The human nervous system differs from that of other mammals chiefly in the great enlargement and elaboration of the cerebral hemispheres. Much of what is known of the functions of the human brain is derived from observations of the effects of disease, from the results of experimentation on animals, particularly monkeys, and from neuroimaging studies of animals and of healthy human subjects. Such sources of information have helped elucidate aspects of the nervous activity underlying certain properties of the human brain, including processes related to vision, memory, speech, and emotion. Although scientists’ knowledge of the functions of this uniquely complex ...(100 of 37287 words)