Commentary on the paper "The contents of consciousness: a
neuropsychological conjecture" by J.A.  Gray, 
in: Brain and Behavioral Sciences. 

Transparent theory of consciousness: is there a problem?

Wlodzislaw Duch 
Department of Computer Methods, UMK
Grudziadzka 5, 87-100 Torun, Poland
duch@phys.uni.torun.pl

1.  Subicular comparator determines the content of consciousness because it
is just a selective attention mechanism - to have a conscious experience
one must pay attention.  Gray falls into a common trap looking for
"conscious components" in the brain processes and complains about
difficulty of labeling neural processes as conscious or unconscious.
Conscious experience is an experience.  As all experiences it is a
particular combination of brain and body states - reflective consciousness
involves the concept of self but is not different in principle from the
primary consciousness.  Relaxation of the brain/body states, labeled as
"conscious experience", is a subtle, nonlinear process based on the
feedback to/from all sensory and motoric subsystems plus a feedback from
those attractors of the brain's dynamics that are close to the final
dynamical state representing the experience.  Some of these relaxation
processes, chosen by the selective attention mechanism, find their way to
the episodic memory and form "the contents of consciousness".
    
2.  Gray calls for a "transparent theory", not being satisfied with
phenomenological correlations only.  Without the concept of space-time, a
highly abstract and metaphorical idea, physical theories could not be
transparent.  Transparent theory of mind requires precise definitions of
mental events, mind states and their dynamics, and a space containing mind
objects (Duch 1994).  It allows to replace such statements as "that the
informational equivalences ...  are jointly instantiated into conscious
experience..." (Gray, p.16/17) with statements that may be given precise
mathematical meaning, such as "when the patterns of excitation of
transcortical neural cell assemblies (TNCAs) reach stable attractor,
binding together in episodic memory many modalities and features of
internal representations into one mind object".  Even if the brain receives
information if such stable patterns are not formed (cf.  the 'blindsight'
cases or 'hide the thimble', Dennet 1991) conscious experience is not
induced.  A preliminary experimental evidence for the existence of TNCAs
has been presented very recently (Pulvermueller et.al 1994).

3.  The ultimate grounding of our conscious experiences is inseparable from
the body (Johnson 1987).  Mental events result from "frozen experiences",
they are really past brain/body states remembered by the brain.  The brain
stores experiences (mind objects) and re-lives them, exploring them in
episodic memory like an eye explores the scene by making saccadic
movements.  Since mind objects are entrained, sharing many features, there
are expectations related to the next moment.  The comparator model
describes this process well but the essence of conscious experiences does
not lie in the evolution from mind object to mind object.  It lies rather
in exploration of a single multimodal object: a thought, a sound, a color,
each having many features and related to brain/body reactions in a
non-linear way, leading to a particular relaxation of the organism, very
individual and hence subjective.  Bodily reactions in anxiety are not just
symptoms but are essential part of this experience: symptoms and causes are
not separable and body therapy may have strong psychological consequences.

4.  Gray agrees that the content of consciousness is not directly based on
sensory stimulation (cf.  5.7), as is especially clear in case of
psychiatric disorders.  Subicular comparator selects from many stable
patterns of neural excitations (multiple drafts, Dennet 1991) that may
potentially engage episodic memory.  Thus (conscious) experience is
restricted to mind objects activated by the sensory or by internal brain
excitations, there is no direct conscious experience of reality.  These
mind objects are slowly formed during infant development and later "tuned"
to reflect new experiences, The transient patterns change too quickly and
carry too much noise to be biologically useful.  In the real world
recognition of objects must be fast, but learning may be slow (cf.  long
infant period), just as in the recurrent neural networks.

This simple extension of Gray's ideas explains the puzzling experiments
related to conscious perception, such as those disussed by Dennet (1991)
(cf.  also sections 5.2-5.7 of the target article).  Long delays and
strange subjective time ordering in Libet's experiments are due to the
nonspecific form of low-level stimulation of the somatosensory cortex,
resulting in long transition times to stable attractors of the TNCA
excitations.  If a whole series of confusing stimuli is presented then a
stable attractor of the TNCA excitation may not be reached for one second
or longer, each new stimulus forcing the system into a new pattern before
the old becomes firmly established and episodic memory engaged.

5.  The evolutionary advantage of consciousness lies in the ability to
avoid unflexible behavior patterns (based mostly on genetic learning) that
animals follow.  Consciousness and intelligence, adaptation to complex
environment, are inseparable.  Conscious experience is nothing else but the
reaction of the mind/body system, reaction very subtle in humans capable of
having qualia (conscious experiences) associated with such abstract
questions like "who am I"?

6.  Summarizing: is there a problem in formulating transparent theory of
consciousness?  It is quite similar to Gray's theory:

a) The structure of mind is based on subjective experiences - what else can
be remembered but the states of brain/body?  Conscious experience is a
particular brain/body relaxation characteristic to complex minds.

b) Conscious experiences allow for more flexible modification of behaviour
and are necessary for intelligence.

c) They arise from stable TNCA attractor states of brain/body dynamics
coupled with the episodic memory.

d) They alter the behaviour since various stable states share many features
of internal representations and thus are basic to the way associations and
predictions are formed.

References

Duch, W. (1994).  A solution to fundamental problems of cognitive
sciences, submitted to PSYCOLOQUY.

Dennett, D.C.  (1991) Consciousness explained (Little Brown, Boston)

Johnson, M. (1987).  The Body in the Mind: The Bodily Basis of Meaning,
Imagination, and Reason.  Chicago: The University of Chicago Press.

Pulvermueller F, Preissl H, Eulitz C, Pantev C, Lutzenberger W, Elbert T
and Birbaumer N. (1994) PSYCOLOQUY 5(48) brain-rhythms.1.pulvermueller