Giuseppe Balsamo et al with Andrea Burgalossi at the University of Tuebingen used NeuroNexus acute, two-shank, dual-fiber Buzsaki16-OA16LP optoelectrodes in the mouse presubiculum (PreS) for simultaneous optical perturbation and single-unit recording. Probes were coated with DiI dye before each recording to mark insertion tracks. The researchers then cleaned the probes in 1% Tergazyme for repeated use. Their findings published in Cell Reports shed light on the species-conserved microcircuitry of head direction representation in cortex.