Extended Data Fig. 4: SNr output to SC segregated both across medial-lateral axis and across layers.

a, left, Example histology section with mSNr axons (red) and lSNr axons (green) from experiment described in Fig. 2c. right, Cartoon diagram summarizing the region and layer specificity of lSNr and mSNr observed. lSNr innervated the lateral SC (abbreviations: Zo: Zona layer of the superior colliculus, Op: optic nerve layer of the superior colliculus, InG: Intermediate gray layer of the superior colliculus, InWh: Intermediate white layer of the superior colliculus, DpG: Deep gray layer of the superior colliculus). lSNr innervated the lSC in InWh, and extending to upper layer of InWh in mSC. mSNr innervated the superfifical part of InG and deeper part of InWh in mSC. Similar results were obtained in n = 4 mice. Scale bar, 500um. b, left, Example histological section with ^VLSSNr (yellow), ^DLSSNr (cyan), and ^DMSSNr (magenta) axons in SC (images reproduced from Fig. 2f). right, Carton diagram summarizing the region and layer specificity of ^VLSSNr, ^DLSSNr, and ^DMSSNr observed. ^VLSSNr targeted the InWh part of lSC, ^DLSSNr targeted the central part of SC, extending to the upper layer of InWh in mSC, and ^DMSSNr targeted the upper InG and the lower InWh. Thus, lSNr axons seem to be a combination of ^VLSSNr and ^DLSSNr. Scale bar, 500um. Similar results were obtained in n = 9 mice, 3 for each site.