Study Finds That a Surprise Stimulus Helps People Stop an Action
Imagine reaching to pet your cat, and it hisses at you. How does your brain take stock of the sound and communicate with your body to pull back your hand?
Neuroscientists are interested in how the brain communicates with the motor system to help your body stop an action. This communication is vital because it helps us avoid surprises and react to potentially dangerous or unforeseen circumstances.
In a new study, University of Iowa researchers studied how people stopped an action. The researchers found that when participants heard an unexpected sound, they stopped an action more often than when they heard no sound at all.
The finding offers promising insight in how an external stimulus—an auditory, visual, or other sensory cue—could speed up the brain’s communication with the motor system. That could help clinicians treat patients with motor-control disorders, such as Parkinson’s disease and ADHD, as well as address the decline in motor control that accompanies aging.
“It seems like the brain’s communication with the motor system is so hard wired, and this ability to stop an action is so innate that even repeated practice won’t really alter it,” says Jan Wessel, assistant professor in the UI Department of Psychological and Brain Sciences and corresponding author on the study, published in the Journal of Neuroscience. “Therefore, finding other avenues to trigger the brain’s rapid stopping and improve stopping outcomes could be of great potential.”
Wessel’s team instructed a small group of participants to tap their foot on a pedal when they saw the letter “W” on a computer screen. The respondents tapped the right foot when the letter appeared on the right side of the screen, and the left foot when the letter appeared on the left side of the screen. When a stop signal (the letter “M”) appeared on screen, the participants were told to not tap either foot, meaning to stop their action.