a curved band of cortex lying within each cerebral hemisphere: in evolutionary terms one of the brain’s most primitive parts. It forms a portion of the *limbic system and is involved in the complex physical aspects of behaviour governed by emotion and instinct.
a network of nerve pathways and nuclei throughout the *brainstem, connecting motor and sensory nerves to and from the spinal cord, the cerebellum and the cerebrum, and the cranial nerves. It is estimated that a single neuron in this network may have synapses with as many as 25,000 other neurons.... reticular formation
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