Neuroscientists Uncover Brain Region Involved in Voluntary Behavior

November 15, 2007

Scientists at the California Institute of Technology have deciphered the activity of an area of the brain that could one day prove vital in the development of neural prostheses--within-the-brain implants that would translate thought into movement in paralyzed patients. The results of this study were published as the featured article in the November 8 issue of Neuron.

Richard A. Andersen, the James G. Boswell Professor of Neuroscience at Caltech, and his postdoctoral fellow, He Cui, looked in particular at the posterior parietal cortex (PPC), a higher brain region where sensory stimuli are transformed into movement.

To tease out the functions of two subregions of the PPC, the parietal reach region (PRR) and the lateral intraparietal area (LIP), Cui and Andersen designed an experiment in which rhesus monkeys were allowed to freely chose one of two actions, an eye movement or an arm movement, to acquire a visual target.

Prior to the monkeys' selection, a computer program "guessed" which of those two actions would be performed by the monkeys, and picked the opposite movement as the choice to be rewarded. (The monkeys were essentially playing a matching game.) The computer's choices were biased by the previous choices made by the monkeys, which gave the monkeys an incentive to mix up their choices. Without it, they would invariably opt for the eye movement, which is the less energetically taxing of the two.

When the monkeys chose the arm movement, the PRR showed the most activity; when the monkeys opted for the eye movement, the LIP was most active.

The experiment shows that it is "the monkey's own choice that activates these areas," says Cui, and not the sensory stimuli provided by the visual target it sees on the computer screen. This finding is significant, Andersen says, because "this is the earliest stage in the brain found so far that is actively related to movement plans."

The research in Andersen's laboratory is focused on understanding the neurobiological underpinnings of brain processes, including the senses of sight, hearing, balance, and touch, and the neural mechanisms of action.

The lab is working toward the development of implanted neural prosthetic devices that would serve as an interface between severely paralyzed individuals' brain signals and their artificial limbs--allowing thoughts to control movement. To assist in designing a more optimal prosthetic, they are now examining whether the decision to make a reaching motion is first made in PRR, or is made in another area of the brain and then transferred to PRR to form the movement plan.

"These areas are prime targets for neural prosthetics. The better we understand these areas, the better we can design prosthetics to decide the subjects' intent," Andersen says.

Source: Caltech

Explore further: Study shines light on brain cells that coordinate movement

Related Stories

Study shines light on brain cells that coordinate movement

June 26, 2017
UW Medicine researchers have developed a technique for inserting a gene into specific cell types in the adult brain in an animal model.

New study suggests blueprint for adult visual system is present at birth

July 18, 2017
For decades, researchers have known that the primate brain is organized into "maps" for each of the different senses: one of the body for touch, one of the visual world for sight, one of tones for hearing. In adults, these ...

World's first child hand transplant a 'success'

July 19, 2017
The first child in the world to undergo a double hand transplant is now able to write, feed and dress himself, doctors said Tuesday, declaring the ground-breaking operation a success after 18 months.

Brain-activated muscle stimulation restores monkeys' hand movement after paralysis

April 18, 2012
An artificial connection between the brain and muscles can restore complex hand movements in monkeys following paralysis, according to a study funded by the National Institutes of Health.

Predicting grip movements of the hand by measuring brain cell activity

January 22, 2015
Tying shoelaces, stirring coffee, writing letters, playing the piano. From the usual daily routine to demanding activities: Our hands are used more frequently than any other body part. Through our highly developed fine motor ...

Previously unknown process explains how brain regions work together, or alone

February 2, 2014
Our brains have billions of neurons grouped into different regions. These regions often work alone, but sometimes must join forces. How do regions communicate selectively?

Recommended for you

Image ordering often based on factors other than patient need: study

September 25, 2017
Do you really need that MRI?

Bone marrow concentrate improves joint transplants

September 25, 2017
Biologic joint restoration using donor tissue instead of traditional metal and plastic may be an option for active patients with joint defects. Although recovery from a biologic joint repair is typically longer than traditional ...

How ketogenic diets curb inflammation

September 25, 2017
Ketogenic diets – extreme low-carbohydrate, high-fat regimens that have long been known to benefit epilepsy and other neurological illnesses – may work by lowering inflammation in the brain, according to new research ...

Researchers develop treatment to reduce rate of cleft palate relapse complication

September 22, 2017
Young people with cleft palate may one day face fewer painful surgeries and spend less time undergoing uncomfortable orthodontic treatments thanks to a new therapy developed by researchers from the UCLA School of Dentistry. ...

Exosomes are the missing link to insulin resistance in diabetes

September 21, 2017
Chronic tissue inflammation resulting from obesity is an underlying cause of insulin resistance and type 2 diabetes. But the mechanism by which this occurs has remained cloaked, until now.

Thousands of new microbial communities identified in human body

September 20, 2017
A new study of the human microbiome—the trillions of microbial organisms that live on and within our bodies—has analyzed thousands of new measurements of microbial communities from the gut, skin, mouth, and vaginal microbiome, ...

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.