Distribution of phasic (gray) and nonphasic (white) neurons across the population of recorded cells in the NAc core (A) and shell (B) during cue presentation before devaluation (i.e., the last day of training, left) or test days when either a different rein... Distribution of phasic (gray) and nonphasic (white) neurons across the population of recorded cells in the NAc core (A) and shell (B) during cue presentation before devaluation (i.e., the last day of training, left) or test days when either a different reinforcer (nondevalued, middle) or the same reinforcer (devalued, right) received during trained was given before testing. The area shaded dark gray represents neurons that showed an increase in firing (excitation) to the cue and the area shaded light gray represents the neurons that showed a decrease in firing to the cue (inhibition). Population responses show no difference in the number of phasic cells in the NAc core across devaluation test days (A). There was a significantly greater number of phasic neurons in NAc shell (gray) activated by the cue presentation in the before devaluation and nondevalued condition compared with the devalued condition (B). *p < 0.05. Elizabeth A. West, and Regina M. Carelli J. Neurosci. 2016;36:1128-1139 ©2016 by Society for Neuroscience