Traditionally, emotions are described as temporary changes in the brain and body that occur in response to certain situations.

"These events or stimuli, depending on the individual's assessment of them in a given context, activate a set of brain areas that generate coordinated responses of several types: cognition (attention, evaluation, etc.), subjective feeling (feeling), body expressions (face and posture), physiology (heart rate, etc.) and action," explains neuroscientist Julie Grèzes, director of research at Inserm. But in recent years, researchers have been revisiting this vision: some limit emotion to feelings alone; others consider it to be a social construct. In all cases, a consensus is emerging around a complex vision of the brain networks involved. Here we trace the birth of fear.

Sensory reception
The senses pick up on the situation: the sight of a threatening dog approaching, the sound of its growling and barking... These stimuli activate sensory receptors, particularly in the retina and auditory apparatus.

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Brain processing
Sensory information arrives in the thalamus. This is the starting point for two information processing pathways.

The unconscious pathway
Information is transmitted directly from the thalamus to the amygdala. The amygdala puts the body on alert and allows reflexive defence reactions (retreat, etc.).

The amygdala then activates two areas: the hypothalamus, which controls the body's autonomic functions (breathing, heart rate, etc.), and the periaqueductal grey matter, which manages motor commands. These two areas send their signals to the rest of the body via the nervous system.

The conscious pathway
Information travels from the thalamus to different areas of the cortex, the outer layer of the brain, notably the sensory cortex (auditory area, visual area, etc.) to decipher stimuli and the prefrontal cortex to analyse the situation, and then is transmitted to the amygdala.

Back and forth between the amygdala and different areas of the brain such as the hippocampus (memorization), the striatum (motivation) and the cortex (attention, analysis) take place. They make it possible to evaluate and memorise the dangerousness of the situation (is the dog big, held on a leash...?), of the experience (has it already been bitten?), etc.

Bodily reactions
The body reacts autonomously
The so-called "sympathetic" nervous system stimulates the adrenal glands, which release stress hormones (adrenaline, etc.). It accelerates the heart rate, increases blood flow to the muscles and the synthesis of glucose by the liver, dilates the pupils...

The person acts in response to the threat
The motor muscles activate in a coordinated manner. Depending on the intensity of the fear or the assessment of the danger, the person may move backwards, run away, use his arms to protect himself, threaten the dog or continue his way.

Thanks to Cyril Dejean, researcher at the Neurocentre Magendie (Herry team), Inserm-University of Bordeaux.

Pièces jointes

from Herry's lab will defend his thesis entitled 'Role of hippocampo-prefrontal circuits in fear memory consolidation'

Defense in english

Pierre Feugas
Herry’s team (Neurocentre Magendie)
Thesiss supervisor: Cyril Dejean

Title
Role of hippocampo-prefrontal circuits in fear memory consolidation

Abstract
Following a pavlovian fear conditioning (FC) task, mice learn to associate a sound with an electric shock. Concurrent with this learning we observed a subset of neurons in the dorso-medial prefrontal cortex (dmPFC) that show synchronous activation on the ascending phase of 4Hz oscillations during fear expression, we named them “assembly neurons” (AN). We hypothesize that this synchronous activation is the cortical representation of the consolidated associative memory. The ventral part of the hippocampus (vHPC) appears as a likely candidate to orchestrate this memory consolidation. Systems consolidation theory posits that memory formation starts in the hippocampus before being transferred to cortical regions for long term retention. The ventral region is specifically implicated in emotional memory and a monosynaptic connection exists between its CA1 field and the PFC. The CA1-field of the vHPC is also the source of high frequency sleep oscillations called Sharp-wave-ripples. These events could act as the supporting mechanism for consolidation, synchronously activating neurons in downstream regions and strengthening their synaptic weights.To test this hypothesis we used in vivo extracellular electrophysiological recordings of single-units and large-field potentials in the PFC and vHPC during sleep and awake behavior. We found that PFC neurons participating in the memory trace display increasing and specific co-activity around sharp-wave ripples (SWRs) throughout post-conditioning sleep, thus highlighting the role of Sharp wave ripples in the consolidation of fear memory. To investigate the causal role of ripples on fear memory consolidation we used optogenetics to inhibit the pathway from vHPC to PFC during ripples using a closed-loop system. We designed and tested the efficiency of a closed-loop system using measures of performances until we obtained results satisfying our conditions of stimulation.
Inhibiting the vHPC-dmPFC pathway during post-conditioning sleep induced a decrease of freezing behavior compared to control animals, indicating the role of this pathway and SWRs in fear memory consolidation.

Keywords: Fear, Memory, Prefrontal Cortex, Hippocampus, Consolidation, Circuits

Jury
Dr. HUMEAU, Yann Directeur de recherche, IINS Centre Broca Président-Examinateur
Dr. WIENER, Sidney Directeur de recherche émérite, Collège de France Rapporteur
Dre. DOYERE, Valérie Directrice de recherche, NeuroPSI-UMR9197 Rapporteur
Dr. LEBLOIS, Arthur Chargé de recherche, IMN Centre Broca Examinateur
Dre. LE MOINE, Catherine Directrice de recherche, INCIA Bordeaux Membre Invité
Date de la soutenance: 19/12/2022 - 14h00
Lieu: Neurocentre Magendie – conference room

Meeting room: Domaine du Haut-Carré Talence

The next Bordeaux Neurocampus Day will take place on Tuesday 8th November 2022 at the Domaine du Haut-Carré.

Registrations are open (free but mandatory – before October 30th):
https://framaforms.org/bordeaux-neurocampus-day-november-8th-1665056861

This day is open to members of Bordeaux Neurocampus and to researchers in neuroscience from the University of Bordeaux and the University of Poitiers.

Poster prize
A poster prize, with 3 prizes of 400 euros each, will be organised with the support of Casden. Please specify your participation in the registration form if you present a poster.

Limited to 38 posters.

Venue
Domaine du Haut-Carré, Talence.
43 rue Pierre Noailles – Talence
Access (maps.google.com)

Programme
8h30 – 9h – Welcome coffee

9h – 9h05 – Welcoming speech, by Jérôme Baufreton, director of Bordeaux Neurocampus

9h05 – 9h35 – Jean-Paul Lasserre, INCIA (MCU – Team; Goizet/Stévanin)
The baker’s yeast Saccharomyces cerevisiae as a model and tool for BPAN pathology

9h35 – 9h50 – Nathalie Piette, IINS (PhD student, Team: Studer)
Synapse on a chip : A quantitative model to investigate synaptogenesis

9h50 – 10h20 – Alexis Dubreuil, IMN (CR CNRS – Team: Mallet/Leblois)
On the role of population structure in neural computations

10h20 – 10h50 – Coffee break

10h50 – 11h05 – Monica Fernandez Monreal, BIC (IR)
Expansion microscopy, a great alternative to get super-resolved images

11h05 – 11h35 – Naoya Takahashi, IINS (Team leader)
Cortical dendrites modulate touch sensitivity

11h35 – 11h50 – Camille Allard, Magendie (Post-doc – Team: Cota)
Cannabinoid receptors type 1: it’s not all in your head

11h50 – 12h20 – Pierre Trifilieff, NutriNeuro (Team leader)
Brain lipids do matter: from biophysical effects to psychiatric disorders

12h20 – 14h00 : Lunch

13h00 – 14h00 : Posters

14h00 – 14h45 – Institutional talks:
. 14h00 – 14h15 – GPR BRAIN_2030, by Daniela Cota
. 14h15 – 14h35 – Bordeaux Neurocampus Parity Committee, by Sandrine Cremona and Michel Thiebault de Schotten
. 14h35 – 14h45 – Bordeaux Neurocampus : Events and communication, by Arnaud Rodriguez

14h45 – 15h00 – Alessandro Piccin, INCIA(Post-doc – Team: Wolff)
Role of prefrontal noradrenergic signaling in flexible behavior

15h00 – 15h30 – Thomas Bienvenu, Magendie, (MCU – Team: Herry)
Frontal oscillations in pathological anxiety, from bench to bedside

15h30 – 15h45 – Anaëlle Braine, IMN (PhD student – Team: Georges/Baufreton)
Building bridges between limbic and motor circuits: anatomical and functional characterization of amygdala-striatal pathway

15h45 – 16h15 – Florian Pécune, Sanpsy

16h15 – 17h00 – Posters & drinks

17h00 – 18h30 – Wine & cheese

17h30 – Poster prize announcement

Félicitations aux lauréats magendiens !

CE13 – Biologie cellulaire, biologie du développement et de l’évolution
Catégorie PRC :

– MODCOM : Modulation de la communication trans- synaptique à la jonction neuromusculaire: des voies de signalisation aux approches thérapeutiques
Laure Strochlic (Institut de Myologie, Paris) / Nathalie Sans (Neurocentre Magendie), Jordi Molgo (CEA SIMOS_Paris) / Rozen LE PANSE (CRM_Paris)

CE14 – Physiologie et physiopathologie
Catégorie PRC :

– NeuroInflamIR – L’altération de l’homéostasie du glucose implique une nouvelle voie inflammatoire hypothalamique Mohammed Taouis (Institut des Neurosciences Paris-Saclay, Paris) / Daniela Cota (Magendie), Agnes Nadjar, (Magendie), Blandine Gatta-Cherifi (Magendie – CHU Bordeaux), Ariane Sharif (Lille Neurosciene & Cognition, Lille)

CE16 – Neurosciences moléculaires et cellulaires – Neurobiologie du développement

Catégorie JCJC (Jeunes Chercheuses et Jeunes Chercheurs) :

– AMY-FEB : Rôle des interneurones en panier et axo-axoniques de l’amygdale dans le contrôle de la
peur et de l’anxiété
Thomas Bienvenu (Magendie)

Catégorie PRC :

– GRINTRACK – Rôle de l’organisation à l’échelle nanométrique des récepteurs NMDA dans le développement normal du cerveau et les troubles GRIN.
Olivier Nicole (IINS) / Emilie Pacary (Magendie)

– PREGNENOID – Étude des mécanismes cellulaires et moléculaires qui constituent la boucle de régulation PREG-CB1R dans des conditions physiologiques et pathologiques
Monique Vallée (Magendie) / Luigi Bellocchio (Magendie)


CE37 – Neurosciences Intégratives et Cognitives

Catégorie PRC :

– CEA : Electrophysiologie des circuits de l’anxiété
Cyril Herry (Magendie), Anna Beyeler (Magendie), Thomas Bienvenu (Magendie), Thomas Tourdias (Magendie)

– EXINmemory : Etude du rôle des synapses excitatrices sur Interneurones dans le processus de mémoire
Yann Humeau (IINS), Daniel Choquet (IINS), Cyril Herry (Magendie)


CE45 – Interfaces: mathématiques, sciences du numérique – biologie, santé
Catégorie PRC :

– CROSS-TRACTS – Revealing the brain’s white matter crossing fibers’ topology: toward a new generation of tractography algorithms integrating the ground truth neuroanatomy.
Laurent Petit (IMN), Sylvain Miraux (CRMSB, Bordeaux), Andreas Frick (Magendie)

Daniel Jercog, a post-doctoral fellow in Cyril Herry's team ("Neuronal circuits of associative learning") at the Neurocentre Magendie, is one of the six 2022 winners of the Académie des Sciences' call for applications for "Great advances in Biology". Congratulations!

He will present his research work on Tuesday, June 28th at the Académie des Sciences, during a public session introduced by Pascale COSSART (Académie des sciences, Institut Pasteur) and Daniel CHOQUET (Académie des sciences, Institut Interdisciplinaire de Neuroscience).

See the programme of the public session: https://www.academie-sciences.fr/pdf/conf/gas_2022.pdf

Daniel Jercog's research work for which the prize was awarded:
Prefrontal coding and avoidance behaviour

In the face of potential danger, mammals exhibit a range of defensive responses, including an avoidance behavioural response that is fundamental to their survival. However, excessive avoidance in the absence of a real threat is a marker of anxiety-related pathologies. Although the medial prefrontal cortex as well as the amygdala play a key role in avoidance behaviour, the underlying neurobiological mechanisms are still largely unknown. In this project, we first trained mice to show an avoidance response to a sound stimulus predictive of an aversive electrical stimulus. We then recorded the activity of neuronal populations in the prefrontal cortex during the behavioural task and performed pharmacological and optogenetic inactivations of the medial prefrontal cortex and amygdala. Our data indicate firstly that the neural representation of danger in the prefrontal cortex requires the functional integrity of the amygdala. Furthermore, our data reveal that the prefrontal cortex is required for the encoding of the upcoming avoidance action. Taken together, these data indicate that information about a hazard as well as the planning of the upcoming action is dynamically represented in the medial prefrontal cortex, thus controlling the temporal evolution of avoidance behaviour.

JERCOG* D, WINKE* N, SUNG K, FERNANDEZ M M, FRANCIONI C, RAJOT D, COURTIN J, CHAUDUN F, JERCOG P E, VALERIO S, HERRY C. Dynamical prefrontal population coding during defensive behaviours.
(2021) Nature 595, 690-694
*Co-first authors

This publication was the subject of a commentary on our website and a video in August 2021:

https://www.bordeaux-neurocampus.fr/daniel-jercog-and-cyril-herry-in-nature/

May 2 – 11:00am
Andreas Frick

May 5 – 9:00am
Cyril Herry (University of Bordeaux, France)
Decoding defensive systems