#69. Storming South [Evolution]

EV

Red, theory; black, fact.

This is a theory of the final stages of human evolution, when the large brain expansion occurred.

At least, they did. Sorry, I don't belong to this species. The Linnaean binomial literally means "wise man." What would be the Latin for "wise guy"?

Homo sapiens: created by ice

H. sapiens appears to have arisen from Homo erectus over the last 0.8 million years due to climate instability in the apparent origin area, namely East Africa. During this time, Europe was getting glaciated every 0.1 million years because of the astrophysical Milankovitch cycle, a rhythm in the amount of eccentricity in the Earth's orbit due to the influence of the planet Jupiter.

However, I am thinking of the hominins who had settled in Europe (or Asia, it doesn't matter for this argument) during the interglacial periods (remember that H. erectus was a great disperser) and when the ice began advancing again, were now facing much worse cooling and drying than in Africa, and thus much greater selection pressures. At least during the last continental glaciation, the ice cap only extended to the Baltic Sea at the maximum, but long before the ice arrives, the land is tundra, which can support only a very thin human population. In any given glaciation, the number of souls per hectare the land could support was relentlessly declining in northern Europe/Asia, and eventually the residents had to get out of Dodge City and settle on land further south, almost certainly over the dead bodies of the former owners. This would have selected Europeans or Asians for warlike tendencies and warfaring skills, which explains a lot of human history. 

Our large brains

However, our large brains seem to be great at something else besides concocting Games of Thrones: that is, environment modification. It's a no-brainer that the first thing someone living in the path of a 2-km wall of ice needs is to keep from freezing to death, and this would have been the first really good reason to modify environments. Unlike chipping a stone axe, environment modification involves fabricating something bigger than the fabricator. Even a parka has to be bigger than you or you can't get into it. This plausibly would have required a larger brain to enable a qualitatively new ability: making something you can't see all at once when it is at working distance.

Our rhythmic evolution

After parkas, early northerners might have evolved enough association cortex (maybe on the next glaciation cycle) to build something a little bigger, like a tent or a lean-to. On the next cycle, they might have been able to pull off a decent longhouse made of wattle. On the next, a jolly good castle surrounded by cultivated lands and drainage ditches. These structures would have delayed the moment of decision when you have to go and take on the Pleistocene-era Low-brows to the south. This will buy you time to build up your numbers, and I understand that winning battles is very much a numbers game. Therefore, environment modification skill would have been selected for in tandem with making like army ants.

Where is the fossil evidence for this theory?

Why do we not find fossil evidence of all this in Europe or Asia? <05-19-2022: Actually, we do: the Neanderthals and Denisovans, who have been difficult to account for in terms of previous theories of human origins.> My scenario can be defended against the inconvenient fossil evidence for a human origin in East Africa in general terms, by citing the well known incompleteness of the fossil record and its many biases, but, of course, I want details. Note, however, what else is in East Africa: the Suez, a land bridge to both Europe and Asia via the Arabian tectonic block, which was created by plate tectonics near the end of the Miocene, thus antedating both H. sapiens and H. erectus. Not only can hominins disperse through it to other continents during interglacials, but they can come back in, fiercer and brainier than before, when the ice is advancing again, to then deposit their fossil evidence in the Rift Valley region of East Africa. The Eurasian backflow event of 3000 years ago may be a relatively recent example of this. The Isthmus of Suez is low-lying and thus easily drowned by the sea, but the probability of this was minimal at times of continental glaciation, when sea levels are minimal. I assume that early hominins expanded like a gas into whatever continent they could access. Increasing glaciation/tundrafication of that continent would have recompressed the "gas" southward, causing it to retrace its path, partly back into Africa. 

Pleistocene selection pressures

To reiterate, this process would have been accompanied by great mortality and therefore, potentially, much selection. Moreover, during the period we are considering, temperatures were declining most of the time; the plot of temperature versus time has a saw-tooth pattern, with long declines alternating with short warming events, and it is the declines that would have been the times of natural selection of hominins living at high latitudes.

Plebius sapiens.

A limestone block in Canada showing scratches left by stones
embedded in the underside of a continental glacier.
The rock has also been ground nearly flat by the same process. Scary.

Glaciated boulder by night. Have a nice interglacial.

#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.

#67. The Trembling-Network Theory of Everything [physics]

PH

Red, theory; black, fact. 

I continue to mine the idea that the world of appearances is simulation-like, in that how we perceive it is strongly affected by the fact that our point of view is inside it, and illusions are rampant.

The slate-of-givens approach is intended to exploit consilience to arrive at a simplified physics that attributes as many phenomena as possible to historical factors and the observer's point of view. Simplified physics is viewed as a stepping-stone to the one, true TOE. The existence of widespread consilience implies that such exists.

The basic theory

The underlying reality is proposed to be a small-world network, whose nodes are our elementary particles and whose links ("edges" in graph theory) are seen collectively as the fields around those particles.

This network is a crude approximation to scale-free, but is structurally only a recursion of three generations (with a fourth in the process of forming), each comprised of two sub-generations, and not an infinite regress. The first generation to form after the big bang was a bunch of triangular networks that we call baryons. In the next generation, they linked up to form the networks underlying light atomic nuclei. These, and individual protons, were big enough to stably bond to single nodes (electrons) to form the network version of atoms. Above the atomic/molecular/electromagnetic level, further super-clustering took on the characteristics of gravitation, whose hallmark seems to be rotation. At the grandest cosmological scales, we may be getting into a fourth "force" that produces the foamy structure of galaxy distribution. The observations attributed to the presence of dark matter may be a sign that, at the intra-galactic scale, the nature of the "fields" is beginning to shift again.

I conjecture that throughout this clustering process, a continuous thermal-like agitation was running through all the links, and especially violent spikes in the agitation pattern could rupture links not sufficiently braced by other, parallel links. This would have been the basis of a trial-and error process of creation of small-world characteristics. The nature of the different "forces" we seem to see at different scales would be entirely conditioned by the type of clusters the links join at that scale, because cluster type would condition the opportunities for network stabilization by cooperative bracing. 

Reconciliation with known science

Formation and rupture of links would correspond to the quantum-mechanical phenomenon of wave-function collapse, and the endless converging, mixing, and re-diverging of the heat signals carried by the network would correspond to the smooth, reversible time-evolution of the wave-function between collapses. The experience of periodic motions would arise from resonances in closed paths embedded in the network. When you see the moon move across the sun in an eclipse, <11-27-2020: no net links are being made or broken; the whole spectacle somehow arises by an energetically balanced creation and rupture of links.>

The photoelectric effect that Einstein made famous can be given a network interpretation: the work function is the energy needed to simultaneously break all the links holding the electron to the cluster that is the electrode, and the observation of an electron that then seems to fly away from the electrode happens by calculation in the remaining network after it has been energized by heat-signal energy in excess of that needed to break the links, reflecting back into the network from the broken ends.

How distance would arise

All the ineffably large number of nodes in the universe would be equidistant from each other, which is possible if they exist in a topological space; such spaces have no distance measure. I think it likely that what you experience as distance is the number of nodes that you contain divided by the number of links connecting the cluster that is you with the cluster that you are observing. It remains to figure out how some of the concomitants of distance arise, such as delay in signal transmission and the cosmological redshift.

Reconciliation with the finite speed of light

11-01-2020: The time-delay effect of distance can be described by a hose-and-bucket model if we assume that all measurements require link breaking in the observer network. The energy received by the measuring system from the measured system is like water from a hose progressively filling a bucket. The delayed overflow of the bucket would correspond to the received energy reaching threshold for breaking a link in the observer network. The fewer the links connecting observer to observed relative to the observer size (i.e., the greater the distance), the slower the bucket fills and the longer signal transmission is observed to take.

11-02-2020: The above mechanism cannot transmit a pulsatile event such as a supernova explosion. It takes not one, but two integrations to convert an impulse into a ramp function suitable for implementing a precise delay. Signal theory tells us that if you can transmit an impulse, you can transmit anything. The second integration has already been located in the observer cluster, so the obvious place in which to locate the first integration is in the observed cluster. Then when the link in the observer cluster breaks, which is an endothermic event, energy is sucked out of both integrators at once, resetting them to zero. That would describe an observer located in the near field of the observed cluster. In the far field, the endothermic rupture would cool only the observer cluster; most of the radiative cooling of the observed cluster would come from the rupture of inter-cluster links, not intra-cluster links. Thus, hot clusters such as stars are becoming increasingly disconnected from the rest of the universe. This can account for the apparent recessional velocity of the galaxies, since I have conjectured that distance is inversely proportional to numbers of inter-cluster links.

Predictions of the fate of the universe

We often hear it said that the reason the night sky is black is that the expansion of the universe is continuously creating more space in which to warehouse all the photons emitted by all the stars. However, the network orientation offers a simpler explanation: inter-cluster links at the grandest scale are being endothermically destroyed to produce the necessary cooling, and the fewer these become, the longer the cosmological distances appear to be. I suppose that when these links are all gone, we all cook. The microwave background radiation may be a harbinger of this. Clearly, my theory favours the Big Rip scenario of the fate of the universe, but a hot Big Rip.

Accounting for the ubiquity of oscillations

05-01-2021: At this point, an improved theory of oscillations can be offered: Oscillating systems feature 4 clusters and thus 4 integrators connected in a loop to form a phase-shift oscillator. These integrators could be modeled as a pair of masses connected by a spring ( = 2 integrators) in each of the observer and observed systems ( = 2 x 2 = 4 integrators).

Motion and gravity

11-30-2020: Motion would be an energetically balanced breaking of links on one side of a cluster and making of links on the other. This could happen on a hypothetical background of spontaneous, random link making and breaking. Acceleration in a gravitational "field" would happen if more links are coming in from one side than the opposite side. More links will correspond to a stronger mutual bracing effect, preferentially inhibiting link breaking on that side. This will shift the making/breaking equilibrium toward making on that side, resulting in an acceleration. <12-11-2020: The universal gravitational constant G could be interpreted as expressing the probability of a link spontaneously forming between any two nodes per unit of time.>

Dimension and direction

01-13-2021: It is not clear how the direction and dimension concepts would emerge from a network representation of reality. If distance emerges from 2-way interactions of clusters, perhaps direction emerges from 3-way interactions and dimension arises from a power law of physical importance versus the number of interacting clusters in a cluster of clusters. This idea was inspired by the fact that four points are needed to define a volume, three are needed to define a plane, and two are needed to define a line.

02-13-2021: Alternatively, angle may be a matter of energetics. Assume that new links form spontaneously at an unalterable rate and only link rupture rate varies. The heat injected by link creation must be disposed of by a balanced rate of link rupture, but this will depend in detail on mutual bracing effects. If your rate of rupture of links to a given cluster is minimal, you will be approaching that cluster. The cluster with which your rupture rate is highest is the one you are receding from. Clusters with which you score average rupture rates will be 90 degrees off your line of travel. The distribution of clusters against angle is predicted from geometry and the appearance of the night sky to be proportional to sin(θ), but a random distribution of rupture rates would predict a bell curve (Gaussian) centered on the average rupture rate. Close, but no cigar. The tails of the Gaussian would produce a sparse zone both fore and aft. Moreover, since there must always be a maximum and minimum, you will always be heading exactly toward some cluster and exactly away from some other: not what we observe.

03-06,07-2021: That the universe is spatially at least three-dimensional can be reduced to a rule that links do not cross. Why the minimum dimensionality permitted by this rule is the one we observe remains to be explained. 

Momentum

Momentum can be explained by attributing it to the network surrounding a cluster, not to the cluster itself. Heat must flow without loss (how?) from in front of a travelling cluster around to the rear (I hope eventually to be able to purge this description of all its directional assumptions), suggesting closed flow-lines through the larger network reminiscent of magnetic field lines. (This is similar in outline to Mach's explanation of momentum, as being due to the interaction of the test mass with the distant galaxies.) It seems necessary to postulate that once this flow pattern is established, it persists by default. An especially large cluster in the vicinity will represent a high-conductivity path for the heat flow, possibly creating a tendency for links to form perpendicular to the line of travel and offset toward the large cluster, which might explain gravitational capture of objects into stable orbits. Finally, the overall universal law would be: heat of link formation = heat of link rupture + increases in network heat content due to increases in network melting point due to increases in mutual bracing efficiency. A simple concept of melting point is the density of triangles in the network. Still to be explained: repulsive forces.

Repulsive forces

04-04-2021: Repulsive forces are only seen with electromagnetism and then only after a local network has been energized somehow. When particles said to be oppositely charged recombine, neutral atoms are re-formed, which creates new triangles and thus increases melting point. The recombination of particles said to be of like charge creates relatively few triangles and is therefore disfavored, creating the impression of mutual repulsion.

 

More on the origin of momentum

Inter-cluster links are not individually bidirectional in their heat conductivity, but a (usually) 50:50 mixture of unidirectional links going each way. Momentum and spontaneous First Law motion become prevalent in classically-sized networks due to small imbalances in numbers of cluster A to cluster B links versus cluster B to cluster A links. This produces a random pattern of spontaneous heat flows across the universe. Converging flows burn out links (and are thus self-limiting) and diverging flows preserve links, causing them to increase in number locally. This process nucleates the gravitational clumping of matter. A directional imbalance in the interior of a cluster causes First Law motion by spontaneously transporting heat from front to back. Front and back are defined by differences in numbers of inter-cluster links (to an arbitrary external cluster) among subsets of cluster nodes.

Case study of a rocket motor

For a rocket motor to work, we have to assume that one of these asymmetrical links can only be burned out by heat applied to its inlet end. During liftoff, the intense heat down in the thruster chambers burns out (unidirectional) links extending up into the remainder of the craft. This leaves an imbalanced excess of links within the rocket body going the other way, leading to a persistent flow of heat downward from the nose cone. This cooling stabilizes links from overhead gravitationally sized clusters ending in the nose cone, causing them to accumulate, thereby shortening the "distance" from the nose cone to those clusters. Meanwhile, the heat deposited at the bottom of the rocket progressively burns out links from the rocket to the Earth, thereby increasing the "distance" between the rocket and the Earth. The exhaust gasses have an imbalanced excess of upward-directed asymmetric links due to the temperature gradient along the exhaust plume that serves to break their connection to the rocket and create the kind of highly asymmetrical cluster required for space travel. <04-11-2021: The details of this scenario all hang together if we assume that link stabilization is symmetrical with link burnout: that is, it is only responsive to what happens at the inlet (in this case, cooling).> Since kinetic energy is associated with motion, the directional link imbalance must be considered a form of energy in its own right, one not sensible as heat as usually understood.

Future directions

05-28-2021: To make further progress, I might have to assume that the links in the universal network are the real things and that the nodes are just their meeting places, which only appear to be real things because this is where the flow of energy changes direction. I then assume that all links are directional and that pairing of oppositely-directed links was actually the first step in the evolution of the universe. Finally, I decompose these directional links into an inlet part joined to an outlet part. With this decomposition, a link pair looks like this:

⚪⚫

⚫⚪

Notice the interesting ambiguity in how to draw the arrows. A purely directional link recalls the one-way nature of time and may represent undifferentiated space and time. A final decision was to treat a repulsive force as a link whose disappearance is exothermic, not endothermic, because this indirectly allows the formation of more of the default kind of link.

#66. Neuromodulators as Peril Specialists [Neuroscience]

NE

Red: theory; black, fact.

Solanum dulcamara, a plant with anticholinesterase activity.

“Life is Difficulty”

My PhD thesis was about a neuromodulator (acetylcholine) acting on mammalian brain. It was tough to decapitate all those rats; I never got used to it. But if you can’t stand the formaldehyde, get out of the lab.

The basic theory

I conjecture that the primordial function of any type of transmitter substance acting on the g-protein-coupled cell-surface receptors or nuclear receptors of neurons was to coordinate the whole-organism response to some class of perils.

 

Complications

Glutamate, GABA, and acetylcholine are usually considered neurotransmitters, not neuromodulators, but all three have G-protein-coupled receptors in addition to ionotropic receptors and are thus both.

In thermoregulation, hypothalamic glutamate and GABA act on the body via the serotonergic raphe pallidus nucleus. The implied connection with predation (See table) would be due to the fact that animals become torpid at extremes of temperature and thus easy prey. The larger predator would have a smaller surface to volume ratio and thus slower warming and cooling after leaving its refugium to hunt. The predator thermal advantage would have been the selection pressure for thermal sensitivity in the anti-predation system, which eventually became upstream of temperature regulation effectors generally. 

The functional assignments suggested in Table 1 would mostly pertain to a very primordial brain. The implication is that any modern biological function of the neuromodulator substance other than organizing the response to a specific type of peril was elaborated out of the primordial function over long-term evolution, which can act opportunistically to confer new functions on preexisting adaptations.

An example of such elaboration is shown for dopamine in the inferred social role. A pre-adaptation for this role split may have been breast-feeding.

Table 1.

Peril	Substance	Failure mode
Extremes of heat and cold	glutamate and GABA	?
Predator	serotonin	depression
Parasite	histamine	phobia
Rival conspecific	noradrenaline	paranoia
Social isolation

#65. Baryogenesis [physics]

PH

(Part 5, Deprecated)

#64. The Drill Sergeants of the Apocalypse [evolutionary psychology, population]

EP     PO     

Red, theory; black, fact.

Seen in a hospital ward.

Updated 10-30-2024

The trickster type may really be a penetration tester. 

The type probably emerges in contexts of unequal power (Elmer Fudd has the shotgun; Bugs Bunny doesn’t). Thus, an abiding fear is the soil out of which tricksterism grows, by the following positive feedback:

A successful trick shows up the Fudds and shows them in a feckless light, which reduces the fear level of the trickster, which reinforces trick-playing. This is a short-term high that comes at the expense of worse relations with the Fudds and thus eventually even greater fear levels for the tricksters, which they try to remedy with still more tricks.

An example of an unequal power relationship is between a foreign invader and the defenders. Invasion is such a common event in history that by now, countermeasures will have evolved. Tricksterism is likely to be a tile in the mosaic of any such adaptation.

A biological precedent for penetrations testing?

Evidence for a biological precedent may be the many retroviruses integrated into the human genome. Presumably, one of these becomes active now and then at random and kills the host cell if the anti-viral defenses of the latter have become weak due to some somatic mutation. The red team-blue team strategy seems to be too good a trick for nature to miss (TGTNM).

Evolution of the trickster

09-27-2020: Modern human populations may have two (independent?) axes of political polarization: oppressor-oppressed and trickster-control freak. The first may sub serve dispersal by generating refugee groups and the second may sub serve building. Any built thing must serve in a complex world in which many constraints must be simultaneously observed. Thus, after the initial build, a long period of tweaking must typically follow. The role of the tricksters is to powerfully motivate this tweaking before the complacency of the control-freak builders leads to disaster. <03-12-2021: This may have been how engineering was done by an archaic version of Homo sapiens.><12-02-2022: The tricksters can also make mistakes, causing damage that cannot have a silver lining in any possible world, and moving to correct this is a natural role of the builders. If you are a builder, ask this: “What is the best use of my indignation?” It is to keep to a strict harm-reduction approach.><01-08-2024: Tricksterism can intensify into sadism, in which the protagonist takes pleasure in the victim’s torment and wants to make it last. Well, boy, if you make it last, you are giving the victim plenty of time and motivation to figure out solutions, like a patient old instructor giving his pupil his lessons one at a time, as he is ready for them, and this is how the wise victim will construct the situation. Such a victim will end up with information and know-how others will pay for.>

A tangent about our evolutionary context

Our evolutionary forebears may have been champion dispersers for a long time <12-21-2020: i.e., Homo erectus*> before the ice age** forced some of them to become champion builders (initially, of shelters and warm clothing). <12-31-2020: "champion environment modifiers" may be closer to the mark than "champion builders"> It is an interesting fact that physically, humans exceed all other animals only in long-distance running, which can be read as dispersal ability. Our carelessness with preserving the local environments and our propensity for overpopulation can be read as typical r-selected disperser behavior. <12-21-2020: The r-selecting niche was probably big game hunting. H. erectus sites indicate consumption of medium and large meat animals. Overhunting would have occurred routinely, due to the slow reproduction rates of large animals and the high hunting efficiency of H. erectus due to tool use, so that dispersal of the hunters to new habitats would likewise have been routine.>

* H. erectus: lived 2 million years ago to 100,000 years ago. H. sapiens: earliest fossils, 300,000 years old. Evidence of behavioral modernity: 100,000–70,000 y ago.

** that is, the Pleistocene ice age, itself a sequence of 5 successive continental glaciations (by oxygen isotope evidence) separated by temperate periods, starting 2.6 million years ago and thought to be not over yet. Over the past 800,000 y, continental glaciation has happened rhythmically on a 100,000-y cycle due to astronomical factors (Milankovitch cycle). Selection for building skill may therefore have occurred in multiple successive episodes over the course of the Pleistocene.

#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