The effect of LSD-25 on the interaction between conditioned and non-conditioned stimuli in a simple avoidance situation.

Abstract

The distractive influence of a series of tonal pips presented simultaneously with a visual conditioning stimulus was assessed using the time taken to carry out the simple conditioned avoidance response as a measure of the interaction between the conditioned and non-conditioned stimuli. Presentation of the tonal pips at three different levels of intensity induced a lengthening of response time, which was potentiated by 10 and 20μg/kg i.p. of LSD-25. When the conditioning stimulus was presented alone, however, a decrease in response time occurred after the drug had been given. The introduction of the auditory stimulus also produced a slight increase in the number of incorrect responses. Again LSD-25, at both dose levels, potentiated the change and induced an increase in the number of failures. The effect produced by LSD-25 on the response time for a simple conditioned avoidance response, therefore, appears to depend upon the presence or absence of stimuli other than used in the conditioning procedure.