3D Imaging of Axons in Transparent Tissue

Traditionally, tracing axonal trajectory in the brain or spinal cord required laborious reconstruction of images from serial tissue sections. New tissue clearing methods combined with the right microscopy techniques now allow the tracing of axonal trajectory in intact tissue, thereby making this process much faster and, importantly, more accurate. However, most studies have used mouse models in which a subset of axons are prelabeled at birth. By using viral tracers, the new technique gives scientists improved spatial and temporal control over their experiments. This application note demonstrates the use of adeno-associated viruses and chemical tracers as well as tetrahydrofuran-based tissue clearing for imaging axons using light sheet and confocal microscopy.