Channelrhodopsin-assisted patching: in vivo recording of genetically and morphologically identified neurons throughout the brain.

Brain networks contain a large diversity of functionally distinct neuronal elements, each with unique properties, enabling computational capacities and supporting brain functions. Understanding their functional implications for behavior requires the precise identification of the cell types of a network and in vivo monitoring of their activity profiles. Here, we developed a channelrhodopsin-assisted patching method allowing the efficient in vivo targeted recording of neurons identified by their molecular, electrophysiological, and morphological features. The method has a high yield, does not require visual guidance, and thus can be applied at any depth in the brain. This approach overcomes limitations of present technologies. We validate this strategy with in vivo recordings of identified subtypes of GABAergic and glutamatergic neurons in deep cortical layers, subcortical cholinergic neurons, and neurons in the thalamic reticular nucleus in anesthetized and awake mice. We propose this method as an important complement to existing technologies to relate specific cell-type activity to brain circuitry, function, and behavior.