Summary: Dopamine may not control the force or speed of movements as long believed. Instead, it appears to function as a foundational chemical that enables movement in the first place. Experiments showed that altering quick dopamine bursts had no impact on how vigorously animals moved, while raising baseline dopamine levels restored normal movement.
This rethinking of dopamine’s role could reshape how movement disorders are treated, including conditions marked by slowed or impaired motor function. The findings highlight a simpler therapeutic target: stabilizing baseline dopamine rather than recreating fast signaling spikes.
Key Facts:
- Rethinking Dopamine: Fast dopamine bursts didn’t change movement speed or strength in experiments.
- Baseline Matters: Restoring baseline dopamine—not momentary spikes—improved movement.
- Treatment Insight: Findings suggest targeting steady dopamine levels may refine approaches to treating movement disorders.
Source: McGill University
A McGill-led study is challenging a popular theory about how dopamine drives movement, a discovery that could shift how scientists think about Parkinson’s disease treatments.
Published in Nature Neuroscience, the research found dopamine does not set the speed or force of each movement, as had been thought. Instead, it appears to act as the underlying support system that makes movement possible.
“Our findings suggest we should rethink dopamine’s role in movement,” said senior author Nicolas Tritsch, Assistant Professor in McGill’s Department of Psychiatry and researcher at the Douglas Research Centre.
“Restoring dopamine to a normal level may be enough to improve movement. That could simplify how we think about Parkinson’s treatment.”
Dopamine is known to be important for motor vigour, which is the ability to move with strength and speed. In Parkinson’s patients, dopamine-producing neurons deteriorate, leading to slower movement, tremors and balance issues.
The standard treatment for Parkinson’s, Levodopa, helps restore movement, but why it works is not well understood. In recent years, advanced tools detected fast dopamine spikes during movement, which led many to believe these spikes control vigour.
The new study points in the opposite direction.
“Rather than acting as a throttle that sets movement speed, dopamine appears to function more like engine oil. It’s essential for the system to run, but not the signal that determines how fast each action is executed,” said Tritsch.
Measuring dopamine in real time
The researchers measured brain activity in mice as they pressed a weighted lever, turning dopamine cells “on” or “off” using a light-based technique.
If fast dopamine bursts did control vigour, changing dopamine at that moment should have made movements faster or slower. To their surprise, it had no effect. In tests with levodopa, they found the medication worked by boosting the brain’s baseline level of dopamine, not by restoring the fast bursts.
A more precise target for treatment
More than 110,000 Canadians live with Parkinson’s disease, a number projected to more than double by 2050 as the population ages.
A clearer explanation for why levodopa is effective opens the door to new therapies designed to maintain baseline dopamine levels, the authors note.
It also encourages a fresh look at older therapies. Dopamine receptor agonists have shown promise but caused side effects because they acted too broadly in the brain. The new finding offers scientists a sense of how to design safer versions.
Funding
The study was funded by the Canada First Research Excellence Fund, awarded through the Healthy Brains, Healthy Lives initiative at McGill University and the Fonds de Recherche du Québec.
Key Questions Answered:
A: No. The study shows that dopamine enables movement but does not dictate its speed or force.
A: It raises baseline dopamine levels, restoring the overall chemical environment that movement requires.
A: Therapies may focus on maintaining stable dopamine instead of mimicking fast bursts, supporting safer and more targeted approaches.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this dopamine and neuroscience research news
Author: Keila DePape
Source: McGill University
Contact: Keila DePape – McGill University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Subsecond dopamine fluctuations do not specify the vigor of ongoing actions” by Nicolas Tritsch et al. Nature Neuroscience
Abstract
Subsecond dopamine fluctuations do not specify the vigor of ongoing actions
Dopamine (DA) is essential for the production of vigorous actions, but how DA modifies the gain of motor commands remains unclear.
Here we show that subsecond DA transients in the striatum of mice are neither required nor sufficient for specifying the vigor of ongoing forelimb movements.
Our findings have important implications for our understanding of how DA contributes to motor control under physiological conditions and in Parkinson’s disease.
