Figure 3.

Emergence of cocaine-selective Acb patterned discharge during the initial exposure to cocaine in the water-cocaine multiple schedule. Cumulative record shows behavioral response patterns during the cocaine self-administration component on day 1 of the multiple schedule. Note that the animal responded quickly for intravenous cocaine at the start of the phase followed by several priming infusions. Thereafter, behavioral responding for cocaine was observed, although somewhat erratic. Stripcharts show Acb cell firing relative to lever-press responding at the start of the self-administration component (top left, indicated by arrows) during priming infusions of cocaine (top center, indicated by arrows) and relative to the last four lever-press responses in the session (bottom right, indicated by arrows). Note the onset of RFe patterned activity during the end of the session. The same neuron exhibited NP firing relative to water-reinforced responding (data not shown).