Figure 6.

Lick-Inactive NAcSh neurons respond phasically to both the Start and Stop auditory cues. (A) The population activity of neurons (Z-score) that was either Active (red) or Inactive (blue) for times around the initiation of licking and during and after the Reward epoch for the Gustatory (upper), Start (middle) and Start/Stop test (bottom panels). Responses to all (Total) licks (licks/s) are shown in gray and the time between peaks indicates one lick cycle (~150 ms) and aligned to the onset of the Initiation epoch (for the Gustatory test) and the Start cue for the Start and Start/Stop tests (left column). For each brief-access test neuronal responses were also realigned to the reward start (RS -middle column) and the reward end (RE (right column). The arrows shown in the Lick-Inactive neurons point to the auditory–evoked phasic activation by both the Start and Stop cues (in Start/Stop and Start tests). Times from −1.5 to −0.5 s before the Initiation epoch were always used as the baseline. (B) Histogram for each test of the percentage of neurons that sustain an Active or Inactive modulation during licking. (C) Histogram showing the percentage of Lick-Active or Lick-Inactive neurons with a significant phasic modulation at the Start cue. (D) The proportion of Lick-Inactive neurons that responded phasically to both the Start (Click) and Stop cues (white noise). Horizontal lines in (C,D) indicate significant differences among tests at an alpha of 0.05 (chi-squared test).