Figure 5.

Expected and received reward encoding in OFC and MFC during learning. A, Spike-density function and raster plot depicting the activity of an OFC neuron during the expected (−1000–0 ms) and received (0–1000 ms) reward periods. Raster plots are sorted by chosen amount of reward and both spike-density functions and raster plots are color coded by reward amount. B, The mean (±SEM) activity of the neuron in A to the three different stimuli during the expected reward period during initial learning. Mean responses are based on a running average of five trials. Yellow dots mark bins in which p < 0.05, false-discovery rate corrected. Inset shows trial-by-trial reward amounts associated with the three stimuli estimated from a reinforcement learning model fit to the data. The red curve is truncated because, as the monkeys learned, they stopped choosing the stimulus predicting 0.0 ml of water. C, Percentage of neurons in OFC (top) and MFC (bottom) classified as being significantly modulated by chosen reward, instrumental response, and the interaction term during either the expected (−500–0 ms before reward onset) or received reward periods (0–1000 ms after reward onset).