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Neurology and Semantics

October 24th, 2013 by Robert DePaolo | Posted in Psychology | No Comments » | 59 views | Send article | Print this Article |


by Robert DePaolo

Abstract

A previous article by this writer on brain function involved a discussion of how learning occurs in the acquisition phase, i.e. by a parallel, neural signaling, imitative mechanism. Here the discussion revolves around access to and retrieval of memories and responses, with an emphasis on language functions. More specifically, the assumption is made that the connectivity and relationships among sounds, words and grammar can provide indicators on how the brain processes information and consolidates memory. It is proposed that language skills such as retrieval, cognition and comprehension operate in a way analogous to the flow of energy from high to low resistance, i.e. along a psychophysical “path of least resistance” both between cortex and limbic system and within various neural circuits in the brain.

Signals among the Living…

While researchers and theoreticians such as Chomsky (1998) Pinker (1994) Luria (1966) and Whorf (1942) have written eloquently about the origin and nature of human language, settling in on a neurologically-based description has been difficult. That is due in part to a lack of technology that would enable us to trace the interaction among pathways as language responses are being formulated. It is also due in part to anthropocentric ideas on the distinction between human language and the communicative behaviors of other creatures.

Some distinctions are obvious. The human brain is more complex and therefore so is our language. The chimp, with a brain of roughly 14 ounces has about 15 distinct vocalizations, (i.e a phonetic vocabulary) that it uses to communicate with fellow troop members. The human brain weighs between 35-65 ounces so it stands to reason that our cortically-driven, enhanced capacity to parse and inter-connect sounds would be much greater. The ability to differentiate between and among sounds is every bit as important as being able to produce them through the fortuitously situated human larynx and hyoid bone.

On the other hand some traditionally espoused distinctions between human and non-human language could be somewhat artificial. For example human speech is often described as being symbolic, i.e. representative of experience rather than real. But that is true of non-human languages as well. The peacock’s plumage display is not in itself a sexual act. It signals intent, fitness, readiness and willingness as representations of the act. Meanwhile, the baring of teeth among alpha male chimps is not in itself an act of aggression but a signal representing the intent to act aggressively. In other words the signals emanating from the language of all creatures is by definition removed from actual experience. It is therefore symbolic; perhaps not couched in written symbols but proffered secondarily nonetheless.

Other comparisons between human and non-human language also seem overplayed. Some have said our speech patterns serve communicative-adaptive purposes; for example in alerting one another to dangers, for mating, or to solicit group cooperation in hunting endeavors, migratory initiatives and so on. But all animals do that, especially those with highly social-interactive societies. They might not do so as grammatically as we, but in the final analysis a communicative signal is a communicative signal. This is particularly when one considers that much of human communication is actually non-verbal (Andersen 2007).

The Volume Distinction…

Despite the above qualifications, human language stands alone as the most versatile and detailed in the phylum. We can conjure up more sounds, words, nuances, idioms and symbolic language “asides”, e.g. sarcasm, metaphor, irony, humor etc. than any other animal. That certainly sets the stage for a discussion on how our brains orchestrate such complexity. In doing so it is important to point out that having more neuronal connections in representing and parsing a wider variety of sounds and symbols is not in itself an advantage – not when it comes to information conveyance. Having greater access to signal input and output also increases the potential for noise and confusion. Put more simply, having larger brains requires an extremely efficient sifting capacity; and more than that, a rhythmic under-toe of neural activity to synchronize a potential cacophony of neural responses in excluding some stimuli and including others in time-effective ways so that attention and memory can be established and sustained.

In light of that one could ask why having so large a brain would be adaptive at all, bearing in mind that all large brained hominids except modern man became extinct. Were these highly encephalized upright walkers caught somewhere between having a large brain and not being capable or orchestrating optimally its voluminous permutations to figure out how to survive with relatively meager physical capacities and a highly visible, predator-friendly bipedal style of locomotion? It is possible a neural threshold had to be reached for homo to attain environmental control and begin mastering his world through the use of sophisticated tools and social organization. As to the nature of that threshold, one possibility is discussed next.

The Discriminatory Paradox…

According to Information Theory principles there is a paradoxical threshold that oversees the transition from complexity to communication. As any system grows in complexity it must develop smaller pockets of redundancy as a compensatory process (Holt 2010). In other words one can only make sense out of complexity through the infusion and governance of simplicity. In the various uses of language and cognition there must be a way to make disparate things appear similar, to create redundant information out of distinctions. It amounts to an act of illusion, because different things are indeed different; in their physical characteristics, chemical properties, in their mass and their behavioral effect on other things. Yet a complex information system must be able to bypass that essential truth. In a sense communication and objectivity are competing entities.

Just how that process unfolded in human evolution is beyond the scope of this discussion. More salient is the neural process by which that might be orchestrated. To address that issue we turn to a familiar source of information.
Caught in the Crosswords

Consider the person working on a crossword puzzle…

Item no. 6 (across) provides the first hint, to wit; solemn statement. The puzzle solver begins his deliberation by referencing various associations of that phrase, such as… oath, vow, protest, prayer, eulogy and testament. The number of letters encompassed in the grid narrows that down a bit but he is not sure whether words unknown or presently inaccessible to him also have the requisite number of letters. He is caught in a complexity trap. For a solution he looks down the grid and sees a three letter box featuring the hint, steal. Words like pilfer, take and swipe come to mind but since the box has only three letters he settles on rob. It just so happens the o in rob corresponds to the second letter of solemn statement. He decides it might be vow and with that he begins to resolve this linguistic conundrum.
In order to solve the crossword puzzle the person had to go through a series of steps that would be reflected in the activity in his brain. One is a shift from the complex to the simple as his brain searched for a smaller, less noisy circuit reflecting content more easily recognized. To do that his brain would have to be wired in a complex to simple circuit sequential arrangement. Circuits with greater information volume would be either structurally and/or functionally adjacent to smaller-bit circuits. Just how would this be accomplished structurally? Perhaps by vertical pathway connections between the mid-brain (limbic ring) and the cortex, whereby the emotional, complexity-reducing effect of emotional circuits whittled down by catecholamines into flight/fight and/or stimulus narrowing perceptions and behaviors could provide the memory references, resolution and conceptual bridges that satisfy the simplicity criterion (and coincidentally create what is typically referred to as insight or the “aha” experience).

Such an assumption would seem at odds with early, classical models of brain function which espoused a localized mechanism, whereby speech functions are said to emanate from the fronto-parietal cortex, motor functions from the mid-parietal lobes, and emotions from midbrain (limbic) structures such as the hypothalamus, amygdala and septum. However, more recent studies point to a more integrative process, particularly with regard to language functions. (Pessoa 2010), (Parkard 2009) The evolving notion of brain function has language centers scattered over a wide variety of circuits – as though an overseer of experience per se rather than a circumscribed faculty. That is not surprising, since humans have a penchant for encoding all experiences.

Pavlov was among the first to suggest that we are virtually compelled to label visual, auditory, tactile, motoric and emotional inputs. Indeed he felt human experience is accompanied by a second signal system whereby all that we perceive is secondarily and reflexively labeled or “commented upon” either overtly or covertly (Windolz 1990). While Pavlov was hypothesizing, subsequent studies on semantic generalization offer empirical support for the existence of a pan-functional language capacity on our species (Ornstein, 1972) (Lambon & Patterson (2008).

With respect to language functions in the limbic ring, and mid-brain more broadly, some studies have shown that cognitive as well as emotional and motivational emanate from this circuit. This was discussed in an article by LeDoux (2000). In a sense that casts the idea of emotion in a broader context. For example the analogy to energy flow alluded to above would suggest the prime interactive mechanism between cortex and midbrain is one of stimulus narrowing…or in a more biophysical context, from a high-noise, high energy complex state to a low noise, simpler state.

If true then the evolutionary advantage of such a mechanism would be obvious. It would facilitate response retrieval in all domains, and particularly, for purposes of this article, for language functions.
It would be one of many trade-offs that occurred in human evolution – the price paid for having a large brain and vast intellectual abilities. One such tradeoff is that giving birth to large-headed infants increases the pain of childbirth and potentially jeopardizes infant and maternal mortality. Beyond that, a longer period of brain maturation would have made infants highly vulnerable, requiring a super-caretaking proclivity among not only mothers and fathers, but extended family and community as well.

In the case of language, a similar bargain is struck. Having a pan-functional encoding (second signal) system means there will be a lot of noise in the central nervous system and a lot of possible labels and behaviors to sift through in coming up with a response. Having a fail-safe, down shifting mechanism that whittles the complex into the simple solves that problem.

It is also possible however that the complex-to-simple process governs other neural interactive circuits, that information retrieval in and of itself requires that sequence. If so, then in tracing neural activity during any cognitive or linguistic task one might see a trend whereby networks with more dendrite connections will tend to seek, or gravitate toward networks with fewer branches. That in turn might explain some aspects of both language memory retrieval and language memory loss. If indeed the human brain operates by a neuropsychological facsimile of Occam’s Razor, then it would be extremely important to keep some networks relatively virginal. Otherwise they could not provide reference points or cognitive closure.

One way to preserve the information retrieval capacities in the brain would be by a kind of neural housecleaning, where detailed memories are either erased or as in a computer function, compressed into simpler categorical formats. Due to its nearly infinite capacity for volumization, language would seem especially dependent on such a compressive mechanism. That might be why we globalize, conceptualize, use idioms, catch-words and in modern times employ an endless array of initials signifying this or that, e.g.…IRS, CEO, IUD, STD,PTSD, AP etc.

This is of course speculative but it does allow for the integration of physical laws and language (a mutuality that will ultimately have to be addressed in research and theory) and it raises interesting questions. One has to do with whether the attainment of human knowledge is cumulative, or is exemplified by a one step forward one step backward process in a battle between discovery and confusion. As an amusing analogy, one can refer to the old adage about a tree falling in the forest, absent an observer. To wit: If no one is there to see or hear it did it really fall? In the case of language and cognition one could ask: If the accumulation of knowledge within the cerebral labyrinth becomes voluminous enough to prevent us from accessing what we have learned – have we really learned? Even more interesting is the question of whether the continued expansion and evolution of human language will lead to more accurate descriptions of the word around us or to compacted, askew distortions substituting neuro- cognitive convenience for objectivity.

REFERENCES

Anderson, P. (2007) Non-verbal Communication (2nd edition) Waveland Press
Chomsky, N. & Ronat, M. (1998) On Language: Chomsky’s Classic Works. Language and Responsibility and Reflections on Language. New Press
Holt, S. 2010 Complex Systems. Theory of Constraints and the Search for Inherent Simplicity. The Boeing Company
Lambon, R., Patterson,K. (March, 2008) Generalization and Differentiation in Semantic Memory: Insights from Semantic Dementia. ANN NY Academy of Sciences. 1124.61- 1124.76
LeDoux, J (2000) Emotion Circuits in the Brain. Annual Review of Neuroscience. 23: 155-184
Luria, A. (1966) Human Brain and Psychological Processes. Harper & Row.
Ornstein, P. (Sept. 1972) Semantic Generalization over a Bipolar Dimension of Meaning. Journal of Experimental Psychology 9,1, 202-210
Parkard, MG (2009) Anxiety, Cognition an Habit; A Multiple Memory Systems Perspective. Brain Research 1293: 121-128
Pessoa, L (2010) Emotion and Cognition and the Amygdala; From What is to What’s to be Done. Neuropsychologia 48 (12) 3416-3429
Pinker, S. (1994) The Language Instinct. Harper Perennial Modern Classics
Wadholz, G. (1990) The Second Signal System as Conceived by Pavlov and his Disciples. Pavlov Journal of Biological Science Oct-Dec. 25 (4) 163-175
Whorf, B. (1942) Language, Mind and Reality. Theosophical Society Vol. 63:1 281-291

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