Extended Data Fig. 3: Inhibitory neuron subclasses exhibit spatial patterns to PSS distributions.

The UMAP embedding of all the perisomatic features, including PSS features, across all inhibitory cells, colored with respect to what fraction of that cell’s input (within the 60 µm cutout) comes from what PSS/distance bin. PSS shape bins were simplified from 29 bins to 5 broad categories to simplify the visualization (bins 0-4: short spines, 5–8: long-spines, 9-18 + 23: smooth shafts, 19–22: spiny shafts, 24–29: soma). This visualization gives insight into how different cells in different parts of this embedding space receive varying amounts of input onto different shapes within different spatial zones of the perisomatic area. Cells on the far left hand side of the embedding, where in general bipolar type neurons were found, have larger fractions of their inputs near the soma, including dendritic shafts which are more irregular in shape (“spiny shafts”), and smooth shaft inputs farther away where the dendrites begin to elaborate. Basket cells on the right hand side of the side of the embedding are dominated by somatic inputs and smooth shaft inputs which are more evenly distributed spatially. The island at the bottom that is dominated by neurogliaform cells is characterized by having relatively fewer somatic inputs, but an increasing amount of shaft and spiny input at distal dendrites.