Abstract: The characteristics of EEG of different ages were studied on rhesusmonkeys (macacas rhesus). 16 animals (mixed malesand females) weredivided into three groups According to different ages, namely new born,immature and mature groups, The effects of chlorpromazine on EEG wereperfromed on 12 animals of them. The results are as follows: The frequencies of spontaneous potential on the EEG in the rhesusmonkeys vary at different ages. The frequency is increased and theamplitude is decreased as the animal's age advances. The driving response elicited by photic stimulation is quite evident in immature animals andsecondary evident in mature animals, and it has not been observed in newborn animals. Different changes of EEG in rhesus monkeys caused by chlorpromazinewere observed. The main characteristics of EEG present high voltages andslow waves. Immature monkeys suffered more effects than maturemonkeys. Chlorpromazine can improve the driving response elicited by photicstimulation.

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