Figure 7.

PEHs showing water-selective (left) and cocaine-selective (right) neurons during reliable responding on the water-cocaine multiple schedule. Left, PEHs show a single Acb neuron (cell 1) exhibiting an increase in firing rate immediately after the reinforced response for water (RFe; top) and nonphasic firing relative to the reinforced response for cocaine (bottom). Right, Another Acb neuron (cell 2) recorded in a second animal exhibited nonphasic firing during the water-reinforcement phase and a shift to PR+RF activity during self-administration.