Effects of scopolamine on a double stimulus discrimination

Abstract Subjects were trained with a light, a temporal cue and light-temporal cue combination as discriminative stimuli. These groups were tested with doses of scopolamine and it was found that the groups trained with one cue were more sensitive to the drug than the double cue group, although their pre-drug responding was comparable. A similar pattern was found among individuals in the double stimulus group where there was a significant correlation between dependency on a single cue, as shown in transfer tests, and drug sensitivity. These results were interpreted in terms of drug-induced changes in stimulus sensitivity due to a modification of the neural mechanisms controlling attention.