Topic: social memory

Social memory, one's ability to recognize and remember experiences with other conspecifics, consists of several discrete psychological processes. These include the ability to rapidly detect whether an individual is novel or familiar (“I know that person, but from where?”) and the recollection of an individual’s specific identity and the associated set of past experiences (“ah, we met at COSYNE last year”). These processes have conflicting demands and requirements. Familiarity is an abstract concept that can readily generalize to any individual in any context. In contrast, social episodes consi

The ability to remember and recognize other individuals is crucial for complex social behaviors. Although the hippocampus is known to be fundamental for social memory (Hitti & Siegelbaum, 2014), how this region represents and supports the two processes of social recognition - familiarity and recollection - remains unknown. We used microendoscopic calcium imaging to measure the activity of hippocampal dorsal CA2 pyramidal neurons (dCA2) - a region known for its importance in social memory - in mice interacting with novel and familiar conspecifics in different spatial contexts. Through a dec

Alzheimer’s disease (AD) early stages are characterized by amyloid beta oligomers (oAβ) toxicity in the hippocampus, leading to its dysfunction. Previously, we characterized a non-transgenic mouse model of early amyloidosis by a single intracerebroventricular (icv.) injection of oAβ1-42, that showed deficient hippocampal-dependent memory and synaptic plasticity impairment in the CA1–CA3 synapse regardless the sex. Social memory impairments have also been described in AD. However, neuronal oscillatory activity in hippocampal CA2 subfield, a region that plays a crucial role in the formation and

Despite extensive research into the classic subfields of the hippocampus, the fasciola cinerea (FC), a medially located structure within the hippocampal formation, remains understudied. In order to gain insight into the unique features and potential functions of the FC, we examined the morphology, physiology, and connectivity of its principal neurons in anesthetized mice. Using in-vivo single-cell juxtacellular recording-labeling and quantitative morphometric analysis, we found that FC neurons exhibit unique firing patterns and dendritic architectures, which are distinct from principal cell po

The entorhinal cortex is an area known to be involved in spatial navigation and episodic memories. While the spatial aspects of episodic memories have been studied in great detail, questions still remain regarding the processing of social information in the brain.Emerging evidence points towards a complex network of brain areas involved in social memory processing. In particular, the hippocampal regions CA2 and ventral CA1 play an important role, but the role of computations within the hippocampus compared to the input regions remains unresolved. With entorhinal cortex being the main input reg

Current capabilities of state-of-the-art in vivo imaging during freely moving behavior can record two, spectrally distinct, fluorophores. This severely limits the number of cell types identifiable in a functional imaging experiment. Here we present a pipeline that enables the distinction of nine neuronal subtypes from regions defined by behaviorally relevant cells during in vivo GCaMP imaging. These subtypes are identified utilizing unique fluorophores that are co-expressed with GCaMP, unmixed by multispectral lambda imaging on a confocal microscope, and spectral fingerprints co-registered wit

The ability to remember and recognize familiar conspecifics is essential for social interaction. Social memory disorders affect normal social interaction. Engram neurons relate to social memory formation with unclear mechanisms. G protein-coupled receptor 50 (GPR50) is an X chromosome-associated orphan receptor and is highly expressed in neurons. In this study, using social disorders mouse model establishing, chemical modulation, electrophysiology, and RNAseq, we herein report a novel role of GPR50 in social memory formation via activating engram neurons. Our results demonstrate that GPR50 upr

Disturbances in the neuronal activity of the hippocampal CA2 subregion have been shown to result in impaired social memory in rodents. However, the current assessment of behavioural role of CA2 within the circuit of cognition relies on classical tests, presenting only a snapshot of the behaviour of subjects. As both clinical and preclinical data have revealed a relevance for CA2 in psychiatric disorders such as schizophrenia, it is crucial to uncover the effects of CA2 E/I imbalance in more natural social environments over longer periods of time. Furthermore, gaining a deeper understanding of

Hippocampal subregion CA2 has been implicated in social memory. CA2 contains spatially modulated “place cells” that change their firing patterns (“remap”) during social interactions (Alexander et al., 2016). Our preliminary results suggest that CA2 place cell remapping is driven by the olfactory content of social experiences. Fragile X Syndrome (FXS) is a neurodevelopmental disorder associated with abnormal social behaviors. To our knowledge, the activity of CA2 place cells during social interactions has not been examined in relation to FXS. Here, we recorded CA2 place cells in wildtype (WT) c

The hippocampus plays an integral role in episodic memory, primarily through neurons in the CA1 subfield. Beyond the well-established canonical circuitry, the CA2 region is implicated in social memory. Notably, there are monosynaptic connections from CA2 that innervate CA1, the functional relevance of which remains relatively unknown. Our study aims to investigate how these CA2-CA1 connections can modulate the maintenance of functional plasticity models, such as long-term potentiation (LTP) and long-term depression (LTD), within the Schaffer collateral (SC)-CA1 synapses. Subthreshold stimulati

Background: Prenatal alcohol exposure (PAE) induces a wide range of neurodevelopmental disabilities grouped under the term fetal alcohol spectrum disorders (FASD). The effects of PAE on brain development are dependent on complex long-lasting neurochemical events, including modification of glutamate receptors. Here, we explored whether PAE may affect the functional connectivity and, further, the molecular composition of the glutamatergic synapses in the prefrontal cortex (PFC) of adolescent mice and its effect on social behaviors.Methods: We generated an in vivo model of PAE, by exposing C57Bl/

Social memory plays a crucial role in the behavioural dynamics of gregarious animals, facilitating interaction, recognition, and appropriate social responses among conspecifics. Specifically, male mice demarcate their territory using urine marks, rich in pheromonal cues, allowing females to discern territorial ownership—a critical factor in mate selection. This recognition process forms distinct engrams, or biological memory traces, for individual conspecifics. Pheromonal signals are primarily processed by the vomeronasal organ (VNO), transmitted through the accessory olfactory bulb (AOB), and

Sleep is essential for memory formation and consolidation, and sleep loss is associated with cognitive decline. The CA2 subregion of the hippocampus is involved in social memory and plays a critical role in altering brain activity and memory performance. Despite the crucial role of hippocampal CA2 in memory, how sleep influences social memory remains relatively unexplored. Our aim was to investigate whether and how sleep loss influences the CA2 region in terms of synaptic plasticity and social memory in mice. We conducted field electrophysiology, Western blot analysis, and behavioral studies.

The ventral hippocampus (vHPC) is particularly sensitive to the pathology of Alzheimer’s disease (AD). Proper activity of the vHPC is mediated by parvalbumin (PV) interneurons, which constitute 25% of all inhibitory GABAergic cells. They play a crucial role in processing prepulse inhibition of the acoustic startle reflex (PPI) and social memory, which are managed by the vHPC. In this study, we first investigated the vHPC-related deficits in PPI and social novelty preference in 10-month-old APP/PS1 mice, a transgenic model of AD. We found a significant impairment in startle reduction in APP/PS1

Animals possess the ability to infer knowledge from experience of others, the social transmission of food preference (STFP) in rodents being a prevalent laboratory model of such memory. The neurobiological mechanisms underlying SFTP, as well as the relationship between individual and social memory acquired in the same animal, remain poorly understood. The goal of the present study was to investigate these questions at the cellular level. For this purpose, we used the STFP paradigm in mice, training them to form both short-term and long-term food preference memory. Using c-Fos immunohistochemic