New brain research reveals that motor neurons adjust to control tasks

April 18, 2017
Credit: Carnegie Mellon University Materials Science and Engineering

New research from Carnegie Mellon University's College of Engineering and the University of Pittsburgh reveals that motor cortical neurons optimally adjust how they encode movements in a task-specific manner. The findings enhance our understanding of how the brain controls movement and have the potential to improve the performance and reliability of brain-machine interfaces, or neural prosthetics, that assist paralyzed patients and amputees.

"Our has an amazing ability to optimize its own information processing by changing how represent the world. If we can understand this process as it applies to movements, we can design more precise neural prostheses," says Steven Chase, assistant professor in the Department of Biomedical Engineering and the Center for Neural Basis of Cognition. "We can one day, for example, design robotic arms that more accurately implement a patient's intended because we now better understand how our brain adjusts on a moment-by-moment basis when we are in motion."

The study explored the change in brain activity during simple motor tasks performed through virtual reality in both 2-D and 3-D. The researchers wanted to know if the motor cortical neurons would automatically adjust their sensitivity to direction when presented with a wide range of possible directions instead of a narrow one. Previous research in the field has suggested that this phenomenon, called dynamic range adaptation, is known to occur in neurons sensitive to sound, touch, and light—prompting the researchers to ask if the same phenomena would apply to neurons in the motor system that are associated with movement.

"When you walk out into the bright summer sun, you squint, and the neurons in your retina use dynamic range adaptation to automatically increase their sensitivity so that you can clearly see until the clouds pass over again," explains Robert Rasmussen, MD/Ph.D. student at the University of Pittsburgh School of Medicine and first author of the study. "This feature allows the brain to better encode information by using its limited resources efficiently. We wanted to find out if our brain encodes movement in the same way."

The results revealed that dynamic range adaptation did indeed occur in the motor cortical . Based on these findings, the researchers concluded that this feature is widespread throughout the brain.

"We found that dynamic range adaptation isn't restricted to sensory areas of the brain. Instead, it is a ubiquitous encoding feature of the cortex," explains Andrew Schwartz, distinguished professor of neurobiology and chair in systems neuroscience at the University of Pittsburgh School of Medicine, and a member of the University of Pittsburgh Brain Institute. "Our findings show that it is a feature of , which your brain uses to efficiently process whatever information it is given—whether that is light, sound, touch, or movement. This is an exciting result that will motivate further research into motor learning and future clinical applications."

The study was published in the April 18 issue of the journal eLife.

Explore further: Cortical nerve function in former amputees remains poor decades after reconstructive surgery

More information: Robert G Rasmussen et al, Dynamic range adaptation in primary motor cortical populations, eLife (2017). DOI: 10.7554/eLife.21409

Related Stories

Cortical nerve function in former amputees remains poor decades after reconstructive surgery

April 12, 2017
Researchers have found that the nerve cells (neurons) controlling sensation and movement of the hands show injury-induced changes for years after hand amputation, reattachment or transplant. The small study, the first of ...

Researchers identify new brain pathway that controls hand movements

April 3, 2017
Picking up a slice of pizza or sending a text message: Scientists long believed that the brain signals for those and related movements originated from motor areas in the frontal lobe of brain, which control voluntary movement.

Discovering the neural mechanisms of skill learning

September 26, 2016
Most people can swing a hammer, but most people cannot swing said hammer with the fluid speed and precision of a master carpenter. The difference is thousands of hours of practice and the systematic organization of hundreds ...

From brouhaha to coordination: Motor learning from the neuron's point of view

February 9, 2017
When starting to learn to play the piano, there is much hesitation and hitting the wrong keys. But with training, the movements of the player become more fluid and accurate. This motor improvement begins in the brain, but ...

Brain-machine interfaces: Bidirectional communication at last

February 22, 2017
A prosthetic limb controlled by brain activity can partially recover the lost motor function. Neuroscientists at UNIGE asked whether it was possible to transmit the missing sensation back to the brain by stimulating neural ...

How the brain improves motor control

July 21, 2016
Adaptation in reaching—gradual improvement of motor control in response to a perturbation—is a central issue in motor neuroscience.However, even the cortical origin of errors that drive adaptation has remained elusive. ...

Recommended for you

Activating MSc glutamatergic neurons found to cause mice to eat less

December 13, 2017
(Medical Xpress)—A trio of researchers working at the State University of New York has found that artificially stimulating neurons that exist in the medial septal complex in mouse brains caused test mice to eat less. In ...

Scientists discover blood sample detection method for multiple sclerosis

December 13, 2017
A method for quickly detecting signs of multiple sclerosis has been developed by a University of Huddersfield research team.

LLNL-developed microelectrodes enable automated sorting of neural signals

December 13, 2017
Thin-film microelectrode arrays produced at Lawrence Livermore National Laboratory (LLNL) have enabled development of an automated system to sort brain activity by individual neurons, a technology that could open the door ...

Discovery deepens understanding of brain's sensory circuitry

December 12, 2017
Because they provide an exemplary physiological model of how the mammalian brain receives sensory information, neural structures called "mouse whisker barrels" have been the subject of study by neuroscientists around the ...

Intermittent fasting found to increase cognitive functions in mice

December 12, 2017
(Medical Xpress)—The Daily Mail spoke with the leader of a team of researchers with the National Institute on Aging in the U.S. and reports that they have found that putting mice on a diet consisting of eating nothing every ...

Neuroscientists show deep brain waves occur more often during navigation and memory formation

December 12, 2017
UCLA neuroscientists are the first to show that rhythmic waves in the brain called theta oscillations happen more often when someone is navigating an unfamiliar environment, and that the more quickly a person moves, the more ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.