Figure 4.

Strength and latency of outcome encoding in the AO and SO tasks. A) To quantify the strength of outcome encoding, for each neuron with a significant main effect of Outcome, we measured the maximum percentage of variance in its firing rate attributable to this factor (PEVo). To compare the strength of this encoding across our neuronal populations, we then ran a three-way ANOVA on the PEV_O values with factors of brain area, task, and whether the cell was selective in one or both tasks. We found that outcome selectivity was stronger in the AO task than the SO task (F_{(1, 247)} = 53, p < 1×10⁻¹¹), but there were no other significant main effects or interactions. In particular, there was no evidence that outcome selectivity was stronger in ACC during the AO task and OFC during the SO task (Task x Area interaction, F_{(1, 247)} = 1.4, p > 0.1). B) For each outcome-selective neuron, we used the sliding analysis to determine the latency with which it first encoded outcome information. We then performed a three-way ANOVA on the neuronal latencies with factors of brain area, task, and whether neurons were selective in one or both tasks. Outcome selectivity was encoded significantly faster by neurons that were selective in both tasks (mean = 576 ± 30-ms) compared to those selective in only one task (mean = 651 ± 25-ms, F_(1,247)=5.3, p < 0.05). There were no other significant main effects or interactions. In particular, there was no evidence that there was any difference between the brain areas in terms of the latency to encode outcome information on the AO or SO task (Task x Area interaction, F_{(1, 247)} < 1, p > 0.1).