Execution of auditory discrimination in rats with the deleted DLS striatopallidal pathway and lesioned DMS. Rats (n = 7–9 for each group) were trained for the auditory two-choice reaction time task. After the 80% criterion achievement, the rats were given a bilateral injection of IT into their DLS and a bilateral injection of IBO or PBS into their DMS, and then tested for the task performance. A, Schematic illustration of IBO lesion range in the DMS. After the behavioral test, brains were taken from the Tg and non-Tg rats; then DMS sections were prepared and stained immunohistochemically for NeuN. 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 < 0.01, compared with the IT/PBS-injected non-Tg group, LSD test. Scale bar, 2 mm.