Fig. 4: Putative extratelencephalic (ET) cells in human frontoinsula (FI) and middle temporal gyrus (MTG) share many common markers but differ in frequency.

a, b Violin plots in human FI (a) and MTG (b) showing expression of all genes enriched in Exc FEZF2 GABRQ, and a subset of genes enriched in the corresponding cluster in human MTG that show divergent patterning between these regions (see the “Methods” section), including many novel marker genes. Gene expression values are displayed on a log2 scale. c Representative inverted images of DAPI-stained sections of FI and MTG. Red dots depict the locations of cells labeled using multiplex fluorescent in situ hybridization (mFISH) for putative ET marker gene POU3F1 and SLC17A7. Scale bars in c: DAPI images 50 μm, mFISH images 10 μm. d Black, quantification of the proportion of SLC17A7+ cells expressing the ET marker POU3F1 in FI and MTG expressed as a fraction of the total number of excitatory (SLC17A7+) cells in layer 5 of either region. Individual data points are represented by black squares (FI) or black dots (MTG). Green, comparable quantification of the fraction of excitatory neurons dissected from layer 5 that are assigned to the ET clusters Exc L4-5 FEZF2 SCN4B (MTG) or Exc FEZF2 GABRQ (FI). By both mFISH and single nucleus RNA-seq (snRNA-seq), a higher fraction of putative ET cells is found in FI than MTG. Bars show the mean and error bars the standard deviation.