Miniature random-access fiber scanner for in vivo multiphoton imaging

Multiphoton microscopy allows imaging of cellular activity in living tissue explants and in whole animals and has thus become a powerful tool for studying neuronal activity. The miniaturization of laser-scanning microscopy promises to extend activity measurements to awake, freely moving animals. Here we describe and evaluate a miniature multiphoton microscope based on a “piezolever fiber scanner” (PLFS). Our current PLFS has a scan range of 1.1 mm and a resonance frequency of 790 Hz. It allows, unlike resonance-based designs, a lateral shift of the scanned area, and offers the prospect of random-access (vector) scanning.