Featured Research

from universities, journals, and other organizations

Brain Input Aids Devices That Move Injured Or Artificial Limbs

Date:
October 18, 2007
Source:
Hebrew University of Jerusalem
Summary:
Neuroscientists have developed a novel approach for measuring and deciphering brain activity that holds out promise of providing improved movements of natural or artificial limbs by those who have been injured or paralyzed.

Neural activity in the premotor cortex carries information about reaching and grasping. Information can be obtained from local field potentials (top left, blue signal), spikes or individual neuronal action potentials (green), and multi-unit activity (red), measuring the activity of populations of neurons. The most accurate information is obtained by combining multi-unit activity from multiple electrodes, depicted by the red-colored shadow hand of the monkey.
Credit: Sandrine Alon

Neuroscientists at the Hebrew University of Jerusalem have developed a novel approach for measuring and deciphering brain activity that holds out promise of providing improved movements of natural or artificial limbs by those who have been injured or paralyzed.

Related Articles


Neuroscientists have long been working towards achieving a better understanding of the relationship between brain activity and behavior, and especially between neural activity in the motor regions of the cortex and hand movements.

In addition to addressing basic scientific questions, this line of research carries important practical implications, since the identification of precise relationships would enable neuroscientists to assist in the construction of devices through which brain signals will activate muscles in a paralyzed limb or a prosthetic (robotic) arm.

In an article recently published in The Journal of Neuroscience, Hebrew University neurophysiologists Eran Stark and Prof. Moshe Abeles report on their new approach for measuring and deciphering brain activity, which avoids many of the drawbacks of current methods and which provides an accurate decoding of brain activity.

Currently, two methods are being used to measure brain activity in the context of neuro-prosthetic devices. The first method is based on the EEG (electroencephalogram) and is measured either over the scalp, directly from the cortical surface, or from the cortex itself. The second method is based on the activity of individual nerve cells within the cortex, and uses intra-cortical electrodes -- which essentially are fine wires.

Each method has advantages but is also subject to considerable drawbacks. To decipher brain activity at a level of accuracy that is sufficient to activate a paralyzed limb or a robotic arm, a large number of parallel and preferably independent measurements must be taken from a relatively small area (in humans, about 4 cm2). Neither of the above two methods is particularly efficient in accomplishing that.

One of the particular drawbacks to the use of the EEG is that nearby electrodes record approximately the same EEG activity, so the gain from employing multiple measurements is limited. A second drawback is that the bulk of the changes recorded in the EEG brain wave occurs after movement and not prior to it, as is required for controlling a paralyzed limb or a robotic arm.

With regard to the fine-wire electrodes, it has been found that, over time, the brain responds to the implanted electrodes by forming glia cells in a process akin to scar formation, with the consequence that a large portion of the brain wave activity is masked.

The approach taken by the Hebrew University scientists entails measuring the activity of all the nerve cells that are located at an intermediate distance (100-200 micrometers) from a recording electrode. In this way, independent measurements can be obtained from many adjacent points. Minor damage to the brain tissue in close proximity to the measurement site scarcely affects the quality of the measurement. Moreover, the measurement remains reliable over a long duration.

In testing the new approach, monkeys were trained to make prehension movements, reaching and grasping various objects located at different positions. Prehension requires coordination between the direction of reach, performed mainly by the arm, and the type of grasp, performed mainly by the fingers. By measuring the activity of populations of nerve cells as outlined above, using no more than 16 electrodes, the upcoming reach direction and grasp type could be predicted at an accuracy of about 90% and, in some cases, at a near-perfect accuracy (above 99%). The prediction errors of the proposed method of measurement were two to three times lower than the errors of predictions based on the other methods of brain activity measurement.

The Hebrew University researchers believe that this new study constitutes a considerable step forward towards deciphering intentions to perform movements by persons who are paralyzed or are amputees, thus paving the way for creation of better instruments for converting brain activity into actual movements.


Story Source:

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


Cite This Page:

Hebrew University of Jerusalem. "Brain Input Aids Devices That Move Injured Or Artificial Limbs." ScienceDaily. ScienceDaily, 18 October 2007. <www.sciencedaily.com/releases/2007/10/071018102018.htm>.
Hebrew University of Jerusalem. (2007, October 18). Brain Input Aids Devices That Move Injured Or Artificial Limbs. ScienceDaily. Retrieved March 3, 2015 from www.sciencedaily.com/releases/2007/10/071018102018.htm
Hebrew University of Jerusalem. "Brain Input Aids Devices That Move Injured Or Artificial Limbs." ScienceDaily. www.sciencedaily.com/releases/2007/10/071018102018.htm (accessed March 3, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Tuesday, March 3, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

This Nasal Treatment Could Help Ease Migraine Pain

This Nasal Treatment Could Help Ease Migraine Pain

Newsy (Mar. 2, 2015) Researchers gave lidocaine to 112 patients, and about 88 percent of the subjects said they needed less migraine-relief medicine the next day. Video provided by Newsy
Powered by NewsLook.com
How Facebook Use Can Lead To Depression

How Facebook Use Can Lead To Depression

Newsy (Mar. 1, 2015) Margaret Duffy of the University of Missouri talks about her study on the social network and the envy and depression that Facebook use can cause. Video provided by Newsy
Powered by NewsLook.com
The Best Foods to Battle Stress

The Best Foods to Battle Stress

Buzz60 (Feb. 26, 2015) If you&apos;re dealing with anxiety, there are a few foods that can help. Krystin Goodwin (@krystingoodwin) has the best foods to tame stress. Video provided by Buzz60
Powered by NewsLook.com
Sleeping Too Much Or Too Little Might Increase Stroke Risk

Sleeping Too Much Or Too Little Might Increase Stroke Risk

Newsy (Feb. 26, 2015) People who sleep more than eight hours per night are 45 percent more likely to have a stroke, according to a University of Cambridge study. Video provided by Newsy
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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