Fig. 4: Bipartite parameterization reproduces the visual features and in vivo responses of nonparametric VEIs.
From: Functional bipartite invariance in mouse primary visual cortex receptive fields
a,b, Schematic of VEI synthesis using the nonparametric approach (VEIs, blue), full-texture parameterization (VEIsfull, purple), and partial-texture parameterization (VEIspartial, orange) for an example V1 texture cell (left) and V1 bipartite cell (right). VEIsfull were synthesized by optimizing an underlying texture canvas, from which random crops masked by the MEI mask maximally activated the target neuron. In contrast, VEIspartial comprised two distinct, nonoverlapping subfields: a fixed subfield directly masked from the MEI, and a shift-invariant subfield preferring random crops from a texture image synthesized similarly to VEIsfull, but using only part of the MEI mask for texture optimization. c, MEI, VEIs, VEIsfull and VEIspartial for three example neurons, with each VEI type indicated by the corresponding color from a. d, VEIspartial were more similar to their corresponding nonparametric VEIs than VEIsfull for both random V1 neurons and closed-loop neurons (two-sided Wilcoxon signed-rank test, W = 2,783, P = 4.6 × 10−195 and W = 65, P = 3.0 × 10−67, respectively). e, VEIsfull failed to stimulate their target neurons in vivo compared to nonparametric VEIs (31 ± 2% of VEI activation, two-sided Wilcoxon signed-rank test, W = 4,389, P = 6.2 × 10−54) with 43.4% of all neurons showing different responses to VEIsfull than VEIs (29.4% after BH corrections) (P < 0.05, two-sided Welch’s t-test with 29.4 average d.f.). f, VEIspartial activated their target neurons in vivo similarly to nonparametric VEIs (86 ± 4% of VEI activation, two-sided Wilcoxon signed-rank test, W = 32,429, P = 7.0 × 10−4) with only 8.5% of all neurons showing different responses (0.0% after BH corrections) (P < 0.05, two-sided Welch’s t-test with 33.5 average d.f.). e,f, In vivo responses to VEIs, VEIsfull and VEIspartial were averaged across 20 different images with single repeat. g, Bipartite invariance indices of V1 neurons were larger than those of simulated simple cells (60 cells, blue) and lower than those of simulated complex cells (60 cells, red) (P = 1.4 × 10−38 and 1.1 × 10−138, two-sided Welch’s t-test with 95.5 and 213.8 d.f., respectively). Data were pooled from six mice, displaying a total of 1,200 neurons for random V1 neurons; closed-loop neurons comprised 401 neurons pooled from eight mice.
