Mind Evolution

My interest in the brain arises from having a brother who is autistic, low functioning and nonverbal. For the longest time I wanted to understand what the brain does and why my brother is the way he is. Today’s post and yesterday’s post focus on an effort from 1934 to define what thought is and how it is represented in the brain.

“What right have we to conjoin mental experience with physiological? No scientific right; only the right of what Keats, with that superlative Shakespearian gift of his, dubbed ‘busy common sense’. The right which practical life, naïve and shrewd, often exercises.”

Sir Charles Sherrington, Neurophysiologist, Nobel Laureate, from Cambridge Rede Lecture 1933 [1]

From yesterday

The main thesis of The Neural Basis of Thought [2] is: the neural counterparts of each concept, thought or idea that the mind acquires are ‘neural schemata’, or patterns of neural impulses. These neural patterns are seen peripherally, from the sensory organs and centrally, from the thalamic relays to the cortex. Elliot Smith claims that consciousness arises from the activation of the schemata associated with a given concept.

Neopallium

Elliot Smith claims that the brain structure that allowed for neural schemata is the neopallium, which came into existence with the evolution of mammals. As the name suggests, this is the newest part of the brain, a seven-layered structure at the outer surface of the brain. This structure in humans is called the cerebral cortex. Elliot Smith states, “It [the neopallium] came into being to form a receptive organ for fibres coming from the thalamus, whereby touch, vision, hearing and taste – in fact all the non-olfactory senses – secured representation in the cerebral cortex.” [3] [Note – olfactory senses arise from an evolutionarily older part of the brain.]

According to Elliot Smith, the entire cortex is involved in each thought, through intracortical connections, integrating memory, cognitive and motor activities. The thalamus is also involved through its relay of sensory input to the cortex.

The hypothalamus, located beneath the thalamus, controls endocrine, metabolic and autonomic functions, as well as being a key component in emotional function. [4] This structure is also subject to stimulation through impulses originating in the cortex, through the thalamus and basal ganglia.

Conclusion

The thesis set forth by Sir Grafton Elliot Smith in 1934 states that impulses circulating through the brain as ‘neural schemata’ compose the substance of each idea and concept. This proposal takes into account the structure of the mammalian brain, particularly the development of the neopallium (cortex), its internal interconnectivity and its interaction with the thalamic relays from the sensory organs of the body.

Although his proposal seems reasonable, it does not seem verifiable. I need to research this topic further to discover other more modern concepts of the origin of thought.

I do not know if it is indeed possible to define thought through physiological means, but it is a worthwhile effort to understand the functions of various parts of the brain and how they interact, even though the whole is undoubtedly more than the sum of its parts.

Perhaps even a glimpse of the origins of thought will help me to better understand my brother.


[1] Quoted from: Campion, G.G. & Elliot Smith, G. The Neural Basis of Thought New York: Harcourt Brace and Co. 1934 pg 15

[2] Campion, G.G. & Elliot Smith, G. The Neural Basis of Thought New York: Harcourt Brace and Co. 1934

[3] Ibid pg 26

[4] Greenstein, B., Greenstein, A. Color Atlas of Neuroscience Stuttgart, New York: Thieme 2000

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