Figure 4
Anterograde labeling of retinal terminals in subnuclei of mouse visual thalamus. A. Retinal projections in P35 wild-type mice were labeled by intraocular injection of fluorescently conjugated cholera toxin subunit B (CTB). Left eyes were injected with Alexa Fluor 555 CTB (magenta) and right eyes were injected with Alexa Fluor 488 CTB (green). LGN from right hemispheres are shown. ‘Contra’ denotes projections originating from the contralateral retina and ‘ipsi’ denotes projections originating from the ipsilateral retina. Outlines of dorsal lateral geniculate nucleus (dLGN) and the external division of ventral lateral geniculate nucleus (vLGN) are depicted with white dots. d, dLGN; ve, external division of vLGN; i, IGL. White boxes depict regions enlarged in B and C. B,C. High magnification images of CTB-labeled retinal terminals in dLGN (B) and vLGN (C). Note the punctate appearance of retinal projections in dLGN and the denser and diffuse labeling of retinal terminals in vLGN. D,E. High magnification image of ipsilateral retinal projections from B,C depict differences in retinal terminal size in dLGN (D) and vLGN (E). F,G. Immunolabeling CTB-labeled tissue with antibodies against VGluT2 demonstrated that CTB was enriched at synaptic sites in LGN and confirmed that VGluT2-positive terminals were derived from retinal projections. All images are maximum projection confocal images. Scale bar in A = 200 μm, in C = 25 μm for B,C, in E = 10 μm for D,E, and in G =10 μm for F,G.