Fig. 2.

Rats reared in the impoverished (IC) and standard (SC) conditions habituated slower than rats reared in the enriched condition (EC), as suggested by the measure of area under the curve (AUC). In each panel, the dashed line separates the pre-exposure (left, sessions 1–2, and 9–10) and light-onset (right, sessions 11–20) phases. In the pre-exposure phase, only the first two (1–2) and last two sessions (9–10) are displayed. (A) & (B) Rats’ responses to the active & inactive holes declined respectively, suggesting within-session habituation. Each data point depicts responses in a 3-min epoch during the first 18 min of the session. (C) & (D) Rats in the IC and SC groups habituated at a slower rate, indicated by larger AUCs, than rats in the EC group, for the active & inactive holes respectively. Plotting is based on two-session blocks, and each measure represents the average from two consecutive sessions. Data are expressed as Mean±SEM. *: p<0.05; %: p<0.01; #: p<0.001, post hoc Tukey test: IC vs. EC groups.