Multiple timescales of sensory-evidence accumulation across the dorsal cortex

SUMMARY

Decisions requiring the gradual accrual of sensory evidence appear to recruit widespread cortical areas. However, the nature of the contributions of different regions remains unclear. Here we trained mice to accumulate evidence over seconds while navigating in virtual reality, and optogenetically silenced the activity of many cortical areas during different brief trial epochs. We found that the inactivation of different areas primarily affected the evidence-accumulation computation per se, rather than other decision-related processes. Specifically, we observed selective changes in the weighting of evidence over time, such that frontal inactivations led to deficits on longer timescales than posterior cortical ones. Likewise, large-scale cortical Ca²⁺ activity during task performance displayed different temporal integration windows matching the effects of inactivation. Our findings suggest that distributed cortical areas accumulate evidence following their hierarchy of intrinsic timescales.