Locomotion and motivational behavior in rats lacking the DLS-derived striatopallidal projection. A, Spontaneous locomotion. Rats (n = 12–16 for each group) received a bilateral treatment of IT or PBS into their DLS. The rats were then placed in the center of the open field, and spontaneous locomotion was recorded in every 10 min session during a 60 min test period. Track length (A1) and average velocity (A2) of ambulation were analyzed by using video tracking software. B, Progressive ratio task. Rats (n = 5 or 6 for each group) were trained by using the continuous reinforcement and fixed ratio 4 schedules. The rats were given a bilateral injection of IT or PBS into their DLS and then used for the progressive ratio task. The total number of lever presses or rewards was counted during the session.