Featured Research

from universities, journals, and other organizations

Researchers Provide First Evidence For Learning Mechanism In Brain

Date:
August 25, 2006
Source:
Massachusetts Institute of Technology
Summary:
Finally confirming a fact that remained unproven for more than 30 years, researchers at MIT's Picower Institute for Learning and Memory report in the Aug. 25 issue of Science that certain key connections among neurons get stronger when we learn.

MIT researchers have shown that certain key connections among neurons get stronger when we learn. From left are Mark F. Bear, Picower Professor of Neuroscience; postdoctorate associate Jonathan R. Whitlock; research scientist Arnold J. Heynen and research affiliate Marshall G. Shuler.
Credit: Photo Donna Coveney

Finally confirming a fact that remained unproven for more than 30 years, researchers at MIT's Picower Institute for Learning and Memory report in the Aug. 25 issue of Science that certain key connections among neurons get stronger when we learn.

"We show what everyone has always believed: LTP (long-term potentiation) is indeed induced in the hippocampus when learning occurs," said Mark F. Bear, Picower Professor of Neuroscience. "This is a big deal for neuroscientists because such evidence has been absent for the 30-plus years we have known about LTP."

The findings described in the Bear paper and in a second, separate paper in the same issue of Science "substantially advance the case for LTP as a neural mechanism for memory," wrote Tim Bliss of the MRC National Institute for Medical Research in the UK, Graham Collingridge of the University of Bristol, and Serge Laroche of the Universite Paris Sud in a commentary on the work.

LTP is an example of plasticity -- the amazing ability of the brain to change in response to experience. LTP builds up synapses, or the connections between neurons, while its counterpart, long-term depression, or LTD, pares unused synapses.

Since LTP was discovered in the late 1960s, thousands of papers have been published based on the assumption that the phenomenon is an important learning and memory mechanism in the hippocampus, the memory center of the brain.

Researchers had found that electrical stimulation of neurons, mimicking the electrical impulses that zap around the brain when it responds to sensory input, strengthens the connections among synapses. The assumption was that LTP occurs in the hippocampus as a consequence of learning, but there had never been conclusive evidence that learning was directly tied to LTP.

The problems were threefold.

Many learning tasks require more than one repetition of an event, and slight differences in animals' rates of learning obscured the time-sensitive markers of LTP. Second, the synaptic changes that occur in hippocampus-based learning are few and far between, making them hard to detect. Third, it became apparent that learning could be stored through LTD as well as LTP.

Using techniques pioneered by MIT's Susumu Tonegawa, director of the Picower Institute, neuroscientists began to pinpoint exactly which genes and proteins are involved in learning.

This created a "big thicket of correlations, but it never proved causality," said Bear, who also holds an appointment in MIT's Department of Brain and Cognitive Sciences. "Our contribution was that we had learned enough about LTP and the traces it leaves in the brain to track changes in proteins. We asked whether learning induces the same subtle changes."

In the experiment, rats learned that if they darted into the darkened area of a two-chambered box, they received an unpleasant foot shock. The animals quickly learned to avoid the darkened chamber and stay in the brightly lit area.

The researchers used biochemical probes that "marked" synapses that had recently been modified by learning, as well as a technique that allowed them to eavesdrop on the synaptic transmissions in the rats' brains as they learned. Learning, they found, did indeed induce LTP among synapses in the hippocampus.

In addition to Bear, the study's authors are Jonathan R. Whitlock, affiliated with Brown University; research scientist Arnold J. Heynen and research affiliate Marshall G. Shuler, both at the Picower Institute.

This work is supported by the Howard Hughes Medical Institute and the National Institute for Mental Health.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute of Technology. "Researchers Provide First Evidence For Learning Mechanism In Brain." ScienceDaily. ScienceDaily, 25 August 2006. <www.sciencedaily.com/releases/2006/08/060824222608.htm>.
Massachusetts Institute of Technology. (2006, August 25). Researchers Provide First Evidence For Learning Mechanism In Brain. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2006/08/060824222608.htm
Massachusetts Institute of Technology. "Researchers Provide First Evidence For Learning Mechanism In Brain." ScienceDaily. www.sciencedaily.com/releases/2006/08/060824222608.htm (accessed September 3, 2014).

Share This



More Mind & Brain News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
Coffee Then Napping: The (New) Key To Alertness

Coffee Then Napping: The (New) Key To Alertness

Newsy (Aug. 30, 2014) Researchers say having a cup of coffee then taking a nap is more effective than a nap or coffee alone. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
Baby Babbling Might Lead To Faster Language Development

Baby Babbling Might Lead To Faster Language Development

Newsy (Aug. 29, 2014) A new study suggests babies develop language skills more quickly if their parents imitate the babies' sounds and expressions and talk to them often. 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