NEUROCHEMICAL CHANGES IN THE AGING HUMAN BRAIN - IMPLICATIONS FOR BEHAVIORAL IMPAIRMENT AND NEURODEGENERATIVE DISEASE

Neurotransmission is impaired in age-related disorders, such as Alzhei mer's and Parkinson's diseases, which has prompted many investigations into the neurochemistry of the aging human brain. Of all the neurotra nsmitter systems studied, age-related changes in parameters of the ser otonergic, cholinergic, and dopaminergic systems are the most reliably measured. The association of these neurotransmitters, respectively, w ith mood, memory, and motor function has fueled interest in hole chang es in neurochemistry may contribute to age-associated behavioral chang es and possibly predispose older persons to diseases of Late life. The evidence suggests that impaired neurotransmission may be responsible for at feast some of the behavioral abnormalities associated with agin g. Moreover, age-related neurodegenerative diseases may evolve from th e interaction between defects in specific neurochemical mechanisms and as-yet undefined pathophysiologic processes.