Performance of auditory discrimination in rats with the eliminated DLS striatopallidal pathway and lesioned NAc. Rats (n = 7–9 for each group) were trained for the auditory two-choice reaction time task. After achievement of the 80% criterion, the rats were given a bilateral injection of IT into their DLS and a bilateral injection of IBO or PBS into their NAc, and then tested for the task performance. A, Schematic illustration of IBO lesion range in the NAc. After the behavioral test, brains were taken from the Tg and non-Tg rats; and sections through the NAc were used for NeuN immunohistochemistry. The maximum (gray) and minimum (black) ranges of the lesions are illustrated. The anteroposterior coordinates (millimeters) from the bregma are shown. B, Auditory two-choice reaction time task. The correct response ratio (B1) and correct response time (B2) in session blocks comprising three serial sessions are plotted. The values at the pretreatment phase (Pre) are the averages at 3 d before the injection. **p < 0.05, compared with each of the IT/PBS- and IT/IBO-injected non-Tg groups, LSD test. Scale bar, 2 mm.