Summary of phasic response in dopamine neurons.

<p>To compare the magnitude of the satiety effect to the magnitude of the mean response, we plotted the responses of all dopamine neurons showing a cue-elicited phasic burst. (<b>a</b>) The phasic response to the cue of increasing DA neurons (<i>n</i> = 19) was higher for the second half of FT60 sessions than it was for the first half. Decreasing DA neurons (<i>n</i> = 74) showed the opposite pattern. The phasic response of unmodulated neurons (<i>n</i> = 35) did not change over time. Modulation of the phasic response was reduced by pre-feeding (<b>b</b>; <i>n</i> = 5 increasing, 15 decreasing, 19 unmodulated) and eliminated during extinction (<b>c</b>; <i>n</i> = 2 increasing, 2 decreasing, 18 unmodulated). The phasic response of increasing neurons was nearly abolished following pre-feeding and during extinction, and the phasic response of decreasing neurons was abolished during extinction.