Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Be afraid, be very afraid, if you learned to

25.01.2007
Study on fear responses suggests new understanding of anxiety disorders

A new study on rats has identified a part of the brain's cortex that controls learned but not innate fear responses.

The results suggest that hyperactivity in a region of the prefrontal cortex might contribute to disorders of learned fear in humans, such as post-traumatic stress disorder and other anxiety disorders, say authors Kevin A. Corcoran, PhD, and Gregory Quirk, PhD, of the Ponce School of Medicine in Puerto Rico. Their report appears in the January 24 issue of The Journal of Neuroscience.

While building on previous findings, this study contradicts prior thinking that the amygdala, which plays a central role in emotional learning, is sufficient for processing and expressing fear, and it opens the potential for new avenues of treatment, the researchers say.

"This is the first paper demonstrating that a region of the cortex is involved in learned fear but not in innate fear," says Markus Fendt, PhD, of the Novartis Institutes for Biomedical Research in Basel, Switzerland, who is not connected with the study.

In their study, Corcoran and Quirk taught rats to associate a 30-second tone with a shock to the foot at the end of the tone. Upon hearing the same tone the next day, rats spent nearly 70 percent of the time of the tone frozen, a typical fear response.

In another group of rats, the researchers chemically blocked activity in the prelimbic cortex, which is located near the front of the brain and close to the midline between the two hemispheres. These rats spent only 14 percent of the time freezing to the sound of the tone.

Yet the rats' innate, or natural, fears seemed unaffected by blocking the prelimbic cortex; they froze as much in response to seeing a cat or being placed in a large open area as they did to hearing the tone. Furthermore, when the team trained rats with the tone after chemically inactivating the prelimbic cortex, and then tested them drug-free the next day, the rats showed a normal fear response, indicating that inactivating the prelimbic cortex did not prevent them from learning to fear the tone.

The prelimbic cortex is connected to the amygdala, and, based on their findings, Corcoran and Quirk speculate that "by modulating amygdala activity, the prelimbic cortex is important for determining the circumstances in which it is appropriate to convey learned fears." In contrast, they propose that fear responses to innate threats are automatic and do not require cortical involvement.

"Corcoran and Quirk's work raises the question of whether learned fear is more controllable--for example, by higher brain functions--than innate fear," says Fendt.

Sara Harris | EurekAlert!
Further information:
http://www.sfn.org

More articles from Studies and Analyses:

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Researchers at IST Austria define function of an enigmatic synaptic protein

22.11.2017 | Life Sciences

Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes

22.11.2017 | Materials Sciences

Women and lung cancer – the role of sex hormones

22.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>