Figure 4. A hierarchy of activity timescales during evidence accumulation.

(A) Top: Example widefield imaging field of view showing GCaMP6f fluorescence across the dorsal cortex. Bottom: Approximate correspondence between the field of view and regions of interest (ROIs) defined from the Allen Brain Atlas, ccv3. (B) Distribution of cross-validated accuracies across mice (n=6, sessions for each mouse are averaged) and ROIs (n=7, averaged across hemispheres). (C) Example of actual ∆F/F (gray) and model predictions (colored lines) for the first 5 s of the same held-out single trial, and four simultaneously imaged ROIs. Traces are convolved with a 1-SD Gaussian kernel for display only. (D) Auto-regressive model coefficients as a function of time lags for an example imaging session and four example ROIs. Gray, coefficient values. Colored lines, best fitting exponential decay functions. (E) Distribution of R² values for the exponential fits across mice (n=6, sessions for each mouse are averaged) and ROIs (n=7, averaged across hemispheres). (F) Exponential decay functions for all seven cortical areas, fitted to the average across mice (n=6). (G) Median time constants extracted from the exponential decay fits, for each area. Error bars, interquartile range across mice (n=6). p-value is from a one-way ANOVA with repeated measures with ROIs as factors. Light gray circles indicate data from individual mice.

Figure 4—figure supplement 1. Time course of sensory-evidence predictors in the encoding model of widefield Ca²⁺ dynamics does not significantly differ between cortical areas.

(A) Average normalized encoding model coefficients for contralateral-tower responses as a function of time lag for each region of interest (ROI). Shaded areas, ± SEM across mice (n=6). (B) Time of peak for contralateral tower coefficients. Gray circles: individual mice, bars: median, error bars: interquartile range. p-value is from a one-way ANOVA with repeated measures. (C–D). Same as (A) and (B), for coefficients for cumulative ∆ towers (#R – #L), taken from left hemisphere ROIs. (E) Coupling coefficients for ROI activity predictors. For each ROI (rows), shown are the average coefficients (n=6 mice) for the predictors consisting of zero-lag activity of the other simultaneously imaged ROIs. Note that the diagonal elements are not defined since zero-lag self-activity predictors were not in the model. Data from the somatosensory cortex ROI has been omitted for symmetry with the inactivation data. L and R indicate left and right hemispheres, respectively.