Dorsomedial striatal activity tracks completion of behavioral sequences in rats

Abstract

For proper execution of goal-directed behaviors, individuals require both a general representation of the goal and an ability to monitor their own progress toward that goal. Here, we examine how dorsomedial striatum (DMS), a region pivotal for forming associations among stimuli, actions, and outcomes, encodes the execution of goal-directed action sequences that require self-monitoring of behavior. We trained rats to complete a sequence of at least 5 consecutive lever presses (without visiting the reward port) to obtain a reward and recorded the activity of individual cells in DMS while rats performed the task. We found that the pattern of DMS activity gradually changed during the execution of the sequence, permitting accurate decoding of sequence progress from neural activity at a population level. Moreover, this sequence-related activity was blunted on trials where rats did not complete a sufficient number of presses. Overall, these data suggest a link between DMS activity and the execution of behavioral sequences that require monitoring of ongoing behavior.

Significance statement

Dorsomedial striatal activity was recorded during a task requiring rats to track progress in the execution of lever press sequences. Dorsomedial striatal activity evolved across the behavioral sequence with a ramp-like pattern of activity, permitting accurate decoding of sequence progress at the population level. Additionally, the magnitude of sequence-related activity was blunted on incomplete trials, suggesting that DMS activity may be critical for proper monitoring and execution of behavioral sequences. This study demonstrates that DMS neurons encode progress toward a goal during execution of action sequences when animals are required to track their own behavior for efficient performance.