Aligning Local Field Potential With ΔF/F

Calcium events from raw ΔF/F were detected as previously described using custom MATLAB scripts (Caccavano et al., 2020). Briefly, slow changes in fluorescence from further photo-bleaching or drifting of the imaging plane was smoothed using a moving average calculated with locally weighted regression. Baseline corrected ΔF/F traces were then interpolated from the raw frame rate of 7.5 Hz–2 kHz and the LFP signal was downsampled from 20 to 2 kHz for post stimulus analysis. Calcium event detection was set at 4 SD above the calculated baseline with start and end times for events set at 2 SD. Baselines for each ROI was determined by an iterative algorithm of Gaussian fitting to the histogram of all data points. After calculating the baseline mean, SD, and event thresholds, features of detected events for each cell were extracted [start, peak, end, inter-event-interval (IEI), amplitude, and frequency]. To detect events occurring during spontaneous epochs and post stimulation, the interpolated calcium traces were trimmed and aligned with the downsampled LFP trace.