Featured Research

from universities, journals, and other organizations

Scientists Decipher The Formation Of Lasting Memories

Date:
November 11, 2009
Source:
Karolinska Institutet
Summary:
Researchers have discovered a mechanism that controls the brain's ability to create lasting memories. In experiments on genetically manipulated mice, they were able to switch on and off the animals' ability to form lasting memories by adding a substance to their drinking water. The findings are of potential significance to the future treatment of Alzheimer's and stroke.

Researchers at Karolinska Institutet have discovered a mechanism that controls the brain's ability to create lasting memories. In experiments on genetically manipulated mice, they were able to switch on and off the animals' ability to form lasting memories by adding a substance to their drinking water. The findings, which are published in the scientific journal PNAS, are of potential significance to the future treatment of Alzheimer's and stroke.

Related Articles


"We are constantly being swamped with sensory impression," says Professor Lars Olson, who led the study. "After a while, the brain must decide what's to be stored long term. It's this mechanism for how the connections between nerve fibers are altered so as to store selected memories that we've been able to describe."

The ability to convert new sensory impressions into lasting memories in the brain is the basis for all learning. Much is known about the first steps of this process, those that lead to memories lasting a few hours, whereby altered signalling between neurons causes a series of chemical changes in the connections between nerve fibers, called synapses. However, less is understood about how the chemical changes in the synapses are converted into lasting memories stored in the cerebral cortex.

A research team at Karolinska Institutet has now discovered that signalling via a receptor molecule called nogo receptor 1 (NgR1) in the nerve membrane plays a key part in this process. When nerve cells are activated, the gene for NgR1 is switched off, and the team suspected that this inactivation might be important in the creation of long-term memories. To test this hypothesis they created mice with an extra NgR1 gene that could remain active even when the normal NgR1 was switched off.

"Doing this, we found that the ability to retain something in the memory for the first 24 hours was normal in the genetically modified mice," says Professor Olson. "However, two different memory tests showed that the mice had serious difficulties converting their normal short-term memories to long-term ones, the kind that last for months."

In order to be able to switch the extra NgR1 gene on and off, the group attached a regulatory mechanism to the gene that reacted to a harmless additive in their drinking water. When the extra gene was then switched off, the mice retained their normal ability to form long-term memories. By subsequently switching it off at different times after a memory-forming event, they were able to pinpoint the effect of the NgR1 gene to the first week after such an event.

"We know that concussion can cause someone to forget events that occurred in the week before the injury, what we call retrograde amnesia, even though they can remember events that occurred earlier than about a week before. This we believe tallies with our findings," says Alexandra Karlén, one of the scientists involved in the study.

The scientists hope that their findings will eventually be of use in the development of new treatments for memory impairments, such as those related to Alzheimer's and stroke. Medicines designed to target the NgR1 receptor system would be able to improve the brain's ability to form long-term memories. The studies were conducted in collaboration with American researchers at the National Institute on Drug Abuse (NIDA), NIH.


Story Source:

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


Journal Reference:

  1. A. Karlén, T. E. Karlsson, A. Mattsson, K. Lundströmer, S. Codeluppi, T. M. Pham, C. M. Bäckman, S. O. Ögren, E. Ĺberg, A. F. Hoffman, M. A. Sherling, C. R. Lupica, B. J. Hoffer, C. Spenger, A. Josephson, S. Brené, & L. Olson. Nogo receptor 1 regulates formation of lasting memories. PNAS, Online Early Edition, 9-13 November 2009

Cite This Page:

Karolinska Institutet. "Scientists Decipher The Formation Of Lasting Memories." ScienceDaily. ScienceDaily, 11 November 2009. <www.sciencedaily.com/releases/2009/11/091110105347.htm>.
Karolinska Institutet. (2009, November 11). Scientists Decipher The Formation Of Lasting Memories. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2009/11/091110105347.htm
Karolinska Institutet. "Scientists Decipher The Formation Of Lasting Memories." ScienceDaily. www.sciencedaily.com/releases/2009/11/091110105347.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) — In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Double-Amputee Becomes First To Move Two Prosthetic Arms With His Mind

Buzz60 (Dec. 19, 2014) — A double-amputee makes history by becoming the first person to wear and operate two prosthetic arms using only his mind. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Prenatal Exposure To Pollution Might Increase Autism Risk

Prenatal Exposure To Pollution Might Increase Autism Risk

Newsy (Dec. 18, 2014) — Harvard researchers found children whose mothers were exposed to high pollution levels in the third trimester were twice as likely to develop autism. Video provided by Newsy
Powered by NewsLook.com
Yoga Could Be As Beneficial For The Heart As Walking, Biking

Yoga Could Be As Beneficial For The Heart As Walking, Biking

Newsy (Dec. 17, 2014) — Yoga can help your weight, blood pressure, cholesterol and heart just as much as biking and walking does, a new study suggests. 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