Figure 2.

Example firing patterns from two nucleus accumbens neurons showing long-lasting inhibition during the delayed-response task. A, Perievent raster (top) and histogram (bottom) are shown for a single NAcc neuron. For each raster and paired histogram, the x-axis shows the time (in seconds) relative to the behavioral event around which the graphs were constructed. The y-axis shows the firing rate for each neuron. Labeled arrows (above middle panels) show the behavioral intervals occurring before and after each event. Labels below each graph show the behavioral event around which the graphs were constructed. NPB, Nosepoke break. Only correct trials are included in these graphs. Filled circles in the raster show white noise cue presentation. B, A second NAcc example neuron. Graph conventions are identical to those shown in A. In both example neurons, firing rate was significantly inhibited relative to baseline (left panels) for the duration of performance in the delayed-response task (during delay, movement, and reward intervals) and recovered to baseline levels only after exit from the RR.