Model predictions vs. experimental data.

(A) (Left Y and Bottom X axes) Optimal E:I ratio based on normalized reconstruction error (See Fig D in S1 Text for other performance measures) as a function of model sparsity constraint λ is depicted by the solid line (mean) with variability (± standard error) denoted by the shaded band. (Right Y and Top X axes) The population sparsity (TR) measure computed for electrophysiology data from experimental studies in mice [52], non human primates (macaques) [53, 54] and cats [55] is shown (mean (markers) ± standard error (horizontal error bars)) as a function of observed E:I ratio ranges in biology (vertical error bars). Unfilled markers represent natural images and filled markers represent natural movies. Interspecies comparisons (B, C) Statistical significance of hypotheses based on model prediction (i.e., higher E:I ratio in biology corresponds to higher population sparsity) examined via inter-species population sparsity comparisons with all available data using hierarchical boostrapping. * and >*** represent p_bootstrap < 0.05 and 0.0001. (B) For natural images, the mice (E:I = 5.7–9:1) exhibit higher population sparsity compared to monkeys (E:I = 4–4.3:1), p_bootstrap = 0.01966. (C) For natural movies, mice (E:I = 5.7–9:1) exhibit higher population sparsity than both monkeys (E:I = 4–4.3:1) and cats (E:I = 4:1), p_boostrap < 10⁻⁸ for both, which is significant after accounting for multiple comparisons.