
precision, so an explanation is in order.
6.1 The Computational Intractability of Survival in the Open
Environment. The principal task of the brain of is to compute
the survival strategy most likely to enable the organism to evade
death and produce viable offspring. A computational problem is
intractable if the number of computational steps required grows
super-exponentially with the complexity of the problem. The travelling
salesman problem (Bern & Graham 1989), finding the shortest
route round n cities illustrates this, growing with (n-1)! A
problem may also be formally undecidable in the sense of Gödel.
Many adaption-survival problems in the open environment share
the characteristics of intractable problems, because each strategy
tends to be matched by a competing strategy in another organism
and the number of options rapidly exponentiates. An active organism
must also complete a processing task within 0.1-1 second if it
is going to have survival utility, regardless of its complexity.
Such arguments make it clear why parallel processing is an integral
feature of vertebrate nervous systems.
The fractal algorithm (Penrose 1989, Dewdney 1989), which in
addition to parallelism, features fractal task assignment, shares
significant features with biological processing. Including attractor
dynamics with chaotic regimes in such a scheme provides additional
features of sensitive dependence, phase space exploration, continuous
resolution of instabilities, and the capacity to form new symbolic
structures through bifurcation. It also provides a dynamic model
for cognition in which bifurcation generates a series of symbolic
structures, which become stable representations forming the successfully-modelled
aspects of a problem. The complementary unstable component may
continue to hunt through chaotic states, either bifurcating to
stability, or forming a fractal instability which could in turn
be perturbed by quantum instabilities.
6.2 Chaotic Excitability as a founding Eucaryote Characteristic.
Chaotic excitability may originate deeper in evolutionary history,
representing one of the oldest features of eucaryote cells (King
1978, 1990). The Piezo-electric nature and high voltage gradient
of the excitable membrane provides an excitable single cell with
a generalized sense organ. Sensitive dependence would enable
such a cell to gain feedback about the external environment,
rather than becoming locked in a particular oscillatory mode.
Excitation could be perturbed mechanically and chemically through
acoustic or molecular interaction, and electromagnetically through
photon absorption and the perturbations of the fluctuating fields
generated by the excitations themselves. Such excitability would
predate the computational role of neural nets, making chaos fundamental
to the evolution of neuronal computing rather than vice versa.
The chemical modifiers may have been precursors of the amine-based
neurotransmitters which span acetyl-choline, serotonin, catecholamines
and the amino acids such as glutamate and GABA, several of which
have a primal status chemically. The use of positive amines may
have chemically complemented the negatively charged phosphate-based
lipids, fig 11, in modulating membrane excitability without requiring
complex proteins. It is thus possible that chaotic excitation
dates from as early a period as the genetic code itself and that
the first eucaryote cells may have been excitable via direct
electrochemical transfer from light energy, before enzyme-based
metabolic pathways had developed.
Fig 11 : Primal chemical aspects of neurotransmitters. (a)
Primal uv-bridge between catecholamines and indoles. (b) Serotonin,
Nor-adrenalin (R=OH) & Dopamine (R=H) and (c) their psychoactive
variants are monoamines. (d) Acetyl-choline and (e) Phosphatidyl-choline
demonstrate a common tertiary amine involvement.
6.3 Consciousness as an Evolutionary Manifestation of Chaotic
Neurodynamics. From this perspective it is natural to postulate
that, far from being an epiphenomenon, consciousness is a feature
which as been elaborated and conserved by nervous systems because
it has had unique survival value for the organism. We are thus
led to an examination of how chaotic excitation may have evolved
from single-celled animals through the early stages represented
by Hydra to the complex nervous systems of metazoa. We have seen
how chaotic excitation provides for exploration of phase space
and sensitivity to internal and external fluctuations. However
the conservation of consciousness may also involve features expressed
only by chaotic systems which are fractal to the quantum level.
It is a logical conclusion that the conscious brain has been
selected by evolution because its biophysical properties provide
access to an additional principle of predicitivity not possessed
by formal computational systems. One of the key strategies of
survival is anticipation and prediction of events (King 1978,
Llinás (1987). Computational systems achieve this by a
combination of deductive logic and heuristic calculation of contingent
probabilities. However quantum non-locality may also provide
another avenue for anticipation which might be effective even
across the membrane of a single cell, if wave reductions are
correlated in a non-local manner in space-time.
7 Quantum Models in the Central Nervous System
7.1 Quantum Sensitivity in the Senses. The limits to the sensitivity
of nervous systems are constrained only by the physics of quanta
rather than biological limits. This is exemplified in fig 1(a)
by the capacity of retinal cells to record single quanta, and
by the fact that membranes of cochlear cells oscillate by only
about one H atom radius at the threshold of hearing, far below
the level of thermodynamic fluctuations. Moth pheromones are
similarly effective at concentrations consistent with one molecule
being active, as are the sensitivities of some olfactory mammals.
The quantum uncertainty of the vesicle in relation to the membrane
has also been noted above as a source of sensitivity of the synapse
to quantum fluctuation.
7.2 Sense Modes as Quantum Modes. The very distinct qualitative
differences between vision, hearing, touch and smell do not appear
to be parallelled in the similar patterns of electrical excitation
evoked in their cortical areas. It is thus hard to see how the
internal model of reality generates such different subjective
modalities as the experiences of vision smell and hearing from
common electrochemical dynamics. One possibility is the senses
are generated in the internal model by the same quantum modes
of sensory excitation, namely photons, phonons, membrane solitons
and weak bonding interactions. If all these excitations can occur
simultaneously in the membrane, its quantum-chaotic excitation
could represent a form of cellular synesthesia, which is subsequently
specialized in representing each individual sense mode.
Fig 12: (a) Excitations of single rod cells shows peaks with
0, 1, or 2 photons being registered, consistent with quantum
statistics of photons being released very slowly at a rate corresponding
to the marks below (Bailer & Lamb ex Blakemore 1991). Dereferencing
of a perceived stimulus back to the original time (Libet et.al.
1979).
7.3 Quantum Mechanics and Wave Packet Reduction. Quantum systems
differ fundamentally from the classical case, in which in principle
conforms to a deterministic description. While the evolution
of the system proceeds according to a deterministic Hamiltonian
equation :
[7.3.1]
the measurement process, results in causality violations in which
the probability interpretation
[7.3.2]
constitutes the limits on our knowledge of the system, resulting
in a stochastic-causal model, in which measurement collapses
the wave function from a superposition of possible states into
one of these states. While quantum-mechanics predicts each event
only as a probability, the universe appears to have a means to
resolve each reduction of the wave-packet uniquely, which I will
call the principle of choice, the subject of Schrödinger's
famous cat paradox, in which quantum mechanics predicts a cat
killed as a result of a quantum fluctuation is both alive and
dead with certain probabilities, while we find it is only one
: alive, or dead! The stochastic-causal processes of quantum
mechanics violate causality because Heisenberg uncertainty
[7.3.3]
prevents a complete causal description of quantum dynamics, which
can predict future [or past] states only as probabilities in
each instance of reduction of the wave packet.
It is one thing to suggest that quantum fluctuations could in
principle evoke global bifurcations of brain function, but quite
another to determine what advantage might accrue from such seemingly
stochastic activity. The possibility of a connection between
quantum mechanics and brain function has been a source of interest
since the discovery of the uncertainty principle, because of
its implications for consciousness & free-will, and several
interesting models have been developed. The connection between
the observer's mind and quantum mechanics is pivotal in some
interpretations of wave function collapse.
7.4 Quantum Chaos versus Uncertainty as Substrates for Classical
Chaos. Repeated attempts to model a variety of quantum analogues
of classical chaotic systems have revealed significant differences
which may prevent the full display of chaotic dynamics in the
quantum analogues. Two theoretical approaches have been mounted
on a variety of transition systems. In the semi-classical approach,
fig 13(b) point particles are replaced by wave packets whose
trajectories are calculated to provide a simulation of the wave
function (Tomsovic & Heller 1991). Complementing this are
quantum wave function approaches, such as quenched quantum mechanics,
and studies of the so-called scarring of some chaotic wave functions
around the periodic orbits (Gutzwiller 1992), which are necessarily
embedded in any chaotic system (a). A variety of systems have
been explored experimentally from hydrogen atom in a magnetic
field to particles such as electrons traversing a molecule or
molecular medium (c).
The spreading of wave fronts results in some smoothing of the
classical picture of chaotic mixing, including tunnelling between
trajectories, non-diffusive or time reversible dynamics, and
the level repulsion between eigenvalues characteristic of the
many-body dynamics of atomic nuclei. At the time of writing,
verdicts on the capacity of quantum systems to fully exhibit
chaos is still in flux, with some quantum systems, including
magnetically excited atoms and electrons traversing molecular
media appearing to display key features of chaos (Schuster 1986,
Casati 1986, Giesel 1989, Wintgen & Honig 1989, Zhang et.
al. 1990, Berry 1991, Peterson 1991, Uzer 1991). The electron
traversing a molecule (Gutzwiller 1992) gives a simplified picture
of chaos in molecular dynamics displaying chaotic variation in
transition time [phase]. Sensitive dependence of molecular kinetics
follows.
However it is the stochastic wave-reduction aspect of quantum
mechanics which ultimately underpins the unpredictabilities found
in chaotic physical systems. Statistical mechanics ultimately
derives its random variation from Heisenberg uncertainty [7.3.3]
in the form of wave-packet reduction. For example the positional
statistics of molecular kinetics is made uncertain through diffraction
of the wave aspect of a molecule by other molecules. An amino
acid at room temperature has a self-diffraction angle of about
5o (King 1989), contributing initial condition uncertainty to
each successive chaotic encounter, fig 13(c) when traversing
a molecular medium. One of the important roles of classical chaos
may thus be the amplification of quantum uncertainty into macroscopic
indeterminacy. Sensitive-dependence in physical systems may thus
result in quantum inflation, the amplification of quantum fluctuation
into global perturbations of the dynamic. The distributed nature
of wave reduction over the eigenspace may thus link to the ergodicity
of chaotic systems.
Fig 13: The quantum stadium represented (a) by quantum wave
functions displays scarring of several wave functions around
embedded periodic solutions (Gutzwiller 1992), (b) semi-classical
approach provides a close approximation using a finite number
of periodic solutions at least for some stages (Tomsovic &
Heller 1991), (c) electron traversing a molecule has continuous
variation of time [phase] with chaotic irregularity (Gutzwiller
1992).
7.5 Quantum Concepts in Brain Function. Bohm's work on the Einstein-Podolsky-Rosen
conjecture, Bell's theorem and the Aspect experiments (Clauser
& Shimony 1978, Aspect et. al. 1982) which display spin-correlations
between a split photon pair over space-like intervals have demonstrated
that hidden variable theories cannot be locally causal, leading
several researchers to postulate the idea of non-local states
correlating the activity of various parts of the brain (Penrose
1987).
Interest in quantum concepts in brain function has had a considerable
history starting from Eddington (1935), and continuing with Eccles
(1970). Basar (1983) has suggested matrix theory and Feynman
diagram approaches (Stowell et. al. 1989) to resonances at the
neurosystems level. Popper and Eccles (1977) and Margenau (1984)
have also discussed the possibility of quantum reduction being
dependent on the mind of the observer, leading to the paradox
of Wigner's friend in which an observer's friend splits the wave
function, and reports on the result. Multiple minds thus lead
to ambiguities of splitting. One way around this paradox is to
require mind to be a unity rather than a multiplicity removing
the ambiguity of the reduction point, another is that the first
conscious observer in the chain collapses the wave function.
Recent studies using down-converters demonstrate that the possibility
of gaining information about a photon's path collapses the wave
function and that such knowledge can be erased to regenerate
a coherent wave (Horgan 1992). Although such istinctions ultimate
reach the conscious observer, collapse appears to occur with
the loss of ambiguity, whether or not immediately manifest in
conscious experience.
Deutch (1985) has analysed the potentialities of a quantum computer,
which has a fuzzy logic representing quantum superposition of
states to form a probability function in the interval [0,1] in
place of the usual {0,1} = {T,F} of formal logic. Although the
algorithmic capacity of such a quantum computer does not extend
the class of functions computable by a conventional Turing machine,
several specific instances have been given in which a quantum
computer might solve special tasks more efficiently, (Lockwood
1989). These do not appear to provide significant advantages
over parallel distributed processing. Both these authors adhere
to the Everett many-worlds interpretation of quantum mechanics
in which the collapse of the wave function never occurs, and
all histories having a non-zero probability under the quantum
prediction are presumed to co-exist as parallel aspects of a
cosmic wave function. This bypasses the Schrödinger cat
paradox, however it contradicts the evidence of our conscious
sensory processes, which in common with physical measuring apparati,
experience a single historical process. Collapse of the wave
function also appears to be the aspect of quantum mechanics which
underlies the indeterminacy of chaotic systems.
The mathematician Roger Penrose (1986,1989) has also studied
the relation between the conscious brain and quantum physics
and attempted to combine quantum theoretic and relativistic ideas.
He has suggested that collapse of the wave function may be a
deterministic process based on the interaction of the superimposed
wave function with the gravitational field at the level of one
graviton, thus having parallels to decoherence theories (Zurek
1991).
7.6 The Supercausal Model. A final model (King 1989), which also
combines quantum theory and relativity, develops a supercausal
hidden-variable theory which is consistent with conventional
quantum mechanics, but allows for correlations between quantum
events over both space and time, replacing the stochasticity
of the quantum model with a transcausal description, which is
non-local in space-time. The temporal ordering of causal events
is thus violated below the quantum level by space-time symmetric
interactions. This description prevents determination of a system
from initial conditions, because the non-local correlations include
future states of the system. It is based on the transactional
interpretation of special-relativistic quantum mechanics.
Such time-reversal is used in the transactional interpretation
of quantum mechanics (Cramer 1986) fig 14(c), a mutual encounter
between emitter and absorber is modelled by the release of crossed-phase
advanced and retarded waves, each having zero-energy, the offer
wave of the emitter and the confirmation wave of the absorber.
While the retarded offer wave travels with elapsing time in the
usual manner, the advanced confirmation wave, back-propagates
in a time-reversing manner from the absorber to the earlier emission
event. The mutual interference of these advanced and retarded
waves produces a real superposition (the photon) between the
emission and absorption events in space-time.
Modelling reduction of the wave packet now depends on the mutual
interaction of all contingent emitters and absorbers as in (e),
on the basis that a photon can only be created linking the two
events and cannot simply disappear into space, following Feynman's
absorber theory (Davies 1974). This means that the probability
distribution is determined by boundary conditions which include
all contingent absorbers which could have alternatively participated
in the emission event (f). However, because these include future
states which have not been causally determined, a logical regress
results, leading to paradox in terms of temporal determinism.
Transactions can also link contingent foci across both time-like
and space-like intervals by linking confirmation waves at any
particular emission vertex, regardless of the proper time interval
to the contingent absorbers, e.g. cA1 and cA2 in fig 14(e), explaining
the pair-splitting experiments of Aspect et. al. (1982).
One way of modelling transactional collapse is via a bifurcation
of a non-linear interaction between all contingent foci, however
the time parameter in any such bifurcation has to be handled
very carefully. Whether or not collapse results from a non-linearity
in gravitation as suggested by Penrose (1989), the space-time
boundary constraints are inconsistent with the usual idea of
temporal causality defined by initial conditions and Laplacian
determinism.
Transactional collapse is also consistent with quantum decoherence
models, which include incidental collapse caused by field and
thermal excitations (Zurek 1991). Although decoherence has the
effect of breaking a transactional contingent set into a class
of smaller sets linked by emission and absorption foci, similar
to higher-order Feynman diagrams, it does not alter the supercausal
properties of transactional reduction, enfolding the implicate
order of quantum non-locality without disruption. Thus similar
space-time properties apply to kinetic molecular systems with
many thermodynamic and other quantum interactions between production
of an intermediate and its reaction.
8 Supercausality and the Conscious Brain
8.1 Superset Correlations and the Evolution of Chaotic Neurosystems
Dual-time supercausality results in pseudorandom behaviour consistent
with the probability interpretation, which is non-local not only
in space, but also in time. This could enable a neural net to
become internally interconnected through sub-quantum effects
which were non-local in time, and hence enable a form of predictivity
unavailable through classical computation. The mutual exchange
of quanta between such units would make them a contingent transactional
set of emitters and absorbers. Such linkage could arise via excitons,
or photon or phonon exchange. The cell membrane topology forms
a global link between its quanta of excitability, making such
linkages possible also in the single cell. A variety of excitons,
including the major oscillations of the EEG could also form a
basis for neurosystems linkage in the brain. The many-to-many
transform nature of the neuron may provide a basis for this effect
through the connection of any given state to a large population
of neurons in the cortex.
An excitable cell or neurosystem which evolved initially to achieve
constrained optimization through chaotic fluctuation, could thus
also display a new type of predictive modelling through non-local
quantum interactions. Predictive optimization may thus have driven
the evolution of the excitable cell and subsequently a structurally-unstable
chaotic brain in which consciousness and free-will become direct
manifestations of the quantum non-locality underlying membrane
and brain-function.
This view combines a reductionist approach, in which biological
phenomena are reduced to chemical and finally physical models
(Skinner et.al. 1989), with a new emphasis on quantum physics
as the limit of a fractal process. A component of panpsychism
is included in the physical description, in which consciousness
can be associated with a real quantum by virtue of the uncertainty
arising from its wave-particle duality. Sentience is the capacity
of the emitter to utilize the confirmation waves of contingent
absorbers in wave-packet reduction, while free-will or intent
is the uniqueness implied by the principle of choice. Emergentism,
the capacity of a system to be more than the sum of its parts,
is also present, because the time-symmetric subquantum associations
in the model are developed as a result of the large number of
units in a parallel net which can become transactionally related
as mutual conditional emitters and absorbers. This gives the
brain a degree of cooperative uncertainty which is lacking in
a single quantum. Free-will raises possibilities that the mind
can at least in some ways alter the future states of the universe.
The limits of such possibilities remain to be established.
8.2 Anomalies of Time Perception Since Grey-Walter first made
subjects witness movement of slide show via a motor cortex probe
and found they witnessed the slide change before they pressed
a dummy button, the time properties of conscious experience have
remained a conceptual challenge.
Two experiments outline some of the puzzling temporal properties
of consciousness. In the first, (Kolers & von Grunau 1976)
alternate lights of different colour flash for 150 ms with an
intervening gap of 50 ms. Subjects report a single moving light
which changes colour at the mid point, even on a first exposure,
or random colour change. This creates an apparent paradox because
the colour change apparently occurs before the second light has
come on.
In a second class of experiment (Libet et. al. 1979), which has
been the subject of repeated discussion (Libet 1985a,b,1987,1989,
Churchland 1981 a,b, Honderich 1984, Snyder 1988) involves the
subjective timing of stimulation of one hand [say the left, which
excites the right somatosensory area] at the same time as direct
stimulation of the opposite [left] finger somatosensory area.
The genuine hand-tingle is perceived before the cortically induced
one even if it actually occurred afterwards. Because of the considerable
delay for the development of neuronal adequacy for the conscious
experience [200 - 500ms] the time of the experience appears to
be referred back to the primary evoked potential [10-20ms after
stimulus], fig 12(b).
Although this referral can be explained as a construct of the
internal model, similar to spatial representations which are
subjectively "out there", temporal projection comes
close to causal paradox. Libet suggests "a dissociation
between the timings of the corresponding mental' and 'physical'
events would seem to raise serious though not insurmountable
difficulties for the ... theory of psychoneural identity".
Penrose (1989) "suggested that a materialistic explanation
of Libet's phenomena would require a revolution in fundamental
physics" (Dennett 1991). "This antedating procedure
does not seem to be explicable by any neurophysiological process...
[but is] attributable to the ability of the self-conscious mind
to make slight temporal adjustments, i.e. to play tricks with
time." (Popper & Eccles 1977).
Dennett (1991) explains such features by looping of the subjective
time sequence out of the physical sequence. The order of consciously
perceived events does not have to be coincident with the physical
or apparent physiological order when parallel processing builds
up a global model of a time sequence. The order in which constructs
become established may be arbitrary, within the space-time constraints
of a large parallel device, but the completed construct will
nevertheless represent the sequence of the original, perhaps
modified by simplifying assumptions of the internal model. This
approach suggests however that the completed representation cannot
be formed until after the sequence ends, [e.g. until both the
red and green lights have flashed and not half-way across], and
may require editing of the partial constructs of the model either
prior or subsequently to their registration.
Further experiments are required. The supercausal model was constructed
to deal with the causal paradox of free-will but could apply
also to these examples. Observational difficulties make the issue
similar to the problems of quantum measurement. One difficulty
is pinpointing the time of subconscious origin of a response
which results in a button press or a verbal signal. Another is
that comparing the absolute times of stimuli and neurophysiological
events with those of perceived conscious events ['it happened
when the hand was at 2'] involves comparing the 'representing
and represented' states (Dennett 1991).
8.3 Supercausality and the Representation of Time in the Cortex
One particularly interesting idea is that time is represented
in the same distributed and holographic manner that other modalities
are. The relationship between the frontal lobes and the rest
of the cortex appears to involve representations of activities
integrating future states [intentions] into time-directed actions
based on past experiences [memories]. The frontal lobes generalize
motor acts into associations in a similar manner to the sensory
association areas in the rest of the cortex. Thus the frontal
cortex may generate a spatially distributed representation of
time in terms of the organization of both remembered and planned
actions spanning the past and future, utilizing oscillatory phase
relations as seen in EEG and evoked potential studies, possibly
in the 40Hz mode suggested by Crick & Koch (1990). Coherent
oscillations would link by Hebbian coincidentality. Both short-term
working memory and the long-term consolidation of the limbic
system may thus form part of a transform representation of time.
Subjective time may thus be an internal model whose basis is
quite different from mechanical notions of linear time, partly
because it requires integrated representation of past memorizations
and learning with future plans and survival strategies. It is
easy to see that visual perception constructs an external spatial
reality but more difficult to accept the possibility that time
is similarly an internal construct. What may be even more difficult
to accept is that the subjective notion of free-will or intent
arises because the function of consciousness is to anticipate,
forming an "ill posed" problem in time.
A holographic representation of time generated by the frontal
cortex and limbic system thus provides a possible realization
of the supercausal model. The central task of the brain is the
representation of the activity of the organism in terms of both
past and future temporal dynamics. While the past is based predominantly
on memory, the future, representing the organism's survival strategy,
may be based on complementary principles of computation and predictivity,
utilizing both attractor-based computation and access to quantum
non-locality. The modal oscillations in such a holographic representation
are time-symmetric in the sense that the beats of phase coherence
measure only a circular phase-shift and not a direction. This
is exactly the same act that is required in quantum measurement
to determine the uncertainty relations, since counting beats
to determine frequency and wavelength requires a time or distance
determined by the uncertainty relations [5.3.3]. It thus raises
the rather odd spectre that cortical oscillations and their corresponding
mental states may be inflated quanta reverberating through the
brain. It also suggests that the subjective notion of the present
may be an extended quantum of the present, forming a reverberating
envelope of past and future states.
Solving the problem of temporal representation is central to
understanding the nature of attention, consciousness, and will,
both because of the causal paradox implied by will, and because
the problem of the 'ghost in the machine' is essentially a problem
of how the temporal dynamics of attention are organised. Enclosing
this ghost of attention within the quantum of the present carries
the paradox into the causality-violating arena of sub-quantum
physics.
8.4 The Experiencing Totality
Although normal waking experience has a reasonable correspondence
to our concept of physical reality, the experiences of dreaming
and other reflexive states such as hypnogogic and meditative
trance, psychotropic hallucinations and near-death experiences,
which transcend correspondence to the physical world, raise fundamental
questions concerning the relation between the mind and the physical
world. Dreaming is one of the most outstanding of these non-collective
conscious states. It is one which we are all aware of, and one
whose intensity, in cases of good recollection, parallels, or
even exceeds that of sense experience of the 'real world'. Dreaming
has definite correlates in central nervous activity in the REM
phases of sleep, originally called paradoxical because of the
appearance of internal waking arousal, illustrated in the EEG's
and PET scans of fig 4, contrasting with the slow wave activity
of deep sleep. The unusual properties of such states suggest
that the more esoteric aspects of mind, which I will term dreaming,
may contain deeper clues to its underlying nature beyond physical
correspondence. In such a dual model, mind is more fundamental
to reality than merely a physical internal model, a complementary
principle to physical reality, emerging physically through indeterminacy.
The concept of a dual totality in which mind and universe are
primary components raises further deep issues. While it may not
be possible to describe mind from the point of view of physical
world constructs alone, it is possible to describe the physical
world as stability properties of conscious experience. Similarly,
although our model of the physical world is inferential, our
conscious experience from birth to death is direct and undeniable.
It is thus possible to mount an alternative description of reality
in which mind is primary and fundamental and the physical world
is merely a stability structure of mind, as is central to the
Indian philosophy of mind. The link between chance, living organisms
and consciousness is also central to the Chinese oracle I Ching
(Wilhelm 1951) in which these three are regarded as joint manifestations
of a unifying predictive cosmic principle.
The status of such reflexive conscious states as dreaming may
thus represent one of the greatest enigmas of scientific enquiry,
because it is here that the temporal paradoxes described enter
into unstable self-feedback without direct input from the external
world. Dreaming is traditionally viewed as an illusory or hallucinatory
invention of the mind, functioning either in the release of psychological
tensions, or as a subjective manifestation of neural processing
during sleep, possibly in the consolidation of long-term memories
(Koukkou & Lehmann 1983, Winson 1990), or even to forget
as Francis Crick has suggested. Although true REM sleep appears
to be a mammalian trait, there is evidence for a paralysis phase
of sleep in animals spanning the arthropods and vertebrates.
Although dreams presumably do serve a physiological function,
as evidenced by metabolic compensation after periods of deprivation,
the origin of the content of dreaming remains obscure.
Complementing physiological studies of dreaming is a parallel
stream of literature addressing the possibility that dreaming
has unusual space-time properties, associated as much with future
as with past experiences (Dunne c1935). Although the significance
of dreaming in western culture has concentrated on the symbolism
of dreaming as an expression of fears and aspirations in daily
life and its analysis as a means of therapy, reference to dreaming
in other cultures, such as Australian aborigines, and the Senoi
of Malaysia includes the use of dreams to anticipate future problems
and events, and is based on the concept that the dreaming state
is another level of conscious reality, which is not an illusory
representation of the 'real world', but is rather a mode of conscious
existence in its own right. I have had many personal dreaming
experiences with attest to such temporal properties of dreaming,
including having a double dream of being stung, reporting the
dream to my wife and an hour later being stung wide awake in
bed.
Similar accounts occur in societies, such as the Huichols and
Mazatecs of Mexico and the Amazonian Cashinahua, Shipibo, Jivaro,
etc. where plants or fungi are taken to induce hallucinatory
trance states during shamanic rites. Five aspects of these states
have been noted by anthropologists; geometrical illusions, visions
of animals and demons, the separation of the mind from the physical
body, clairvoyant visions of distant places, and divination of
past or future events (Harner 1973)."On the day following
one ayahuasca party, six of nine men informed me of seeing the
death of my 'chai', my mother's father. This occurred two days
before I was informed by radio of his death".
The apparent capacity of people, in near-death experiences to
have perceptions of their surroundings from another physical
position [out of their body] invites further questions concerning
the physical location of consciousness, particularly when they
[occasionally] report accurate details they could not have witnessed
from their physical position, such as the patient who correctly
perceived a discarded shoe on a ledge three floors above the
room where she had cardiac arrest (Groff S. 1988).
In what I would loosely describe the Sorcerer's Explanation,
the dreaming aspect of reality underlies the physical so that
the waking experience of the physical world is just one manifestation
of a wider dreaming totality, rather than vice versa. Castenada
(1976) in his many allegories, discusses the technique of dreaming
in which the dreaming and waking state are connected by intent
so that dreamer can gain control. The technique involves picking
some simple action that the dreamer will perform as an act of
volition to assume temporary command of their will, and check
the onrush of dreaming attention. For example the act of looking
at the backs of one's hands while in the dream. This technique
is parallelled in Stephen LaBerge's (1985,1990) research into
lucid dreaming (Blackmore 1990), in which the subject learns
to make a variety of reality tests of the dreaming state by combining
waking practice tests with setting intent during the sleep phase.
These are complemented by waking techniques such as looking for
the gaps (see 1.4.3) in conscious experience, stopping the internal
dialogue and stalking (Abelar 1992).
The empirical investigation of such reflexive conscious states
constitutes the best hope we have for discovering the foundations
of the mind-brain relationship. While research is dominated by
clinical tinkering with the brain from outside, a comprehensive
description will continue to elude society. Thus balancing the
pictures gained by brain lesions, EEG studies and PET scans should
be an emphasis on pure consciousness research, combining scientific
techniques with the traditional means used by societies throughout
history, namely meditative and shamanic trance, the use of power
plants and dreaming techniques. Several of these have been largely
ignored as unscientific, or prohibited as dangerous to consumer
society because of their very capacity to induce fractal or chaotic
conscious states, thus setting back by decades society's development
of an understanding of the mind-brain relationship. Complementing
such traditional techniques are new devices emerging from brain
research laboratories. One valuable such device is the Dream
Light developed by LaBerge (1990) from research studies on dreaming
EEGs, which detects REM periods and alerts the subject by a flashing
light or acoustic signal. Such devices can help to bring the
relatively uncharted and inaccessible realms of consciousness
into the scientific arena.
9 The Cosmological Perspective
The brain may be one of the few places where the supercausal
aspect of wave-packet reduction can be clearly manifest, as a
result of its unique capacity to utilize correlations in its
dynamics. Although other unstable systems such as the weather
may also display such features of non-locality, it is difficult
to think of a physical experiment which could in any way match
the brain as a detector of correlations within the stochastic
model of quantum mechanics. In this respect it should be noted
that cosmology is not simply a matter of vast energies, but also
quantum rules. The diversity of wave-particles resulting from
symmetry-breaking of the fundamental forces finds its final interactional
complexity, in which all forces have a common asymmetric mode
of expression, in complex molecular systems. It is thus natural
that fundamental principles of their quantum interaction may
be ultimately realized in the most delicate and complex molecular
systems known - those of brain dynamics.
10 Conclusion
The importance of developing a model of brain function which
gives a consistent description of mind, consciousness and free-will,
is profound. The model described links the structural instability
of brain dynamics, quantum uncertainty and the dual-time model.
The quantum-physical brain may thus be more than just an interface
between sensory input and decision-making. It may in fact be
a doorway between complementary aspects of the physical universe,
the time-directed nature of real-particle symmetry-breaking and
the time-symmetric aspect of the sub-quantum domain (King 1989).
If so, the role of consciousness and mind-brain duality may be
central to cosmology.
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