Chronically implanted Neuropixels probes enable high-yield recordings in freely moving mice

The advent of high-yield electrophysiology using Neuropixels probes is now enabling researchers to simultaneously record hundreds of neurons with remarkably high signal to noise. However, these probes have not been comprehensively tested in freely moving mice. It is critical to study neural activity in unrestricted animals, and the field would benefit from the inclusion of ethological approaches to studying the neural circuitry of behavior. We therefore adapted Neuropixels probes for chronically-implanted experiments in freely moving mice. We demonstrate the ease and utility of this approach in recording hundreds of neurons across weeks, and provide the methodological details for other researchers to do the same. Importantly, our approach enables researchers to explant and reuse these valuable probes.