EFFECTS OF PHENCYCLIDINE, LSD AND AMPHETAMINE ON NEURONAL-ACTIVITY IN THE POSTERIOR PARIETAL ASSOCIATION CORTEX OF THE MONKEY

The effects of three drugs of abuse, phencyclidine, LSD and amphetamine on the multineuronal impulse activity of the posterior parietal association cortex was studied in non-anaesthetized stump-tailed (Macaca speciosa) monkeys. Moderate doses of phencyclidine (less than 0.5 mg/kg) produced a rhythmic discharge and increased the spontaneous activity and the responses to visual, somaesthetic and auditory stimuli. The increase in activity was very marked in comparison with the effects of alcohol and pentobarbital which usually merely decreased the activity in this region. Larger doses of phencyclidine depressed both the spontaneous activity and sensory responses. Similar effects on the spontaneous activity were noted at recording sites where cellular responses were related to motor behaviour. Amphetamine and LSD produced only minor effects. Phencyclidine thus has a unique effect in the parietal association cortex. Small doses of phencyclidine which produce euphoria and hallucinations caused a strong increase in neural activity and larger doses, that produce anaesthesia. blocked the activity. © 1979.