Optogenetics and wave front shaping

The combination of optical methods with, optogenetic actuators and reporters enables today an all-optical analysis of a well-defined neuronal population within intact neuronal circuits and systems. However, these tools imply a number of constraints on the opto-stimulation method to be used. A perfect light-delivery method should be: efficient, multi-scale, allow millisecond temporal resolution and μm spatial resolution, and be robust to scattering. Several solutions have recently been proposed to fulfill these requirements, and can be divided in two main categories: laser scanning and parallel excitation methods. Laser scanning methods use galvanometric mirrors or acousto-optic devices to quickly scan a laser beam across several positions. With parallel methods all the regions in the target area are excited simultaneously. Here we review a series phase-modulation parallel methods for single-photon (1P) and two-photon (2P) patterned photostimulation and demonstrate their use in exemplary experiments in vitro and in vivo.