The area of the brain which may control the motivation to exercise — along with other rewarding activities — has been identified by a new study.
The tiny area of the brain, called the dorsal medial habenula, was found to control mice’s motivation to exercise (Turner et al., 2014).
Since the brain structure is similar in humans and mice, it is likely that the effects on motivation and the emotions are the same.
Dr. Eric Turner, the study’s lead author, suggests the research might be the first step in developing new treatments for depression:
“Changes in physical activity and the inability to enjoy rewarding or pleasurable experiences are two hallmarks of major depression.
But the brain pathways responsible for exercise motivation have not been well understood.
Now, we can seek ways to manipulate activity within this specific area of the brain without impacting the rest of the brain’s activity.”
The study, published in the Journal of Neuroscience, used mice whose brains were genetically engineered to block signals from the dorsal medial habenula.
When compared with regular mice, the altered mice were lethargic and even took less interest in sugary drink that normal mice would have found rewarding to drink.
Dr. Turner explained:
“Without a functioning dorsal medial habenula, the mice became couch potatoes.
They were physically capable of running but appeared unmotivated to do it.”
A second study used sophisticated laser technology to allow the mice themselves to switch on or off their dorsal medial habenula by turning a wheel.
The mice much preferred to have this small part of their brains activated, thus showing it is tied to motivation and rewarding behaviour.
While it may be a long way off, the hope is that techniques can be developed to help people who are depressed ‘switch on’ their motivation and once again find pleasure in life.
Dr. Turner, who treats people with depression, concluded:
“Working in mental health can be frustrating.
We have not made a lot of progress in developing new treatments.
I hope the more we can learn about how the brain functions the more we can help people with all kinds of mental illness.”
Image credit: Banalities