Comparison of amnesias induced by electroconvulsive shock administered after training-trial footshock or noncontingent footshock in rats.

Used a 1-trial fear-conditioning paradigm in 2 experiments with 75 and 105 male Long-Evans rats, respectively. The amnesia pattern resulting from ECS delivered .5 sec after the training-trial footshock (FS/ECS) was compared with the amnesia resulting from an ECS delivered .5 sec after a noncontingent footshock (NCFS/ECS) administered 24 hrs after the training-trial footshock. FS/ECS produced a relatively strong and permanent amnesia, whereas NCFS/ECS resulted in a relatively weak and transient amnesia. Several possible explanations of these results are discussed, and it is suggested that both amnesias resulted from a disruption of memory-retrieval processes. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)