Sunday, June 5, 2016

Phylogeny of brain systems

These systems are superfluous and additive
1. System one-Automatic and somatic reflexes
2. Compound movements such as posture, breathing, saccadic eye movements and locomotion
3.  Functions such as nutrient, fight or flight reactions, sexual responses, feeding and drinking
4.  Motor activities involving cerebrum, basal ganglia and cerebellum eg. birds flying,
5.  Cerebral association functions in primates.
Notes expansion of cortex in mammals is proportional to expansion of striatum and cerebellum but in humans, cerebrum expands much more rapidly than the striatum.  The striatum receives projections from all cortical areas except the primary visual cortex.  The ratio of inputs is 20,000 cortical association neurons to 1 medium spiny neuron. It is estimated that 95 % of humans' activities are outside conscious cognitive control and are automatic.
Higher order systems of cognitive control coexist with primitive automatic systems. Vertically organized corticostriatal and corticocerebellar systems underlie cognitive control

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