Extended Data Fig. 1: Morphological measurements of dendritic protrusions.
From: Filopodia are a structural substrate for silent synapses in adult neocortex
a, Illustration of a dendritic protrusion and corresponding measurements: head diameter. (dhead), neck diameter (dneck), length (l). b–d, Population histograms of morphological characteristics across all dendritic protrusions (n = 2234). e, Population histogram of the relationship between dhead and dneck. Shaded area indicates a ratio below 1.3, the first criterion used to classify filopodia versus spines. f, Population histogram of dhead/l for protrusions with dhead/dneck below 1.3 (shaded area in e). Protrusions with dhead/l above 3 were classified as filopodia, those below 3 were likely short stubby spines and were not analyzed further (shaded area= (dhead /dneck < 1.3) ∩ (l/ dhead>3)). g, Same as e but for each of the 4 mice. h, Fraction of dendritic protrusions classified as filopodia per mouse (n = 527, 944, 435, 328 dendritic protrusions and 30, 47, 25, 21 dendritic branches for mouse 1, 2, 3, 4 respectively). Box plot represents median and IQR with whiskers extending to the most extreme points not considered outliers. ns P = 0.093, Kruskal-Wallis test.
