Extended Data Fig. 2: Diversity of ultrastructural and functional properties for individual synapses.
From: Cortical response selectivity derives from strength in numbers of synapses
a, Distribution of the number of presynaptic boutons contacting single, visually-responsive spines. b, Distribution of visually-responsive spines with a simple or perforated postsynaptic density (PSD). c, Spine head volume and PSD area are strongly correlated in individual synapses (Spearman’s correlation, one-sided test, n = 155 from 5 cells from 3 animals). d, Spine head volume is not correlated with spine neck length (Spearman’s correlation, two-sided test, n = 155 from 5 cells from 3 animals). e, For each synapse reconstructed, a NEURON model (Methods) was used to simulate voltage depolarization in the spine head and soma (ΔVm). A schematic of this model is shown (inset). Spines with longer necks show greater voltage attenuation (ΔVmsoma/ΔVmspine, left) and spines with larger PSDs drive larger ΔVmsoma (right). f, Distributions of spine-soma preference difference for orientation (median = 31.2, IQR = 48.4, n = 155 from 5 cells from 3 animals), direction (median = 106 deg, IQR = 114 deg, n = 155 from 5 cells from 3 animals), and ocular dominance (median = 0.43, IQR = 0.60, n = 155 from 5 cells from 3 animals). Except for direction preference, distributions are significantly different from a uniform distribution (Kruskal–Wallis test). g, Distributions of spine selectivity for direction (left) and orientation (right). Selectivity computed as vector strength (Methods) of peak responses elicited by stimulation of the preferred eye.
