Fig. 4

Reciprocal connectivity between MO_s and V_RL/A/AL. a–d Connectivity from the MO_s to the V_RL/A/AL. a The experimental design for the dual-virus injections. AAV-tdTomato was injected into the MO_s in the right hemisphere and AAV-GFP was injected into the occipital regions in the left hemisphere. b A corresponding whole-brain image. c, d The tdTomato projection from MO_s overlapped with areas RL, A, and AL (V_RL/A/AL). GFP-labeled callosal projections delineated boundaries between the V1 and higher visual areas. The image c was taken with a fluorescent stereoscopic microscope from the dotted rectangle in b, and the image d was taken with a two-photon microscope from a region indicated in b. e–n The V_RL/A/AL projects back to the MO_s. e The experimental design for the sequential virus injections. First, AAV-tdTomato was injected into the MOs, and then a couple weeks later AAV-GFP was injected into the tdTomato-labeled axonal band (the V_RL/A/AL). f A corresponding whole-brain image. g At the injection site of AAV-GFP, the expression overlapped with the tdTomato-labeled axonal band (the location of V_RL/A/AL). h At the injection site of AAV-tdTomato (the MO_s), the expression overlapped with the GFP-labeled axonal band. The two black arrowheads indicate the midline, and the white dotted line is the expected areal border based on coordinates and Paxinos and Franklin’s atlas. i–k A coronal section that includes the MO_s. The injection site for AAV-tdTomato at MO_s (j, tdTomato) and the axon terminals from the V_RL/A/AL (k, GFP) overlapped well. l–n A coronal section that includes V_RL/A/AL. The axon terminals originating from the MO_s (m, tdTomato) and the inection site for AAV-GFP (n, GFP) overlapped well. The dashed lines in j, k, m, and n indicate the areal borders based on Nissl staining. o Projections from the MO_s and the V_RL/A/AL in thalamus. Note that projections from the V_RL/A/AL to the higher visual thalamus (LPLR)⁷³ overlapped with those from the MO_s. The borders were drawn based on descriptions in refs. ^{42, 74}