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In order to grasp an object, our brains have to use specialized areas to process visual cues. Then, other areas of the brain work with these signals to control our hands to reach for and manipulate the object.

A new study suggests that the cerebellum, a region of the brain that has changed very little over time, may play a critical role. The findings could lead to advancements in assistive technologies for people with disabilities.

“We live in a world of advanced technology in which a button can move a crane or open a door,” says Scott Frey, professor of psychological sciences and director of the Brain Imaging Center at the University of Missouri.

“For those with disabilities, assistive technologies, such as robotic arms or sensors inserted in the brain, make it possible to accomplish actions like grasping with the press of a button or directly through brain activity; however, little is known about how the human brain adapts to these technologies.

“We found that the brain didn’t necessarily evolve to control modern robotic arms, but rather the cerebellum, an ancient portion of our brain that has remained relatively unchanged, plays a vital role in helping us reach and grasp with these tools—often with only minimal training.”

Buttons and a robotic arm

In the study, participants completed a series of ordinary reaching and grasping tasks involving colored wooden blocks. Regions of the brain were monitored by functional magnetic resonance imaging (fMRI).

Then, in a training session, participants were introduced to a robotic arm that performed the same reaching and grasping tasks when they pressed specific buttons. Participants were told that the next day’s tasks would involve their controlling the robot remotely by video feed from within an MRI scanner.

“We found evidence that the brain is very flexible and can be rapidly conditioned to associate new consequences with a variety of movements,” Frey says. “Pressing a button is a very simple act that does not naturally result in grasping.

“Nevertheless, after subjects learned that pressing one button would result in grasping objects with a robotic arm, this same movement resulted in a dramatically different pattern of brain activity than pressing an identical button known by them to have no effect on the robot’s behavior.

Focus on the cerebellum

“Localized activity within the cauliflower-shaped cerebellum, or ‘small brain’ sitting toward the back of the head, increased dramatically. These findings suggest that we might look to the cerebellum when seeking potential targets for brain-controlled interfaces.”

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For many years the cerebellum, an ancient structure that contains more neurons than the rest of the brain combined, was believed to control very basic motor and balance functions, Frey says. Results from this study provide further evidence of the cerebellum’s role in higher cognitive functions.

The study appears in the Journal of Cognitive Neuroscience.

The Army Research Laboratory’s Army Research Office and the National Institutes of Health National Institute of Neurological Disease contributed funding to the work. The content is solely the responsibility of the authors and does not necessarily represent the official views of either funding agency.

Source: University of Missouri