Figure 4. Dense innervation and distance-dependence of connectivity.

A, Proportions of connected (red) and unconnected interneurons (blue) and false positives responses (black) within all tested sGFP interneurons. B, Connection probability for all stimulated interneurons in all maps. C₁, Distribution of intersomatic distances for all the sGFP interneurons tested and schematic representation of the measurement. The peak was centered on 230.83±5.3 μm (n=1,245). C₂, Averaged intersomatic distances between PCs and connected (red) and unconnected (blue) interneurons and false positive cells (black). Connected interneurons were significantly (p<0.0001, Mann-Whitney) closer to the PC than unconnected ones but not significantly different than false positive cells. D₁, Distributions of the intersomatic distances between PCs and connected (red) and unconnected interneurons (blue) and false positives (black). Peaks were centered on 170.54±4.55 μm (n=520) for connected interneurons, 300.63±5.02 (n=584) for unconnected interneurons and 192.15±14.80 (n=141) for false positives. D₂ Distributions of ratios of intersomatic distances between PCs and connected (red) and unconnected interneurons (blue) and false positives (black), normalized over the total number of stimulated interneurons. E, Distribution and averages of the connection probabilities for stimulated interneurons within a radius of 400 μm or 200 μm from the PCs. ***: p<0.0001.