Essay: Brain Genesis and the Frontal Cortex : An Approach/Avoidance Model

Reference & EducationCollege & University

  • Author Robert Depaolo
  • Published January 18, 2023
  • Word count 4,324

Abstract

This article discusses the structure, function and systemic nature of brain evolution, as a mechanism operating on two levels: one devoted to address the demands of the external environment, the other to maintaining internal stasis with emphasis on how approach/avoidance dynamics. Within that framework There is a particular focus on the functions of the frontal cortex. The case is made that while various structures in the brain seem to correlate with specific functions, such as motor control, speech and memory the evolution of the frontal cortex created a diversion from functional specificity toward what is referred to here as a "interference." By virtue of its mass and broad neural connectivity this circuit is believed to have increased neuropsychological "noise" that resulted in a filtering, streamlining effect that ultimately enhanced self-talk regulatory functions, the curiosity drive, general intelligence and the brain's overall integrative capacities.

A Neural Threshold...

The advent of brains seems to have occurred on two levels. With the advent of metazoans (a class that includes jellyfish) there was a capacity to perceive general sensory inputs and either move toward or away from them. While their primitive nerve nets are generally assumed to have provided simple stimulus response connections it might well have involved more than that. In order to move toward or away from stimuli those organisms had to determine on some level whether these stimuli were to be approached or avoided. Certainly, coming close to the stimulus would have inflicted a state of discomfort, thereby creating a reflexive response requiring no memory or sense of anticipation. However, such encounter-and-react immediacy would not have augured well for long term survival. Eventually memory was required.

In fact, all neural structures have several functions. They must have either memory or some inborn template by which to determine the good from the bad. They also must have some capacity to register an adaptive response in memory, whether it be a successful evasive maneuver or approach or appetitive response leading to satiation. In other words, there has to be feedback.

While that seems to suggest the evolution of nerve nets and, subsequently, brains was a complex evolutionary process there might have been a central mechanism involved that governed all neural structure, especially since the general structure of neurons has not changed very much over time.

As Ross Ashby wrote, one aspect of that template would be for the brain to function as a homeostat. (Conant 1981). It must operate on two levels: one devoted to addressing the outside environment, the other concerned with maintaining internal stasis. It is, after all part of the body, and the body is a homeostat whose fundamental purpose is to sustain equilibrium. Whether in the form of temperature regulation, emotional composure, control of arousal levels, heartbeat, breathing or blood pressure, one physiological mandate is to keep physiological parameters within normal ranges. That in turn involves being able to set and adjust the internal gauges and recognize deviations from the gauges. Only through those capacities can an organism operate efficiently, meet its needs, eat and drink just enough to reach satiation, and prompt arousal and activation levels commensurate with (but not exceeding) the demands of any given task.

While larger and more complex than any other brain the human brain likely adheres to that same set of principles. This seems true even with respect to the highest of brain centers in the cerebral cortex, and to the most recently evolved frontal and prefrontal lobes

Transcendent Regulation...

One of the more common descriptions of frontal lobe activity involves regulation, specifically the capacity of the frontal cortex to influence and/or control various functions and structures in the brain. This assumption is based partly on the fact that the frontal cortex has more connections to other structures than any other brain site (Rojkova, Volle et al. 2016). Since almost much neural activity must pass through it. It seems to be a gateway leading from global reactivity to fine-tuned responses.

Still another factor on its pan-influence is that it contains heavily myelinated neural pathways - myelin being an insular fatty layer encasing neurons and fibers that dampens the impact of stimulation. That same insular quality facilitates faster transmission from cell to cell. In other words, the myelin sheath serves to enhance neuro psychological focus by overriding distractions and the emotional noise that would arise from the primal impulses emanating from the limbic and reticular activation systems.

All of that makes sense in strict neurological terms. Yet further examination of that process seems a bit more complex, especially when one takes into account the randomness of brain evolution.

Brains did not evolve to "do this or that" They simply evolved as expanded mutations of primitive nerve nets that served to alert primitive organisms to stimulus attractions such as beneficial heat, light and nutritive sources and to aversive stimuli such as freezing or extreme heat. In other words, nervous systems likely arose as energy sensing tissues and simply expanded through protein synthesis (Kaas 2013). Just as generations of organisms tend to be larger than previous generations so do clusters of protein. This occurred happenstance in living organisms and became adaptive because the tissue growth (being necessarily comprised of electrochemical properties) provided the life sustaining capacity for approach and avoidance behaviors.

Psychologist Theodore Millon has argued that the approach/avoidance mechanism is entrenched in all brains and in effect defines the essential make up of all brains and of the personality (1990). The idea is that the technology, art, cognitive and language capacities of the human brain are increasingly complex manifestations of primary approach-avoidance (or pleasure/pain) sensing mechanisms. This suggests the fundamental nature of brains has not changed throughout the course of evolution and that the modifications in brains over time have largely been variations on a theme.

At face value, that assumption might seem simplistic. Indeed, it is hard to explain how such a binary model could lead to the complex, regulatory, linguistic, imaginative tendencies of the frontal human brain. For instance, In conjuring up the special and general relativity theories was Albert Einstein simply engaged in a pleasure/pain experience? Furthermore, are various aspects of religious worship, including the frontally facilitated capacities for morality, guilt and transcendent beliefs nothing more than enhanced versions of approach/ avoidance behaviors?

This offers a dilemma. On one hand, whittling human progress down to behavior patterns not fundamentally different from those of metazoa might seem absurd. On the other hand, if the central nervous system evolved as an energy sensing approach/ avoidance organ why would this process change its basic nature in the course of evolution?

For example, the GI tracts of simple and complex organisms all serve to digest nutritive substances and eliminate waste. The GI tracks of a human and a tree shrew look different but both act the same. The eyes of an octopus and a tiger look different but both provide vision.

If the basic structure of neurons was different among various organisms one could argue against a binary model. But neural transmission occurs via the sodium pump mechanism for all encephalized creatures. And while there are different types of nerve cells even within the human brain they obey essentially the same reactive principles.

An interesting aside has to do with evolution itself. If, as Darwin suggested there is no a priori "purpose" to evolution and that mutations resulting from the probabilistic reshuffling of genetic pairings are selected by nature for adaptation or extinction, then it is difficult to explain how something as wondrous as the brain could simply 'crop up" by accident. One possible explanation is that brains did not arise from a random process, i.e. an accidental growth of neuronal tissue. Rather, their existence might have simply been consonant with how nature works; their emergence being inevitable even if their conglomerations and functional, integrative tendencies required an evolutionary boost.

Nature, particularly the biotic world is comprised of petrochemical properties and interactions. All of its makeup, its reactions. Its energy principles are a function of energy sensing processes. Thus, the prototype of brains could be said to be everywhere in nature. Consequently, any organ arising in the most primitive life forms would have had to obey the same petrochemical properties as everything else in the cosmos. It would have to send signals regarding when and how to move toward and away from attractions and aversions. Absent that capacity the entity could not survive.

While, the approach/avoidance, energy sensing process might seem overly simplistic, it is actually quite complex because it has systemic regulatory implications. Once brains increased through the addition of more neural clusters the basic approach/avoidance mechanism began to provide redundancy. One layer of neural tissue could create approach or avoidance behavior, while a second layer could register that reaction in memory until such time as the increasingly complex layers of neural tissue became able to predict and anticipate when, where and how attractions and aversions could occur.

From the Simple to the Complex and Back...

Resolving the question of how a simple, binary brain model could lead to human intelligence and creativity would seem important because such an explanation might help resolve the enduring question of how the brain works - something that has not yet been determined.

One potential answer is simple, particularly in evolutionary terms. One could simply assume the brain has not changed with time; that evolution did not make it different, merely larger in certain species. While much of brain growth would have been devoted or orchestrating the movements of increasingly large creatures, as with many types of organic tissue it expanded over time in random manner - perhaps influenced by changes in sunlight, general climate and reinforced by environmental challenges but nonetheless without a predetermined purpose. It is conceivable that its size led to the advent of human cognition including the vast, regulatory functions of the frontal lobes.

To explain how this could occur requires a diversion from neurology to Information Theory. This theory is based on a mathematical/conceptual formula first developed by Claude Shannon. (1998). Its most basic principle holds that information cannot exist on its own, can only be extracted from a prior state of uncertainty.

For example, holding a coin in one hand provides no information about whether flipping it will result in heads or tails. In the person's hand the coin is mere noise - or uncertainty. Only after flipping it and observing the result can information be obtained. It will either be heads or tails. Because there are two possibilities, reducing it down to one will have provided one bit of information. If there are ten coins in the person's hand and all are flipped simultaneously the result would be ten bits of information - in other words ten reductions of uncertainty. This suggests that as any entity expands, so will its level of uncertainty, which means its capacity to provide information will increase accordingly.

A Trip Along the Neural Pathways...

The approach/avoidance brain model seems consistent with the various functional pathways leading from the hind brain to the mid brain. The system branching up from the spinal cord (typically referred to as the reticular activating system (R.A.S) summons general arousal for purposes of alerting the brain to stimulus inputs. The R.A.S. is active during contemplation, problem solving, during periods of duress and heightened emotional states. The fact that the R.A.S sends signals regarding the onset and termination stimuli puts it directly within the approach/avoidance domain because those signals also accompany arousal and resolution or satiation.

Another circuit, a massive cluster of neurons called the cerebellum is situated in the occipital or rear section of the brain. It is concerned with two main factors; motor stability and what is often referred to as automaticity (meaning a capacity to make action memories so entrenched in mind that no matter how complex, they can be performed without deliberation (Han 2020). Having such a neuro-functional anchor point not only enables the person to react automatically but, due to its motor and cognitive stabilizing functions, allows the responder to take responses for granted. That too serves to ameliorate the stress and strain involved in juggling motor, sensory and cognitive balance while searching for responses. It facilitates both approach and avoidance behaviors, particularly in urgent situations.

The cerebellum has often been referred to as the brain's computer but it might more accurately be likened to gauge function - like a home thermostat that maintains a reprogrammed temperature despite the weather outside, or homeothermy in a warm blooded mammal that retains a constant body temperature despite climatic vagaries. All of those functions serve to remove input barriers and enhance the capacity to move toward attractions and avoid aversions.

As one moves up to the mid brain, particularly the limbic system, the approach/avoidance process seems even clearer. Circuits such as the hypothalamus, amygdala, septum and hippocampus all function to either seek pleasure (to address sexual or nutritive appetites), avoid danger and pain or, in the case of the hippocampus, to register in memory the onset of stimuli and responses dealing with those phenomena.

A more difficult task comes in trying to attribute the complex functions of the cerebral cortex to the basic approach/avoidance model. This is particularly true with regard to the frontal cortex.

The frontal lobe is the most recently evolved part of the human brain. It is often viewed as functionally separate from, yet structurally entwined, not just with the vast neural circuitry of the remaining cerebral cortex but with virtually all the brain. While the cortex supports capacities such as fine motor precision, vision, hearing, and language through interaction with the frontal lobe the latter is assumed to have more abstract, non-specific functions; for example, self-regulation, impulse control, anticipatory cognition, even providing the capacities for guilt, a sense of self and moral thinking.

However, if one looks beyond conventional thought it is possible to see the cortex and neocortex (the frontal lobe) as providing basically the same purposes, albeit in escalated fashion. They are all ostensibly "colander circuits," whose growth over time fine-tuned the lower brain functions via inhibitory, myelinated neural structures. In simpler terms, the high volume of neurons in the cortex and neo cortex provided, among other things, interference activity along the complex pathways of the brain. Due to this process gross motor responses were streamlined in the parietal cortex so that the fingers and tongue movements could become more refined and subtle. The visual cortex in the occipital lobe (the rear portion of the cortex) was able to make finer distinctions among visual stimuli and the same is true of the temporal lobes with regard to hearing.

In that context, resolution to the question of how the evolution of brain tissue could, in accord with natural selection have no a priori "purpose" yet turn out to be so purposeful as to create intelligence can be found by assuming the massive cluster of neurons in the cortex became an evolutionary filtering mechanism that in a sense could tease out response subtlety from overreaction, over exertion, inhibit the unbridled expression of emotional and appetitive inputs and put things like potential danger into enough perspective so that human beings could guard against behavioral over inclusiveness and thereby conserve neuropsychological energy. In other words, it is possible to view the various and wondrous faculties provided by the human brain in terms of what Darwin referred to as adaptive conversions.

Still although a fine-tuning, neural interference premise seems to support the notion of an approach/avoidance brain model the complexity of human language offers a potential contradiction - or is that quite true?

Human language is so complex as to appear virtually transcendent. Yet the neural systems that give rise to it resulted from an evolutionary process. Its sheer complexity, juxtaposed on natural selection raises an interesting question. Is it biologically derived or "something different." Linguists such as Noam Chomsky (Theodore 2020) and Benjamin Whorf (Subbing 2005) have offered opinions on its structure and origin but few theoreticians have opined about the true biological roots of human language.

One place to start would be by acknowledging the fact that virtually all organisms have some sort of vocal-communicative capacity. This is especially true with primates. For example, chimpanzees, our closest genetic relatives use about 20 different sounds to signal the presence of snakes, other predators and imminent dangers. They do not apparently use language to comment on one another, other than by their presence or absence (they do seem to express sadness at the death of a family member (Sarusi 2019). For the most part their language is based on the approach/avoidance dynamic. It comprises a warning and gratification signal system.

The fact that neither chimps nor any other primate can use language in the myriad ways humans do raises the question as to whether there is a fundamentally biological aspect to human speech. I believe there is.

Before explaining - a return to the streamlining/interference process. To wit; how can human language be considered a streamlined version of the howling, hooting, panting vocalizations of chimps? Part of this can be explained in terms of anatomical evolution. With upright posture came a lowering of the diaphragm and realignment of the larynx and hyoid bone in the throat. Those changes enabled human ancestors to prolong sound making, making expression last longer. That in turn gave the early human time to extend vowels and conjure up a sing-song type of expression far more melodic than other primates and to include greater emotional content in their vocalizations. It is true that bonobos, gibbons and other primates can engage in lengthy sound making (so to can whale for that matter). However, they cannot whittle down the sounds to a great enough point of differentiation to create high information volume. Due to the vastness of the cortex and neocortex, humans can. The sheer volume of neural (frontal) tissue thus uses its typical interference effect to produce subtlety and nuance.

Also, since the prefrontal cortex features even more inhibitory pathways and enhanced myelination in the nerve cells, language and communicative sound making can be streamlined to such an extent as to facilitate an internal thought process, including the capacity for covert self- talk and self-regulation. Humans can then look within. self- monitor, self-criticize, plan well before acting, anticipate and worry.

Internalization and worry are the keys. With internalization comes the capacity to consider what might go wrong, what others think about you in light of statements you make or behaviors you submit. Anticipatory processing within the circuitry of the frontal lobe will be fairly chronic and require fairly constant resolution. In that instance the frontal lobe is not concerned with avoiding lions and tigers or with pursuing game or other pleasures but it is concerned with regulating the internal turmoil arising from the neurological uncertainty and arousal created by conflicting, worrisome inputs that require resolution. Thus, while the mid brain and limbic system specifically are concerned with approaching and avoiding of tangible objects and events the higher brain centers operate by the very same dynamic. However, instead of fleeing from and approaching objects (which entails an uncertainty/resolution dynamic) they are concerned with the satisfaction that derives from resolving an internal conflict and with avoidance or discontinuation of arousal levels resulting from uncertainty.

Perhaps the most significant challenge to the approach/avoidance hypothesis can be contained in the question; What does everyday conversation among people have to do with such a binary model? It is not an easy question to answer but there are possibilities.

First, begin by examining human language development; in this case the child's first attempts to communication - pointing. Why does the infant point at objects and direct his observation at adults? The reason seems to be twofold. One is because he seeks to interact with another. A second reason is that the child is seeking confirmation of his perception and trying to resolve something in his own mind, for example .... "Is what I see the same as what others see?."...or "Are you as interested in what I see as I am." The child is attempting to resolve a conflict by establishing mutuality between brains.

The attempt at closure and mutuality reflects the same approach/ avoidance process seen in more urgent situations. There is a temporary, mildly discomforting disagreement within the brain (i.e. an unresolved question) that requires closure to alleviate the temporary duress.

On a very basic level all language interactions are attempts to obtain information and are, by definition, attempts to resolve uncertainty. It follows that all language is most fundamentally an exercise in conflict resolution, and therefore geared toward the avoidance of discomfort and the search for pleasurable resolution.

Arguably. The same process could be involved in almost any conversation. For example, when person A says something to person B he is actually engaged in an interrogatory. He is perhaps (and covertly) asking: "Does the listener want to know what I have to say?" Will he approve or be interested in the subject matter? "Will my statement enhance or detract from my status and reputation?" Will I seem intelligent or dull. Entertaining or boring?" All of this is included in any human interaction. That suggests every interaction, no matter how assertive is really a question and thus entails some level of uncertainty. That means the speaker is always in the final analysis, using speech to avoid discomfort and create satisfaction resulting from resolution.

While this hypothesis is speculative there is some anecdotal evidence to support it. Researcher Daniel Berlyne studied the effects of what he called 'conceptual conflict' and its impact on language and cognition - particularly regarding the curiosity drive. His research suggested this internal mechanism contributes too much of human cognition and language (1960). Beyond that are various theories proposed by psychologists such as Wassermann (1971), Lazarus (2020) and Luria (1973) who all in one way or another expressed the opinion that internal language plays a significant role in both normalcy and the onset of psychopathology, and that conflict and tension levels resulting from cognitive dissonance is a driving force in language and thought.

In some ways, however research evidence provides conflicting results, A Study in the Library of National Medicine (Muazzami, Wittered et al. 2020) showed that high activation of the language areas of the prefrontal lobes accompanied stress reactions in cardiovascular patients. In addition, the value of self talk as conflict a resolving strategy and anxiety control mechanism is supported anecdotally in clinical settings, as referenced in an article in Counseling Directory (Bell 2016). However, a study with rats suggested the frontal lobes shut down during duress, as mid brain (limbic) flight/fight circuits took over. (Arnsten, Raskind et.al 2015). That study and others did not suggest vocalizations by the experimental subjects stopped. Indeed, one can assume they increased in intensity because vocalizing during stress is the norm for most creatures. Sometimes this is a signal for help. Other times it is an attempt to ward off predators or to express fear. However, it would not be out of the question to assume vocalizing has a regulatory purpose in the brain which is fairly automatic, in a way analogous to Pavlov's notion of the second signal system (Windhoek 1990). That would tend to support the hypothesis that brains, even human brains operate most fundamentally according to a biological approach/avoidance mechanism.

One advantage of binary model of brain function however simplistic, is that it places the brain in its proper biological context - as a homeostat that can produce art, science, politics, human interaction and culture itself, yet is, like all other biological systems a regulatory organ, consisting of gauges for stability, with the capacity to recognize and address deviations from that gauge and with mechanisms by which to make corrections to restore stasis. As Freud implied, the brain (and psyche) is a restorative correction machine designed to address negative and positive drives and maintain stasis through a homeostatic process that governs the body - of which it is part.

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Robert DePaolo retired practitioner in clinical psychology neuropsychology and educational psychology, author of six books and many articles on psychology, cosmology, religion and science. Retired Adjunct Prof, of psychology NH University System, Screen writer and producer on educational film Morality; A Historical Perspective.

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