Lateral collateral projections of bladder afferents in the lumbosacral spinal cord of the male rat.

 The afferents of the bladder directly innervate the sacral preganglionic nucleus in the L6 and S1 spinal cord, but also innervate segments of the spinal cord that do not contain this nucleus, such as rostral L6 and caudal L5. The dataset shown here is from injection of cholera toxin B (CTB) into the wall of the bladder body (male rat). The spinal cord was immunolabelled for CTB and choline acetyltransferase (ChAT) and cleared using iDISCO. The cleared sample was imaged on a light sheet microscope (Ultramicroscope II, LaVision), and the subsequent image stacks reconstructed using Imaris (Bitplane). Autofluorescence of the spinal cord surface is also evident in the CTB channel (green), which was removed from view in order to visualize afferents. Pes9: pes motoneurons of lamina 9; SPN, sacral preganglionic nucleus.