Modern Neuroscience has discovered hundreds of billions of neurons, trillions of axons (electical cables), many trillions of synapses (nerve axon to nerve dentrite electrochemical transmission), and as many post-synaptic receptors. Receptors receive the stimulus of a neurochemical released by the synaptic ending, and initiate the generation of an action potential (nerve signal.) Many (about 30) different neurochemical transmitters have been identified. PET and SPECT scanning can determine synaptic density, synaptic release (normal, decreased, or increased quanta), receptor density, the type of receptor, receptor up regulation, and receptor down regulation.
This has shown that there are no so-called centres of function. Functions are governed by complex networks, supercircuits, and circuits. These circuits are diffuse, widespread, and overlapping with thousansds of other circuits. In fact they share many pathways between different supercircuits that compose programmes. This multiple redundancy is necessary to have a brain “small” enough for us to carry it. What we once called centres were merely electrical relay stations where neurons received signals. Signals activate the neuron (action potential) that generates impulses. These are passed on by Saltatory Conduction, segmental axonal fluxes of Na+ and K+ ions as the signal to hundreds of thousands of other neurons in other so-called "centres." This formed complex feedback loops to be sent through transcortical and subcortical to other circuit systems. This formed complex supercircuits for information processing, storage, and retrieval.
Actually the complex networks, circuits, and supercircuits are all that we are, all that we do, and all that we feel and think. Our brain structure is genetically determined by at least 34 regulatory genes from the large “lobes” down to the microcircuits. Regulatory genes regulate the neuronal cell mass migration after month 5 of gestation, the major structure of the circuits, supercircuits, and networks. These regulatory genes are already being associated with observed neurobehavioural functions. And neurobehavioural disorders are being identified now by the gene abnormality as well as PET, fMRI imaging of metabolic uptake in specific behavioural circuits, TMI (Tran cortical magnetic stimulation), and Single Fibre Mapping. Specific data and input, including experience and memory that are our soft-ware programmes. These programmes are not only used by our hard ware circuits, but they in fact alter those circuits. Any perception or action causes microscopic changes in brain (synaptic density, neurochemical synaptic release quanta, synaptic sprouts, numbers of receptors, up regulation, or down regulation, of receptors. And if given enough time and rehearsal of the data, an actual increase in axons (i.e. the size of circuits) is altered.
The Brain's ARAS (Ascending Reticular Activating System) determines our consciousness and our attention. It activates highter diencephalic and cortical areas for more complex cognition or motor activity. In Pikaea, our ancient ancestor 550 million years ago, that same structure was a purely primitive motor escape mechanism. We added layers upon layers to the brain over the millions of years of evolution in an onion like fashion. The older brain areas lost their function. Then these older areas (e.g.Mesencephalon) acquired more basic activation, vegetative, and coordinative jobs for the higher cognitive, affective, perceptive, and motor cortical brain. Higher Cortical layers acquired more complex cognition, associations, emotions, reasoning, language, mathematics, and abstract concepts.
These networks especially the frontal are the most complex and critical in cognition. And frontal circuitry is most advanced in the Ape-Human Family. We receive input. It is processed in the frontal networks. Data from association and memory areas is organised in priority. That priority may be chronological, class type, colour, structure, and memory. Then it goes through the frontal rational screening supercircuit which I call the rubbish filter. This system rejects irrational ideas but accepts and stores rational or logical concepts. Thus the healthy brain accepts “a straight line is the shortest distance between two points.” The healthy brain rejects ‘cubical spheres” and “the square root of -1.”
If a response is required, the frontal circuits analyse the data. They employ new information, working memory, long term memory, past experience with similar data, and associations with other classes of data. A response is formulated and coded for expression. The interacting circuits come up with a protocol of action which we call a choice or decision.
But is the response resulting from these complex interacting supercircuits really a decision or choice?
Is this free will, or is it an automatic computer-like response?
Does the rapidiy of brain circuit action give us the illusion that we are maknig a choice?
Do our brain circuits arrive at the action with such rapid processing that we get an illusion of choice?
When our brains are analysing particularly complex issues with many contributing factors, it will do the preliminary rational thinking, critical analysis, comparison of associated stored data, and screening through the sceptical module. The latter is a network of several supercircuits that analyse evidence and conclusions looking for faults (like you own Norton’s Antivirus.) In very complicated issues (especially in science) the brain may re-run the conclusion through the whole system again and again, until it identifies the flaws, or eliminates them. This multiphased process is what humans call “thinking it over,” “rehashing it in my mind,” or “worrying over it.” Sometimes it may be complex enough that processing continues while we do something else. It may actually be screened during sleep (“I need to sleep on it.”) This “subconscious processing continues even when concentration is diverted. An example is inability to remember what superstar played third base for the 1962 Baltimore Orioles. But you can’t remember it. Later while watching David Suzuki on CBC Telly, the name “Brookes Robinson” pops into your head. Your brain had been working on it all of the time unnoticed by your conscious programmes.
Amergin
