Laser axotomy on cerebellar climbing fibers

Abstract

In the adult nervous system, different population of neurons corresponds to different regenerative behavior. Although previous works show that olivocerebellar fibers are capable of axonal regeneration in a suitable environment as a response to injury [1], we have hitherto no details about the real dynamics of fiber regeneration. We coupled two photon imaging to laser-induced lesions to perform in vivo multiphoton nanosurgery in the CNS of living mice expressing fluorescent proteins to investigate the reparative properties of Climbing Fibers (CFs) in the adult CNS, following the time evolution of this plastic process in vivo. Here we show that sprouting may take place in a murine model in the days that follow a sub-micrometric lesion on the distal portion of the CF. Furthermore this unique model allows, through manipulation of the viral vector, to explore the biochemical mechanisms underlying the reparative process. The great potential of long-term two-photon imaging, coupled to genetic manipulation, opens great opportunities to further investigate the dynamic properties of neurons and their rearrangement following an injury.