Figure 4.
Inactivation of STN attenuates cocaine seeking. (A) Twenty-four hrs following the last cocaine self-administration session, bilateral STN muscimol microinfusion pretreatment significantly reduced unreinforced responding on the first day of extinction compared to pretreatment with aCSF vehicle (n = 8, paired t-test, t7 = 4.31, p < 0.01). (B) This suppression of unreinforced responding with muscimol microinfusion into STN was significantly correlated with microinjector distance from STN center (n = 8, Pearson, r = 0.77, p < 0.05), indicating inactivation of STN, not a nearby structure, was driving reduced drug seeking in early extinction. (C) After extinction of cocaine self-administration, responding was significantly reinstated with cocaine-associated light and tone cues (n = 8, extinction vs. aCSF reinstatement, Tukey, q = 6.78, ***p < 0.001). Muscimol pretreatment into STN blocked cued reinstatement of cocaine seeking (n = 8, extinction vs. muscimol reinstatement, Tukey, q = 1.46, p = 0.74, n.s. = not significant), and cue-reinstated responding was significantly lower with muscimol pretreatment compared to aCSF pretreatment (n = 8, Tukey, q = 5.09, **p < 0.01).