Experimental animals were injected bilaterally with AAV5-CamKII-Jaws-KGC-GFP-ER2 (UNC vector core, titer: 5.9 × 1012) using 16 injections each of 50nL (total 800nL) spread across 4 injection tracks (2 per hemisphere) at coordinates: AP: 0, 0.5, ML: ± 0.4, DV: −1, −1.2, −1.4, −1.6mm relative to dura. Control animals were injected with AAV5-CaMKII-GFP (UNC vector core, titer: 2.9 × 1012) at the same coordinates. Injections were performed at a rate of 4.6nL/5 s, using a Nanojet II (Drummond Scientific) with bevelled glass micropipettes of tip diameter 50-100um. A circular craniotomy of diameter 1.8mm was centered on AP: 0.25, ML: 0, and a high power red led (Cree XLamp XP-E2) was positioned above the craniotomy touching the dura. The LED was mounted on a custom designed insulated metal substrate PCB (Figure 6A). The LEDs were powered using a custom designed constant current LED driver. In both two-step and reversal learning tasks, on stimulation trials red light (50mW, 630nM) was delivered from when the subject entered the side poke and received the trial outcome, until the subsequent choice, up to a maximum of
