Featured Research

from universities, journals, and other organizations

Scientists use light to map neurons' effects on one another

Date:
December 18, 2009
Source:
Harvard University
Summary:
Scientists have used light and genetic trickery to trace out neurons' ability to excite or inhibit one another, literally shedding new light on the question of how neurons interact with one another in live animals.

Scientists at Harvard University have used light and genetic trickery to trace out neurons' ability to excite or inhibit one another, literally shedding new light on the question of how neurons interact with one another in live animals.

The work is described in the current issue of the journal Nature Methods. It builds upon scientists' understanding of the neural circuitry of the nematode worm Caenorhabditis elegans, frequently used as a model in biological research. While the detailed physical structure of C. elegans' scant 302 neurons is well documented, the new research helps measure how neurons in this organism affect each others' activity, and could ultimately help researchers map out in detail how neural impulses flow throughout the organism.

"This approach gives us a powerful new tool for analyzing small neural circuits, and directly measuring how neurons talk to each other," says Sharad Ramanathan, an assistant professor of molecular and cellular biology and of applied physics at Harvard. "While we've only mapped out the interplay of four neurons, it's the first time scientists have determined the ability of multiple neurons in a circuit to excite or inhibit their neighbors."

Zengcai Guo and Ramanathan combined genetically encoded calcium sensors and light-activated ion channels with optics. The scientists used a mirror array to excite individual neurons -- each just two to three millionths of a meter wide -- while simultaneously measuring calcium activity in multiple other neurons. This calcium activity serves to indicate whether these other neurons were activated or inhibited by the neuron that was primed with a burst of light.

"Using this technique, for the first time, we could excite both a sensory neuron and an interneuron and monitor how activity propagates," says Guo, a research assistant in Harvard's Center for Systems Biology, Department of Molecular Biology, and School of Engineering and Applied Sciences. "We expect that our technique can eventually be used more broadly to measure how activity propagates through neural circuits."

Manipulating neurons with light, Guo and Ramanathan were able to evoke an avoidance response -- causing the worm to back away from light -- that is normally prompted only when the organism is touched.

With a compact nervous system consisting of only 302 neurons linked by some 7,000 synapses, the nematode C. elegans is an ideal system for studying the interplay between neural circuits and behavior. While the physical connectivity of the neurons in this nematode is well known, scientists know very little about which of these connections are excitatory and which are inhibitory.

Because of the small sizes of the neurons and a tough cuticle surrounding the worm, electrophysiological recordings can be made from only one neuron at a time, precluding the possibility of any circuit-level analysis of neural activity. By establishing this first fully genetically encoded light-based electrophysiology, the authors have developed a way to overcome this limitation.

Guo and Ramanathan's Nature Methods paper was co-authored by Anne C. Hart of Massachusetts General Hospital and Harvard Medical School. Their work was funded by the National Institute of General Medical Sciences.


Story Source:

The above story is based on materials provided by Harvard University. The original article was written by Steve Bradt. Note: Materials may be edited for content and length.


Journal Reference:

  1. Guo et al. Optical interrogation of neural circuits in Caenorhabditis elegans. Nature Methods, 2009; 6 (12): 891 DOI: 10.1038/nmeth.1397

Cite This Page:

Harvard University. "Scientists use light to map neurons' effects on one another." ScienceDaily. ScienceDaily, 18 December 2009. <www.sciencedaily.com/releases/2009/12/091217102302.htm>.
Harvard University. (2009, December 18). Scientists use light to map neurons' effects on one another. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2009/12/091217102302.htm
Harvard University. "Scientists use light to map neurons' effects on one another." ScienceDaily. www.sciencedaily.com/releases/2009/12/091217102302.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
101-Year-Old Working Man Has All The Advice You Need

101-Year-Old Working Man Has All The Advice You Need

Newsy (Aug. 19, 2014) Herman Goldman has worked at the same lighting store for almost 75 years. Find out his secrets to a happy, productive life. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
American Ebola Patient Apparently Improving, Outbreak Is Not

American Ebola Patient Apparently Improving, Outbreak Is Not

Newsy (Aug. 19, 2014) Nancy Writebol, an American missionary who contracted Ebola, is apparently getting better, according to her husband. The outbreak, however, is not. 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:
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