#56. 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

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, 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. (e.g., 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

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

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. A higher vertebrate may have 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 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. The NMDA receptor, which is also strongly implicated in schizophrenia, enters the picture as the source of excitation of the ventral tegmental area.

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#55. Gender is Pecking Order [evolutionary psychology]

EP

Red, theory; black, fact

Gender is pecking order

Gender, social status, and testosterone are clearly interrelated, but exactly how requires clarification when the very nature of gender is in question, as now. One possibility is that the male pecking order sits directly atop the female pecking order, and there is no barrier between. Thus, a male who falls low enough in the male pecking order will undergo a reversal in gender identification from male to female (and maybe keep on going down) and a female who rises high enough in the female pecking order will likewise undergo a reversal in gender identification from female to male (and maybe keep on going up). The entire structure could be called "the" pecking order, with the statistical median of the status ranks, and possibly the ranked testosterone levels, always dividing females from males, at least in terms of gendered social signaling. This could be an example of what is called an exact theory replacing its approximate counterpart. In this case, the corresponding approximate theory would be the gender binary. ("You are either a man or a woman.") 

A limitation of this “median theory” is that no causative mechanism is provided.

Recent history of trans

Since the early Sixties, we have seen a trend of increasing media exposure of trans and non-binary individuals, and this was also a period of ever-increasing human population numbers. I conjecture that the latter trend caused the former. The population trend may have produced an upward trend in the average population density at which people are living, suburban expansion notwithstanding. This may have caused an increasing incidence of aggressive one-on-one interactions among humans due to the Calhoun effect, which is much discussed in these pages. See post #36. Aggressive, one-on-one interactions are well known to change the social status of the combatants, the winner enjoying increased status (i.e., a higher ranking in the pecking order) and the loser suffering reduced status. Overall, population density increases can thus be expected to increase the amount of traffic on the social ladder, both upward and downward, leading to increasing numbers of individuals crossing the median and becoming trans or nonbinary. The increasing numbers of trans and nonbinary individuals in society was then faithfully reflected in the content of the news stories of the day. QED.

Trans not genetically determined

Consistent with this, PLOS blogger R. Lewis, who has a PhD in genetics, found remarkably little evidence of a direct genetic causation in transgenderism. Moreover, out of 58 studies on "transgender" listed on clinicaltrials.gov, nothing worth mentioning was found about genetics. This could be an instance of the filing-drawer effect (negative results not published but left to languish in the filing cabinet).

How pecking-order dynamics may lead to dispersal and a mechanism 

I am indebted to Jordan Peterson for turning me on to the pecking-order idea. It can explain aspects of dispersalism, as follows: If people have no emotional memory of their social wins and losses, we would expect their distribution on the social ladder to be Gaussian (aka, a bell curve). However, if a win or loss leaves you with an emotional residue of optimism or pessimism (and, of course, it does), a positive feedback can set in if conflicts are coming faster than the emotional fallout from each can dissipate, so that the more you lose, the greater your pessimism, and the more likely you are to lose in the future. Moreover, the more you win, the greater your optimism, and the more likely you are to win in the future. (Following Peterson, this emotional fallout effect may be due to prolonged up- and down-regulations of serotonin concentrations in the brain.) This dynamic then splits the population into a bi-modal social distribution, resulting in dispersal when most of the underdogs become refugees. Those who remain conceal their potential to reproduce (and thus compete) in gay-trans relationships. The frequency of conflicts could be measuring population density, and the conflicts would not necessarily be over resources, but over proxies for these such as land or jobs. With the addition of these ideas, the splitting and separation of overcrowded rodent populations in the behavioral-sink phase of a Calhoun experiment is explained. To connect these ideas with my earlier idea of the sadness cycle, I conjecture that sadness and its attendant social signaling expresses anger colored by pessimism about winning, whereas contempt and its social signaling expresses anger colored by optimism about winning.

 

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# 54. Disaster Biology [evolution, evolutionary psychology]

EP    EV 

Red, theory; black, fact

The habitat may have been a unit of selection in early hominins, leading to group selection, and much of our evolution may have proceeded by an accumulation of founder effects.

Opportunities for colonization of recently-emptied habitats are ephemeral. Under disaster-prone conditions, this plausibly leads to selection pressure for migrant production and evolvability (i.e., a high rate of evolution, especially founder-effect evolution).

Language diversification in humans may be an evolvability adaptation. Language diversity would work by preserving genetic founder effects from dilution by late-coming migrants, whose reproduction would be held back by the difficulties of learning a new language. Xenophobia and persistent ethnicity markers can be explained in the same way. The spread of linguistic and cultural novelties in a hominin population is predicted to be especially fast in newly colonized, previously empty habitats. Alternatively, the linguistic novelties may start as a thick patois developed by an oppressed group in the home habitat prior to becoming refugees, as a way to make plans "under the noses" of the oppressing group.

Refugee-producing adaptations sub-serving dispersal can be called "tough altruism." Populations producing more refugees are more likely to colonize further empty habitats, a selective advantage.

Disaster biology may be what is conceptually missing from theories of the origin of life (abiogenesis). i.e., the forerunners of the first cells may have been spores that formed by budding from the surface of bodies of water.

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