Figure 2.

Zif268 expression in the cortex after acquisition and reinstatement of CPP. Zif268 expression was induced after cocaine CPP and social interaction CPP in the PrL, IL, and LO cortex. Social interaction CPP increased more Zif268 expression in the PrL than cocaine CPP. Shown are Zif268 positive immuno-reactive nuclei per mm² of the respective brain area in naive rats, after acquisition of cocaine CPP (coc CPP) and after acquisition of social interaction CPP (social CPP) (left side of each graph of individual brain area). In addition, Zif268 expression was shown in rats that expressed cocaine CPP and underwent extinction in absence (coc CPP + saline ext) or presence of social interaction during extinction (coc CPP + saline and social ext) then reconditioned with cocaine in the previously cocaine-associated chamber (right side of each graph of individual brain area redrawn from Fritz et al., 2011a). Shown are group means ± SEM. ^* P < 0.05; ^** P < 0.01 compared to naive group; #P < 0.05 compared to coc CPP group. Brain area abbreviations follow the nomenclature of Paxinos and Watson (Paxinos and Watson, 2007).