Fig. 3.

Panel a: The mean (±SEM) number of active and inactive nosepokes made during baseline training sessions, when all rats received cocaine at the same rate (5 sec), and during short access (ShA) sessions when rats were assigned to groups that received cocaine over either 5, 45, or 90 sec. Baseline data are averaged over 2 sessions. Panel b: The mean (± SEM) number of infusions received during the same baseline training and ShA sessions as Panel a (note Log2 scale). Panel c: the pattern of self-administration behavior in 3 representative rats during ShA session 3. The horizontal line represents the duration of the session, and vertical marks indicate the time during the session when a rat injected itself with cocaine.