As partially distinct populations of neurons were active before and after trial outcome (Figures 3D and S5), we asked whether the population representation of second-step state was different at these two time points. We plotted the second-step state regression weights for each neuron at a time point mid-way between choice and outcome (which we term the pre-outcome representation of second-step state) against the weights 250 ms after outcome (the post-outcome representation) (Figure 3F). These pre- and post-outcome representations were uncorrelated (R2 = 0.0033), indicating that although second-step state was strongly represented at both times, the representations were orthogonal and involved different populations of neurons. To evaluate the time course of these two representations, we projected the second-step state regression weights at each time point across the trial onto the two representations (Figure 3G), using cross-validation to give an unbiased time course estimates. The pre-outcome representation of second-step state peaked shortly before second-step port entry and decayed rapidly afterward, while the post-outcome representation peaked shortly after trial outcome and persisted for ∼500 ms.
