Single or Double Patch-Clamp Recordings In Ex Vivo Slice Preparation: Functional Connectivity, Synapse Dynamics, and Optogenetics.

Patch-clamp recordings are the method of choice to define cell-type specific electrophysiological properties of single neurons and the synaptic connectivity between pairs of connected neurons in brain slices. In combination with optogenetic tools, patch-clamp recordings allow for the investigation of long-range afferent connectivity from identified distant brain areas. Here we describe the necessary equipment to carry out patch clamp recordings, surgical methods for dissection and preparation of horizontal brain slices containing the hippocampus, and a step-by-step guide for establishing patch clamp recordings in the whole-cell configuration. We provide protocols for single neuron stimulation via the patch pipette and for photostimulation experiments that activate axon terminals expressing light sensitive ion channels.