Electroconvulsive shock- or puromycin-induced retention deficits in goldfish given two active-avoidance sessions.

In a factorial design, goldfish received 15 active-avoidance training trials on Days 1, 7, and 13 followed by electroconvulsive shock (ECS) or n o treatment after the training session on Days 1 and 7. The final retention deficits observed when ECS was given after the f'trst session only or after the second session only were similar. Fish given ECS after both sessions showed a cumulative deficit that approximated the sum of the two effects. Similar results were obtained with puromycin. These data support the hypothesis that ECS and puromycin impair only recent learning. Retrograde amnesia gradients confirmed that the efficacy of these amnestic agents was not altered by a second administration.