Combining Optical Stimulation with Extracellular Electrophysiology in Behaving Mice

Optical manipulation allows researchers to alter the activity of genetically defined neural populations with millisecond-scale temporal accuracy. This facilitates the activation and inactivation of functionally distinct subnetworks at precise times relative to behavior, something that was not previously possible. This chapter describes the construction of an implant for simultaneous light delivery and extracellular electrophysiology in unanesthetized, unrestrained mice. The implant contains eight stereotrodes surrounding a central fiber optic cable, is compact and lightweight, and can be modified for other recording/stimulation configurations.