A Neural Correlate of Predicted and Actual Reward-Value Information in Monkey Pedunculopontine Tegmental and Dorsal Raphe Nucleus during Saccade Tasks

Figure 10

Schematic drawing of the activity changes of dopaminergic, PPTN, and DRN neurons for the two-valued saccade task. Cue and reward indicate the timing of reward-cue presentation (either fixation target shape or saccade target location) and large- and small-reward delivery, respectively. The colors indicate the responses in the large-reward trials (red) and small-reward trials (blue) and the responses of neurons with no significant reward modulation (black). (A) Dopaminergic neurons exhibited phasic burst firing to a reward-predictive cue and an unexpected reward (dashed lines). (B, D) Two different groups of PPTN neurons exhibited a tonic reward prediction response (B) and a phasic actual reward response (D). (C) PPTN neurons with no significant reward modulation often exhibited tonic activity during the task period. (E, G) DRN neurons exhibited correlated central fixation and reward modulation, preferring either larger (E) or smaller rewards (G). (F) DRN neurons with no significant reward modulation often exhibited a phasic response to target presentation.