RETROGRADE AMNESIA FROM ELECTROCONVULSIVE SHOCK IN A ONE-TRIAL APPETITIVE LEARNING TASK.

Rats deprived of water were placed, for 4-minute sessions, into a chamber containing a hole in one wall. After several sessions the number of times these rats explored the hole markedly decreased. Rats given access to water at the hole for a brief period explored the hole more frequently than controls, when they were tested later. This increase in hole explorations was abolished when the water reinforcement was followed by electro-convulsive shock but not when followed by foot shock.