The mind of man, like that of an animal for that matter, is something that we cannot see or touch or stimulate. It is the faculty which is responsible for that portion of human behaviour which does not seem to be automatic… Everyone knows that the mind of man is something that depends upon the action of the brain. Things are seen, heard, felt or smelt only when electrical currents are conducted along appropriate nerve tracts to the brain. Problems are worked out by using the brain. A voluntary act is dictated somehow at a high level of organization within the cranial cavity. Then executive messages are flashed down the spinal cord… It is obvious that there must be a co-ordinating centre within the ‘house’, a sort of telephone exchange or switchboard to which messages come, and from which messages depart after appropriate decisions be reached, decisions that are based upon memories of previous experience and influenced by present desires. The brain is a large spherical organ that is divided into two partially separated halves, the right and the left hemisphere. A superficial layer of nerve cells covers the whole of the cerebral hemispheres in an outer mantle of grey matter. This is the cerebral bark, or cortex… The cortex covers the surface of the two hemispheres with a mosaic of functional areas. […]