Abstract
SUMMARY:The morphological, chemical, and physiological changes in the brain accompanying old age are reviewed. The deterioration of the striatal and hypothalamic dopaminergic systems were implicated in the onset of age related Parkinsonian-like slowing of performance and altered affect. Cholinergic hippocampal and neocortical systems were chemically and physiologically abnormal in the aged. The implications for slowed cognitive processing and persistance of the memory trace are presented.