Featured Research

from universities, journals, and other organizations

Freeze or run? Not that simple: Scientists discover neural switch that controls fear

Date:
August 25, 2010
Source:
European Molecular Biology Laboratory
Summary:
Scientists have identified the specific type of neurons that determine how mice react to a frightening stimulus, showing that deciding whether or not to freeze in fear is a more complex task for our brains than we realized.

New research has identified the specific type of neurons that determine how the brain reacts to a frightening stimulus.
Credit: iStockphoto/Özgür Donmaz

Fear can make you run, it can make you fight, and it can glue you to the spot. Scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy and GlaxoSmithKline in Verona, Italy, have identified not only the part of the brain but the specific type of neurons that determine how mice react to a frightening stimulus.

In a study published in Neuron, they combined pharmaceutical and genetic approaches with functional magnetic resonance imaging (fMRI) in mice. Their findings show that deciding whether or not to freeze to fear is a more complex task for our brains than we realised.

The scientists used an innovative technique to control the activity of specific cells in the brain of mice that were experiencing fear. The mice were genetically engineered so that only these cells contain a chemical receptor for a specific drug. When the scientists inject the mouse with that drug it acts on the receptor and blocks the electrical activity of those cells allowing the researchers to find out how these cells are involved in controlling fear. In this case, they used this pharmaco-genetic technique to turn off a set of neurons, called type I cells, in a region of the brain called the amygdala, which was known to be involved in responses to fear. To measure fear in mice, the EMBL scientists trained the mice to associate a sound with an unpleasant shock: when the mice heard the sound, they would freeze in fear.

"When we inhibited these neurons, I was not surprised to see that the mice stopped freezing because that is what the amygdala was thought to do. But we were very surprised when they did a lot of other things instead, like rearing and other risk-assessment behaviours," says Cornelius Gross, who led the research at EMBL, "it seemed that we were not blocking the fear, but just changing their responses from a passive to an active coping strategy. That is not at all what this part of the amygdala was thought to do."

To find out what other parts of the brain were involved in these responses, the scientists used a magnetic resonance brain scanning technique developed for use in mice by Angelo Bifone's team at GlaxoSmithKline. Much to their surprise, they found that the switch from passive to active fear was accompanied by the activation of large parts of the outer layer of the brain -- the cortex -- and blocking this activation with the drug atropine could reinstate freezing behaviour and flip back the fear switch. This will give scientists interested in fear circuitry some thinking to do, as the amygdala was thought to control fear via the brain stem, not the cortex.

"This is a powerful demonstration of the ability of functional MRI to resolve brain circuits involved in complex tasks, like processing of emotions and control of behavioural responses," says Bifone, now at the Italian Institute of Technology.

We humans, too, show freezing and risk-assessment behaviours in response to fear. Understanding how to switch from passive to more active fear coping strategies might be helpful for us in adapting to the stress and unpredictability of modern life, the scientists say.


Story Source:

The above story is based on materials provided by European Molecular Biology Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gozzi, A., Jain, A., Giovanelli, A., Bertollini, C., Crestan, V., Schwarz, A.J., Tsetsenis, T., Ragozzino, D., Gross, C.T., & Bifone, A. A neural switch for active and passive fear. Neuron, 2010; 67 (4): 656-666 DOI: 10.1016/j.neuron.2010.07.008

Cite This Page:

European Molecular Biology Laboratory. "Freeze or run? Not that simple: Scientists discover neural switch that controls fear." ScienceDaily. ScienceDaily, 25 August 2010. <www.sciencedaily.com/releases/2010/08/100825131548.htm>.
European Molecular Biology Laboratory. (2010, August 25). Freeze or run? Not that simple: Scientists discover neural switch that controls fear. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2010/08/100825131548.htm
European Molecular Biology Laboratory. "Freeze or run? Not that simple: Scientists discover neural switch that controls fear." ScienceDaily. www.sciencedaily.com/releases/2010/08/100825131548.htm (accessed October 23, 2014).

Share This



More Plants & Animals News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Working Mother DIY: Pumpkin Pom-Pom

Working Mother DIY: Pumpkin Pom-Pom

Working Mother (Oct. 22, 2014) — How to make a pumpkin pom-pom. Video provided by Working Mother
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) — The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Raw: Bear Cub Strolls Through Oregon Drug Store

Raw: Bear Cub Strolls Through Oregon Drug Store

AP (Oct. 22, 2014) — Shoppers at an Oregon drug store were surprised by a bear cub scurrying down the aisles this past weekend. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Family Pleads for Pet Pig to Stay at Home

Family Pleads for Pet Pig to Stay at Home

AP (Oct. 22, 2014) — The Johnson family lost their battle with the Chesterfield County, Virginia Planning Commission to allow Tucker, their pet pig, to stay in their home, but refuse to let the board keep Tucker away. (Oct. 22) Video provided by AP
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

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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