Inhibitory Avoidance with a Two-way Shuttle-box

so called passive avoidance), the animal precludes the aversive stimulus by not showing a behavior regularly shown in a particular environment. Inhibitory avoidance is acquired in only one trial, where the subject is punished for doing something such as entering a new compartment (test). Then, in a second session (retest), behavioral inhibition, for example not entering the compartment, is measured (see Bures̆, Bures̆ová and Huston, 1983, for the usual procedures). This procedure is frequently used in memory experiments (e.g., Berger-Sweeney, Arnold, Gabeau and Mills, 1995; for a review, Izquierdo and Medina, 1997), perhaps because it is not a time consuming procedure. Also and more important, it is easy to decide the appropriate moment for pharmacological treatment taking into account the learning processes of acquisition, consolidation and retention (Heise, 1987). Separate equipment exists for experiments of inhibitory (passive) and active avoidance. Nevertheless, mixed procedures alternating trials of both are performed with two-way shuttle-boxes and are well known in scientific literature. These procedures inPsicothema, 1998. Vol. 10, no 2, pp. 387-391 ISSN 0214 9915 CODEN PSOTEG Copyright © 1998 Psicothema