Fig. 2: Neurons with higher signal correlation are more likely to form synapses.
From: Functional connectomics reveals general wiring rule in mouse visual cortex
a, Anatomical control selection schematic. For each presynaptic neuron (yellow), true postsynaptic partners (black) have controls drawn from unconnected neurons with non-zero axon–dendrite co-travel distance (ADP, red) or zero co-travel distance in the same cortical region (blue). b, Meshes showing presynaptic (yellow axon), postsynaptic (black dendrite) and ADP control (red dendrite) neurons. c, Presynaptic axons in EM space for all projection types (V1→V1, HVA→HVA, V1→HVA and HVA→V1), with soma centroids of connected partners (black), ADP controls (red), same-area controls (blue) and all other functionally matched neurons (grey). Orange triangles represent presynaptic soma. Dashed line is the V1–HVA boundary. Scale bars, 100 μm. Nucleus IDs: V1, 327859; HVA, 560530. d, Mean signal correlation differs between synaptic partners, ADP controls and same-region controls across projection types. Data are mean ± s.e.m.; two-sided paired t-test. Sample size in Supplementary Table 2. e, Ld increases with signal correlation (Δ co-travel distance and Δ signal correlation represent deviations from mean per presynatic neuron). V1→V1: mean Ld = 9.03 μm; HVA→HVA: mean Ld = 9.83 μm; V1→HVA: mean Ld = 4.17 μm; HVA→V1: mean Ld = 1.53 μm. Bands represent bootstrapped s.e.m. Sample sizes for GLMM statistics are shown in Supplementary Tables 3 and 4. f, Synapse density (Nsyn/Ld) increases with signal correlation across projections. V1→V1: mean Nsyn/Ld = 1.12 mm−1; HVA→HVA: mean Nsyn/Ld = 0.83 mm−1; V1→HVA: mean Nsyn/Ld = 1.55 mm−1; HVA→V1: mean Nsyn/Ld = 1.26 mm−1. Bands represent bootstrapped s.e.m. Sample sizes for GLMM statistics are shown in Supplementary Tables 5 and 6. g, Meshes with small (896 voxels) and large (41,716 voxels) synapse cleft volumes. h, Synapse size (log10 cleft volume in voxels) correlates with signal correlation (6,608 pairs, P = 3.997 × 10−21, linear regression on unbinned data). Residual signal correlation adjusted for Ld. Bars show bin-wise s.e.m. i, Multisynaptic meshes (yellow, presynaptic; black, postsynaptic). j, Signal correlations increase with synapse count (6,608 pairs, P = 0.009, linear regression on unbinned data). Residual signal correlation adjusted for Ld. Bars show bin-wise s.e.m. *P < 0.05, **P < 0.01, ***P < 0.001 for all figures; corrected for multiple comparisons by Benjamini–Hochberg procedure.
