Diversity index

To calculate neurons’ diversity indexes on a meaningful spectrum with interpretable reference points, we estimated theoretical references for diversity indexes of idealized simple and complex cells. Particularly, we estimated the lower/upper bounds (dlower and dupper) as the median average pairwise Euclidean distance of DEIs from a population of noiseless simple/complex cells, respectively. To get a precise estimation, we identified DEIs via performing an exhaustive search through the Gabor filter parameter spaces. Since DEIs are standardized with a fixed mean and standard deviation, idealized simple cells have the same average pairwise Euclidean distance regardless of the underlying Gabor parameters. Similarly, idealized complex cells with different Gabor parameters have identical but higher average pairwise Euclidean distance among themselves. Then for each real neuron, a diversity index (D) is calculated for each mouse V1 neuron i based on the average Euclidean pairwise distance of its DEIs di as