Figure 7.

Time course of cocaine seeking (a, b) and taking (c, d) during PL optogenetic manipulation in Low (ChR2) (a–c) and High frequency rats (ArchT) (b–d). Cocaine seeking and taking are expressed by the cumulative active nose-pokes and the cumulative infusions over time (per min), respectively. (a) PL activation in Low frequency rats (ChR2) did not alter active nose-poking (Stim On as compared to Stim Off). (b) PL inactivation (ArchT) in High frequency rats increased active nose-pokes in a time-dependent manner (Stim On as compared to Stim Off) with a significant difference occurring after 14 min. (c, d) Time course of self-administration was altered by optical stimulation neither in Low nor High frequency rats. Over 60 min of self-administration, High frequency rats self-administered more infusions than Low frequency rats, as expected.