Featured Research

from universities, journals, and other organizations

Competition between brain cells spurs memory circuit development

Date:
June 24, 2011
Source:
University of Michigan Health System
Summary:
Scientists have for the first time demonstrated how memory circuits in the brain refine themselves in a living organism through two distinct types of competition between cells. Their results mark a step forward in the search for the causes of neurological disorders associated with abnormal brain circuits, such as Alzheimer's disease, autism and schizophrenia.

Scientists at the University of Michigan Health System have for the first time demonstrated how memory circuits in the brain refine themselves in a living organism through two distinct types of competition between cells.

Their results, published in Neuron, mark a step forward in the search for the causes of neurological disorders associated with abnormal brain circuits, such as Alzheimer's disease, autism and schizophrenia.

"Much of our understanding of the brain's wiring has come from studying our sensory and motor systems, but far less is understood about the mechanisms that organize neural circuits involved in higher brain functions, like learning and memory," says senior author Hisashi Umemori, M.D., Ph.D., assistant research professor at U-M's Molecular and Behavioral Neuroscience Institute and assistant professor of biological chemistry at the U-M Medical School.

Brain cells grow and extend along pathways to link different parts of the brain, Umemori explains. As the brain develops, these connections fine-tune themselves and become more efficient. Problems with this refinement process may be responsible for some neurological disorders.

"We wanted to know how brain circuits become more efficient during the brain's development," Umemori adds. "Does the brain choose to keep good connections and get rid of bad ones and, if so, how?"

To examine how neural activity organizes memory circuits, researchers used mice that had been genetically modified so that neurons of interest purposefully could be switched off.

The scientists focused on an important connection between the hippocampus, which is crucial for learning and memory, and the cerebral cortex, which is key for perception and awareness. They deactivated about 40 percent of the neurons in the connection and, over a matter of days, watched as the brain eliminated the inactive neural connections and kept only the active ones. A subsequent part of the experiment showed that if all the neurons were deactivated, their connections were not eliminated.

"This tells us that the brain has a way of telling among a group of neurons which connections are better than others," Umemori says. "The neurons are in competition with each other. So when they're all equally bad, none can be eliminated."

The researchers also looked at a part of the hippocampus called the dentate gyrus, which is only one of two areas of the brain that continues to generate new neurons throughout life. Here they found a second distinct type of competition: newborn cells were competing with mature cells, rather competition occurring between mature cells.

When scientists blocked the dentate gyrus' ability to make new cells, the elimination stopped and the brain kept the existing cells even if they were deactivated.

"The better the brain is at eliminating bad connections to keep the circuitry at its most efficient, the more efficient learning and memory will be as well," Umemori explains.

He adds, "The better we understand how these mechanisms work, the better we'll be able to understand what's happening when they aren't working."

Additional Authors: Masahiro Yasuda, Ph.D.; Erin M. Johnson-Venkatesh, Ph.D.; Helen Zhang, M.S.; Jack M. Parent, M.D.; Michael A. Sutton, Ph.D.; all of U-M

Funding: U-M Center for Organogenesis, Ester A. & Joseph Klingenstein Fund, the Edward Mallinckrodt Jr. Foundation, the March of Dimes Foundation, the Whitehall Foundation and the National Institutes of Health


Story Source:

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


Journal Reference:

  1. Masahiro Yasuda, Erin M. Johnson-Venkatesh, Helen Zhang, Jack M. Parent, Michael A. Sutton, Hisashi Umemori. Multiple Forms of Activity-Dependent Competition Refine Hippocampal Circuits In Vivo. Neuron, 2011; 70 (6): 1128-1142 DOI: 10.1016/j.neuron.2011.04.027

Cite This Page:

University of Michigan Health System. "Competition between brain cells spurs memory circuit development." ScienceDaily. ScienceDaily, 24 June 2011. <www.sciencedaily.com/releases/2011/06/110623085949.htm>.
University of Michigan Health System. (2011, June 24). Competition between brain cells spurs memory circuit development. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2011/06/110623085949.htm
University of Michigan Health System. "Competition between brain cells spurs memory circuit development." ScienceDaily. www.sciencedaily.com/releases/2011/06/110623085949.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. 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