Behavioral differences on memory retrieval between two variants of step-through inhibitory avoidance task in mice.

For several decades, one-trial inhibitory avoidance (IA) tasks have been used in the study of memory processing. In the present work, the effects of diazepam (DZP) (0.5mg/kg) and picrotoxin (PIC) (0.3mg/kg) on memory retrieval were assessed using two variants of a step-through IA situation in CF-1 mice. In the first variant, animals get into a dark compartment from an open illuminated platform (platform), whereas in the other, from an enclosed illuminated one (box). PIC impaired retention performance in the "platform-type" IA, but not in the "box-type". DZP enhanced retention performance in both types of IA task. These results evidence critical differences between the two step-through inhibitory avoidance tasks used, that might be relevant not only for retention performance during memory retrieval, but also for the theoretical interpretations and conclusions obtained from behavioral results.