The Central Enigma of Consciousness
Chris King
Mathematics Department,
University of Auckland
© 3-11-08, 13-11-09
Abstract:
The nature and physical basis of consciousness remains the central enigma of
the scientific description of reality in the third millennium. This paper seeks
to examine the phenomenal nature of consciousness and elucidate a possible
biophysical basis for its existence, in terms of a form of quantum anticipation
based on entangled states driven by chaotic sensitivity of global brain states
during decision-making processes.
1
Introduction to the Enigma:
The
term consciousness itself is enigmatic.
Both ÔmindÕ and ÔconsciousnessÕ present a varied array of associated words
and concepts, which we need to clarify, to even begin to close in on the
central enigma, which the terms present to us. Mind conjures up a plethora of concepts from minding i.e.
emotional caring, or objecting, through the rational mind of thought and
language based reasoning, mindfulness or focused concentration, to absent-,
clear- or small- mindedness to the mindless blunders many of us consciously
make, despite ourselves. Consciousness can mean everything from the root
capacity to have subjective experiences at all, through awake alertness, as
opposed to the slumber, or coma, of unconsciousness, through the fuzzy boundary
between subconscious or unconscious processing that accompanies conscious
cognition, to the restrictive idea of self-consciousness, as knowing that you
know - Òa conscious state is one
which has a higher-order accompanying thought which is about the state in
questionÓ [1].
Wikipedia
[2],
[3] has the following introductory
descriptions, chosen because they are a product of a social process of
consensual agreement as to their meaning and content:
ÒMind collectively refers to
the aspects of intellect and consciousness manifested as combinations of
thought, perception, memory, emotion, will and imagination; mind is the stream
of consciousness. It includes all of the brain's conscious processes. This
denotation sometimes includes, in certain contexts, the working of the human
unconscious or the conscious thoughts of animals. "Mind" is often
used to refer especially to the thought processes of reason.Ó
ÒConsciousness has been
defined loosely as a constellation of attributes of mind such as subjectivity,
self-awareness, sentience, and the ability to perceive a relationship between
oneself and one's environment. It has been defined from a more biological and
causal perspective as the act of autonomously modulating attentional and
computational effort, usually with the goal of obtaining, retaining, or
maximizing specific parameters (food, a safe environment, family, mates).
Consciousness may involve thoughts, sensations, perceptions, moods, emotions,
dreams, and an awareness of self, although not necessarily any particular one
or combination of these.Ó
Although
these contain a constellation of meanings, in which mind is sometimes focused
on the attributes of reasoned, or even language-based thought, and
consciousness is sometimes given the more restrictive meaning of
self-awareness, both contain a central arena of subjectivity and sentience,
while conceding that the boundaries between consciousness and the sub- or
unconscious may be fuzzy, both in varied brain states, from waking thought to
sleep and coma, and in complex autonomous processes, which go on below the
level of immediate awareness, during activities like driving a car.
The
central enigma we are referring to is not self-consciousness, but subjective
consciousness – the capacity of a conscious sentient being to have a
subjective experience of the existential condition, both of the everyday world,
and of dream, memory and reflection [4],
hallucination, psychedelic reverie, and other forms of internal subjective
experience, not necessarily correlated with the immediate events of the
physical world.
In
the face of the apparent causality of the Laplacian universe, many 20th
century philosophers assigned to consciousness the orphan status of an
epiphenomenon, a mere reflection of physical reality which could have no
influence upon it. Some, such as Gilbert Ryle [5],
who coined the term Ôthe ghost in the machineÕ, went further, attempting to
deconstruct the dualistic notion of mind altogether, as a form of false
reasoning, claiming Òthat the idea of Mind as an independent entity, inhabiting
and governing the body, should be rejected as a redundant piece of literalism
carried over from the era before the biological sciences became established.
The proper function of Mind-body language, he suggests, is to describe how
higher organisms such as humans demonstrate resourcefulness, strategy, the
ability to abstract and hypothesize and so on from the evidences of their
behaviourÓ [6].
Derived
from the dualistic cosmology of Rene Descartes, this subjective arena is
frequently referred to as the ÒCartesian theatreÓ, sometimes constructively, as
in Barrs [7],[8],
who describes the theatre of the conscious in terms of working memory and its
associated backdrops, but other times in somewhat disparaging terms as in
Dennett [9],
who, rather than explaining consciousness, as he claims, replaces it with a
Ômultiple drafts modelÕ, more representative of the publishing industry, than
either the conscious mind, or the sentient brain.
Some
of these criticisms arise from the practical difficulties of defining the
borders of consciousness and the difficulty of finding the actual mechanisms
for generating the Ôinternal model of subjective realityÕ in terms of brain
centers and their electrochemical dynamics, in the absence of clear evidence
characterizing which brain states other than general focused global activity
are responsible for consciousness, and as a result of the binding problem - how
and where the disparate components of brain processing are all brought together
in the hypothetical ÔCartesian theatreÕ of the mind. Some of these problems are
misplaced because they are falsely identifying brain and mind states. For example, the Ôbinding problemÕ of
brain dynamics may be resolved in practical terms through the phase coherence
of excitations that are related, to form resonant neural circuits,
differentiating them from the incoherent noise of the background, even though
there is no specific brain centre as such where consciousness is generated.
At
issue is a fundamental frame of subjective reference, and a confusion on the
part of brain researchers and philosophers alike, between the physical world,
and our representation of it in the so-called Ôinternal model of realityÕ,
which tends to become finessed in the dialectics of discourse on the problem.
The
veridical reality is that from birth to death each of us is a subjective
conscious observer of the existential condition. All our experiences of the
physical universe are without exception subjective conscious impressions, which
only we as individual subjective observers have access to. Ultimately all data
and scientific observations of the universe likewise achieve validation through
the subjective conscious experience of the researchers and those who read their
papers and witness their results.
Far
from being the fundamental components of veridical reality, the physical
universe and all the constructs applied to it, from wave-particles through
atoms and molecules, to complex biological systems such as the sentient brain
and all our experiences of the everyday world around us are entirely, and
without exception, purely and completely, abstract models of subjective conscious
impressions, knitted together by a consensual agreement between subjective
perceivers - that the table before us is solid and made of wood, plastic, or
metal, as the case may be, and that our impressions of the world, from the
lemon, or coffee cup on the table, to the horizon upon which we gaze, from a
lonely hill top, looking out to sea, or the stars and galaxies we perceive in
the sky, and entertain the humbling specters of an eventual demise in the heat
death or big crunch, according to cosmological theories of the time.
Subjective
consciousness is thus the primary veridical conduit of existential reality, and
the phenomena of the objective world, for all the convincing lessons that we
are biological organisms which bleed if we are cut, and lose consciousness if
we slumber, or are concussed, are consensual stabilities of our subjective
consciousness. This remains true, notwithstanding our obvious dependence on our
brain states, and the fact that some of the most bizarre and interesting states
of altered consciousness arise from psychoactive molecules, which mimic
neurotransmitters, or transport processes affecting synapses and thus radically
altering brain states.
However,
based on the consistency of the scientific description of the physical universe
and our part in it, as biological organisms dependent on our functioning brains
to survive, this veridical logic has tended to become reversed, on the basis of
the inaccessibility of subjective experiences to objective experimental testing
and replication, so that consciousness has either been relegated to an
epiphenomenon, merely reflecting, but not influencing, physical processes, e.g.
in the brain, or banished to the wilderness, as Ôna•ve or imaginaryÕ concepts
not well founded in the domain of philosophical or scientific discourse.
Put
in its completion, the relationship between consciousness and physical reality,
rather than being either an epiphenomenon, or mere identity, or a fully divided
Cartesian duality has characteristics more of the complementarity we see
between the wave and particle aspects of the quantum world, in which a quantum
can manifest wave, or particle natures, but not both at the same time, and in
which the two aspects are also qualitatively symmetry-broken, one being discrete
and the other continuous. It is this type of complementarity that Lao Tsu
called a Tao or ÔwayÕ of nature, and subjective consciousness and the objective
physical universe clearly have just such a qualitative complementarity
existentially.
Fig 1: BaarsÕ
description of the Cartesian Theatre of consciousness and its ÔplayersÕ in
terms of functional working memory processes.
The
nature of this complementarity and its fundamentality in the light of attempts
on the part of functionalists to finesse consciousness to be merely an aspect
of the attention process, or certain classes of excitation, such as those in
the gamma range of the eeg (30-60 Hz), have been highlighted in David ChalmersÕ
[10]
enunciation of the so-called ÒHard ProblemÓ in consciousness research, -
Òexplaining why we have qualitative phenomenal experiences. It is contrasted
with the Òeasy problemsÓ of explaining the ability to discriminate, integrate
information, report mental states, focus attention, etc. Easy problems are easy
because all that is required for their solution is to specify a mechanism that
can perform the functionÓ [11]. For example Crick and Koch [12]
identify conscious states accompanying attentive processes with higher
frequency electroencephalogram (eeg) signals in the gamma range. Defining
consciousness as a functional process associated with attention and/or working
memory is addressing an ÔeasyÕ problem in consciousness research. The dilemma
of the ÔhardÕ problem implies that no purely objective mechanism can suffice to
explain subjective consciousness as a phenomenon in its own right.
Completing
the enigma of consciousness is the thorny spectre of Ôfree-willÕ, upon which
all concepts of law and personal accountability hinge, as well as the
assumptions of virtually every religious tradition. Although it is possible to
couch questions of personal accountability in purely behavioural terms of
social conditioning, the problem of free-will remains a shibboleth for the
effectiveness of the scientific description. While many scientifically-trained
people consider that they may in principle be a chemical machine driven by
their brain states, the notion that subjective consciousness decision-making
has no capacity whatever to influence the physical circumstances around leads
to catatonic stasis. Everyone who
gets up in the morning and does something so predictable as pouring a cup of
coffee is making a direct investment in the notion that they are in some sense
in control of their personal decisions and that their feeling of subjective autonomy
is a valid expression of their condition.
We act in the world on this assumption and upon this investment.
Like
subjective consciousness, free-will has become an orphan of the scientific
description, seemingly inconsistent with the hypothesis that the behavior of
the organism is purely a function of its brain reacting as an electrochemical
machine, albeit a very complex one to the physical conditions of the organismÕs
environment. However, from the
outset of the quantum era, scientific researchers have noted that, since the
quantum description of reality is not deterministic, the apparently stochastic
nature of quantum uncertainty could provide a loophole for free-will, since the
universe is no longer in-principle a Laplacian mechanism [13]. Arthur Eddington [14],
for example noted that the uncertainty of position of a synaptic vesicle was
large enough to correspond to the thickness of the cell membrane, giving a
possible basis for a change in neurodynamics arising from quantum uncertainty.
Concluding that intentional volition might then be inconsistent with the chance
probability-based calculations of particle statistic, Eddington then
effectively suggested a form of hidden correlation in sub-quantum dynamics: a
correlated behaviour of the individual particles of matter, which he assumed to
occur for matter in liaison with mind.
This
ÔloopholeÕ has led to a continuing tradition of physicists, mathematicians and
brain researchers, speculating on various models by which the quantum world might
interpenetrate with the sort of brain dynamics associated with conscious
decision-making. We will look at
these in detail, once we have examined the brain dynamics associated with
conscious states.
2
A Dynamic View of the Conscious Brain
Unlike
the digital computer which is a serial digital device based on a discrete logic
of 0s and 1s, the brain is a massively parallel dynamic organ. Although the
action potential of long neuronal axons is a pulse coded firing rate
proportional to membrane depolarization, many neurons and indeed those forming
the organizing centre of many processes have continuously graded
potentials. Thus although some
individual neuron outputs may be pulsed action potentials, the electrical
activity of the human brain, as expressed in the eeg consists of broad spectrum
excitations indicative of chaos [15],
rather than the discrete resonances of ordered states. While some aspects of
the eeg, such as the alpha rhythms of visual relaxation, may be housekeeping
activities, as noted, oscillations in the gamma band have been associated with
specific conscious thought processes. The basis of the eeg appears to lie in
dynamic feedback between excitatory and coupled inhibitory neurons which set up
mutual oscillations through a phase-delayed feedback loop, which implicates it
as a major dynamical feature of cerebral processing.
Fig
2: Evidence for both dynamical chaos and phase wave-front ÔholographicÕ
processing. (a) Wavelet (morlet) transform, showing time evolution of
amplitudes with a peak in the gamma band accompanying recognition of an
anomalous note is consistent with phase-front processing. Broad-spectrum
excitation (extended vertical distribution of frequencies) is also consistent
with chaotic dynamics in the time domain. (b) Coherent distribution of
electroencephalogram over the cortex, is consistent with globally coupled
excitation. (c) Extended spatial distribution of cortical activation
accompanying recognition of an odour. (d) FreemanÕs [16]
[17]
model of olfactory recognition involves a transition from high-energy chaos on
inhalation to enter a new or
existing strange attractor basin as the energy is lowered on exhalation.
Although this is a transition from chaos to an ordered outcome, the attractor
may be a strange attractor, still supporting chaos locally within the basin.
(e) Fourier transforms of electroencephalogram, showing broad-spectrum
excitation and correlations dimensions consistent with global chaotic dynamics.
(f) Putative strange attractors in the electroencephalogram.
While
it might seem a contradiction that a brain state leading to any form of
strategic decision could be chaotic, this is not actually the case. Ordered dynamical systems are
inexorably drawn towards existing equilibria or resonant attractors making them
insensitive to their surroundings. A key characteristic of chaotic dynamics is
the Ôbutterfly effectÕ – their arbitrary sensitivity on their initial, or
boundary conditions – which in the words of Lorenz [18]
enable fluctuations as small as those of a butterflyÕs wings to become
amplified onto a tropical cyclone.
The
dynamical brain needs to be arbitrarily sensitive to its external conditions to
respond effectively to the sometimes very subtle clues from the world around us
that are absolutely essential for survival. A second key characteristic
particularly of high-energy chaos is that it tends to explore the entire space
of available states, sometimes called the Ôphase spaceÕ, pseudo-randomly, so
that it can appear anywhere, without prejudicing the outcome or missing an
angle. Thus a fundamental theme, which has proved very useful in exploring
brain dynamics, is a transition from chaos to order, in which an unstable
high-energy chaotic exploration falls into an ordered attracting state,
corresponding to recognition of a smell, or the ÔahaÕ of eureka that replaces
the confusion of a problem with the flash of inspiration of an insight that
appears to pop out of nowhere.
While
these excitations may be chaotic in the time domain, the dynamics accompanying
perceptual recognition shows spatially correlated excitations similar to a
hologram, in which the recognition process arises from populations of neurons
firing together in a resonant phase-coherent manner, which distinguishes the
recognized stimulus from the random ground swell of unrelated excitations. In
this respect Karl Pribram [19],
[20]
has noted that such processes are analogous, if not identical to, quantum
measurement based on constructive phase-dependent wave interference.
Phase
coherence is consistent with chaotic dynamics in the time domain because
mode-locked resonances between oscillators are a feature of non-linear systems.
For example the heart beat, although approximately periodic, has dynamics
comparable to a chaotic sinusoidally kicked rotator [21],
which enables it to maintain mode-locked non-linear resonance with heart
pacemaker cells which in turn are under central nervous system influence.
Fig
3: Structual outlines of the brain as a dynamical organ. (a) Major anatomical
features including the cerebral cortex, its underlying driving centres in the
thalamus, and surrounding limbic regions involving emotion and memory,
including the cingulate cortex, hippocampus and amygdala. (b) Conscious activity
of the cortex is maintained through the activity of ascending pathways from the
thalamus and brain stem, including the reticular activating system and
serotonin and nor-adrenaline pathways involved in light and dreaming sleep. (c)
Processing in the cortex consists of up to six layers of neurons, forming
modular processing columns around 1 mm in size, illustrated in cortex stained
for ocular dominance (right). (d) Such modularity is dynamic as shown by
changes on ocular dominance as a result of covering one eye during development.
(e) Modular cortical processing illustrated in pet scans of cortical activity
during language processing and the parallel processing of movement and colour
in the visual cortex.
By
contrast with a digital computer which relies on gigahertz speed to perform
discrete serial computations, the brain is a massively parallel organ, using
wave-front processing, containing between 1010 and 1011
neurons each of which can have up to 104 excitatory and inhibitory
synapses using a variety of chemical neurotransmitters to modulate
electrochemical transfer. The extreme parallel-distributed basis of this
processing is emphasized by the fact that there may only be around 10 serial
synaptic junctions between sensory input and motor output. By contrast, a
digital computer needs to make as many serial iterations as the computation
requires before coming up with an answer, and the latest PCs allow for only up
to 4 parallel units and even the largest super-computers have no more than a
few thousand, principally used in a restricted form of matrix calculation, such
as weather prediction, where each unit is essentially carrying out a similar
computation on differing initial conditions.
As
shown in figure 3, the cerebral cortex of the mammalian (and thus human) brain
consists of a large convoluted sheet about 1 m2 consisting of up to
six layers of neurons, organized into functional columns on a scale of around 1
mm2 and mini-columns of 28–40 µm performing unique processing
in a modular manner on aspects of sensory and cognitive processing, from lines
of a given orientation, through sounds of a given pitch to more abstract
features, such as recognition of specific faces, or facial expressions, to
associating the sound of a word with its semantic meaning. The cortex is
broadly divided between frontal areas responsible for action and its
abstraction in terms of plans and goals and perception and its abstractions in
terms of spatial orientation (parietal), semantic meaning (temporal) and other
creative, expressive, and classificatory skills.
The
organization of these modular columns is dynamic to the extent that covering
one eye will dynamically alter the balance of binocular dominance, and in a
blind person even use visual areas for spatial orientation based on sound
rather than vision. Many aspects of sensory processing occur in a parallel
modular manner, for example, separate local regions process colour and
movement, so that pathological conditions can result in loss of colour, or
motion perception, independently of the other.
The
electrical activity of the cortex is driven by centres in the underlying nuclei
in the thalamus, which have reciprocal connections with corresponding
areas of the cortex. In isolation,
cortical tissues tend to be electrochemically quiescent, which emphasizes that
to a certain extent the cortex represents complex boundary conditions,
modulating underlying thalamic excitations. Moreover the entire span of
cortical activity accompanying waking consciousness is dependent on a general
level of excitatory activity welling up from the brain stem centres of the
reticular activating system and major modes of dynamical brain activity
modulation, such as light and dreaming sleep are likewise modulated through
ascending nor-epinephrine, dopamine and serotonin pathways passing from the
brain stem upwards to permeate specific layers of the whole cortex.
Active
cognition is believed to involve an interplay of so-called Ôworking memoryÕ in which
frontal regions modulating the goals and direction of the thought process, are
interacting with parietal and temporal areas providing the spatial and semantic
information involved. There are actually two cortices, left and right,
connected by large parallel tracts of nerve fibres, the corpus callosum. The left and right
cortices are lateralized to varying degrees, particularly in men, so that
language articulacy and other more structured forms of cognitive processing are
predominantly in the left cortex and more generalized diffuse types of
processing occurs in the right cortex.
Consistent
with edge of chaos processing involving a transition to order from chaos,
studies of the kind of insight process that leads to phenomena such as
ArchimedesÕ ÒEureka!Ó [22]
appear to stem from the right anterior superior temporal gyrus, when distracting
structured ÔthinkingÕ activities of the left hemisphere have been replaced by
the relatively ÔcontemplativeÕ relaxation of alpha activity.
In
addition, feedback systems involving emotional recognition, flight and fight
reactions and the establishment of long-term sequential memory surround the
periphery of the cortex in the so-called limbic system, comprising the cingulate
cortex,
fornix,
hippocampus, amygdala and associated structures. The semantic significance of
the temporal cortex appears also to be able to combine with the intense
emotional significance of the closely associated amygdala to create mystical
and other symphonic experiences in temporal lobe epilepsy, a region coined by
Ramachandran [23], [24]
as Òthe God SpotÓ for this mix of emotional significance and ultimate meaning.
This association may have a genetic basis in religiosity [25]
as an evolutionary adaptation enabling larger, more dominant societies [26].
3
Edge of Chaos, Self-organized Criticality and Fractal Sensitivity
Between
the global level, the cellular level and the molecular level are a fractal
cascade of central nervous processes, which in combination, make it
theoretically possible for a quantum fluctuation to become amplified into a
change of global brain state. The
neuron is itself a fractal with multiply branching dendrites and axonal
terminals, which are essential to provide the many-to-many synaptic connections
between neurons, which make adaptation possible. Furthermore, like all tissues,
biological organization is achieved through non-linear interactions which begin
at the molecular level and pass upward in a series of scale transformations
through supra-molecular complexes such as ion channels and the membrane,
through organelles such as synaptic junctions, to neurons and then to neuronal
comp-lexes such as cortical mini-columns and finally to global processes.
At
the molecular level, the ion channel is activated by one, or two,
neurotransmitter molecules. Because neurons tend to tune to their threshold
with a sigmoidal activation function, which has maximum slope at threshold,
they are capable of becoming critically poised at their activation
threshold. It is thus possible in
principle for a single ion channel, suitably situation on the receptor neuron,
e.g. at the cell body where an activation potential begins to act as the
trigger for activation.
Fig
4: Quantum fractality differs from classical fractality in that it becomes
discrete at the quantum level. Fractal scale transformations emerge from
quantum non-linearities forming the chemical bond, in emergent stages through
tertiary and quaternary molecular structures, to cellular organelles, cells,
tissues and finally the whole organism, with its successive bifurcations of
development to form the tissue layers and later, interactive migrations of
specific cell types. Nervous system organization is thus fractal, running from
the molecular level of ion-channels, to neurotransmitter vesicles and synaptic
junctions (upper), then to neurons (lower right), then to neuronal complexes
such as mini-columns (lower left) and finally to whole brain activation.
The
lessons of the butterfly catastrophe combined with evidence for transitions
from chaos in perceptual recognition therefore suggest that if a brain state is
in a transition at the edge of chaos or is in a state of self organized
criticality, in which the system tunes to a critical state such as a sand pile
where there are fractal ÔavalanchesÕ of activity global instabilities, which
are encoding for the unresolved perceptual or conceptual context may be
ÔresolvedÕ through amplification of a local fluctuation at the neuronal,
synaptic or ion-channel level.
Although
neuroscientists have tended to discount the idea that micro-instabilities could
lead to global changes in brain dynamics, on the basis that mass action will
overwhelm such small effects, a variety of lines of evidence have demonstrated
that fluctuations in single cells can lead to a change of brain state.
In
addition to the issue of sensitive dependence in chaotic systems, two further
lines of evidence suggest changes in ion channels and/or single cells can
influence global brain states.
Fig 5: Evidence for
complex system coupling between the molecular and global levels. Stochastic
activation of single ion channels in hippocampal cells (a) leads to activation
of the cells (c). Activation of such individual cells can in turn lead to
formation of global excitations as a result of stochastic resonance (d).
Individuals cells are also capable of issuing action potentials in
synchronization with peaks in the eeg (e).
The first of these phenomena is
stochastic resonance [27],
in which the occurrence of noise, somewhat paradoxically, leads to the capacity
of ion channels to sensitively excite hippocampal cells and in turn to cause a
change in global brain state. In this sense noise is playing a similar role to
the ergodic properties of dynamical chaos, which likewise distribute the
dynamic pseudo-randomly and so prevent the dynamic getting stuck into the rut
of a given ordered attractor and it is thus able to fully explore its ÔphaseÕ
or dynamical space. Thermodynamic ÔannealingÕ is likewise used in classical
artificial neural nets to avoid them becoming locked in sub-optimal local
minima.
Fig 6: Left: Single pre-synaptic
pyramidal action potential leads to multiple post-synaptic excitations.
Right: Structure of chandelier or
axon-axonal cells with dendrites (blue) and axons (red).
More recently it has been
discovered that a specific class of cortical neuron, the chandelier cell is
capable of changing the patterns of excitation between the pyramidal neurons
that drive active output to other cortical regions and to the peripheral
nervous system, in such a way that single action potentials of human neurons
are sufficient to recruit Hebbian-like neuronal assemblies that are proposed to
participate in cognitive processes. Chandelier cells, which were only
discovered in the 1970s, and are more common in humans than other mammals such
as the mouse, and were originally thought to be purely inhibitory, are
axon-axonal cells, which can result in specific poly-synaptic activation of
pyramidal cells [28], [29].
The research paper and review
note:
The increased signal-to-noise
ratio in the network provided by hyperpolarizing GABAergic synapses is further
amplified by the coincident action of chandelier cells, resulting in a sparse
and potentially task-selective activation of pyramidal neurons. Thus, the human
microcircuit appears to be tuned for unitary-EPSP–activated Hebbian-like
functional cell assemblies that were proposed as building blocks of
higher-order cortical operations and could contribute to single cortical
cell–initiated movements and behavioral responses.
This reveals an extremely
efficacious means of activity propagation in the cortical network. Although
earlier work had shown polysynaptic activations following a single chandelier
spike, the current study demonstrates much longer responses. Moreover, one of
the most interesting results relates to the temporal structure of the activity
patterns elicited after stimulation of a single neuron. While most of them
appear to propagate through the circuit with increasing disorganization,
occasionally the authors were able to trigger an amazingly precise temporal
pattern. This implies that the microcircuit is capable under some circumstances
of generating patterns of activation with low jitter and high temporal
precision.
Given the potential for
fluctuations at the molecular, ion-channel, synaptic or neuronal level to
become the organizing centre resolving instabilities in global brain dynamic,
it becomes possible to form an edge-of-chaos model for resolving situations of
cognition involving intuition, insight and the ÔeurekaÕ attributed to
ArchimedesÕ sudden discovery of his principle. In this model, the dynamic of
the ÔproblemÕ remains unresolved and thus contains instabilities, which in turn
become sensitive to perturbation on descending fractal scales leading to the
molecular and quantum level.
Such an unstable dynamic is
tending to a transition from higher-energy chaos to order by developing a new
attractor, out of the fractal diversity of repelling attractors in the chaotic
dynamic. In terms of an active brain state, this would be likely to correspond
to a global excitation, say in the gamma range containing several uncorrelated
phase components representing features of the problem that cannot be put into
coherent relationship. Hence the essential instability at the fractal level
would consist of a transition from multiple uncorrelated phases to the
emergence of a correlated Ôorganizing centerÕ resolving the global instability.
Fig 7: (a) EEG sweeps are
coherent when anticipating a regular tone but decoherent when the tone becomes
erratic in its timing 39. (bi) Neural connection hubs are scale
independent in terms of frequency forming a small world network consistent with
self-organized criticality, (bii) Hubs compared in resting and tapping .
(c),(d) Intelligence measures correlate positively with phase shift duration
and negatively with phase lock duration 40. (e) Evidence for self-organized criticality in neuronal networks. Sorted correlation matrix and dendrogram of avalanches in a cortical slice 36.
A recent growth area of research
consistent with, but not limited to the edge of chaos concept, is the
development of models based on self-organized criticality, the tuning of
processes from sand piles to earthquakes towards a critical state in which
fractal avalanches maintain the process in a critical state. In the case of a
sand pile, as in an hour-glass, if the angle is too steep, massive avalanches
return it to the critical angle. Likewise, if it is too shallow more sand will
pile up with few or on avalanches until the critical angle is reached. Edge of
chaos processes share this tuning towards the critical state at the boundary,
but the reasoning also extends to stochastic systems such as the Ising model [30]
of magnetization.
Companion article with Matlab working source code for Ising model of Magnetization
Karl PribramÕs concept of the
holographic brain [31]
has drawn attention to the deep analogy, and possible physical correspondence,
between phase coherence in brain dynamics and the wave phase basis of all
quantum measurements. Phase
coherence provides a basis for distinguishing the processes the brain is paying
attention to from the decoherent groundswell of background noise. Key experimental investigations [32],
[33]
have repeatedly confirmed a relationship between phase coherence in central
nervous electrodynamics and recognized, or anticipated, stimuli.
More recently a variety of key
experimental research results [34]
have shown a close correspondence between self-organized criticality and brain
dynamics in processing real perceptual and cognitive tasks. These are reflected in several
different forms of analysis. Study of avalanches is isolated neuronal circuits [35]
[36]
shows the avalanches are tuned to a critical threshold where a given avalanche
is like to elicit only one further one, consistent with self-organized
criticality in neural circuits.
The fractal power law dynamics
of active brains states has been found to correspond closely with
self-organized criticality related to computational simulations of the Ising
model [37]. Brain processing states have also been
found to reflect a small-world network architecture consistent with
self-organized criticality [38],
[39]
across all frequency scales used in electroencephalogram studies &delta, &theta, &alpha, &beta, &gamma. Small-world
networks lie between regular networks, where each node is connected to its
nearest neighbours, and random networks, with no regular structure but many
long-distance connections between nodes at opposite sides of the network. A
small-world network enables communication between any two locations of the
network through just a few nodes - the "six degrees of separation"
reputed to link any two people in the world. In the brain, the number is closer
to 13.
In an intriguing 2008 study [40],
high intelligence, as measured on IQ scores, was found to consistently
correlate with longer times of phase decoherence, between phase-locked coherent
states, and shorter phase-locked episodes. The idea behind this is that longer
decoherence times corresponds to bringing larger systems of neurocircuits into
play, in cognitively analyzing a given situation and that shorter phase-locked
episodes corresponds to not getting stuck in a non-adaptive so called Ôfixed
positionÕ.
By contrast with the earlier
work on chaos in brain dynamics which tended to deal predominantly with
house-keeping states, rather than active cognition, these studies involve
intelligence and thought processes. They are consistent both with a stochastic
approach to criticality and with edge of chaos dynamics in the active brain.
3b Sensory Transduction and Subjective Experience
The occurrence of putative sensory transduction genes in the central nervous system is consistent with a novel biophysical model supporting subjective consciousness (King [99] ) - that the distributed functioning of the central nervous system provides an 'internal sensory system' which can generate abstracted sensory experiences of reality forming an 'internal model of reality' using the same quantum principles as are involved in sensory transduction in a bi-directional manner, enabling coherent generation and reception of biophysical excitations, particularly those associated with vision and audition. Olfaction has a fundamentally different basis, both in brain architecture and in the fact that it involves specific molecular receptors, which cannot regenerate their stimuli by reverse transduction, although there is evidence for olfactory synesthesia. Some forms of synesthesia, such as responding with feeling to seeing another person's finger touched, may also involve specific interactive circuitry, including mirror neurons.
Recent research in whole genome mapping of the mouse brain has made it possible to investigate the potential central nervous function of genes that might otherwise be associated primarily with peripheral sensory transduction. At the same time, the actual molecules involved in sense transduction, in vision, hearing and touch are being characterized. The first putative transduction molecule for mammalian touch, stomatin-like protein 3 (SLP3, or Stoml3) was reported this year in Nature, and putative molecules in the auditory transduction pathway, epsin, and cadherin 23 (otocadherin) have only been reported in the last five years and otoferlin in 2006. Research into the genetic evolution of the visual system has also unearthed provocative new findings about vision, which became the trigger for this hypothesis. In parallel with the usual cilia-based photo-transducer molecule c-opsin are retinal ganglion cells, which use melanopsin, or r-opsin related to insect opsins (based on organelles called rhabdomeres), which depolarize rather than hyperpolarize. It has also been discovered that both types of opsin work in opposition in the reptile parietal (pineal) eye.
Fig 7b: Large scale mouse brain expression profiles of encephalopsin (Opn3), otocadherin (Cdh23), espin (Espnl), otoferlin (Otof) and Stom3 (Allen Brain Atlas1) illustrate the wide and discretely specific expression of sensory transduction molecules for three senses, vision, hearing and touch in the central nervous system. Does this mean that the 'internal model of reality' evokes subjective experience using similar molecules to the physical senses?
4 Computational
Intractability, Classical Chaos and Quantum Uncertainty
The apparent contradiction
between the idea of precise classical computation (which abhors disrupting
noise) and the apparent unruliness of chaotic excitation, (which, although
being in principle deterministic, becomes unpredictable, through amplification
of small discrepancies due to sensitive dependence, resulting in an ÔergodicÕ
trajectory, filling phase space in a similar to a random walk) can be resolved
immediately we look more closely at the sort of computational problems a living
nervous system actually needs to solve in minimal time to survive.
The traveling salesman problem
– how to find the shortest path around n cities – is classed as np-complete [41].
Characteristically to classically compute a given solution requires checking
each of the 
possible cyclic
paths and finding the smallest.
However because this is super-exponential, even for a small number of
cities like say 25, the computation time required stretches out to the age of
the universe. The same
consideration applies to virtually every environmental decision-making process
a living organism faces, such as which path to take to the water hole, since
these all involve an exponentially increasing number of combinations of
contingent factors in the open environment. An animal cannot afford to wait
more than a split second making a real survival decision, or it may be leapt
upon by a tiger and consumed, so nervous systems have to find an immediate
real-time way of solving any such potentially intractable decision-making
problem.
The solution used by artificial
neural nets, which model a problem like the traveling salesman problem as an
energy minimization on a landscape representing the distances between the
cities, is to apply thermodynamic annealing, starting with a high temperature
which prevents the dynamic becoming stuck in a high local minimum, gradually
reducing the temperature of random fluctuations, arriving at a reasonable
sub-optimal local minimum. Statistical computational methods of solution work
similarly.
The Freeman model of perception
fig 2(d) uses a transition from high-energy chaos to a lower energy
strange-attractor in much the same way, using the high-energy chaos to avoid
the system becoming trapped in a far-from-optimality attractor until the
ÔphaseÕ space of the system has been fully explored.
Such a system provides for a
smooth transition between a situation in which the boundary conditions lead to
a clear computational outcome and hence a decision based on one choice having a
manifestly higher probability of survival, and other situations, in which, like
the problem of ArchimedesÕ possibly crown, there is no predisposing resolution
of the system because the problem has not yet been solved and the contextual
factors remain ambiguous, or inconsistent.
Unlike the discrete Von Neumann
or Turing machine, biological nervous systems appear to work on dynamical
principles which provide the capacity to induce a transition from chaos to
order, where the classical computer would run into the Turing halting problem
– unable to determine whether, or when, the computational process will
end.
Clearly such a transition will
involve sensitive dependence on initial and other boundary conditions and will
be in a classical sense unpredictable (just as the butterfly effect is) and
since it involves molecular processes at the quantum level, may invoke quantum
uncertainty as well. We thus need to investigate how these two effects might
come together, and explore whether and how they might play upon the processes
of perceptual recognition and conceptual insight.
The first point of reference is
a brief review of the wave-particle relationship and how the uncertainty
relationship comes about. By EinsteinÕs law 
, the energy of a particle is equivalent to the frequency of
the wave as the momentum is likewise to the wavelength. If we then want to
measure the energy, this will be equivalent to measuring the frequency, but as
we canÕt sample parts of a quantum wave, the only way we can know the frequency
is effectively to count the beats against a reference frequency. The time delay
between
successive fronts where the two waves are in phase, giving constructive
interference, then gives us the uncertainty relation 
.
Constructive interference from
corresponding phase fronts passing through two slits also gives us the basis in
wave-particle complementarity of the two-slit interference experiment fig
8. Complementarity is demonstrated
in the release of a photon from an excited atom in the bulb, as a discrete
localized ÔparticleÕ, corresponding to an orbital transition from an excited
atomic orbit. The photon then travels through both slits as a wave, which
overlaps itself to form bright bands of constructive interference and is again
absorbed as a particle by a silver atom on the photographic film. Although these discrete particles
arrive one at a time and could appear anywhere the wave function is not precisely
zero, as numbers of particles arrive, their statistical probability of
occurrence is distributed according to the complex square of the amplitude of
the wave 
.
The particle incidence gives
rise to one of the fundamental unresolved questions of quantum theory. As the
wave function doesnÕt determine where the particle should end up, it is deemed
that the wave function has ÔcollapsedÕ at the point the particle is detected
and unlike the linear evolution of the wave function, this collapse process is
stochastically unpredictable, leading to the idea that there may be a deeper
Ôhidden variableÕ theory explaining how each photon actually ÔdecidesÕ where it
ends up.
The contrast between quantum
theory, which leads only to parallel probabilities that the photon could be
anywhere in its wave function, and the real world in which unique histories
always occur, led to Schršdinger coining the Ôcat paradoxÕ, in which a cat is
predicted to be both alive and dead by quantum theory with differing
probabilities, if a Geiger counter is set to break a vial of cyanide, but when
we open the box the cat is either alive, or dead but not both. Various
approaches, including hidden variable theories and quantum decoherence [42]
caused by interaction with Ôthird-partyÕ quanta have been invoked to explain
this process but none eliminate the essential complementarity.
Fig 8: Top right: Beats of
constructive wave interference determine the uncertainty principle. Bottom:
Two-slit interference experiment illustrates wave-particle complementarity. Top
left: Cat Paradox experiment.
When we come to consider how
systems, which would classically display features of chaos behave in the
quantum world, we find a series of apparent contradictions, in the so-called quantum
suppression of chaos. In fig 9 the quantum stadium is used to illustrate
several features of this phenomenon.
The classical stadium billiard is chaotic because the periodic orbits,
some of which are shown in (d), are unstable, so that a ball with a trajectory
differing by an arbitrarily small amount is deflected by increasing amounts by
the curved boundary of the region, so that the periodic orbits are all
repelling and almost every orbit is a chaotic trajectory which eventually fills
the region ÔergodicallyÕ in an unpredictable, pseudo-random manner, as in (a),
due to sensitive dependence on initial conditions.
The quantum wave function
solutions (b) work differently, displaying peaks of the probability function
around the periodic orbits, defying their repelling nature. The reasons can be easily understood of
we use a semi-classical approximation, by releasing a small wave packet and
watching the way it bounces back and forth as in (c). Whenever the wavelength
of the packet forms a rational relationship with the length around a transit
any of the reflecting periodic orbits, we get an eigenfunction of the quantum
wave function, which constructively interferes with itself, as a standing wave,
just as do the orbitals of an atom, to form a probability peak around the
periodic orbit. Even when a trajectory is a little off the periodic orbit, the
spreading wave packet still overlaps itself contributing to the probability
peak.
The end result is that for a
variety of closed quantum systems, wave spreading eventually represses
classical chaos by scarring, causing the periodic eigenfunctions to become
eventual solutions of any time-dependent problem, although the initial
trajectory behaves erratically, just as does an orbit in the classical
situation. For example, a periodically kicked quantum rotator [43],
[44]
will stochastically gain energy, just as in the classical situation, until a
quantum break time [45],
after which it will become trapped in one of the quantum solutions. A highly excited atom in a magnetic field
will have its absorbance peaks at the periodic solutions, and quantum tunneling
will likewise use scarred eigenvalues as its principle modes of tunneling [46],
[47].
These constraints do not apply
to open systems, such as molecular kinetics where diffusion can carry molecules
relatively vast distances. As a
rough example, a glycine molecule at biological temperatures has a
self-diffraction angle of wave-spreading of about 6.5o, showing this
effect is significant [48].
Moreover, the larger the system, the longer the delay until quantum break time
sets in.
The implication is that
sensitive dependence on initial conditions eventually gives way, at the quantum
level, to quantum uncertainty of the scarred orbit, globally traversing the
space concerned, and it does so by performing a transition from chaos to order
dependent on the initial conditions initially following a chaotic trajectory
and eventually entering into a periodic orbit. Since a chaotic system, whether quantum or classical has a
dense set of periodic orbits there, is potentially an infinite number of these,
although quantum separation of chaotic eigenfunctions [49],
another feature of quantum repression of chaos, will lead to only a finite
number being available at the energies concerned.
Fig 9: Quantum chaos: The
classical stadium billiards is chaotic.
A given trajectory has sensitive dependence on initial conditions. As
well as space-filling chaotic orbits (a) [50],
the stadium is densely filled with repelling periodic orbits, three of which
are shown in black in (d). Because they are repelling, neighbouring orbits are
thrown further away, rather than being attracted into a stable periodic orbit,
so arbitrary small deviations lead to a chaotic orbit, causing almost all
orbits to be chaotic. The quantum solution of the stadium potential well (b) [51]
and (d) [52]
shows ÔscarringÕ of the wave function along these repelling orbits, thus
repressing the classical chaos, through probabilities clumping on the repelling
orbits. A semi-classical simulation (c) shows why this is so. A small wavelet bounces back and forth,
forming a periodic wave pattern, because even when slightly off the repelling
orbit the wave still overlaps itself and can form standing wave constructive interference
when its energy and frequency corresponds to one of the eigenvalues of a
periodic orbit, even though the orbit is classically repelling. The quantum solution is scarred on
precisely these orbits (d). This
causes resonances such as absorption peaks of a highly magnetically excited
atom (e) to coincide with the eigenfunctions of the repelling periodic orbits,
just as the orbital waves of an atom constructively interfere with themselves,
in completing an orbit to form a standing wave, like that of a plucked string.
The result is that, over time, in the quantum system, although the behaviour
may be transiently chaotic, it eventually settles into a periodic solution.
Experimental realizations such as the scanning tunneling view of an electron on
a copper sheet bounded by a stadium of carefully-placed iron atoms (f) [53],
confirm the general picture, although, in this experiment, tunneling leaked the
wave function outside too much to demonstrate proper scarring. The
semi-classical approach matches closely to the full quantum calculation (g).
Electronic article on simulating the Quantum Stadium in cellular automata with source Matlab code
The implications are threefold:
1. Quantum suppression of chaos leads to
a situation where:
(a) quantum chaotic systems
model a transition from chaos to order, just as insight processes involve a
transition from chaos to order, and
(b) quantum suppression of chaos
by phase coherence parallels the way brain processes may use coherence to
distinguish critical processes in conscious attention from the background.
2. The eigenfunctions of chaotic quantum
processes are globally distributed over the phase space and thus, in so far as
the outcomes depend on stochastic properties of wave-particle reduction, enable
uncertainty to affect outcomes on the scale of the phase space orbit.
3. In processes that involve open
systems, or large phase spaces whose quantum break time is much longer than the
real time window, chaos and quantum uncertainty may combine to amplify
uncertainty, so that it can affect global outcomes.
An indication of how the transition from classical to quantum chaos might lead to complex forms of quantum entanglement can be gleaned from an ingenious experiment forming a quantum analogue of the kicked top using an ultra-cold cesium atom kicked by both a laser pulse and a magnetic field. In figure 9b is shown the classical dynamical phase space of the kicked top showing domains of order where there is periodic motion and complementary regions of chaos where there is sensitive dependence on initial conditions as a result of horseshoe stretching and folding. In the quantum system (second row) in the ordered region (left), the linear entropy of the system is reduced and there is no quantum entanglement between the orbital and nuclear spin of the atom. However in the chaotic region (right) there is no such dip, as the orbital and nuclear spins have become entangled as a result of the chaotic perturbations of the quantum top's motion
[97]
,
[98]
.
Fig 9b Classical and quantum kicked top and entropies.
4 The Evolution of Chaotic
Sensitivity and the Emergence of Consciousness
We now return to the biological
arena, to consider how nervous systems might have evolved the dynamics we
associate with consciousness. Is
the sort of dynamics we associate with the conscious brain a product of the
complex interconnectivity of circuitry of relatively trivial neurons, as work
with artificial neural nets and computational approaches, such as artificial
intelligence might suggest? Or is it a fundamental aspect of living cells,
which evolved with the earliest eukaryotes? Is it in the senses of a single
celled-organism that we will naturally find the origin of chaotic excitability
as a source for the quantum sensitivity that ultimately shaped the evolution of
the conscious brain in higher organisms?
A realistic assessment of pyramidal
neurons confirms that they are very complex dynamical systems in their own
right, far from the trivial additive units which McCulloch-Pitts ÔneuronsÕ
present in theoretical artificial networks, containing up to 104
synaptic junctions, having a variety of excitatory and inhibitory synaptic
inputs involving up to four or five different types of neurotransmitter, with
differing effects depending on their location on dendrites, the cell body, or
axon-axonal connections.
Furthermore many of the critical
features we associate with neurons, and their associated neuroglia, in the
conscious brain, including excitability and the use of neurotransmitter
molecules, are not only shared by other cells in the human body, but extend
down to the earliest single-celled eukaryotes.
Fig 10: Real-time purposive
behavior in single cells (a) Paramecium reverses, turns right and
explores a cul-de-sac. (b) Human neutrophil chases an escaping bacterium
(black), before engulfing it. (c) Chaos chaos engulfs a paramecium. Action potentials in
Chaos chaos (d) and paramecium (e). Period 3 perturbed excitations in Nitella confirm chaos. (g)
Frog retinal rod cells are sensitive to single quanta in an ultra-low intensity
beam, with an average rate of one photon per click, but sometimes zero, or two,
due to uncertainty in the beam.
The connection between bursting
and beating in excitable cells was established by the Chay-Rinzel model and
ensuing experiments [54],
which established chaotic dynamics in neurons, pancreatic b-cell exocytosis, and
inter-nodal cells in the alga Nitella [55].
The association between excitability and exocytosis spanning the eukaryotes [56]
is doubly significant in that, in addition to graded electrochemical and action
potentials in the neuron, synaptic vesicles are also produced by exocytosis.
Earlier work had already
demonstrated membrane potentials in Amoeba proteus [57]
associated with pseudopod formation, and action potentials in the amoeba Chaos
chaos
[58],
[59],
aptly so-named by Linnaeus [60].
In ciliated protozoa, such as Paramecium,[61],
[62]
and Tetrahymena [63]
action potentials are associated with the motile actions of cilia in cellular
locomotion.
The aggregation of slime moulds
such as Dictyostellium is mediated by cyclic-AMP [64],
[65].
The ciliated protozoan Tetrahymena pyriformis [66],
[67]
and flagellated Crithidia jasciculata [68] utilize serotonin,
and the former also metabolizes dopamine and epinephrine [69],
[70].
Tetrahymena pyriformis also has circadian light-related
melatonin expression [71].
Both amoebae and ciliates show
purposive coordinated behaviour over real time, as do individual human cells
such as macrophages. The multi-nucleate slime mould Physarum polycephalum can solve shortest
path mazes and demonstrate a memory of a rhythmic series of stimuli, apparently
using a biological clock to predict the next pulse [72],
[73].
Chaotic excitation provides an excitable single cell with a generalized quantum
sense organ. Sensitive dependence would enable such a cell to gain feedback
about its external environment, perturbed by a variety of quantum modes -
chemically through molecular orbital interaction, electromagnetically through
photon absorption, electrochemically through the perturbations of the
fluctuating fields generated by the excitations themselves, and through acoustic
and mechanical interaction.
Amoebae for example, although they lack specific sense organelles, are
highly sensitive to chemical and electrical signals, as well as to bright
light.
Such excitability in the single
cell would predate the computational function of neural nets, making dynamical
chaos fundamental to the evolution of neuronal computing rather than vice
versa. A single cell has no capacity to solve decision-making problems through
a neural net consisting of many cells, so has to rely on membrane excitation
and internal regulatory systems, such as biological clocks and genetic switches
to provide memory and a strategy for survival.
Fig 11: Hydra has only an
undifferentiated nerve net (a), yet catches prey by coordinated action of its
tentacles (b) and has no less than 12 different forms of motion, from stages of
somersaulting to snail-like gliding.
When we move to the earlier
metazoa such as Hydra, which supports only a primitive diffuse neural net and
whose tissues can dynamically reorganize themselves, for example if it is
turned inside out, we find the organism has a rich repertoire of up to 12 forms
of ÔintuitiveÕ locomotion, and is able to coordinate tentacle movements and
tumbling, and other forms of movement using similar global dynamics to those in
amoebae and Paramecium, or a more advanced organism, such as a snail. We can
thus see that nervous systems have arisen from the adaptive dynamics of
individual eucaryote cells, rather than being composed of a logical network made
out of essentially trivial formal neurons.
As we move up the evolutionary
tree to complex nervous systems, such as in vertebrates, we still see the same
dynamical features, now expressed in whole system excitations such as the eeg, in
which excitatory and inhibitory neurons still provide a basis for
broad-spectrum oscillation, phase coherence and chaos in the global dynamics,
with the synaptic organization enabling the dynamics to resolve complex
context-sensitive decision-making problems, involving memories of past
situations and specific adaptations to current ones. However the immediate decision-making situations around
which life or death results, in the theatre of conscious attention in real
time, are qualitatively similar in nature to those made by single celled
organisms, such as Paramecium, based strongly on immediate sensory input,
combined with a short term anticipation of immediate threats, in a context of
remembered situations from the past that bear upon the current existential
strategy.
Looking back more deeply in
time, chaotic excitability and electrochemistry generally may be one of the
founding features of eucaryote cells, dating from the RNA era, before coded
protein translation [74],
[75],
[76].
Nucleotide coenzymes, believed to be molecular fossils from the RNA era,
pervade electron transport pathways. Key chemical modifiers may have been
precursors of the amine-based neurotransmitters, spanning acetyl-choline,
serotonin, catecholamines and amino acids such as glutamate and GABA, several
of which have potential pre-biotic or trans-biotic status. Positive amines for
example may have chemically complemented negatively charged phosphate-based
lipids in modulating membrane excitability in primitive cells without requiring
complex coded proteins.
The sense modes we experience
are not simply biological as such, but more fundamentally are the qualitative
modes of quantum interaction between molecular matter and the physical
universe. They thus have potential cosmological status. Vision deals with
interaction between photons and orbitals, hearing with the harmonic excitations
of molecules and membrane solitons, as evidenced in the action potentials
arising from cochlear cells. Smell is the consequence of orbital-orbital
interaction, as is taste. Touch is a hybrid sense involving a mixture of these.
The limits to the sensitivity of
nervous systems are likewise constrained by the physics of quanta, rather than
biological limits. This is exemplified by the capacity of retinal rod cells to
record single quanta fig 10(g), and by the fact that membranes of cochlear
cells oscillate by only about one H atom radius at the threshold of hearing,
well below the scale of individual thermodynamic fluctuations and vastly below
the bilayer membrane thickness. Moth pheromones are similarly effective at
concentrations consistent with one molecule being active, as are the
sensitivities of some olfactory mammals.
The very distinct qualitative
differences between vision, hearing, touch and smell do not appear to have a
physiological support in the very similar patterns of electrical excitation
evoked in their cortical areas. However, if all these excitations can occur
simultaneously in the single cell, chaotic excitation could effectively become
a form of cellular multi-sensory synaesthesia [77],
which is later specialized in the brain in representing each individual sense
mode. Thus in the evolution of the cortical senses from the most diffuse,
olfaction, the mammalian brain may be using an ultimate universality, returning
to the original quantum modes of physics in a way which can readily be
expressed in differential organization of the visual, auditory, and
somato-sensory cortices according to a single common theme of quantum
excitability. This is consistent with cortical plasticity, which for example,
enables a blind person
to use their visual areas for
other sensory modes.
It is thus natural to postulate
that cellular ÔconsciousnessÕ, as a focused global dynamical electrochemical
response to a cellÕs environment, is a pivotal feature which as been elaborated
and conserved by nervous systems because it has had unique survival value for
the organism. 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
predictivity not possessed by formal computational systems. One of the key
strategies of survival implicated in brain dynamics is anticipation and
prediction of events [78],
[79],
[80],
[81]. 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. We shall examine this possibility next.
5 Quantum Entanglement and
the Transactional Interpretation
All forms of quantum field
theory stem from the special relativistic form of the energy 
. This gives two
solutions, one a positive energy solution traveling in the usual (retarded)
direction in time and the other a negative energy (advanced) solution,
traveling backwards in time.
All quantum mechanical calculations
are based on these dual solutions of special relativity, including those of
quantum electrodynamics, the most accurate physical theory ever devised [82].
Wheeler and Feynman noted that ÔabsorberÕ theory [83],
in which the advanced solutions were included, gave the same predictions as
descriptions in which the advanced solutions were omitted as unphysical. Indeed
all Feynman space-time diagrams implicitly contain both the advanced and
retarded solutions. For a photon, which is its own anti-particle, the advanced
and retarded solutions of electron-electron repulsion by exchanging virtual
particles fig 12(3a-c) are identical, as a negative energy advanced photon IS a
positive energy retarded photon. Likewise electron scattering becomes positron
creation-annihilation when time reversed (d). The delayed choice experiment and
quantum erasure, fig 12 (1,2) confirm that changes after emission, or even at
absorption, can influence the path taken by a photon or other exchanged
particle [84].
In John CramerÕs transactional
interpretation [85], such an
advanced Ôbackward travelingÕ wave in time gives a neat explanation, not only
for the above effect, but also for the probability aspect of the quantum in
every quantum experiment. Instead of one photon traveling between the emitter
and absorber, there are two shadow waves, which superimposed make up the
complete photon. The emitter transmits an offer wave both forwards and
backwards in time, declaring its capacity to emit a photon. The potential
absorbers of this photon transmit a corresponding confirmation wave. These,
traveling backwards in time, send a hand-shaking signal back to the emitter,
fig 12(4a). The offer and
confirmation waves superimpose constructively to form a real photon only on the
space-
time path connecting the emitter
to the absorber.
Fig 12: Wheeler delayed choice
experiment (1) shows that a decision can be made after a photon from a distant
quasar has traversed a gravitationally lensing galaxy by deciding whether to
detect which way the photon traveled or to demonstrate it went both ways by
sampling interference. The final state at the absorber thus appears to be able
to determine past history of the photon. Quantum erasure (2) likewise enables a
distinction already made, which would prevent interference, to be undone after
the photon is released. Feynman diagrams (3) show similar time-reversible
behavior. In particular time reversed electron scattering (d) is identical to
positron creation-annihilation. (4a) In the transactional interpretation, a single
photon exchanged between emitter and absorber is formed by constructive
interference between a retarded offer wave (solid) and an advanced confirmation
wave (dotted). (b) EPR experiments of quantum entanglement involving
pair-splitting are resolved by combined offer and confirmation waves, because
confirmation waves intersect at the emission point. Contingent absorbers of an
emitter in a single passage of a photon (c). Collapse of contingent emitters
and absorbers in a transactional match-making (d).
The transactional interpretation
offers the only viable explanation for the apparently instantaneous connections
between detectors in pair-splitting EPR experiments in which a pair of
correlated photons are emitted by a single atom [86],
[87],
[88],
in which neither of the photons has a defined polarization until one of them is
measured, upon which the other immediately has complementary polarization. In
fig 12(4b), rather than a super-luminal connection between detectors A1 and A2,
the two photonsÕ advanced waves meet at the source emission point in a way
which enables the retarded waves to be instantaneously correlated at the
detectors. One can also explain the arrow of time, if the cosmic origin is a
reflecting boundary that causes all the positive energy real particles in our
universe to move in the retarded direction we all experience in the arrow of
time and increasing entropy [89].
The hand-shaking space-time
relation implied by the transactional interpretation makes it possible that the
apparent randomness of quantum events masks a vast interconnectivity at the
sub-quantum level, reflecting BohmÕs implicate order [90],
although in a different manner from BohmÕs pilot wave theory [91].
Because transactions connect past and future in a time-symmetric way, they
cannot be reduced to predictive determinism, because the initial conditions are
insufficient to describe the transaction, which also includes quantum boundary
conditions coming from the future absorbers. However this future is also
unformed in real terms at the early point in time emission takes place. My eye
didnÕt even exist, when the quasar I look out at emitted its photon, except as
a profoundly unlikely branch of the combined probability ÔwavesÕ of all the
events generating parallel Ôprobability universesÕ throughout the history of
the universe between the time, long ago, that the quasar released its photon,
and me being in the right place, at the right time to see it distant epochs
later.
In the extension of the
transactional approach to supercausality [92],
[93],
a non-linearity collapses the set of contingent possibilities to one offer and
confirmation wave, fig 12 (4c,d). Thus at the beginning, we have two sets of
contingent emitters and absorbers and at the end each emitter is now exchanging
with a specific absorber. Before collapse of the wave function, we have many
potential emitters interacting with many potential absorbers. After all the
collapses have taken place, each emitter is paired with an absorber. One
emitter cannot connect with two absorbers without violating the quantum rules,
so there is a frustration between the possibilities, which can only be fully
resolved if emitters and absorbers are linked in pairs. The number of
contingent emitters and absorbers are not necessarily equal, but the number of
matched pairs is equal to the number of real particles exchanged.
This transactional time symmetry
is paralleled in the implicit time reversibility of quantum computation, which
also depends on a superposition of states. The transactional interpretation may thus combine with
effective forms of biological quantum computation to produce a space-time
anticipating quantum entangled system, which may be pivotal in how the
conscious brain does its processing.
6 Consciousness Revealed
It is at this point that the
influence of the conscious observer and the hard problem become an intriguing
challenge to the scientific description. The brain is not a marvelous computer
in any classical sense - we can barely manage a seven-digit span, but it is a
phenomenally sensitive anticipator of environmental and behavioral change.
Subjective consciousness has its survival value in enabling us to jump out of
the way when a tiger is about to strike, not so much in computing which path
the tiger might be on, (because this is an intractable problem, and the tiger
can also take it into account in avoiding the places we would expect it to most
likely be), but by intuitive conscious anticipation.
Fig 13: Evidence of
immediate anticipatory subjective consciousness. A seagull just manages to
escape a shark strike, before flying off.
The brain, using phase
correlation in its own wave dynamics, as a basis for decision-making, parallels
the way in which the wave function and its constructive interference determines
the probabilities in the reduction of the wave packet. We thus may need to
consider the possibility that global brain excitations form an ÔinflatedÕ
quantum system and that the brain uses a form of quantum anticipation involving
emission and absorption of its own excitations in a way which enables it to
have an ÔintuitiveÕ non-computable representation of future states which
complement computational processing and which would be unavailable to a
classical computer. Quantum coherence is already a technique in imaging,
demonstrating an example of quantum coherence in biological tissues at the
molecular level [94], [95].
In this sense, the enigma of
subjective consciousness may exist partly because such excitations cannot be reduced
to classical prediction, or quantum transactions would introduce a causal
Ôback-to-the-futureÕ feedback loop. Thus the brain, in developing the internal
model of reality represented by the ÔCartesian theatreÕ, may have opted for a
complementarity between subjective consciousness and objective brain function,
to maintain ÔentangledÕ anticipation, which is an evolutionary adaptation to
the transactional relationship underlying wave-particle complementarity,
bringing the two complementarities into conjunction.
In this respect, subjective
consciousness may present an existential cosmological situation, as noted in
Indian philosophy, in which consciousness is described as ÔfinerÕ than matter,
thus gaining a complementary existential status to the physical universe, in
the manner of the Tantric dance of Shiva as the undivided field of subjective
consciousness and Shakti as maya – the multiplicity of
material manifestations, again reflecting the continuous-discrete wave-particle
relationship, and do this by manifesting in subjective consciousness aspects of
the space-time traversing sub-quantum dynamics that underlies the wave-particle
complementarity at the foundation of the quantum description of the
cosmological universe.
To make this point in a closing
tale we narrate the following descriptive evolutionary account:
A hunter is at a
fork in the path to the water hole, seeking to get an antelope for meat, but
wary of himself getting taken by a big cat in the process. As the man stands
pondering and studying the tracks on the path and the sounds and smells 
blowing
across the savannah and through the jungle, his brain develops a resonant
coherent excitation – the hunterÕs ÔstealthÕ – a state of awareness
empty of structured thought, anticipating the slightest movement around him.
Fig 14: Transactional view of a
hunter trying to find a safe path to the waterhole. Both the open hilly path
and the jungle path (right) have lions or tigers, which might attack the
hunter. Paranoia suggests the hunter takes the hilly path as his quantum
anticipation makes him feel uneasy about the forested path, since in the
probability universe where he take this path he gets a severe fright. Usually
these anticipations will be almost immediate, as in fig 13.
There are two histories
of varying duration, from immediate awareness, to the imminent future, that the
vagaries of fate on the day could bring about. The man could walk down the
shady path or the one over the rocks.
As things transpire,
there is a hungry tiger on the shady path, which is poised to leap on anything
coming its way. However the manÕs brain wave is resonating in an entanglement
with his future brain states and there are two parallel universes of future
states, one down the shady path and the other down the rocky one.
Now the brain state
going down the shady path has a catastrophe - one hell of a scare, or outright
death, painfully mauled by the big cat. The hunterÕs stalking brain state gets
absorbed down there and the absorber's advanced wave runs back through
space-time in his brain state along the path he just traversed, to the point
where the man is still standing at the fork trying to decide what to do.
On the other path he
simply walks to the water hole, because the lions are elsewhere today, and
shoots a small antelope with his poisoned arrow and takes it back to a woman in
the village, so she might consent to have sex with him. This outcome also
absorbs the resonating brain wave and sends its advanced wave back to the
hunter at the crossroads, but it doesnÕt excite his paranoia.
At the crossroads
the man is feeling disquiet. His
amygdala is giving him conniptions of foreboding. He feels bad about the shade
under the trees. He doesn't like the
rocky path either, because lions spend a lot of time slouching in the little
gullies in the rocky hills, but having already pondered for long enough to
contemplate, and being desirous of having sex before the moon sets, he decides,
on a sheer hunch, which he canÕt fully describe, to go ahead on the hunt, by
walking carefully along the stony path.
He ends up having
children and his children have too and each have often since felt pretty
paranoid about a lot of things, but sometimes they just feel its a sunny day,
and the shade under the trees looks cool, and although a few have been picked
off by big cats, most of them have taken some good hunks of meat back to the
village and had some sex for themselves too. And so the story carries on long
enough for the hunterÕs great-grandson to sit down and get ready to share a
good roast leg of antelope, while the women throw some sweet potatoes into the
fire, to pick up his flute and cock his bowstring against a cooking pot to
pluck for a tune, and tell a few jokes, and scary stories too, to get the woman
he admires to draw in close and put her arms around him, and do that funny
thing of wiggling her middle finger in the palm of his hand that means she
wants to take him off for the night for a Ôwalking marriageÕ, once the fire has
died down low [96].
So it is that the
anticipatory quantum chaos of the living cell has become the contemplative mind
of the lonely hunter, in the generations of conscious beings traversing the
sentient wave-particle universe.
References: