Fig. 3: Neuronal populations encode variables of the reward dynamics.

a, Sample neurons for which the pre-press firing rate covaries with either waiting time (left) or reward ratio (right). The firing rate was calculated for a 200 ms sliding window starting 2 s before and ending 1 s after presses. Firing rates were averaged across presses with low (<20th percentile, gray) and high (>80th percentile, colored) of either the waiting time or the reward rate. Data are presented as mean values ± s.e.m. b, Decoded and measured waiting time (left) and reward ratio (right) for two sample sessions. Forty-five neurons in the session on the left and 60 neurons in the session on the right were used. The shown value of Pearson correlation coefficient is the average value across the cross-validated sets in each session. c, Decoding the waiting time (top) or the reward ratio (bottom) for 30 sessions as a function of the number of neurons used as predictors. The predictor neurons were chosen randomly from the population. Data are presented as mean values ± s.e.m. across 20 randomly selected subset of units. Sessions of monkey G are shown with a darker color, and sessions of monkey T are shown with a lighter color.