The Specificity of Words & Nerves | 1
What the nervous system reveals about sensation, language & communication:
The nervous system is the repository and source of all language…
…It grows and develops to fulfil 4 fundamental functions: to sense, associate and discern between stimuli, and in processing the information, to then respond appropriately.
These neurological functions are still emergent during the development of language postnatally, although they quickly become the absolute requirements for language synthesis in everyday infant life, progressing into adulthood.
Where the anatomical functions of sensation, signalling pattern and processing combine, information is mediated through neuroanatomical mechanisms, revealing not only what language fundamentally is, but for human beings especially, why language has in turn become a tool of such precision.
As the first part of a series, this explorative science article looks at why the synthesis of thought into language occurs at its most fundamental level.
To describe complex structural functions is the aim of neuroanatomy as a medical science, and a mode of enquiry which directly observes this aspect of human nature.
Brain tissue consists of modular units connected by neural pathways, which are stimulated to function in a localised and yet integrated manner, connecting dynamically with other pathways within the cerebral hemispheres, brainstem and the wider nervous system.
Before coming to how neurolinguistic functions can evince the nature of language, and why the power of descriptive communication through word composition is such a cornerstone of human existence, we can first explore examples of neuroanatomy outside of the brain to contextualise precision language, and in the same vein, draw on real world examples of neurolinguistic function, where neural structures underlie the process of language use in human life.
Through the specificity of words we can make distinctions, and within neuroanatomy, make scientific distinctions between human tissues and the forms they take; muscle for example is very distinct from bone, yet bone and muscle also vary within themselves, as also do neural structures. We can also make generalisations, such as the fact of nucleated cells being native to bone, muscle and nervous tissues all. This commonality between tissues is a fact of cell lineage, beginning from undifferentiated cells that become specialised into specific tissues. The differentiation of a cell’s form and function allow for these tissues to be generated, maintained and repaired in an organised manner. Not all cells are equally dedicated to these tasks within their respective tissues however.
Schwann cells of the peripheral nervous system, for example, differ greatly in morphology and location when compared to astrocyte cells, due to their respective functions. Both have primary yet differing roles in the support of neuronal axons, the neural conduits which conduct electrochemical signals.
The eponymously named Schwann cell, is found enwrapping segments of neuronal axons that are local to the peripheral nervous system (distal to the brain), in a process known as myelination. Myelin acts as electrical insulation for select neural conduits, and thereby reduces the amount of axonal diameter (and overall space) that would otherwise be required for rapid conduction to be feasible over those distances found within human tissue. As well as the efficiency of space through form, the metabolic efficiency of our bodily tissues is likewise fundamental to retaining the energy needed to utilise higher brain functions.
By comparison, astrocytes are the most abundant cell in the brain, influencing the growth, metabolism and the protection of neuronal connections, yet surprisingly possess no direct neuronal functions in terms of electrical potential, although neither are they electrically silent. The astrocytes are found exclusively within the white and grey matter of the brain and spinal cord, and comprise fibrous and protoplasmic subtypes, designated respectively to more and less myelinated nerve fibre tissues of the central nervous system, which present respectively as the white and grey matter of the brain and spinal cord. We can intuit, being ‘star-like’ in appearance, that astrocytes differ greatly from the insulatory structure of Schwann cells, due to the radial processes which extend from their nucleated cell bodies. Within the category of astrocyte cells however, their namesake denotes an easily identifiable appearance, yet we cannot specify their subtype by it.
The specificity of terms used to identify these cells and the living tissues they organise into is imperative, not only for their being the clinical and scientific means of delineating and labelling their microanatomy in a meaningful way, and for making neurological diagnoses and interventions in the presence of disease, but also in that the nature of language has deep implications for how we as human beings understand ourselves and the world around us. The functional differences between neural tissues such as these allow for the physical orchestration of the sensory when compared to the motoric (movement) functions, through which respectively we experience and engage in physical actions throughout life.
To expand on this further in living tissues, which by definition are neurally innervated, a general somatic sensation such as tactile sense via the skin - a fly landing on one’s arm say; - differs both in embryogenic derivation of its structure and its function, to that of the special senses - such as vision and audition; - which in health obviously allow us to see and hear the fly which has landed on us. Both our general and special senses evolved to avoid environmental hazards, seek both resource and advantage, to avoid predation and to participate in it. As we shall explore in further articles on this topic, the specificity of terms we use to communicate has become not just a recourse, but the mainstay of adaptations that contribute to human survivability and thriving.
The form of living tissues and all their neural innervation, at the most fundamental level result from the demands for life to adapt to those physical forces that inform the world we inhabit. These include light, gravity, pressure, electric conductance, but also the elemental properties of calcium, sodium and potassium, to name a few. It is these forces which have stimulated the human form into being over deep time; and yet within a lifetime, also stimulate that same human form into growth and repair. All told, this has resulted in tissues which confer adaptive traits which in turn undergo genetic conservation, and subsequently, establish a continuity between the composition of tissues within and between species. All mammals for example, have skin, ears, eyes, limbs, mammary glands etc.
The epithelial cells of the skin for instance, which can be termed as the integumentary system when referring to the tissue as a cohesive anatomy, among other things serves to protect the deep tissues of the body, and to act as a medium for sensation. It is surprising to note that the cornea of the eye is composed of adapted epithelial cells on its interior and exterior surfaces, meaning these cells are ultimately of the same lineage as those of the skin, yet which in the cornea are transparent. There are cellular and acellular components to the cornea, and each contributes to the maintenance and function of its light refractive properties, allowing light to enter the eye, converge at a focal point through the crystalline lens, and for clear vision to be possible. All at once we find that this clear transparent exterior of the surface, a living tissue which resembles glass, is not as deceptively simple as it outwardly appears, but is a piece of precision, albeit blind engineering.
We see in the cornea, and the eye in general, the wider principle of nature already mentioned; that when something works, and functions in the real world, nature conserves this functionality through the genetic expression of that trait across the generations - something which in a manner of speaking, requires an intensive specificity of language (in the form of protein coding genes). Another fact of evolution is its convergence, in that an adaptive anatomical form, such as a dorsal fin or the eye, has evolved many times over, with no genetic continuity of lineage between each instantiation, due simply to the consistency of demands placed by the physical and chemical world on the organism. The genetic specificity of language is one of nucleic acids, that allows for physical forms to be generated from the encoding of proteins into complex structures, with traits being adapted for other purposes, refined and optimised. A scientific understanding of nature means that we be able to directly observe its complexity as it is, requiring that we articulate the underlying reality of nature through language which holds true to what is specifiable. When meaningful, this gives us an opportunity to communicate the intricacy of how the world within the human body, and the world without, come to influence each other through sensation and language.
Life takes physical form, and in doing so meets the various demands needed to survive, thrive and operate in a complex world. In this task, form and function are essentially equivalent, simply because living tissues must answer the rigorous demands placed upon them, and pass on their genes. The evidence of this physical relationship is intuitive, but is overwhelmingly established in science, engineering, medicine and other fields of interest besides.
To describe the relative complexity of human tissues therefore requires a precision of language; one that through direct observation, can capture all of the most isolated to the most cohesive of morphologies across varying states and functions, from physical exertion to rest, from the cochleal hairs of the inner ear to the terminal hairs of the scalp.
‘Medical training taught me the art of breaking down the complex maze of stories, symbols and rituals into clear systems. You could say that it helped me figure out the anatomy and physiology of mythology and its relevance in a society more incisively. How is it that no society can, or does, exist without them?’ ~ Devdut Pattanaik
This article series will orient its focus on language through the human nervous system, because it is this system which is responsible for language, and any specificity of communication through language. Language is after all, a physical form, as it assumes visual structure when written, and travels as sound when spoken in an atmosphere.
Taken as a whole, there is an intimate continuity between the development of our senses, and the ability to communicate experiences through verbal speech. As human beings, we can relate the reality of what we have experienced through our senses, but also, we are capable of displacing our account into tenses other than the present. We can relate an experience from the past, or posit another in expectation of the future. We can even convey concepts which may deviate from reality entirely, and produce works of imagination. The ability to specify our place in time’s constant through language, has allowed posterity, prescience, and presence of mind to be ever ready in our consciousness, such that tense is a norm of language.
Temporal processing is the responsibility of the brain, being both the remit of the dorsolateral prefrontal cortex, and the entrainment of circadian rhythms by the suprachiasmatic nucleus. Each of these brain structures form key parts of our neuro architectural inheritance in evolutionary terms, contributing to the electrochemical system as a modular yet integrated whole, allowing us to be cognisant and physiologically readied or resting. The brain is itself the most complex system known to our species, and these temporal processing units allow us to understand when we learned a fact such as this as listeners or readers, and approximately what time of day our body is most responsive to such information. Humanity has existed as the embodiment of this system, without any means of gaining direct observation of its function, and reflecting on its form, for the vast majority of human existence. We can now however, specify all of its elegant features and functions.
Through stimulation of the senses, we learn to differentiate those stimuli generated by our physical world, processing them through a combination of sensory, affective (emotional) and cognitive functions.
The influence of emotion is an especially nuanced process, one which is so dynamic and expansive in its interactions with general cognition that it deserves its own separate article. Suffice it to say that emotion, especially extremes of emotion, are the most potent in effect on neural pathways when it comes to their influence on the consolidation of memory, and have great bearing on how we develop and specify our experience of the world through language.
The next article will differentiate how and why sensation, which as a process is galvanised and cohered more immediately than cognitive and affective processes, informs the precision with which we think by providing us with information about the world, mediating our experience, for us to then differentiate consequences, and so establish what we value, such that we can communicate this through language.
Our focus shall primarily be on why language exists, and what the loss of language specificity in neural dysfunction reveals about this very human capacity. We shall start by describing the first means of exposure through which language is formed, that of sensation, and why the language used to describe neural sensation need itself be specific.