To quantify how accurately ACC activity differentiated between task states, we decoded which of ten different locations in the task’s state-action space neuronal activity came from, using a multinomial logistic regression. Locations were defined by time point in the trial (pre-choice, post-choice, and post-outcome) and the trial’s choice, second step, and outcome (Figure 4D). The analysis combined activity from 1,053 neurons from the nine sessions in which each location was visited at least ten times, yielding a cross-validated decoding accuracy of 95% (Figure 4E), where chance level is 10%. These data show that ACC activity represents the full set of trial events that constitute the state-action space of the task.
