Science Discovers Parts Of Brain That Control Reaction Impulse, Urges

A new study published in the Nature journal found a link between brain activity and the ability to self-govern spontaneous action.

If you’ve ever put your foot in your mouth, absent-mindedly stepped into traffic, or performed any other task without fully internalizing the risks, then you understand what a real impulse feels like. Scientists think they’ve isolated the part of the brain that regulates these impulses, which they call “drives.”

“We discovered a brain area responsible for driving action and another for suppressing that drive. We could also trigger impulsive behavior by manipulating neurons in these areas,” said the study’s senior author, Joe Paton, Director of the Champalimaud Neuroscience Program in Portugal.

The research sprang from a study of neurological diseases like Huntington’s and Parkinson’s. Though each disease manifests as different loss of movement control (uncontrolled versus stagnant), each disease stems from the same portion of the brain: the basal ganglia. Therefore, this part of the brain obviously supports different ranges of spectral movement, and can adversely affect patients in different ways when compromised.

Scientists like Paton interpreted the data as evidence that the basal ganglia operates with two separate features, called direct and indirect pathways. They long-believed that direct pathways promote movement, while indirect pathways suppress movement; but few other details were known.

Whereas most studies focused upon the direct pathways in an attempt to understand movement behavior, Paton and his team decided to focus on indirect pathways, instead. To study the brain function, scientists created an experiment where mice had to objectively suppress the impulse to seek a reward too quickly. The results were inmpressive.

Learning about decision-making in the brain can improve artificial intelligence and machine automation one day

“Interestingly, unlike the coactivation we and others have observed during movement, activity patterns across the two pathways were strikingly different during the action-suppression period. The activity of the indirect pathway was overall higher and it continuously increased while the mouse waited for the second tone,” said Bruno Cruz, a doctoral student in the lab.

Basically, the team identified a brain region that actively suppresses the drive to act. Not only does the work affect neurological disease studies, but it may next be used to examine impulse disorders like OCD or addiction.

“We knew the mice were experiencing a strong drive to act because removing suppression promoted impulsive-like action. But it wasn’t immediately clear where else the site of action promotion could be. To answer this question, we decided to turn to computational modeling,” Paton recalled.

The study of the brain’s internal mechanisms led to a better understanding of the various regions of the basal ganglia; and in some instances, their evidence seriously challenged preconceived notions of that area of the brain.

“Our study indicates that there are potentially multiple neural circuits in the brain that are constantly competing over which action to execute next. This insight is important for understanding more deeply how this system works, which is imperative for treating certain movement disorders, but it goes even further,” Paton said.

“Observations from neuroscience are at the core of many machine learning and AI techniques. The idea that decision-making can happen through the interaction of numerous parallel circuits within the same system might prove useful for designing new types of intelligent systems,” he added.