Cortical chauvinism

Long ago in my previous life as a fifth grade teacher right after college, I read a good many classics in early neuroscience and linguistics, books by A. R. Luria, L.S. Vygotsky, Karl Pribram, Noam Chomsky, Eric Lenneberg, etc.  And reading and talking to some others I thougt then that much of our thinking was distorted by cortical chauvinism, i.e., we thought that our cortex does everything important and lower neural structures were beneath us humans.  I understood two reasons for this narrow-minded view.  First, and most understandable, were the technological challenges of studying and understanding subcortical structures.  The cortex was more available through EEG and experimental studies of higher functions especially when combined with clinical studies following strokes, e.g. aphasias, etc., and trauma, e.g., Phineas Gage.  Subcortical structures were and are much more difficult to access unless we use other animals for our studies, and this brings up the second reason for cortical chauvinism.  Even back in the 1960s we thought that our minds were oh so special and that this was due to our remarkable cerebral cortex, which led to the assumption that we could learn little of the human mind by studying other animals and lower neural structures.

Thankfully these days have seen many of those myths about our specialness revealed as ignorance and we have developed quite powerful techniques for studying the entire brain. This includes the brains of our own species but also now we can study the brains of other animals and understand more about our own. Shining examples of our progress here include the work of Jaak Panksepp (of course), Frans der Waal (of course), and many others, e.g., Antonio Damasio, Michael Tomasello, Jean Decety, and many, many more.  (Damasio points out the case of Phineas Gage who suffered subcortical brain injury (also involving a little cortex) who recovered virtually all of his cortically based intellectual functions yet was extremely disabled because he could not focus or make anydecision—see post 12/9/18).

A couple of ancillary developments have furthered our better understanding.  Back in the days of cortical chauvinism, many thought that our intellect was powerfully rational, even logical. Scientists like Amos Tversky and Daniel Kahneman have showed how hollow that claim to a powerful rationality is, and many, like Jonathan Haidt and Antonio Damasio have shown we mostly form our opinions and then devise a rationale for them, e.g., Haidt’s description of our minds’ functioning as an intuitive dog wagging a rational tail. In Moral Tribes Joshua Greene shows how our moral principles are also thinly constructed and compares our rationalizing our moral stance to a stroke patient’s confabulatory renderings trying to explain their strange reality.

Another development would seem to leave behind the old notion of our higher cortical centers controlling the lower emotional centers in favor of understanding the remarkable interplay in 3 dimensions:  up and down between horizontally organized neural structures, e.g., cortical hemispheres, limbic system, basal ganglia, etc.; back and forth between anterior (descending) and posterior (ascending) systems at various levels; and within this back and forth interplay between processing organized into dorsomedial and ventrolateral systems.  (This last will need further explication below).  Notice I did not mention coordination between left and right hemispheres; while our conception of this has also evolved I want to address this in a later post because my ideas here are well outside the boundaries of orthodox thinking.

Consider the connectome (see posts 1/10/15 & 8/2/16) not just as it appears cortically but in the whole of the brain.  I read one of the grand visions of this in Edelman and Tononi’s book as they explained re-entrant processing (see post 7/7/16).  As different systems interact up and down, back and forth, medially and laterally (and I suppose left and right), the input from one is recalibrated through further processing and returned to its source (a very relative term here) to enhance or diminish the neural patterns and forms currently in process. Yes, the cortex does inhibit subcortical centers but this inhibition can result in diminishing a pattern, e.g., anger modulation, or in enhancing a form, e.g., sharpening the figure out of the ground or permitting a positive emotion to grow stronger.  We now know that GABA, a widespread inhibitory neurotransmitter, plays such a complex role, even as its counterpart, glutamate operates as a ubiquitious excitatory neurotransmitter.  Ponder the connectome from this perspective for a short moment and you will understand why I think an estuary is a very apt metaphor for our brain.

Finally, back to the dorsomedial/ventrolateral organization. Lateral is along the sides of the brain or the outer surface and medial is inside more down the midline.  Several research lines have coalesced into the dual loop theory, as it is sometimes called (please revisit post from 2/11/16). Now Joshua Greene in his book, Moral Tribes, proposes a dual process model for our moral decision making. Simply put, simple decisions involving oneself and one’s own tribe can be done quickly and routinely through a station in the medial system, the dorsomedial prefrontal cortex, while more difficult decisions are better resolved through a slower, more reflective process involving a station in the ventrolateral prefrontal cortex.  These more difficult decisions typically involve us vs. them, i.e., a conflict between the values of two different tribes.

The lateral loop operates more reflectively because, as the great Antonio Damasio puts it, it operates with ‘as-if’ situations that involve less immediate personal involvement.  I intentionally used the word ‘stations’ for both the ventrolateral prefrontal and the dorsomedial prefrontal cortical areas to signify their many connections up/down, back/front, and medial/lateral. They are interconnected with posterior cortical areas via long nerve tracts, i.e., fasciculi, and with the limbic system through a variety of connections and loops.  Remember Tversky and Kahneman’s idea that we think fast by using heuristics and slowly by reflective analysis.  Following Greene, I wonder if heuristics are likely more associated with the dorsomedial system while reflective considerations more with the ventrolateral.  Our brains operate importantly upon two dimensions; one is old/new through the hippocampal system and the other is variant/invariant through several different systems.  Their heuristics, Bourdieu’s habitus, vocabulary of meaning-sound mappings, and others are more invariant and will be found to be supported by the dorsomedial loop. Novel analyses, modulating habitual and skilled cultural actions, and the subtleties underlying individual performance, e.g., playing a sonata with passion, are supported by the ventrolateral loop.  Both loops involve back and forth and up and down integrations.

Viewing the connnectome through the prisms of these three neural dimensions, up/down systems, back/front systems and dorsalmedial/ventrolateral systems shows how incredible brain functions must be to engage in the old/new and variant/invariant features of human cultural behaviors.  Yes, our cortex is really magnificent but let’s not be chauvinistic here:  that magnificence depends upon the connections with subcortical and autonomic systems.  To purloin Daniel Dennett’s critique of consciousness as a Cartesian theatre, nothing cortical could play without the subcortical stage, props, lighting, etc.  Indeed the cortex alone would not foster much of any significant activity without that stage.  Without the whole embodied system a mind would be sleeping emptily.  The estuarine brain really is a sort of muddy mix of salt and fresh water enlivened by a phantasmagoria of vital activity, and that is what makes it and conscious animals (& there are so many more even without a cortex similar to ours) so special.

Forensic science finds ancient crimes, but solving the mystery?

My wife is a big fan of Lin Anderson’s detective novels featuring Rhona MacCleod, forensic scientist; she likes the gritty details of Rhona’s investigations (otherwise she does not like blood or crime or anything like that) and the insight the writer shows into human motivations, behaviors, and relationships.   Now archeologists are using the tools of forensic science to investigate the ancient times.  A report came out a while back that forensic science figured out Otzi, the stone age man whose body was mummified in ice found in the Italian alps 10 years ago, was killed by an arrow in the back 5000 years ago.  His clothes had the blood from 4 other individuals on them and he had other wounds some partially healed and some at time of death. The researchers put together a plausible narrative wherein he had a fight and won, took off to the mountains to escape retribution, and was shot in the back because his assailants did not want to face him again in a fight.  Even then Otzi rolled over and tried to pull the arrow out, a futile task because of the fatal damage done.  It also appears that his enemies ended his life quickly then with some blows. Sounds like a good plot for a novel or script for a movie, eh?

A recent report on PLOS (that’s the Public Library of Science) details the techniques forensic scientists use as they find evidence for interpersonal violence 30,000 years ago:  https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216718.   This analysis was on a skull found in Romania some time ago.  The researchers examined the skull through CT scans and visual inspection, analyzing the pattern of injuries, whether they had healed or not, whether the bone was still plastic (indicating that the person was alive when injured), and other features.  They also used synthetic skulls to experimentally replicate the pattern of injuries through various means, e.g., blunt force trauma, falling, etc.  They concluded that the skull injuries occurred at the time of death, not before and not after, and that the only probable means for an injury with this pattern was blunt force trauma with a club-like weapon.

Now this person was a modern human, not a Neandertal or other variant, but who knows who killed him.  I tend to think that early tools were developed for hunting, digging, etc., but maybe the first tool was a weapon.  Our biological nature is one wherein we fight for defense and to protect resources from the others, e.g., not of our clan, though culturally this has developed to become violence in the service of aggrandizing power and thus resources, e.g., slaves, land, taxes, etc.  And another motivation, as I posted about on 3/28/19, was to appease the gods and so control the supernatural forces controlling weather and harvests. In this instance Incan priests sacrificed 140 child prisoners and 200 animals in response to, so the primary hypothesis runs, a natural disaster.  This was done around 1400 CE.  It probably did not achieve its desired end, unless that was to bring Spanish conquistadors and priests a few decades later to subjugate the indigenous peoples.  (In a cynical aside, I wonder if our efforts to mitigate climate change are any more effective, at least so far?  Maybe some alien life form will arrive to ‘help’ us?)  But I digress.

Or maybe I don’t.  In my last post on Davis and Panksepp’s Emotional Foundations of PersonalityI presented their idea that 6 basic emotional systems operating in subcortical neural structures underlay, constrain, motivate and flavor our personality structure and cognitions.  They said this succinctly towards the end of the book, “Although we humans are highly cognitive creatures, it is clear that we are not liberated from ancient emotional arousals”.  Amen.  In modern America the availability of guns, these products of our cognitive and technological precision, amplifies through tragic actions the motivations for violence, e.g., turf wars, domestic violence, and now mass murders in the service of what?  Imagined invasions and the incredibly vile and mistaken cognitive efforts to see ‘others’ as dangerous aliens when all reasoned and realistic minds understand the value of these others and cherish their presence in our country.  And even more prescient minds understand that we are all one on one planet.  And our American culture seems to worship guns in ways no other culture or nation does, or has ever done, so that our laws make sure everyone can have as many lethal weapons as they want.  These are not the clubs of 30,000 years ago, nor the arrows of 5000 years ago, nor the ritual sacrificial and horrid killings of 600 years ago, but modern tools of fatal warfare.  After each modern mass murder or once we notice a surge or pattern in individual murders, another ritualized pattern of behavior is enacted to somehow cleanse the nation’s psyche, e.g., thoughts and prayers, affirmations of resilience, etc., and then we are, I can only assume, ‘ready’ for the next instance.

I have begun reading a book recommended by Davis and Panksepp, Moral Tribes: Emotion, Reason, and the Gap Between Us and Themby Joshua Greene.  So far he has articulated the notion that our evolution has prepared us for resolving conflicts through moral means between an individual and others in his tribe, e.g., through reconciliation or making up, but that part of this development involves serious problems resolving conflicts between tribes.  As I have assumed and said here, we evolved with strengths in intimate and small group relationships.  These were adequate when the human population was sparsely distributed, tribes were small, and resources relatively adequate.  However, as many have noted, with a burgeoning population, large, rather artificially constructed groups called nations, and increasingly inadequate resources, especially water (you know, the basic stuff of life) our evolutionary abilities to relate peacefully and morally are being tested in new ways and are all too often falling short.  This is so even as the overall level of violence on a global scale has fallen, according to Stephen Pinker.

I will continue reading Greene’s book, hoping to learn more about our biological roots and how we can draw upon them to live better with all others.  I will continue to read fine fiction that presents the human condition in clarifying aesthetic light. While forensic tools can detect and clarify the nature of the crime; solving the mystery is another matter.  And I will advocate for the notion that our culture can act upon better impulses—cultures can and do change: gun worship is not intrinsic or necessary to who we are. We are certainly not trapped by our biology to be violent with each other; in fact human nature is just the opposite.  Time to travel on.