Allison Hamilos

For decades, we've known that rewards and movement are coupled. If you put a mouse in an environment that has rewards like sugary treats, they start moving around more. But why this happens is not understood.

My lab studies dopamine, a chemical messenger in the brain that is related to both rewards and movement. It's been thought that dopamine serves distinct functions in both reward signaling and movement initiation. But serendipitously, we've discovered a link between these two processes.

Sometimes you want to move more, and sometimes you want to move less. What our work is telling us is that when it's more advantageous — more rewarding — to move, the level of dopamine signal increases. In turn, dopamine neurons calibrate the degree to which animals are moving.

This link between reward and movement helps us understand what's going wrong in diseases like Parkinson's, where dopamine neurons are known to die off. Parkinson's patients not only have difficulty moving, they have trouble increasing the vigor of their movements in moments when it's advantageous to do so. This added context may someday lead to better treatments for this disease.