Fig. 5: Connectome measurements constrain neural networks in circuits with sparse connectivity.
From: Connectome-constrained networks predict neural activity across the fly visual system
a, We constructed synthetic ‘ground-truth connectome’ networks with varying degrees of sparse connectivity for classifying handwritten digits. For each ground-truth connectome network, we simulated connectome measurements and constructed a connectome-constrained and task-optimized the unknown parameters (magenta) in the ‘simulated network’ (Methods). We measured the correlation of the neural response vector, across all stimuli, between a ground-truth (dark green) and a simulated (light green) network. b, Median neural response correlation coefficients from 100 randomly sampled neuron pairs from each layer and across 25 network pairs. Two conditions were considered in which connectome measurements revealed either only binary connectivity (blue) or also connection strength (orange). The fly visual system model presented here probably falls in the region between the two curves, as measured synapse counts inform relative connection strengths between pairs of neurons for the same pair of cell types, but not absolute connection strength.
