Featured Research

from universities, journals, and other organizations

How Memories Are Made, And Recalled

Date:
September 16, 2008
Source:
University of California - Los Angeles
Summary:
What makes a memory? Single cells in the brain, for one thing. For the first time, scientists have recorded individual brain cells in the act of calling up a memory, thus revealing where in the brain a specific memory is stored and how the brain is able to recreate it.

Artist's rendering of neuron activity. Researchers have recorded the activity of hundreds of individual neurons making memories.
Credit: iStockphoto/Sebastian Kaulitzki

What makes a memory? Single cells in the brain, for one thing.

Related Articles


For the first time, scientists at UCLA and the Weizmann Institute of Science in Israel have recorded individual brain cells in the act of calling up a memory, thus revealing where in the brain a specific memory is stored and how the brain is able to recreate it.

Reporting in the current online edition of the journal Science, Dr. Itzhak Fried, senior studyauthor and a UCLA professor of neurosurgery, and colleagues recorded the activity of hundreds of individual neurons making memories inthe brains of 13 epilepsy patients being treated surgically at UCLA Medical Center.

Surgeons had placed electrodes in the patients'brains to locate the origin of their seizures before surgical treatment — standard procedure in such cases. Fried made use of the same electrodes to record neuron activity as memories were being formed.

The patients watched several video clips of short duration, including such things as landmarks and people, along with other clips of Jerry Seinfeld, Tom Cruise, "Simpsons" character Homer Simpsonand others. As the patients watched, the researchers recorded the activity of many neurons in the hippocampus and a nearby regionknown the entorhinal cortex that responded strongly to individual clips.

A few minutes later, after performing an intervening task, the patients were asked to recall whatever clips came to mind.

"They were not prompted to recall any specific clips," Fried said, "but to use 'free recall' — that is, whatever popped into their heads."

The researchers found that the same neurons that had responded earlier to a specific clip fired strongly a second or two before the subject reported recalling that clip. These neuronsdid not fire, however,when other clips were recalled. Ultimately, it was possible for the researchers to knowwhich clipa patientwas recallingbefore the patient announced it.

Fried noted that the single neurons that were recorded as they fired were not acting alone but were part of a much larger memory circuit of hundreds of thousands of cells caught in the act of responding to the clips.

The study is significant, he said, because it confirms for the first time that spontaneous memories arisethrough theactivity of the very same neurons that fired when the memory was first being made. This link between reactivation of neurons in the hippocampusand conscious recall of past experience has been suspected and theorized for sometime, but the study now provides direct evidence for such a link.

"In a way, then," Fried said, "reliving past experience in our memory is the resurrection of neuronal activity from the past"

Other authors of the study included first author Hagar Gelbard-Sagiv, Michal Harel and Rafael Malach of the Weizmann Institute and UCLA postdoctoral scholar Roy Mukamel.

The research was funded by the U.S. National Instituteof Neurological Disorders and Stroke, as well as the Israel Science Foundation and the U.S.–Israel Binational Science Foundation.


Story Source:

The above story is based on materials provided by University of California - Los Angeles. The original article was written by Mark Wheeler. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hagar Gelbard-Sagiv, Roy Mukamel, Michal Harel, Rafael Malach, and Itzhak Fried. Internally Generated Reactivation of Single Neurons in Human Hippocampus During Free Recall. Science, 2008; DOI: 10.1126/science.1164685

Cite This Page:

University of California - Los Angeles. "How Memories Are Made, And Recalled." ScienceDaily. ScienceDaily, 16 September 2008. <www.sciencedaily.com/releases/2008/09/080908101651.htm>.
University of California - Los Angeles. (2008, September 16). How Memories Are Made, And Recalled. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2008/09/080908101651.htm
University of California - Los Angeles. "How Memories Are Made, And Recalled." ScienceDaily. www.sciencedaily.com/releases/2008/09/080908101651.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) Video provided by AP
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) Researchers find that as people approach new decades in their lives they make bigger life decisions. 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