Neurocentre Magendie

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La publication de l'équipe de Cyril Herry dans Nature relayée par Sciences et Santé

L'équipe de Cyril Herry publie une nouvelle fois ses travaux dans Nature. La publication de juillet 2016 porte sur les mécanismes de l'expression de la peur dans le cortex préfrontal dors médian. Elle est relayée par le Magazine Sciences et Santé de l'Inserm.

Nature. 2016 Jul 21;535(7612):420-4.
Prefrontal neuronal assemblies temporally control fear behaviour.
Dejean C, Courtin J, Karalis N, Chaudun F, Wurtz H, Bienvenu TC, Herry C.

Over the past decades, numerous studies demonstrated a critical role of the medial prefrontal cortex (mPFC) in regulation emotional behaviour, in particular learned fear responses. In these studies, in which the neuronal substrates of aversive learning were investigated, encoding of fear behavior was assumed to rely on the activity of single neurons through a rate coding mechanism in which the sole firing rate determine the behavioral output. This form of neuronal cording is strongly limited by the fact that over long distances, rate codes are not optimal for the fast information transmission that is required for rapid behavioural adaptation when facing threatening stimuli. In addition to this rate coding mechanism, neurons with different and specific firing sequences may cooperate and collectively provide information, a phenomenon referred to as "temporal coding".

In temporal coding, precise timing of firing is important, whereas average firing rates can remain stable. Assemblies of neurons enable temporal coding, and one of its obvious advantages is its great flexibility. Thus, neurons might rapidly switch between multiple functional networks according to sensory and internal inputs and determine specific behavioral outputs. Brain oscillations are thought to be instrumental in temporal coding by binding cell assemblies, organizing individual firing into meaningful collective activity, and coordinating remote areas. Whereas temporal coding has been described for sensory processing and spatial learning, its role in encoding emotional behaviour is virtually unknown.

To address this question we use a combination of single-unit and local field potential recordings along with optogenetic manipulations to show that, in the dmPFC, expression of conditioned fear is causally related to the organization of neurons into functional assemblies. During fear behaviour, the development of 4 Hz oscillations coincides with the activation of assemblies nested in the ascending phase of the oscillation. The selective optogenetic inhibition of dmPFC neurons during the ascending or descending phases of this oscillation blocks and promotes conditioned fear responses, respectively. These results identify a novel phase-specific coding mechanism, which dynamically regulates the development of dmPFC assemblies to control the precise timing of fear responses.

Fear response to traumatic or threatening situations helps us evade or escape danger. At the same time fear response is learned in the form of association between stimulus or situation and the presence of a stressor. This association is very powerful and leaves a memory trace that persists for years after a single experience, generating profound structural and functional changes in the brain that can potentially develop into post-traumatic stress and other anxiety-related disorders.

02/03/2016 12h00
Cyril DEJEAN from Herry's lab will give a presentation entitled "Prefrontal neuronal assemblies temporally control fear behaviour"

Circuits neuronaux impliqués dans l'expression et la récupération des réponses de peur: avancées récentes et potentielles stratégies thérapeutiques.

24/06/2015 13h00
Fabrice CHAUDUN from Herry's lab will give a presentation entitled 'Prefrontal-ventral periaqueductal gray pathway regulates fear behavior'

Encoding of fear learning and memory in distributed neuronal circuits.Herry C, Johansen JP. Nat Neurosci. 2014 Dec;17(12):1644-1654. doi: 10.1038/nn.3869. Epub 2014 Nov 21. Review.Cyril Herry dans Nature neuroscience

07/05/2014 12h00
Einar EINARSSON from Herry's lab will give a presentation entitled "Neuronal circuits in the basal amygdala supporting fear memory strengthening"

From discrepancy to paradox through optogenetic: Inactivation of the Prelimbic cortex can indeed inhibit and promote cocaine seeking. - See more at:

13/12/2013 14h00
Julien Courtin Thèse Julien Courtin

Thèse Julien Courtin
Rôle des interneurones corticaux parvalbuminerques dans les comportements de peur'.

Directeur de thèse: Cyril Herry du Neurocentre Magendie

Date de la soutenance: 13/12/2013 - 14h00
Lieu: amphithéâtre 11, Université Bordeaux Segalen site Carreire

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