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Conférence mensuelle - Steven SiegelbaumNavigating social behavioral space through the hippocampal CA2 region

Abstract :

Although hippocampus is well known to play a central role in declarative memory, it has also been implicated in controlling innate motivated behaviors, such as feeding, mating and aggression. Is the mnemonic function of hippocampus important for the regulation of motivated behaviors or are circuits distinct from those involved in memory recruited? We have focused on the CA2 subregion of the hippocampus, a relatively small and understudied area located between CA3 and CA1 that has been difficult to study using conventional lesioning.
We developed a genetic approach to examining CA2 by generating an Amigo2-Cre line that allows for selective expression of genetically encoded tools and sensors in CA2 pyramidal neurons. Our previous results using genetic silencing of CA2 through tetanus toxin expression revealed that dorsal CA2 is critical for social memory, the ability of an animal to recognize and remember a conspecific. We now find that dorsal CA2 also promotes social aggression.
Through circuit tracing and targeted silencing of CA2 output paths, we demonstrate that social memory is mediated by dorsal CA2 projections to regions of ventral CA1 that project to the nucleus accumbens. In contrast we find that CA2 promotes social aggression by sending outputs to lateral septum, which trigger a disinhibitory circuit that enhances activation of ventro-medial hypothalamus, a region known to promote aggression. Thus distinct CA2 intra- and extra-hippocampal circuits selectively control social memory versus social aggression.

Selected publications

Age-Dependent Specific Changes in Area CA2 of the Hippocampus and Social Memory Deficit in a Mouse Model of the 22q11.2 Deletion Syndrome . Rebecca A. Piskorowski, Kaoutsar Nasrallah, Anastasia Diamantopoulou, Steven A. Siegelbaum, Joseph A. Gogos, Vivien Chevaleyre. Neuron 89, 163–176, January 6, 2016 ª2016 Elsevier Inc. 

The hippocampal CA2 region is essential for social memory. Frederick L. Hitti & Steven A. Siegelbaum 2014 | VOL 000 | NATURE | 1

Input-Timing-Dependent Plasticity in the Hippocampal CA2 Region and Its Potential Role in Social Memory .Felix Leroy, David H. Brann, Torcato Meira, Steven A. Siegelbaum. Leroy et al., 2017, Neuron 95, 1089–1102


La Fédération Bordeaux Neurocampus, en concertation avec l'Ecole Doctorale SVS, a mis en place une série de conférences destinée à l'ensemble des étudiants effectuant leur thèse dans les laboratoires de neurosciences de Bordeaux Neurocampus. Les doctorants Neuroscience in Bordeaux Association (NBA)sont chargés de l'organisation.

Modalités : tous les premiers vendredi de chaque mois à 11h30 (durée : 1h), puis pizzas avec les étudiants et rencontres avec les personnes intéressées l'après-midi

If you are interested to share pizzas and a good moment with the speaker (12h30 - 14h),please register on this Doodle : (maximum 15 people, first-come-first-served!)