Featured Research

from universities, journals, and other organizations

Grouping Muscles To Make Controlling Limbs Easier

Date:
April 26, 2009
Source:
Northwestern University
Summary:
Researchers have shown that it could be possible to control a limb by stimulating groups of muscles rather than individual muscles -- a finding that could be useful in future treatments of paralysis patients. The research team used a model of the muscles in a frog's hind leg to perform a computational analysis that shows researchers can control the limb using muscle groups just about as well as if they controlled individual muscles.

With more than 30 muscles in your arm, controlling movement -- whether it's grasping a glass or throwing a baseball -- is a complex task that potentially takes into account thousands of variables.

But researchers at Northwestern University have shown that it could be possible to control a limb by stimulating groups of muscles rather than individual muscles -- a finding that could make it easier to restore muscle movements in people who have become paralyzed.

The researchers used a model of the muscles in a frog's hind leg to perform a computational analysis that, when run as a simulation, shows that researchers can control the limb using muscle groups just about as well as if they controlled individual muscles.

"By controlling muscle groups instead of individual muscles, we're reducing the variables, but we're not losing efficiency," said Matthew Tresch, assistant professor of biomedical engineering at the McCormick School of Engineering and Applied Science and of physical medicine and rehabilitation at the Feinberg School of Medicine. Tresch and colleagues from the Rehabilitation Institute of Chicago conducted the research.

The idea that the body's nervous system controls a limb using muscle groups, or "synergies," has been a controversial hypothesis in the research community for the last decade. If this were the case, it would reduce the number of variables that the nervous system needs to control.

"We still don't know if that's how the central nervous system works, but what has been missing from the rhetoric is the question of whether this is a viable way to produce behavior," said Tresch. "That's what our experiment tried to do."

Using both analytical approaches and techniques from control theory, the researchers chose the muscle combinations that let the frog's hind leg do what it wants to do most effectively. The simulation showed that by choosing the most effective balance of muscle synergies, the researchers could control movement without degrading performance.

"Having all these muscle variables complicates control of behavior, but it also makes certain behavior easier," said Tresch. "The complexity might be there to make certain kinds of movements more efficient than others."

By having this framework, researchers might be able to predict how muscle activation changes when a person loses a muscle or becomes paralyzed.

"Whether or not the nervous system uses this, it does seem like an approach that can simplify control for a complicated mechanical system, like a limb," said Tresch. "For people with spinal cord injuries, you can put electrodes into their muscles and stimulate them. We can use this synergies approach to make controlling a limb simpler."

Next Tresch will perform similar research using a rat model, and he is currently working with other professors at Northwestern to bring the research to patients.

"The end goal is to restore movement in people who are paralyzed," he said.

The findings were published recently by the Proceedings of the National Academy of Sciences. In addition to Tresch, other authors of the paper include Max Berniker and Anthony Jarc of Northwestern University and Emilio Bizzi of the Massachusetts Institute of Technology.


Story Source:

The above story is based on materials provided by Northwestern University. Note: Materials may be edited for content and length.


Cite This Page:

Northwestern University. "Grouping Muscles To Make Controlling Limbs Easier." ScienceDaily. ScienceDaily, 26 April 2009. <www.sciencedaily.com/releases/2009/04/090420170917.htm>.
Northwestern University. (2009, April 26). Grouping Muscles To Make Controlling Limbs Easier. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2009/04/090420170917.htm
Northwestern University. "Grouping Muscles To Make Controlling Limbs Easier." ScienceDaily. www.sciencedaily.com/releases/2009/04/090420170917.htm (accessed September 3, 2014).

Share This



More Plants & Animals News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Snack Attack: Study Says Action Movies Make You Snack More

Snack Attack: Study Says Action Movies Make You Snack More

Newsy (Sep. 2, 2014) You're more likely to gain weight while watching action flicks than you are watching other types of programming, says a new study published in JAMA. Video provided by Newsy
Powered by NewsLook.com
Get A Mortgage, Receive A Cat — Only In Russia

Get A Mortgage, Receive A Cat — Only In Russia

Newsy (Sep. 2, 2014) The incentive is in keeping with a Russian superstition that it's good luck for a cat to be the first to cross the threshold of a new home. Video provided by Newsy
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Sharks Off the Menu and on the Tourist Trail in Palau

Sharks Off the Menu and on the Tourist Trail in Palau

AFP (Sep. 2, 2014) Tourists in Palau clamour to dive with sharks thanks to a pioneering conservation initiative -- as the island nation plans to completely ban commercial fishing in its vast ocean territory. 01:15 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins