Dogs, language and laterality

The linguistic lateralization of our dog buddies spotlights a theoretical mystery

Many news outfits have published stories about a recent study wherein dogs were trained to lie still enough in an fMRI while listening to humans talk to them. The results indicated that our evolutionary partners processed emotional tones on the right side of their brains and specific words on the left, just like humans. The more we study dogs, the more we find how smart they are and how much we have adapted to each other for interaction. Check out the research done by Brian Hare and colleagues.

I first read about the fMRI study in Science News from 10/1/16. It provides a good summary (as they usually do—what a good magazine) and then they ended the article with the idea that because dog-human relations have only developed over the last 30,000 years, too short a time for evolutionary progress to produce such linguistic abilities, “some older underlying neural mechanism for processing meaningful sounds is present in other animals”.

This highlights for me the theoretical mystery on the biological nature not just of language but of symbolization in general (so it includes art as well). As I have said before, understanding symbolization is the holy grail of understanding ourselves biologically, and so let me render a conceptual outline of this mystery. First consider the bond between dogs and humans and that emotional communication through voice (and sight) is processed by the right side of the brain in both of us. We have researched this broadly in humans as intonation or non-verbal vocal communication, and/or kinesics. All of this to my mind is empathic communication and its processing is right sided; we find a cortical area for its integration there at the tempo-parietal junction that I call Empathy Central but the academics call ToM (Theory of Mind). Do dogs have an Empathy Central area? Unknown for now but I am taking bets they do and planning on how to spend my winnings.

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Looking left, currently bored

Next consider this basic feature of lateralization. The right side processes emotional expression and empathic communication just like it processes the current perceptual-motor domains, i.e., the right side processes the specious present. The left side then directs its energies towards information displaced in time and space, initially as a supplement to the specious present by recognizing and recalling information and then increasingly as a virtual domain for information to be composed independently from current objective events. Language, as a symbolic function, is so powerful because it allows us not only to control the input and retrieval of displaced information from memory, not only because it allows the composition of new information from imaginal processes, but also and especially because it allows us to communicate about what isn’t there in front of us but exists only in our minds, apprehensible only to oneself and in symbolic communication.

So when the article ends by asking what the underlying neural mechanism might be, my answer is not about language but about its precursor in the symbolic control of displaced information. Why should that be lateralized to the left? Ah, because timing is important. The right side matures at a faster pace than the left, due primarily to the differential effect of testosterone which slows the left’s maturation more than the right’s (and so males show more distinct patterns of lateralization and more language problems from sometimes too slow a pace on the left side). The right side develops the capabilities to process current information early on while the left side is coming online, so to speak, a bit later, and when it does come on line, it is not totally in sync with the right sided processes for the specious present. Its information is displaced (read out of sync) almost from the beginning of the incipient specious present. Symbolic processes enable finer, more powerful control of such displaced information. So the right side focuses more on the current coin of interaction, i.e., empathic communication, and the left side more on non-current, i.e., displaced, information. Verbally this relies on lexical knowledge, the processing nexus of which is in the left temporal-parietal junction. As we learn more about animals, especially mammals, we will find the precursors of these underlying neural mechanisms in virtually all of them. You can count on it.

A couple more quick notes. It would seem likely that dogs were domesticated and became our close buddies because the genetic streams feeding their evolution ran close to ours—our brains are sympatico in how they process social information.   Human genetic streams, however, also evolved a lower larynx and hyoid bone, greater breath control, and oral-facial musculature thereby enabling articulate speech and even more critically to our humanity, gave rise to longer cortical fasciculi. The arcuate fasciculus is a prime example here. Remember that it carries the surface structure of words on the left side between front and back so that we can repeat what we just heard said. On the right side it might could carry emotional expressions for mimicking. (See my most popular post from 4/24/14, Arcuate fascicles, mirror neurons, and memes). The important feature here, however, is that these long fasciculi facilitate the composition of invariant information forms, e.g., words, discrete emotional forms, and their expression. (And how about art and its special modes of symbolization? Ah, beautiful). The creation of these invariant forms is what enables the separation of deep and surface structures and the subsequent development of syntactic control of their compositional connection. The creation of these invariant forms, both long-standing (lexical items) and in passing (conversation), by the welter of connectome activity in the presence of ambient flux is the remarkable basis for humanity’s intelligence and it has grown from deep roots.

Finally, remember to mark your calendars for Mammalian Heritage Day on November 2 and celebrate those roots. Travel on.

Theta moments, completion of a composition, & cortical fasciculi

Following up from last post: Ah, theta moments, specifically hippocampal theta moments when the apprehension of something new instigates the mental response composing a new situation. I have written about this several times before. Theta waves manifest during key behaviors, simple ones like the chicken’s head bob (yes, almost everything is new because so little is old) or a rat’s step (yes, safety demands almost constant appraisal and memory for location to gain food or avoid danger) or more complex ones like a cat’s orienting response (of what interest is that and should I bother the cat must ask) or a chimpanzee’s expression of bewilderment when an expected treat does not materialize (now what does this mean and what should I do?). Theta is named for the slower waves which accompany these behaviors and signals that diverse areas are focused on the salient event. As the animal processes incoming information the theta disappears as faster, more irregular waves in diverse areas indicate specific information is being processed to help delineate the contextual situation.

amygdala

The hippocampus is old, deeply embedded cortex. Cortical input flows into the thicker end and the output from the narrower part.

The important thing here is that the hippocampus receives highly processed perceptual information (forms, movement, id of conspecifics, predators, etc. are more automatically recognized) that it processes and then sends the results on upward to the frontal areas engaged in planning and implementing actions and downward as it contributes to the emotional processing carried on by the limbic system. As I have noted before, the hippocampus is way cool. Consider, then, that a theta moment is when the animal formulates a new situational gestalt, a governing form or proto-narrative structure developed from ambient information as discussed in my last post, and then other processes fill in the details, i.e., they finish the composition with perceptual analyses and emotional streams. Of course, these theta moments are actually completed when the animal initiates its next action, e.g., fight or flight, eating, exploration, retreat, or social behaviors.

We humans have a strong network of cortical fasciculi or fiber connections between and among perceptual areas and frontal action areas. These fibers connect the same areas which contribute to hippocampal input and receive its output to initiate the plans and structure of behaviors but they bypass the hippocampus and its situational construct of the immediate ambient and the pressure to act accordingly as well as with the emotional dynamics governing the animal’s responses. By doing so, bypassing this involvement through lower channels, these cortical fasciculi would seem to permit the processing of information apart or displaced from ambient and emotional conditions. What happens to our theta moments there?

Sobo_1909_670_-_Uncinate_fasciculus

Hippocampal theta, remember, first marks something as new or salient and then holds that as a gestalt for the brain to fill in needed information. In this some information, even as it is noticed as new, is held as invariant or as old, so that it can operate as an anchor for further processing of variant information. With the systems connected by the cortical fasciculi, old and new are not contingent upon perceptual notice but upon, at least for us, the gestalts and composition of symbolic information, e.g., the syntax for a linguistic utterance, the intuitive form for aesthetic pieces. So theta moments may be relegated to eurekas, epiphanies, ‘sudden’ insights, realizations, or coming to your senses, etc., the function of generating an invariant form as an anchor for further composition may now continue independently of hippocampal circuits.

I do not want to go into the sleepy land of complicated thinking here about propositional forms based upon the invariance of the verb case frames or how the arcuate fasciculus of the dorsal loop

arcuate fasciculus

helps to maintain the invariant relationship between phonemes and articulatory movements (see recent post on dual loop model) or the invariance of memes as cultural constructs or the invariant memories held in place by guilt or joy, etc. I do want to say that artistic inspiration, that theta moment, major or minor of ‘aha’ or ‘ummm’, when the artist intuits the commanding form and begins to add newly variant elements to compose his or her artistic piece, is one of the most important moments in terran biology and that when we evolved to do this, the universe, well, as it were, sort of, changed for the better. Life began to create new out of the old on its own intentionally without relying on the universal flux of the environment that is slowly, entropically degrading to ‘om’ and that creation was based upon our feelings of fitness, aesthetics, or our sense of beauty.

Now last post I said that Daniel Stern’s understanding of the ‘proto-narrative envelope’ [commanding form) and vitality affects [vital feelings abstracted from experience] from his studies of infants was important. Consider that state of an infant known as the quiet alert state that occurs after feeding. Then the child is most available for social interaction, most readily engaged in rhythmic social exchange and in playful affect modulation. Then the parent helps the child develop the capability for positive affect through engagement. And then it seems to me, the infant sees its whole life as a theta moment as he or she begins to accrue the schemas needed to interpret experience and live a human life. Artistic inspiration and effort has often been compared to these child-like energies and for good reasons. We can see this clearly in the quiet alert state now open for reflection, inspiration and beginning a composition. Artistic creation is clearly related to such youthful joy and we sense this in many artistically talented people (though perhaps cloudily in the tormented geniuses of historical stature). And this has biological roots. I will travel on now to work simply in the garden.