Figure 4.

CTb/VGLUT1 boutons contact vertical cell spines in a CTb injected animal. a, Projection of a confocal image stack (75 optical sections at 0.5 μm z-spacing) to show one of the vertical cells from a rat that had received an injection of CTb into the ipsilateral sciatic nerve (cell 8 in Table 1). The dashed line shows the dorsal limit of the dense plexus of VGLUT1-immunoreactive axons, and the boxes show the positions of the images in the remaining parts of the figure. b, c, d show parts of the dendritic tree in fields scanned to reveal Neurobitin (green), VGLUT1 (blue) and CTb (red) in a stack of 7 optical sections (0.5 μm z-spacing). Arrows in b and c indicate contacts from VGLUT1⁺/CTb⁺ boutons onto dendritic spines of this cell. Arrowheads in d show contacts from small VGLUT1-immunoreactive boutons that lacked CTb onto dendrites in lamina IIo. Scale bars: 50 μm (a), 10 μm (b-d).