Dopamine Ramping and Goal-Directed Behavior
The neurotransmitter dopamine is involved in feelings of reward and in goal-directed behaviors. Melissa Warden, Neurobiology and Behavior, is investigating a distinctive pattern of rapidly increasing dopamine neuron activity called ramping. By exploring the mechanisms that underlie ramping dopamine activity, this research seeks to elucidate the neural basis of goal-directed behavior, perseverance, spatial learning, and a person’s ability to stay focused on goals.
Researchers in Warden’s lab recently discovered that dopamine-producing neurons in the ventral tegmental area (VTA) become increasingly active as mice approach spatially distant goals. But the persistence of ramping activity in dopamine neurons depends on the nature of the task. When mice run toward newly discovered rewards at either end of a straight track, ramping appears immediately but fades as mice gain experience over several days of training. However, when mice must run on a wheel for a certain number of turns to receive a reward, ramping activity in dopamine neurons persists indefinitely. This project investigates the hypothesis that ramping is persistent when a task requires an internal, mental representation of progress in the absence of spatial cues to track progress toward a goal. Specifically, researchers will 1) explore whether neural activity in the ventral hippocampus contributes to ramping activity in midbrain dopamine neurons; 2) compare patterns of ramping activity in VTA dopamine neurons with patterns of ramping dopamine release in the ventral striatum; and 3) characterize VTA neural activity during spatial and non-spatial goal-oriented tasks.
Findings from this research could provide insights into mental disorders involving goal-directed behavior, including attention deficit hyperactivity disorder, obsessive compulsive disorder, depression, and addiction.
NIH Award Number: 1R01DA055075-01