PhD Scientific Days 2025

Poster Session III. - R: Neurosciences

Median Raphe Controls Fear Memory

Előadó neve

Dr. Major Abel

Neptun code

vf49ul

Előadó munkahelye

Semmelweis University Doctoral College, HUN-REN Institute of Experimental Medicine

Előadó telefonszáma

+36309402198

Előadó e-mail címe

major.abel@stud.semmelweis.hu

Az előadás címe

Median Raphe Controls Fear Memory

Szerző(k) neve és munkahelye

Dr. Abel Major¹

1: Semmelweis University Doctoral College, HUN-REN Institute of Experimental Medicine

Bemutatás módja

Poszter

Szekció

Poster Session III. - R: Neurosciences

Language of the presentation

Hungarian

Preferred session

Neurosciences

Összefoglaló szövege

Introduction
Fear, an evolutionarily conserved defensive mechanism, can become maladaptive in disorders such as PTSD and depression, therefore understanding recall and extinction of fear memories is crucial in both physiological and pathological conditions. The median raphe region (MRR) harbours glutamatergic (vGluT2+) neurons implicated in fear acquisition, but their role in memory recall remains unexplored.
Aims
This study investigates the role of MRR vGluT2 neurons in contextual/cued fear recall and their neuronal connectivity.
Methods
Optogenetic inhibition/activation, viral tracing, and behavioural trials were performed on transgenic mice. Neuronal connectivity was assessed using immunohistochemistry. Using classical contextual and cued fear-conditioning tests, mice were evaluated during the recall of previously acquired fear memory while inhibiting the vGluT2 cells in the MRR. After two days of recall-inhibition sessions, we measured the residual fear levels in the same paradigm but without inhibiting these cells.
Results
To test whether the activity of MRR vGluT2 neurons is necessary for fear memory recall, we inhibited MRR vGluT2 neurons optogenetically during potential fear recall periods in mice. We found that in contextual, cued, and mixed fear paradigm, optogenetic inhibition of MRR vGluT2 neurons during recall impaired contextual and cued fear responses, resulting in accelerated and persistent fear extinction. Enhancing fear extinction took only two recall sessions with the inhibition of MRR vGluT2 cells. On the last day, animals were exposed to the fearful context or auditory cue without any optogenetic intervention. We found significant decrease in freezing behaviour in all the three paradigms. Our tracing studies reveald that MRR vGluT2 cells establish connections with the fear-related lateral habenula (LHb), responsible for fear modulation.
Conclusion
We found that MRR vGluT2 neurons are necessary for both fear recall and control of fear extinction and exhibit persistent activity during fear processing. Therefore, MRR vGluT2 neurons may play a role in fear recall and mood regulation, dynamically updating fear perception via connections with other fear-processing brain regions. This highlights their potential function in both physiological and pathological conditions.
Funding
Supported by ÚNKP-ÚNKP-21-2-I-SE-52, EKÖP-2024-194

University

Semmelweis University

Supervisor

Prof. Dr. Gabor Nyiri

Publication of my abstract

I do not give consent to the publication of my abstract on the website of the congress.

phd.section.field

in doctoral studies before complex exam (PhD)

Kind

Szabad

Status

elfogadva

Accepted presentation method

poszter

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

9063

Start

14:12

End

14:18