Extended Data Fig. 7: Transsynaptic labeling of ATLASsn_Cre from the cortex to the striatum and thalamus.

a. Coronal section from striatum of mouse in Fig. 6c, d injected with AAV8-ATLASsn_Cre in medial prefrontal cortex and AAV8-DIO-mCherry in the striatum and incubated for two weeks showing At labeling of presynaptic termini. b. Coronal section from striatum of same mouse as in a. showing mCherry-labeled neurons. c. Coronal section at the level of the striatum of mouse brain injected with AAV8-ATLASsn_Cre + AAV8-BACE-GFP in the M1 cortex and AAV8-DIO-mCherry in the striatum and thalamus. Sections were stained for GFP (green), mCherry (red), and fluorescent Nissl stain (blue). d. Closeup of area marked in c. showing overlap of projections from neurons expressing AAV8-BACE-GFP (green) and neurons expressing mCherry. e. Coronal section at the level of the thalamus of the same mouse brain as in c. and d. showing projections of neurons expressing BACE-GFP (green), neurons expressing mCherry (red) and Nissl stain (blue). f. Closeup of area marked in e. showing overlap of projections from neurons expressing AAV8- BACE-GFP (green) and neurons expressing mCherry. g. Coronal section at the level of the striatum of a control mouse injected with AAV8-DIO-mCherry in the striatum in an identical manner to the mice in c.-f. but with no injections in the cortex. Negligible mCherry labeling (red) is visible in the striatum. Sections were also stained with Nissl stain (blue). h. Closeup of area marked in g. showing negligible mCherry labeling. Scale bars in a, b, d, f, and h 100 μm; in c, e, and g 1 mm.