Fig. 4.

Effect of habituation on the response to DOI in the rat Behavioral Pattern Monitor (BPM). Male Sprague-Dawley rats were tested in novel BPM chambers (Left panels) or familiar BPM chambers (Right panels). In the novel environment paradigm, rats (n = 5/group, 10 total) were injected SC with vehicle (saline) or DOI (0.15 mg/kg), 10 min prior to being placed in the BPM for a 60-min test session. In the familiar environment paradigm, rats (n = 8/group, 16 total) were tested in the BPM on three occasions at 48-h intervals, but only injected with the drug prior to their third exposure to the BPM chamber; rats were injected SC with vehicle (saline) or DOI (0.15 mg/kg), 10 min prior to being placed in the BPM for a 60-min test session. Data from the test sessions are presented in 10-min time blocks (crossings, a measure of locomotor activity) or 30-min time blocks (holepokes, rearings, center entries). Data are shown as mean ± SEM. *p < 0.05, **p < 0.01 versus vehicle control (Bonferroni’s multiple comparisons test)