Figure 3.

Medulla connectome module. (a) Synaptic connectivity matrix for modular cell types assembled from 2495 synapses (Supplementary Table 1). Three pathways, identified via the Louvain clustering analysis²⁵, are labeled by colored boxes. They are named by their primary input neuron(s): the L1 (magenta), L2 (green), and L3/R7/R8 (cyan) pathways. The pathways are ordered by the total number of connections within a pathway, in descending order, and the cell types, within each pathway, are ordered by the sum of their pre- and postsynaptic connections to and from other cell types within their pathway, also in descending order. (b) Medulla connectome module as a 3D graph. Cell types with stronger connections are positioned closer to each other, using the visualization of similarities (VOS) layout algorithm²⁶. Three spatially segregated groups are observed that closely match the pathways identified through clustering (coloring of spheres). The dominant direction of signal flow is oriented into the page²³. Inset in (b) shows the fraction of synaptic connections within the full connectome having a connection weight greater than indicated.