Patterned Optogenetic Stimulation Using a DMD Projector.

Optical manipulation is a powerful way to control neural activity in vitro and in vivo with millisecond precision. Patterning of light provides the remarkable ability to simultaneously target spatially segregated neurons from a population. Commercially available projectors provide one of the simplest and most economical ways of achieving spatial light modulation at millisecond timescales. Here, we describe the protocol for constructing a projector-based spatio-temporal light patterning system integrated with a microscope on a typical electrophysiology rig. The set-up is well suited for applications requiring rapid, distinct, and combinatorial inputs, akin to brain activity. This equipment involved is fairly economical (<$5000 including all optical and mechanical components), and the set-up is easy to assemble and program.