Relationships between spine location and the location of the presynaptic cells. (A) XY-plane-projected distribution of presynaptic neurons (xpre, ypre) and the spines they innervated (xsp, ysp). Black, blue, orange and red closed circles represent the cells innervating spines with an xsp of 0-40 μm (black open circles), 40-80 μm (blue open circles), 80-120 μm (orange open circles), and >120 μm (red open circles), respectively. (B) Histograms of the lateral distance between the postsynaptic and presynaptic somata (left), ; the lateral distance between the dendritic spine and the presynaptic soma (middle), ; and the straight-line distance of the dendritic spine from the presynaptic soma (right), . Black, blue, orange and red bars indicate spines with an xsp of 0-40 μm, 40-80 μm, 80-120 μm, and 120-160 μm, respectively. (C) Histograms of xpre. Black, blue orange and red bars indicate the presynaptic cells innervating the spines with an xsp of 0-40 μm, 40-80 μm, 80-120 μm and 120-160 μm, respectively. *P < 0.05 (one-way ANOVA followed by Tukey's test).