#68. Consciousness is Google Searches Within Your Brain [neuroscience]

NE

Red, theory; black, fact.

The Google search is one of those things that are too good a trick for Nature to miss (TGTNM) and she didn't, and it's called consciousness.

Brain mechanism of consciousness

I conjecture that the human brain launches something like a Google search each time an attentional focus develops. This is not necessarily a literal focus of activity on the cortex; it is almost certainly a sub-network activation. The sub-net activity relays through the prefrontal cortex and then back to sensory cortex, where it activates several more sub-nets; each of these, in turn, activates further sub-nets via the prefrontal relay, and so on, exponentially. At each stage, however, the degree of activation declines, thereby keeping the total cortical activation limited.

Accounting for subjective experience

The first-generation associations are likely to be high in the search rankings, and thus subjectively "close" to the triggering attentional focus and relatively strongly in consciousness, although still in the penumbra that is subjectively "around" the attentional focus. Lower-ranking search results would form a vast crowd of associations only dimly in consciousness, but would give conscious experience its richness. Occasionally, an association far out in the penumbra will be just what you are looking for, and will therefore be promoted to the next attentional focus: you get an idea.

The role of emotions

The evaluation process responsible for this may involve the mediolateral connections of the cortex, which lead back to the limbic system, where emotions are thought to be mediated, at the cingulate gyrus. Some kind of pattern recognition seems unavoidable, whereby a representation of what you desire <06-25-2021: itself a sub-network activation> elaborated by the mediolateral system is matched to retrieved associations. Your target may be only a part of the retrieved association, but will suffice to pull the association into the attentional focus.

This is a great system, because it allows a mammal to converge everything it knows on every task, rather than having to perform as a blinkered if-then machine.

Brain mechanisms and our evolutionary history

01-02-2021: Why should we have this back-and-forthing between the prefrontal cortex and the sensory association cortex? Two possibilities: 1) the backward projections serve a priming function, getting certain if-then rules closer to firing threshold in a context-sensitive manner; 2) This is a uniquely human adaptation for our ecological niche as environment modifiers. In ordinary tool use and manufacturing, dating back to Homo habilis, the built thing is smaller than the builder's body, but in environment modification, the built thing is larger than the builder's body—an important distinction. Thus, the builder can only see one part of it at a time. Viewings must therefore be interleaved with reorientations involving the eyes, neck, trunk, and feet. These reorientations, being motoric in nature, will be represented frontally, and I place these representations in the prefrontal cortex. The mental representation of the macro-built-thing therefore ends up being an interleaved collection of views and reorientations. <07-11-2021: In other words, a simulation.> The reorientations would have to be calibrated by the vestibular system to allow the various views to be assembled into a coherent whole. By this theory, consciousness is associated with environment modification.

05-24-2021: Consistent with this theory, the cortical representation of vestibular sense data is atypical. There is no "primary vestibular area." Rather, islands of vestibular-responsive neurons are scattered over the sensory cortex, distributing across the other senses. This seems analogous to a little annotation for xyz coordinates, etc., automatically inserted in a picture, as seen in computer-generated medical diagnostic images.

#61. Stress and Schizophrenia [neuroscience]

NE

Red, theory; black, fact.

Introduction

The main positive symptoms of schizophrenia, namely hallucinations, word salad, and loosening of associations, all seem to be variations of the latter, so loosening of associations will here be taken as the primary disorder. Stress and the brain's dopaminergic system are strongly implicated in the causation of schizophrenia. In connection with stress, psychologists speak of "the affective [emotional] pathway to schizophrenia." 

Organismal responses to stress

Stress is known to increase genetic variability in bacteria, a process known as transformation. Stress is likewise known to increase the meiotic recombination rate in sexually reproducing organisms such as fruit flies. (Stress-induced recombination and the mechanism of evolvability. Zhong W, Priest NK. Behavioral ecology and sociobiology. 2011;65:493-502.) It seems that when an organism is in trouble, it begins casting about ever more widely for solutions. If evolution is the only mode of adaptation available, this casting about will take the form of an increase in the size and frequency of mutations. In conscious humans, however, this casting about in search of solutions in the face of stress may well take the form of a loosening of associations during thought. Should the person find the solution he or she needs, then presumably the stress levels go down and the thought process tightens up again, so we have a negative feedback operating that eventually renormalizes the thought process and all is well. In optimization theory, this process is called "simulated annealing."

Disorder of a cognitive stress response

But what if the person does not find the solution they need? Then, presumably the loosening of associations gets more and more pronounced ("reverse annealing") until it begins to interfere with the activities of daily living and thus begins to contribute net stress, thus making matters worse, not better. Now we have a pernicious positive feedback operating, and it rapidly worsens the state of the sufferer in what is known as a psychotic break, resulting in hospitalization. That these psychotic breaks are associated with tremendous stress is made clear by the fact that post-traumatic stress disorder is a common sequel of a psychotic episode.

 

Stress: Molecular aspects

01-06-2020: Messenger substances (i.e., hormones and neuromodulators) known to carry the stress signal are: CRF, ACTH, cortisol, noradrenaline, adrenaline, dopamine, NGF, and prolactin. The well-known phenomenon of stress sensitization, <05-31-2020: which may be part of the disease mechanism of schizophrenia,> probably inheres in long-term changes in protein expression and will not be apparent in a simple blood test for any of the above substances without a prior standardized stress challenge. (Could that be the process of getting the needle itself? In that case, you would install a catheter through the needle to permit repeated blood sampling and collect the baseline sample long after the intervention sample, not before, as is customary in research.)

Other mental illnesses

05-31-2020: Bipolar disorder may result from an analogous positive feedback affecting another problem solving adaptation of the brain, which would be modelled by the alternation of brainstorming sessions (mania) with sessions in which the brainstormed productions are soberly critiqued (depression).

Brain mechanisms

12-04-2020: How does the loosening of associations of schizophrenia arise? I conjecture that one activated sensory memory represented in the posterior cortex does not activate another directly, but indirectly via an anatomically lengthy but fast relay through the prefrontal cortex, which has a well known dopaminergic input from the ventral tegmental area of the midbrain. Imagine that a higher vertebrate has a free-will spectrum, with machine-like performance and high dopaminergic tone at one end, and at the other, a carefully considered performance verging on overthinking, with low dopaminergic tone. Persons with schizophrenia have presumably pushed past the latter end of the spectrum into dysfunction. Dopamine could orchestrate movement along the free-will spectrum by a dual action on the prefrontal cortex: inhibiting associational reflexes passing back to posterior cortex while facilitating direct outputs to the motor system. Dual actions of neuromodulators are a neuroscientific commonplace (e.g., my PhD thesis) and dopamine is a neuromodulator. It remains to be explained how the NMDA receptor, which is also strongly implicated in schizophrenia, enters the picture. <03-07-2021: It could simply be the source of excitation of the ventral tegmental area.>

Photo by Ameer Basheer on Unsplash

#36. The Thought Process Through the Ages [evolutionary psychology]

EP

Red, theory; black, fact.

2-01-2018: An alternative title of this post could be: "Where religion possibly fits in the big scheme of things."

If politics and science seem like strange bedfellows, consider that ancient rulers used to consult astrologers before making major decisions.

In the beginning, there was theology. At some point, intellectual endeavor split into wrestling with reality questions vs. morality questions. Then they had to figure out when to go with your gut and when not to.

Thought sources	Inputs	Outputs (all insights):
		Reality (What is)	Blend	Morality (Thus…)
PGSd+sensory data	Emotion	politicsc		religionc
	Blend	astrologyb ^ v	< theologya >	Jewish lawb ^ v
Education+sensory data	Reason	sciencec		lawc

a. primordial condition

b. output distinction added

c. input distinction added

d. “post-zygotic gamete selection,” amateur theory of accelerated evolution purporting to explain God. See “Emotions” post on this blog.

2-23-2018: Just as emotion must not be allowed to contaminate scientific thought, is it equally true that reason must not be allowed to contaminate religious thought? Is failure to observe this restriction the cause of religious schisms?

08-03-2019: Thought-like processes dominated by emotion are believed to exist, e.g., the "emotional processing" of traumatic memories.