Fig. 7.
Strip charts of an LPE cell in control and eticlopride sessions. A, Control session in which vehicle was preadministered to the animal. B, The same cell in a session in which 20 μg/kg eticlopride was systemically administered 30 min before the start of the session. C, The same cell in a session in which 40 μg/kg eticlopride was preadministered. Bin width for strip charts is 30 sec. Vertical dashesabove strip charts indicate lever presses; numbers indicate the number of lever presses leading to the reward. BP indicates breakpoint.D–F, Dose–response curves relating average LPE cell firing rate to modeled cocaine level. Each graph shows the dose–response curve in the presence of a different dose of eticlopride, as well as in the same cells during vehicle control sessions. *p < 0.05, significant difference between the firing rate in eticlopride and in control at the same cocaine level (Tukey's test). Two-way ANOVA results (listed as factor,F value, significance) are as follows. D, DA antagonist, F(1, 19401) = 2.1, NS; cocaine level, F(7,19401) = 133.0,p < 0.001; DA antagonist × cocaine level,F(7,19401) = 7.2, p< 0.001. E, DA antagonist,F(1,17695) = 39.8,p < 0.001; cocaine level,F(7,17695) = 84.8,p < 0.001; DA antagonist × cocaine level,F(7,17695) = 3.3, p< 0.01. F, DA antagonist,F(1,16166) = 180.0,p < 0.001; cocaine level,F(7,16166) = 19.9,p < 0.001; DA antagonist × cocaine level,F(7,16166) = 37.5,p < 0.001.