Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
The Mundane Components of Consciousness
British neurologist Adam Zeman showed how mundane consciousness is: a little more or less of this or that chemical makes a big difference as to how you “feel”. Consciousness depends, mostly, on events that take place within the brain. A lack of this or that chemical is enough to alter our personality. After all, consciousness is a product of neural activity, and neural activity is a material process that uses material elements, which, ultimately, are the (indirect) constituents of consciousness.
By the same token, he describes perception as the brain’s reaction to being bombarded with energy picked up by the body’s sensors. Without that external energy, there would be no visual or auditory or any other kind of processing. Whatever the brain does, it is initiated by an energy impulse coming from the outside. It is then processed according to the chemical structure of the brain, which, by definition, depends on the amount and kinds of chemicals in the brain.
Zeman is quite convinced that the thalamus is the central site of consciousness. During sleep, the thalamus interacts with the cortex in rhythmic bursts, while inhibiting all sensory inputs. When the body is awake, the thalamus works as an intermediary between the periphery and the cortex, shuttling back and forth sensory inputs and commands to move. The brainstem is the switch that turns the thalamus on and off.
Zeman’s experiments raise the issue of whether consciousness is really a whole that cannot be reduced to components. Different neurotransmitters seem to contribute to different aspects of consciousness. If a neurotransmitter is inhibited, the person is affected, both physically and emotionally. If each neurotransmitter helps shape consciousness, can’t we also claim that consciousness is not a whole but, trivially, a sum of its parts?
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