Featured Research

from universities, journals, and other organizations

Eliminating useless information important to learning, making new memories

Date:
January 9, 2013
Source:
Georgia Health Sciences University
Summary:
As we age, it just may be the ability to filter and eliminate old information -- rather than take in the new stuff -- that makes it harder to learn, scientists report.

As we age, it just may be the ability to filter and eliminate old information -- rather than take in the new stuff -- that makes it harder to learn, scientists report.
Credit: gunnar3000 / Fotolia

As we age, it just may be the ability to filter and eliminate old information -- rather than take in the new stuff -- that makes it harder to learn, scientists report.

Related Articles


"When you are young, your brain is able to strengthen certain connections and weaken certain connections to make new memories," said Dr. Joe Z. Tsien, neuroscientist at the Medical College of Georgia at Georgia Regents University and Co-Director of the GRU Brain & Behavior Discovery Institute.

It's that critical weakening that appears hampered in the older brain, according to a study in the journal Scientific Reports.

The NMDA receptor in the brain's hippocampus is like a switch for regulating learning and memory, working through subunits called NR2A and NR2B. NR2B is expressed in higher percentages in children, enabling neurons to talk a fraction of a second longer; make stronger bonds, called synapses; and optimize learning and memory. This formation of strong bonds is called long-term potentiation. The ratio shifts after puberty, so there is more NR2A and slightly reduced communication time between neurons.

When Tsien and his colleagues genetically modified mice that mimic the adult ratio -- more NR2A, less NR2B -- they were surprised to find the rodents were still good at making strong connections and short-term memories but had an impaired ability to weaken existing connections, called long-term depression, and to make new long-term memories as a result. It's called information sculpting and adult ratios of NMDA receptor subunits don't appear to be very good at it.

"If you only make synapses stronger and never get rid of the noise or less useful information then it's a problem," said Tsien, the study's corresponding author. While each neuron averages 3,000 synapses, the relentless onslaught of information and experiences necessitates some selective whittling. Insufficient sculpting, at least in their mouse, meant a reduced ability to remember things short-term -- like the ticket number at a fast-food restaurant -- and long-term -- like remembering a favorite menu item at that restaurant. Both are impacted in Alzheimer's and age-related dementia.

All long-term depression was not lost in the mice, rather just response to the specific electrical stimulation levels that should induce weakening of the synapse. Tsien expected to find the opposite: that long-term potentiation was weak and so was the ability to learn and make new memories. "What is abnormal is the ability to weaken existing connectivity."

Acknowledging the leap, this impaired ability could also help explain why adults can't learn a new language without their old accent and why older people tend to be more stuck in their ways, the memory researcher said.

"We know we lose the ability to perfectly speak a foreign language if we learn than language after the onset of sexual maturity. I can learn English but my Chinese accent is very difficult to get rid of. The question is why," Tsien said.

Tsien and his colleagues already have learned what happens when NR2B is overexpressed. He and East China Normal University researchers announced in 2009 the development of Hobbie-J, a smarter than average rat. A decade earlier, Tsien reported in the journal Nature the development of a smart mouse dubbed Doogie using the same techniques to over-express the NR2B gene in the hippocampus.

Doogie, Hobbie-J and their descendants have maintained superior memory as they age. Now Tsien is interested in following the NR2A over-expressing mouse to see what happens.

Tsien is the Georgia Research Alliance Eminent Scholar in Cognitive and Systems Neurobiology. The research was funded by the National Institutes of Health and the GRA.


Story Source:

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


Journal Reference:

  1. Zhenzhong Cui, Ruiben Feng, Stephanie Jacobs, Yanhong Duan, Huimin Wang, Xiaohua Cao, Joe Z. Tsien. Increased NR2A:NR2B ratio compresses long-term depression range and constrains long-term memory. Scientific Reports, 2013; 3 DOI: 10.1038/srep01036

Cite This Page:

Georgia Health Sciences University. "Eliminating useless information important to learning, making new memories." ScienceDaily. ScienceDaily, 9 January 2013. <www.sciencedaily.com/releases/2013/01/130109124227.htm>.
Georgia Health Sciences University. (2013, January 9). Eliminating useless information important to learning, making new memories. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2013/01/130109124227.htm
Georgia Health Sciences University. "Eliminating useless information important to learning, making new memories." ScienceDaily. www.sciencedaily.com/releases/2013/01/130109124227.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Sunday, December 21, 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