Navigation Links
The cortex plays an essential part in emotional learning
Date:12/9/2011

The study, initiated by the Swiss researchers and published in Nature, constitutes ground-breaking work in exploring emotions in the brain.

Anxiety disorders constitute a complex family of pathologies affecting about 10% of adults. Patients suffering from such disorders fear certain situations or objects to exaggerated extents totally out of proportion to the real danger they present. The amygdala, a deep-brain structure, plays a key part in processing fear and anxiety. Its functioning can be disrupted by anxiety disorders.

Although researchers are well acquainted with the neurons of the amygdala and with the part those neurons play in expressing fear, their knowledge of the involvement of other regions of the brain remains limited. And yet, there can be no fear without sensory stimulation: before we become afraid, we hear, we see, we smell, we taste, or we feel something that triggers the fear. This sensory signal is, in particular, processed in the cortex, the largest region of the brain.

For the first time, these French and Swiss scientists have succeeded in visualising the path of a sensory stimulus in the brain during fear learning, and in identifying the underlying neuronal circuits.

What happens in the brain?

During the experiments conducted by the researchers, mice learnt to associate a sound with an unpleasant stimulus so that the sound itself became unpleasant for the animal.

The researchers used two-photon calcium imaging to visualise the activity of the neurons in the brain during this learning process. This imaging technique involves injecting a chemical indicator that is then absorbed by the neurons. When the neurons are stimulated, the calcium ions penetrate into the cells, where they increase the brightness of the indicator, which can then be detected under a scanning microscope.

Under normal conditions, the neurons of the auditory cortex are highly inhibited. During fear learning, a "disinhibitory" microcircuit in the cortex is activated: thus, for a short time window during the learning process, the release of acetylcholine in the cortex makes it possible to activate this microcircuit and to disinhibit the excitatory projection cells of the cortex. Thus, when the animal perceives a sound during fear learning, that sound is processed much more intensely than under normal conditions, thereby facilitating formation of memory. All of these stages have been visualised by means of the techniques developed by the researchers.

In order to confirm their discoveries, the researchers used another highly innovative recent technique (optogenetics) to disrupt the disinhibition selectively during the learning process. When they tested the memories of their mice (i.e. the association between the sound and the unpleasant stimulus), the next day they observed a severe deterioration in memory, directly showing that the phenomenon of cortical disinhibition is essential to the process of learning fear.

The discovery of this cortical disinhibitory microcircuit opens up interesting clinical prospects, and researchers can now imagine, in very specific situations, how to prevent a traumatism from establishing itself and from becoming pathological.


'/>"/>
Contact: Inserm Presse
presse@inserm.fr
INSERM (Institut national de la sant et de la recherche mdicale)
Source:Eurekalert

Related medicine news :

1. Frontal cortex dysfunction may contribute to compulsive sexual behavior
2. Metabolic protein plays unexpected role in tumor cell formation and growth
3. Where Folks Live Plays Role in Health Disparities: Study
4. Ancestry plays vital role in nutrition and disease, study shows
5. Unemployment Plays Role in Early Deaths, Research Shows
6. New fusion gene plays role in some stomach cancers
7. UCLA study finds cholesterol regulator plays key role in development of liver scarring, cirrhosis
8. Researchers find brain insulin plays critical role in the development of diabetes
9. Parents Have Stronger Relationship When Dad Plays With Kids
10. For non-whites, geography plays key role in colon cancer screening
11. Protein involved in cystic fibrosis also plays role in emphysema, chronic lung disease
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... Battle Creek, Michigan (PRWEB) , ... June 26, 2016 , ... ... abuse, joined as sponsor of the 2016 Cereal Festival and World’s Longest Breakfast Table ... held in honor of the city’s history as home to some of the world’s ...
(Date:6/26/2016)... Carolina (PRWEB) , ... June 26, 2016 , ... ... of a new product that was developed to enhance the health of felines. The ... centuries. , The two main herbs in the PawPaws Cat Kidney Support ...
(Date:6/26/2016)... ... June 26, 2016 , ... ... they have been diagnosed with endometriosis. These women need a treatment plan to ... a comprehensive approach that can help for preservation of fertility and ultimately achieving ...
(Date:6/25/2016)... , ... June 25, 2016 , ... Austin residents seeking ... American College of Mohs Surgery and to Dr. Russell Peckham for medical and surgical ... effective treatment for skin cancer. The selective fellowship in Mohs Micrographic Surgery completed by ...
(Date:6/25/2016)... Viejo, California (PRWEB) , ... June 25, 2016 , ... ... to fit their specific project," said Christina Austin - CEO of Pixel Film Studios. ... fully customizable and all within Final Cut Pro X . Simply select a ...
Breaking Medicine News(10 mins):
(Date:6/26/2016)... OTTAWA, Ontario , June 27, 2016  VMS ... the Company,s Board will take whatever measures required to ... the Company,s stock which is currently listed on the ... S Wexler, Company Chairman and CEO, "We are seeing ... be difficult to understand, not only by the Company, ...
(Date:6/24/2016)... , June 24, 2016  Global Blood ... biopharmaceutical company developing novel therapeutics for the treatment ... today announced the closing of its previously announced ... stock, at the public offering price of $18.75 ... offering were offered by GBT. GBT estimates net ...
(Date:6/24/2016)... The Academy of Managed Care Pharmacy (AMCP) ... would allow biopharmaceutical companies to more easily share health ... and coverage decisions, a move that addresses the growing ... The recommendations address restrictions in the sharing of ... label, a prohibition that hinders decision makers from accessing ...
Breaking Medicine Technology: