We further found 38 excitatory and inhibitory cell types of the diencephalon (thalamus and hypothalamus) and midbrain, forming a unified taxon. These types segregated nearly perfectly into glutamatergic (mostly VGLUT1) and GABAergic subsets but included two cholinergic types (of the red nucleus and the habenula). The thalamus proper contained only glutamatergic neurons, except for the Meis2-expressing neurons of the reticular nucleus that forms a capsule around the thalamus. In the midbrain, the superior and inferior colliculi were the most diverse, comprising 17 excitatory (exclusively VGLUT1) and inhibitory (GABA) cell types, showing distinct spatial distributions. In the ventral midbrain, we identified two types of dopaminergic neurons, one cholinergic and four GABAergic.
