Navigation Links
Study breaks ground in revealing how neurons generate movement
Date:4/24/2008

When the eye tracks a birds flight across the sky, the visual experience is normally smooth, without interruption. But underlying this behavior is a complex coordination of neurons that has remained mysterious to scientists. Now, UCSF researchers have broken ground in understanding how the brain generates this tracking motion, a finding that offers a window, they say, into how neurons orchestrate all of the bodys movements.

The study, reported in the April 24 issue of Neuron, reveals that individual neurons do not fire independently across the entire duration of a motor function as traditionally thought. Rather, they coordinate their activity with other neurons, each firing at a particular moment in time.

Scientists have known that neurons that connect to muscles initiate movement in a coordinated fashion. But they have not known how the neurons we are studying which coordinate these front-line neurons -- commit the brain to move the eyes, says co-lead author David Schoppik, PhD, who conducted the study while a doctoral candidate in the laboratory of senior author Stephen Lisberger, PhD, at the University of California, San Francisco.

For decades, scientists have been asking, Do the signals involve a handful of neurons or thousands" What is the nature of the commands" The classical understanding has been that one class of neuron is responsible for one movement, such as generating eye movement to the left, and that it remains active across the entire duration of a behavior, he says.

The new findings suggest a totally different way of looking at how movement is controlled across time, says Lisberger, a Howard Hughes Medical Institute Investigator at UCSF, where he is professor of physiology, director of the W.M. Keck Foundation Center for Integrative Neuroscience, and co-director of the Sloan Center for Theoretical Neurobiology.

The findings, the researchers say, could inform efforts to develop neural prosthetics to treat paralysis and motor dysfunctions, such as those resulting from stroke. The brains messages dont reach the muscles in these conditions, says Schoppik, so its critical that the drive to these prosthetics reflect what the brain is trying to do to move muscles. Understanding how multiple neurons work together could influence the type of software created to drive these devices.

The investigation of how neurons give rise to motor behaviors has been stymied until now, says Schoppik, by the difficulties inherent in studying more than one neuron in action at a time during the course of a behavior. In the current study, the scientists overcame this obstacle in a study of macaque monkeys that had been trained to track a moving object with their eyes.

Basing their approach on two key pieces of information -- first, that when a neuron responds to a stimulus there is always a slight variation in its performance, a phenomenon that neuroscientists traditionally refer to as noise, and, second, that each attempt of the eye to pursue a moving target is also unique they proposed that some aspects of neural variation may reflect behavioral variation.

They used this inherent variability as a probe. Using a formula from financial securities market analysis that looks at how individual stocks behave at a given time within the context of fluctuations in the larger financial market, they explored how individual neurons would behave relative to their neighbors.

They compared the deviations from the average spiking activity of single neurons and simultaneous deviations from the mean eye velocity. They also measured the degree to which variation shared across two pairs of concurrently active neurons.

The data demonstrated that individual neurons encode different aspects of behavior, controlling eye velocity fluctuations at particular moments during the course of eye movement, while the population of neurons collectively tiles the entire duration of the movement.

The analysis also revealed the strength of correlations in the eye movement predictions derived from pairs of simultaneously recorded neurons, and suggests, the researcher say, either that a small number of neurons are sufficient to drive the behavior at any given time or that many neurons operate collectively at each moment.

The finding, says Lisberger, underscores the importance of recording for more than one neuron at a time. There is a lot that we can learn from how multiple neurons interact.


'/>"/>

Contact: Jennifer OBrien
jobrien@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
Source:Eurekalert

Related medicine news :

1. Study Details New Molecular Approach to Preventing Alzheimers
2. NSF awards $1.5M for study of in-home health care via wireless networks
3. Study shows positive findings in treating patients with advanced hepatitis C
4. Study finds racial disparities in smoking cessation treatment
5. Antipodean Pharmaceuticals Announces Results of Phase 2 Study of Lead Compound MitoQ(R)
6. Harvard Business School Publishes a Case Study on Robert Wessman and Actavis
7. Study finds that competency in colonoscopy requires experience with 150 cases or more
8. Study finds cisplatin less effective than standard treatment for patients with anal cancer
9. Potential viral therapy weapon for difficult cancers is safe and effective in study
10. Study: Counseling trauma victims causes secondary trauma
11. Rat study suggests why teens get hooked on cocaine more easily than adults
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/25/2017)... (PRWEB) , ... June 24, 2017 , ... Create a feel-good lyric music video in ... footage and sound in the timeline and write in the lyrics to any song. ProLyric ... back out. Each line of the text can be added modularly for optimal control. ProLyric ...
(Date:6/25/2017)... ... , ... With a heatwave currently bearing down on Northern California pushing temperatures to the maximum, ... ready is easy with laser hair removal. , The process of summer waxing and ... when all you want to do is get out, dive in and cool off. There ...
(Date:6/24/2017)... ... June 24, 2017 , ... Dr. Mitchell Mehlman and ... in Lake Ronkonkoma, Dental365 offers patients high-quality and affordable routine and emergency dental ... dentist fit into their patients’ busy lifestyles. Dental365 also gladly work with most ...
(Date:6/23/2017)... Alexandria, VA (PRWEB) , ... June 23, 2017 ... ... short of what is needed and will ultimately do significant harm to people ... care to everyone. , "While it leaves in place the Affordable Care ...
(Date:6/23/2017)... ... June 23, 2017 , ... The Military Officers Association of America (MOAA) ... of Veterans Affairs, retired Marine Col. Thomas G. Bowman. , Bowman currently serves as ... brings an intimacy with the issues and challenges veterans face with the VA. Following ...
Breaking Medicine News(10 mins):
(Date:6/7/2017)... 6, 2017  Diplomat Specialty Infusion Group, a brand of Diplomat ... its Iowa location. The ... now features an ISO 7 cleanroom—the standard needed to compound intravenous ... low level of pollutants. "Our ... and better serve our Iowa patients," said ...
(Date:6/1/2017)... , June 1, 2017 Nutriceutical Holdings (NH), ... Recommended Solutions (VRS), and KD Pharma Group have decided ... Holdings by KD Pharma Group. KD Pharma Group will ... option to acquire the entire company. "We ... They are committed to growing the NH companies by ...
(Date:5/26/2017)... DUBLIN , May 26, 2017  Endo International plc ... Campanelli , President and CEO, will represent the Company in ... Global Healthcare Conference on Tuesday, June 13, 2017 at 10:40 ... held at Terranea Resort in Rancho Palos Verdes, ... archive for the event will be available on the Company,s ...
Breaking Medicine Technology: