Consciousness, New Thinking About
matt at automagic.org
Sun Jun 23 05:52:36 EST 2002
Perhaps this is too much of a perpendicular to consciousness, but
something I have wondered about is the basis for intuition, perhaps
framed as preanalytic thought, and its relationship to consciousness.
John H. wrote:
> Transient yes, like that, the idea that the basal ganglia in co-ordination
> with other regions is regulating a moment by moment awareness that is not
> predicated on some single 'entity' arising thereof. The body may be
> permanent (though I've heard analyses to the effect that over 5 years 95% of
> our atoms are replaced) but attentional processes are selection processes
> giving rise to momentary conscious states.
> I think concepts like surround inhibition, the D1-D2 'balancing act' (note
> efficacy of D2 agents on schizophrenia), play a fundamental role in
> understanding the nature of consciousness. Additionally, while long term
> potentiation is typically associated with memory formation another angle I
> read on this recently is that LTP in the hippocampus may be more about
> attentional processes. Haven't looked at this closely though and seems odd.
> Ha! advice of physicist John Wheeler, "In any discipline find the strangest
> thing and then explore it."
> There is no one set of modules giving rise to conscious experience,
> attentional processes determine conscious experience and these are mediated
> by regions of the brain generally assumed to be 'underneath' our conscious
> experience. As you note our conscious experience is mediated via a set of
> modules at any given time but this is a constantly subtly shifting set. If
> the self is a thing that thing is the capacity of these attentional
> processes to create sustained activation of various neocortical regions
> allowing the creation of representations that are temporally transcendent in
> the sense that their ongoing activation is no longer contingent on
> environmental stimuli. These representations exist independently of the
> environment and so sometimes these representations are not subject to the
> typical future corrective influences of the environment.
> Is it no wonder then that it is often impossible to change our fundamental
> personality. Neocortical regions may demonstrate remarkable plasticity but
> regions like the basal ganglia and thalamus much less so, these structures
> seem to be determined relatively early in the maturation process and the
> broad dynamics of attentional selection processes may be largely determined
> by circa age 5, at which point human beings seem to undergo some fundamental
> shift in the way they perceive themselves, perhaps because it is around that
> age that we fully develop the idea of 'my-self'. Note: at that age
> hippocampus 90% of adult size.
> It's very easy to think about consciousness as 'states of excitation' but if
> you take the view that the human CNS is 'dancing with chaos' all the time,
> ready to flip out of control, consciousness only becomes possible through
> strong inhibitory processes to dull the cacophony and keep the organism
> pointed in the right direction. Consciousness is not primarily a higher
> cognitive function but a primitive attentional-selection processes where the
> point of reference is the body and later the created self.
> Peter, I found these good texts:
> Terrance Deacon, The Symbolic Species.
> Big read, first rate, highly reviewed, very creative and empirically
> grounded approach.
> Below a weird but interesting twist on the problem.
> Cooperation of the basal ganglia, cerebellum, sensory cerebrum
> and hippocampus: possible implications for cognition,
> consciousness, intelligence and creativitypprint
> Rodney M.J. Cotterill * Biophysics, Danish Technical Uni6ersity, DK- 2800
> Lyngby, Denmark Received 8 July 2000
> Progress in Neurobiology 64 (2001) 1-33
> It is suggested that the anatomical structures which mediate consciousness
> evolved as decisive embellishments to a (non-con-scious) design strategy
> present even in the simplest unicellular organisms. Consciousness is thus
> not the pinnacle of a hierarchy whose base is the primitive reflex, because
> reflexes require a nervous system, which the single-celled creature does not
> possess. By postulating that consciousness is intimately connected to
> self-paced probing of the environment, also prominent in prokaryotic
> behavior, one can make mammalian neuroanatomy amenable to dramatically
> straightforward rationalization. Muscular contrac-tion is the nervous system
> 's only externally directed product, and the signaling routes which pass
> through the various brain components must ultimately converge on the motor
> areas. The function of several components is still debatable, so it might
> seem premature to analyze the global operation of the circuit these routes
> constitute. But such analysis produces a remarkably simple picture, and it
> sheds new light on the roles of the individual components. The underlying
> principle is conditionally permitted movement, some components being able to
> veto muscular contraction by denying the motor areas sufficient activation.
> This is true of the basal ganglia (BG) and the cerebellum (Cb), which act in
> tandem with the sensory cerebrum, and which can prevent the latter's signals
> to the motor areas from exceeding the threshold for overt movement. It is
> also true of the anterior cingulate, which appears to play a major role in
> directing attention. In mammals, the result can be mere thought, provided
> that a second lower threshold is exceeded. The veto functions of the BG and
> the Cb stem from inhibition, but the countermanding disinhibition develops
> at markedly different rates in those two key components. It develops rapidly
> in the BG, control being exercised by the amygdala, which itself is governed
> by various other brain regions. It develops over time in the Cb, thereby
> permitting previously executed movements that have proved advantageous. If
> cognition is linked to overt or covert movement, intelligence becomes the
> ability to consolidate individual motor elements into more complex patterns,
> and creativity is the outcome of a race-to-threshold process which centers
> on the motor areas. Amongst the ramifications of these ideas are aspects of
> cortical oscillations, phantom limb sensations, amyotrophic lateral
> sclerosis (ALS) the difficulty of self-tickling and mirror neurons. © 2001
> Elsevier Science Ltd. All rights reserved.
> "PF" <fell_spamtrap_in at ozemail.com.au> wrote in message
> news:VilQ8.705$5l4.29218 at ozemail.com.au...
>>"John H." <John at overhere> wrote in message
>>news:8bZN8.282$O4.6972 at ozemail.com.au...
>>Much good stuff in this post!
>>The basal ganglia can IMO be viewed as a central switching-station for
>>one "actention module" (of an individual's "Actention Selection System")
>>become transiently rendered "a dominant" (chapter 7 in The Learning Brain,
>>MIR Publishers Moscow 1982/83) actention module, whilst all functionally
>>incompatible and on relative balance insufficiently 'life-situationally'
>>stimulated (energized) other actention modules are roughly simultaneously
>>rendered 'subliminal' (mainly via the general principle/mechanism of
>>"lateral inhibition"(alternatively put, "centre/surround
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