Targeted neural circuit manipulation

ALM (AP 2.5 mm; ML 1.5mm; diameter 1.5 mm) is the cortical area that produced behavioral effects with photoinhibition during the delay epoch ^{3 (link),24 (link)}. For the thalamic reticular nucleus the coordinate was AP -0.7, ML 1.6, DV 3.7 - 3.3 mm, as retrograde labeling from thal_ALM showed labeling in this sector of the thalamic reticular nucleus (Extended Data Fig. 9). Virus and tracer were injected through the thinned skull using a volumetric injection system (modified from Mo-10 Narishige) ^{48 (link)}. Glass pipettes (Drummond) were pulled and beveled to a sharp tip (outer diameter ∼ 20 - 30 μm), back-filled with mineral oil and front-loaded with viral suspension immediately before injection. The injection rate was 15 nl/min. See Supplementary Table 2 for description of viruses and injection coordinates used for each experiment. We used the following viruses and tracers: AAV2/1-CAG-EGFP (Penn vector Core, University of Pennsylvania), AAV2/10 CAG-flex-ChR2(H134R)-tdTomato (Penn vector Core, University of Pennsylvania), AAV1-CAG-mRuby2-FLAG⁴⁹ , WGA-Alexa Fluor® 555 (Thermo Fisher Scientific)^{50 (link)} (WGA555), and Red RetroBeads (Lumafluor).