Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny brain region better part of valor

10.03.2009
Piece of hypothalamus is key to animals' fear of territorial rivals and predators, according to a study in the Proceedings of the National Academy of Sciences

Mice lose their fear of territorial rivals when a tiny piece of their brain is neutralized, a new study reports.

The study adds to evidence that primal fear responses do not depend on the amygdala – long a favored region of fear researchers – but on an obscure corner of the primeval brain.

A group of neuroscientists led by Larry Swanson of the University of Southern California studied the brain activity of rats and mice exposed to cats, or to rival rodents defending their territory.

Both experiences activated neurons in the dorsal premammillary nucleus, part of an ancient brain region called the hypothalamus.

Swanson's group then made tiny lesions in the same area. Those rodents behaved far differently.

"These animals are not afraid of a predator," Swanson said. "It's almost like they go up and shake hands with a predator."

Lost fear of cats in rodents with such lesions has been observed before. More important for studies of social interaction, the study replicated the finding for male rats that wandered into another male's territory.

Instead of adopting the usual passive pose, the intruder frequently stood upright and boxed with the resident male, avoided exposing his neck and back, and came back for more even when losing.

"It's amazing that these lesions appear to abolish innate fear responses," said Swanson, who added: "The same basic circuitry is found in primates and people that we find in rats and mice."

The study was slated for online publication the week of March 9 in Proceedings of the National Academy of Sciences.

Swanson predicted that his group's findings would shift some research away from the amygdala, a major target of fear studies for the past 30 years.

"This is a new perspective on what part of the brain controls fear," he said.

He explained that most amygdala studies have focused on a different type of fear, which might more accurately be called caution or risk aversion.

In those studies, animals receive an electric shock to their feet. When placed in the same environment a few days later, they display caution and increased activity of the amygdala.

But the emotion experienced in that case may differ from the response to a physical attack.

"We're not just dealing with one system that controls all fear," Swanson said.

Swanson and collaborators have been studying the role of the hypothalamus in the fear response since 1992.

Because of its role in basic survival functions such as feeding, reproduction and the sleep-wake cycle, the hypothalamus seems a plausible candidate for fear studies.

Yet, said Swanson, "nobody's paid any attention to it."

The PNAS study is the most recent of several by Swanson on fear and the hypothalamus. The few other researchers in the area include Newton Canteras of the University of Sao Paulo in Brazil, who collaborated with Swanson on the PNAS study, as well as Robert and Caroline Blanchard of the University of Hawaii.

Carl Marziali | EurekAlert!
Further information:
http://www.usc.edu

More articles from Studies and Analyses:

nachricht Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena

nachricht Drone vs. truck deliveries: Which create less carbon pollution?
31.05.2017 | University of Washington

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>