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The cerebellum may deserve more credit that it traditionally has gotten for its ability to control higher brain functions, and could play a vital role in controlling assistive technologies such as robotic arms. New fMRI images suggest the cerebellum, in fact, could be a target for brain-controlled interfaces.
In the course of human evolution, the cerebellum is a region of the brain that has changed very little. Researchers at the University of Missouri (MU), however, suggest the cerebellum can play a critical role in control tasks associated with assistive technologies that would benefit individuals affected by a physical disability.
“We live in a world of advanced technology in which a button can move a crane or open a door,” said Scott Frey, professor of psychological sciences in the College of Arts and Science and director of the Brain Imaging Center at MU. “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.”
A media release from MU reports that 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 specific buttons were pushed. Participants were told that the next day’s tasks would involve their controlling the robot remotely by video feed from within an MRI scanner.
Frey notes that the researchers uncovered evidence that the brain is highly flexible and can be rapidly conditioned to associate new consequences with a variety of movements. Pressing a button, for example, is a simple act that does not naturally result in grasping. In any case, Frey adds, after subjects learned that pressing one button would cause a robotic arm to grasp an object, this same movement resulted in a dramatically different pattern of brain activity than pressing an identical button known by the study subject to have no effect on the robot’s behavior.
According to the researchers there was a dramatic increase in localized activity within the cerebellum.
“These findings suggests that we might look to the cerebellum when seeking potential targets for brain-controlled interfaces,” Frey says.
He adds that the cerebellum contains more neurons than all other regions of the brain combined, but has typically been assumed to control only basic motor and balance functions. “Results from this study provide further evidence of the cerebellum’s role in higher cognitive functions,” Frey says.
The study, “Grasping with the Press of a Button: Grasp-Selective Responses in the Human Anterior Intraparietal Sulcus Depend on Nonarbitrary Causal Relationships Between Hand Movements and End-Effector Actions,” was recently published in the Journal of Cognitive Neuroscience.
[Source: University of Missouri]