There is a large amount of data indicating that the amygdala, a particular structure in the brain, is strongly involved during the learning of "conditioned" fear.
However, until now, the underlying neuronal circuits have remained largely unknown. Now, research involving several Swiss and German teams and a researcher from Inserm Unit 862, "Neurocentre Magendie", in Bordeaux, has been able to identify, for the first time, distinct neuronal circuits within the central nucleus of the amygdala which are specifically involved in acquisition and control of behavioural fear responses. Details of these results are published in this week's edition of the journal Nature.
In this study, laboratory mice were first subjected to a simple behavioural task which consisted of learning that an audible stimulus presaged the arrival of an unpleasant event. Following this conditioning, presentation of the audible stimulus induced a set of behavioural manifestations of fear such as freezing of the animals. Using highly innovative pharmacological and optogenetic techniques, the researchers have shown that the medial and central nuclei of the central amygdala were differentially involved in either learning or behavioural manifestation of fear responses (see the diagram on the next page). Indeed, the researchers were able to show that after inactivating the lateral subdivision of the central nucleus of the amygdala, the animals no longer learnt the association between the sound and the unpleasant event. By contrast, inactivation of the medial subdivision of this nucleus did not disrupt the learning of fear; however, the animals were now no longer able to give a behavioural manifestation to their fear, i.e. freezing.
In that second step, real-time recording of the activity of the neurons in the lateral and medial subdivisions of the central amygdala, using unique electrophysiological techniques, made it possible for the researchers to identify the specific neurons, within the structures, which were involved in conditioning and behavioural manifestation of fear responses.
These neurons are inhibitor cells belonging to very organized and strongly interconnected neuronal circuits. Modification of the activity of these circuits enables the relevant behavioural fear response to be selected as a function of the environmental situation.
Hence, our work defines the functional architecture of the neuronal circuits of the central amygdala and their role in acquisition and regulation of fear behaviours. Precise identification of the neuronal circuits which control fear is a major clinical challenge. Patients suffering from disorders, such as post-traumatic stress disorder or anxiety problems, exhibit disruption of certain neuronal circuits which leads to unsuitable anxiety behaviour responses. The selective manipulation of neuronal circuits that we have identified, using new therapeutic approaches which need to be developed further, could make it possible to regulate the pathological manifestations of fear in these patients.
Nature, 11 November 2010, DOI 10.1038/nature09559Contact chercheur
Séverine Ciancia | EurekAlert!
Microfluidics probe 'cholesterol' of the oil industry
23.10.2017 | Rice University
Salmonella as a tumour medication
23.10.2017 | Helmholtz-Zentrum für Infektionsforschung
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
23.10.2017 | Event News
17.10.2017 | Event News
10.10.2017 | Event News
23.10.2017 | Materials Sciences
23.10.2017 | Life Sciences
23.10.2017 | Press release