Figure 1.

Experimental design of the behavioral procedure. Mice were either submitted to a cue–shock pairing procedure (predicting-cue group) or to a cue–shock unpairing procedure (predicting-context group). Immediately after conditioning, animals received intra-hippocampal infusions of artificial cerebrospinal fluid (aCSF), corticosterone (CORT), or dexamethasone (DEX). The next day, mice were first re-exposed to the cue alone in a neutral chamber, then (2 h later) were re-exposed to the conditioning context without the cue. During these tests, the freezing responses were measured during 2-min periods.