Each day, humans and animals rely on habits to complete routine tasks such as eating and sleeping. As new habits are formed, this enables us to do things automatically without thinking. As the brain starts to develop a new habit, in as little as a half a second, one region of the brain, the dorsolateral striatum, experiences a short burst in activity. This activity burst increases as the habit becomes stronger. A Dartmouth study demonstrates how habits can be controlled depending on how active the dorsolateral striatum is. The results are published in the Journal of Neuroscience.
In prior research at MIT, the senior author found that this burst in brain activity in the dorsolateral striatum correlated with how habitual a running maze task was for rats. The activity was found to be accentuated at the beginning and end of the maze run.
For this study, the researchers sought to manipulate this burst in brain activity in rats using a method called optogenetics. With this method, the neurons (brain cells) in the dorsolateral striatum, which have been found to be associated with forming habits, can be excited or inhibited using light. Optogenetics enables the brain cells to express a receptor that is sensitive to light, and is painless. A flashing blue light excites the brain cells while a flashing yellow light inhibits the cells and shuts them down.