Archaerhodopsin (ArchT)-mediated axon terminal inhibition of glutamate afferents in the Nucleus accumbens (NAc) increases reward-seeking behavior. (A) Schematic of viral injections and optic probe placements (left). Representative coronal brain slices showing ArchT-eYFP expression in PVT and BLA neurons (middle) and their associated axons in the NAc (right). Scale bar, 500 μm. (B,C) Photoinhibition of PVT and BLA axons increased active lever responses (nGFP = 11; nPVT = 14; nBLA = 10; F(2,32) = 3.96, p < 0.05; for significant post hoc tests t(32) > 2.63) but not food port entries when reward was available (F(2,32) = 2.52, p = 0.10). (D) During extinction, photoinhibition of PVT and BLA axons increased inactive lever responses (nGFP = 7; nPVT = 15; nBLA = 10; F(2,29) = 4.70, p < 0.05; for significant post hoc tests t(29) > 3.31). Error bars represent SEM. *Signifies p < 0.05. 3V, third ventricle; ac, anterior commissure; BLA, basolateral amygdala; BMP, posterior basomedial amygdaloid nucleus; CM, central medial thalamic nucleus; HPC, hippocampus; LA, lateral amygdaloid nucleus; MD, mediodorsal thalamic nucleus; PV, paraventricular thalamic nucleus.