Figure 1.

Inhibitory avoidance apparatus and contextual modifications. Box (A) (red frame) did not have any contextual modifications. Footshock was delivered in this apparatus only. Box (B,C) had some distinct contextual modifications and served as non-shock safe training and/or test contexts. Box (B) (blue frame) had four vertical white stripes taped on the wall of the dark compartment together with tape placed on the floor, closing the gap between the two plates along the entire length of the apparatus. Box (C) (gray frame) had two white circles taped on each wall of the dark compartment, and the gap between both plates was closed with tape. The colored frames refer to the diagrams in Figures 2, 3.