(a–b) Representative injection sites of Lumafluor retrograde beads in the dorsomedial (DMS, a) and posterior striatum (PS, b). Left, reference coronal section from PMBA; center, immunostained sections (gray, inverted lookup table) with Lumafluor beads (red); and right, the striatal subdivisions (DMS, red; PS, green) based on Figure 5. (c–k) Retrograde-labeled cells in the thalamus, midbrain, and several other subcortical regions, as indicated after injection of DMS (c, e, f, i, j) and PS (d, g, h, k). (c–d) Left, thalamic confidence maps indicating the thalamic origins of the thalamostriatal projections to DMS and PS, as shown in Figure 5. Thal1 and Thal2, red, were used for optogenetic stimulation of thalamostriatal projections to the DMS (Figure 8); center, corresponding coronal sections (gray, inverted lookup table) of the thalamus with retrograde-labeled cells (red dots) and thalamus outline (grey line); right, enlarged raw images corresponding to the boxed areas in center. (e–k) Retrograde labeled observed in the basolateral amygdala (BLA, e, g), dorsal/ventral anterior cingulate cortex (d/vACC, f), primary auditory cortex (Au1, h), substantia nigra pars compacta (SNc, i, k), and primary visual cortex (V1, j). Left, reference sections from PMBA, right, immunostaining of retrograde-labeled cells (gray, inverted lookup table). Ai, agranular insular cortex; APT, anterior pretectal nucleus; fr, fasciculus retroflexus; Hip, hippocampus; L1-6, cortical layer 1–6; Pir, piriform cortex; S1, primary somatosensory cortex; SNr, substanta nigra reticulare; Str, striatum. Scale bars: a–d, 500 µm; c1–c4 and d1–d3, 100 µm; e, g, i, k, 100 µm; f, h, j, 250 µm.