Telencephalon-projecting neurons (expressing high Ptk2b, Ddn, Icam5) formed a distinct set of 32 clusters including pyramidal cells of the cortex and hippocampus, as well as medium spiny neurons (MSNs) of the striatum. The cerebral cortex was the most diverse, with 20 projection cell types, which were glutamatergic (all VGLUT1, but some additionally VGLUT2 or VGLUT3). Closely related were the hippocampal pyramidal cells (three types) and the dentate gyrus granule cells, as well as a single cluster from the basolateral amygdala, all of which—like the isocortex—develop from the pallium.
