Extended Data Fig. 2: Optogenetic activation of corticostriatal neurons in visual cortex serves as the cue.

a, Virus injections to retrogradely label striatum-projecting neurons in visual cortex, called the cue neurons (Methods, ‘Virus injection’). b, Histology of example mouse injected with AAV/retro carrying Flp recombinase (red, Flp) into pDMSt bilaterally and injected with AAV carrying FlpOn Channelrhodopsin2 (green, ChR) into the visual cortex unilaterally. Green axons visible in pDMSt. c, Cue neuron cell bodies in visual cortex (top row) and projection pattern of cue neuron axons in striatum (next 3 rows, with close-ups at right). Green arrow shows anterior-most extent of cue neuron axons in only the medial-most part of striatum. d, Recordings in visual cortex to verify optogenetic activation of ChR-expressing cue neurons. left, Average±s.e.m firing rate of all single units (SU) measured by multi-channel extracellular electrophysiology in visual cortex (n = 640 SU from 5 mice). Blue bar represents the duration of LED illumination of visual cortex through a thinned skull. Insets are data from different individual mice over same X axis time window (Y axis range: 0–7 Hz, 0–12 Hz, 0–12 Hz, 2–9 Hz, 1–11 Hz, from top to bottom). right, Response of same neurons to the LED distractor, which is an external visual stimulus with the same blue color and duration as the cue. e, Cue- (left-most panel) or distractor- (middle-left panel) evoked change in firing rates of all individual SU across layers of the visual cortex, ordered from superficial to deep. Change in firing rate is the average firing rate over 0.25 s just after the cue minus the average firing rate over 2 s just before the cue in spikes per s (or aligned to distractor onset). (middle-right panel) Average cue- (blue) or distractor- (orange) evoked change in SU firing rate across depths, as min-subtracted, max-normalized and smoothed by 20 µm bin. (right-most panel) Close-up of visual cortex (V1) histology showing ChR-expressing cue neurons in layers 5 and 2/3 (white arrows point to example cells).