Two animals were injected unilaterally with the JAWS-GFP virus using the coordinates described above and implanted with the LED implant and a movable bundle of 16 tungsten micro-wires of 23 μm diameter (Innovative-Neurophysiology) to record unit activity. After 4 weeks of recovery, recording sessions were performed at 24 hour intervals and the electrode bundle was advanced by 50 um after each session, covering a depth range of 300 – 1300um from dura over the course of recordings. During recording sessions mice were free to move inside a sound attenuating chamber. Light pulses (50mW power, 5 s duration) were delivered at random intervals with a mean inter-stimulus interval of 30 s. Neural activity was acquired using a Plexon recording system running Omniplex v. 1.11.3. The signals were digitally recorded at 40000 Hz and subsequently band-pass filtered between 200 Hz and 3000 Hz. Following filtering, spikes were detected using an amplitude threshold set at twice the standard deviation of the bandpass filtered signal. Initial sorting was performed automatically using Kilosort (Pachitariu et al., 2016). The results were refined via manual sorting based
