Fig. 1.

Mean (±SEM) responses during signaled availability and nonavailability periods for cocaine-maintained operant sessions. Left panels (a, c, e, and g) depict responding for cocaine under signaled availability, while right panels (b, d, f, and h) depict responses under signaled nonavailability conditions. Panels a–d compare responding maintained cocaine by females and males during adolescence to responses when retested as adults 30 days later. Panels e–h depict responses for adult females and males during initial testing and during a retest 30 days later. Both adolescents and adults responded more during the availability period during the initial test vs. the retest (a, c, e, and g; *p<0.01), and adolescents also responded more during the signaled nonavailability period during the initial test vs. the retest (b and d; *p<0.01). Adolescents responded more during the availability and nonavailability periods than adults during the initial test (a and c vs. e and g and b and d vs f and h; #p<0.01), and among the adults, females responded more than males during both signaled availability and nonavailability periods for both the initial test and retest (e and f vs. g and h; †p<0.05). Adults with adolescent cocaine exposure made more cocaine-reinforced responses than rats that received initial cocaine exposure as adults (a and c vs e and g; @p<0.01)