Drug effects on memory: assessment of a combined active and passive avoidance task.

We evaluate a little-known avoidance task first described by Carew, which enables the simultaneous assessment of two indices relevant to the study of memory processes, passive avoidance re-entry latency, and active avoidance choice. As an illustration, the effects of 0, 1 and 10 mg/kg amphetamine, peripherally injected immediately following the learning trial, were studied using two different shock intensity conditions (mild and moderate). The latency measure indicated that the drug improved consolidation, but the choice measure suggested that this enhancement was at best marginal; shock intensity was found to be a critical factor. It is concluded that this unique task is superior to some traditional avoidance techniques used in assessing memory.