Figure 4.

Approximate percentage of active cells among annotated cells in the training datasets. To determine the activity of the cells in a movie, we used the following approximate analysis. First, we downsample the movie by averaging 10 frames. For every annotated cell, we compute the average intensity over time of the pixels in the spatial footprint. This time series is used an estimate of the signal of the cell. A cell is then considered active if the Δ f/f (Jia et al., 2011) of this time series is at least 3.5 SDs above the median of Δ f/f for a minimum of 3 potentially nonsequential time steps. Due to the approximate nature of this analysis, its interpretation should be limited to understanding the general ratio between active and inactive cells in the datasets.