Featured Research

from universities, journals, and other organizations

Mechanism Behind Fear Discovered

Date:
July 22, 2007
Source:
Massachusetts Institute of Technology
Summary:
Researchers have uncovered a molecular mechanism that governs the formation of fears stemming from traumatic events. The work could lead to the first drug to treat the millions of adults who suffer each year from persistent, debilitating fears -- including hundreds of soldiers returning from conflict in Iraq and Afghanistan.

Emotional disorders such as post-traumatic stress and panic attacks stem from the inability of the brain to stop experiencing the fear associated with a specific incident or series of incidents. For some people, upsetting memories of traumatic events do not go away on their own, or may even get worse over time, severely affecting their lives.
Credit: iStockphoto/Viorika Prikhodko

Researchers from MIT's Picower Institute for Learning and Memory have uncovered a molecular mechanism that governs the formation of fears stemming from traumatic events. The work could lead to the first drug to treat the millions of adults who suffer each year from persistent, debilitating fears - including hundreds of soldiers returning from conflict in Iraq and Afghanistan.

Related Articles


A study conducted by the Army in 2004 found that one in eight soldiers returning from Iraq reported symptoms of post-traumatic stress disorder (PTSD). According to the National Center for PTSD in the United States, around eight percent of the population will have PTSD symptoms at some point in their lives. Some 5.2 million adults have PTSD during a given year, the center reports.

Li-Huei Tsai, Picower Professor of Neuroscience in the Department of Brain and Cognitive Sciences, and colleagues show that inhibiting a kinase (kinases are enzymes that change proteins) called Cdk5 facilitates the extinction of fear learned in a particular context. Conversely, the learned fear persisted when the kinase's activity was increased in the hippocampus, the brain's center for storing memories.

Cdk5, paired with the protein p35, helps new brain cells, or neurons, form and migrate to their correct positions during early brain development. In the current work, the MIT researchers looked at how Cdk5 affects the ability to form and eliminate fear-related memories.

"Remarkably, inhibiting Cdk5 facilitated extinction of learned fear in mice. This data points to a promising therapeutic avenue to treat emotional disorders and raises hope for patients suffering from post-traumatic stress disorder or phobia," Tsai said.

Emotional disorders such as post-traumatic stress and panic attacks stem from the inability of the brain to stop experiencing the fear associated with a specific incident or series of incidents. For some people, upsetting memories of traumatic events do not go away on their own, or may even get worse over time, severely affecting their lives.

Treating these disorders involves methods geared toward making the behavior go away, or become extinct, but the molecular mechanisms underlying the extinction process are not well understood. However, Tsai said, studies have shown that some of the molecular machinery that initially encodes the troubling memories also regulates their extinction.

In the current work, genetically engineered mice received mild foot shocks in a certain environment and were re-exposed to the same environment without the foot shock. Mice with increased levels of Cdk5 activity had more trouble letting go--or extinguishing--the memory of the foot shock and continued to freeze in fear. Conversely, in mice whose Cdk5 activity was inhibited, the bad memory of the shocks disappeared when the mice learned that they no longer needed to fear the environment where the foot shocks had once occurred.

"In our study, we employ mice to show that extinction of learned fear depends on counteracting components of a molecular pathway involving the protein kinase Cdk5," said Tsai, a Howard Hughes Medical Institute investigator. "We found that Cdk5 activity prevents extinction, at least in part by negatively affecting the activity of another key kinase.

The team will report their results in the July 15 advance online publication of Nature Neuroscience.

In addition to Tsai, authors include MIT affiliate Farahnaz Sananbenesi; Picower Institute research affiliates Andre Fischer and Xinyu Wang; Christina Schrick and Jelena Radulovic of Northwestern University; and Rachel Neve of McLean Hospital in Belmont, Mass.

This work was supported by the National Institutes of Health and the National Institute of 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. "Mechanism Behind Fear Discovered." ScienceDaily. ScienceDaily, 22 July 2007. <www.sciencedaily.com/releases/2007/07/070716133135.htm>.
Massachusetts Institute of Technology. (2007, July 22). Mechanism Behind Fear Discovered. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2007/07/070716133135.htm
Massachusetts Institute of Technology. "Mechanism Behind Fear Discovered." ScienceDaily. www.sciencedaily.com/releases/2007/07/070716133135.htm (accessed October 31, 2014).

Share This



More Mind & Brain News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Studying Effects of Music on Dementia Patients

Studying Effects of Music on Dementia Patients

AP (Oct. 30, 2014) The University of Wisconsin-Milwaukee is studying the popular Music and Memory program to see if music, which helps improve the mood of Alzheimer's patients, can also reduce the use of prescription drugs for those suffering from dementia. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Techy Tots Are Forefront of London's Baby Show

Techy Tots Are Forefront of London's Baby Show

AP (Oct. 28, 2014) Moms and Dads get a more hands-on approach to parenting with tech-centric products for raising their little ones. (Oct. 28) Video provided by AP
Powered by NewsLook.com
Cocoa Could Be As Good For Memory As It Is For A Sweet Tooth

Cocoa Could Be As Good For Memory As It Is For A Sweet Tooth

Newsy (Oct. 27, 2014) Researchers have come up with another reason why dark chocolate is good for your health. A substance in the treat can reportedly help with memory. Video provided by Newsy
Powered by NewsLook.com
Five-Year-Olds Learn Coding as Britain Eyes Digital Future

Five-Year-Olds Learn Coding as Britain Eyes Digital Future

AFP (Oct. 27, 2014) Coding has become compulsory for children as young as five in schools across the UK. Making it the first major world economy to overhaul its IT teaching and put programming at its core. Duration: 02:19 Video provided by AFP
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