Figure 1.

Experimental procedure. (A) Drawing illustrating the habituation, sociability and the SNP phases of the three‐chamber test. (B) Wild‐type and CRF₂−/− mice are tested (ticks) once a week in the three‐chamber task using a 0, 2 or 4 h ITI between the sociability and the SNP test. Then, over an 11 day period, cocaine (5–20 mg·kg⁻¹, i.p.) is injected twice a day (0800–2000 h), except for the last day when only one injection is given in the morning, immediately prior to testing (cocaine withdrawal day 0). Following cessation of cocaine administration, the mice are tested weekly in the three‐chamber task throughout a relatively long period using a 0 h ITI between the sociability and the SNP test. Then, using a within‐subject design, on cocaine withdrawal day 40 or 42, the mice are exposed or not to an EPS 1 h prior to the three‐chamber test.