THE DIFFERENTIAL EFFECTS OF METHAMPHETAMINE UPON VISUAL EXPLORATORY BEHAVIOR AND SPONTANEOUS MOTOR ACTIVITY IN RHESUS MONKEYS (<I>Macaca mulatta</I>)

Abstract

The differential effects of methamphetamine (2 mg/kg, i.m.) upon visual exploratory behavior and spontaneous motor activity were studied with rhesus monkeys (Exp. I, n=10, Exp. II, n=6).The frequency and cumulative time of the approach response to the visual stimulus (either a flickering light or a peer monkey) were recorded as an index of visual exploratory behavior and spontaneous motor activity was also measured in terms of photobeam breaks by the S's spontaneous movements. It was found that methamphetamine significantly inhibited the approach response to the visual stimulus, but spontaneous motor activity obtained concurrently with visual exploratory behavior was elevated in some monkeys but depressed in other monkeys. The results were discussed in relation to Berlyne's arousal hypothesis.