Led by Eric Turner, scientists from the Seattle Children’s Research Institute have discovered the area of the brain that is responsible for controlling a mouse’s motivation to run and participate in the rewarding activities. They found that a tiny region in the brain known as the ‘dorsal medial habenula’ controls the desire to exercise or run in mice.
Since the structure of the habenula is similar in both humans and rodents, scientists assume that it is likely to have similar functions in regulating mood and motivation across the two species. In the first part of the study, researchers made use of the genetically engineered mice to block signals from the dorsal medial habenula. Thereafter, it was revealed that the mice were lethargic and ran far less than their normal counterparts who enjoyed running on exercise wheels. In the second part of the experiment, the scientists used optogenetics to emit light on the dorsal medial habenula. The mice were now allowed to activate dorsal medial hebenula by turning one of the two response wheels with their paws. It was found that the mice strongly preferred turning the wheel that stimulated their dorsal medial habenula. This indicated the role that dorsal medial habenula plays in rewarding behaviour.
The new finding has given scientists a vital clue for treating depression in humans. So far, exercise is one of the most effective and non–pharmacological therapies for depression. Determining that such a specific area of the brain may be responsible for motivation to exercise, it could help researchers develop more targeted and effective therapies for treating depression.