Neuronal mechanisms of social behaviours

26.04.2026, Sunday, 10:30-12:00

General focus of the symposium:

Social behavior, defined broadly as any form of physical interaction or non-physical communication between members of the same species, represents one of the most powerful drivers of behavior across mammals. It encompasses diverse interactions, including mating, parental care, aggression, and affiliation. Aggressive behaviors establish dominance hierarchies and regulate access to resources, while affiliative behaviors, such as grooming and cooperation, promote cohesion and reduce conflict. Social structures emerge from ecological pressures such as resource distribution, predation risk, and habitat organization, which shape the costs and benefits of group living. Much like physiological drives such as hunger or sleep, social needs are homeostatically regulated. In humans, altered social responsiveness and disrupted social motivation characterize several neuropsychiatric disorders, including autism spectrum disorder, schizophrenia, and psychopathy, all of which involve dysfunction in social reward processing. In rodents, unmet social needs have profound consequences: social deprivation causes long-term social, cognitive, emotional and metabolic impairments. Thus, maintaining social connectedness is not merely advantageous but biologically essential, supporting adaptive behavior and mental health. Despite their importance, the neurobiological mechanisms underlying the formation and maintenance of peer relationships remain largely unexplored. The symposium presents the latest research on the mechanisms controlling social behavior, focusing on pathways that control motivation driving social interactions and the rewarding effects of social contact.

10:30 Felix Leroy, Ph.D.

Instituto de Neurociencias en Alicante

"Neuronal Circuits Regulating Social Preferences"

Neuronal circuits regulating social preferences: social preference, the decision to interact with one conspecific over another, is a feature displayed by gregarious animals which is critical to navigate their social space. Thus, adult rodents prefer to interact with their kin, individuals from specific strains and members of the opposite sex. In addition to innate factors (e.g., kin, strain, and sex), social preference is also influenced by social memory, social hierarchy and the affective state of the conspecific. In the lecture, I will explore brain pathways and neuronal mechanisms controlling social preference.

11:10 Alicja Puścian

Centre of New Technologies, University of Warsaw, Poland

"Neuroeconomics of Social Influence"

Insights from mice tested under semi-naturalistic conditions. Social context is central to how individual preferences emerge. While individual taste preferences are well characterized, the dynamics of group conformity and its persistence after social influence remain poorly understood. We investigated how changing social contexts affect taste preferences in mice and examined the underlying neural mechanisms. Voluntary behavior of group-housed mice was assessed using the automated Eco-HAB assay, which closely follows murine ethology. Individual taste preferences were first measured during brief, isolated access to two nutritionally equivalent flavors. The social environment was then modified to allow group access to the same rewards, enabling mutual influence, followed by a return to isolated testing. Group housing induced convergence toward a shared preference, which reversed once mice were tested individually, indicating that social influence is strong but transient. Chemogenetic activation of parvalbumin-expressing neurons in the prelimbic cortex reduced sociability, potentially disrupting the transmission of social influence - a mechanism currently under investigation.

11:23 Paula Gómez-Sotres (PhD)

Neurocentre Magendie, Bordeaux

"Olfactory Bulb Astrocytes Link Social Transmission of Stress to Cognitive Adaptation in Male Mice"

Emotions and behavior can be affected by social chemosignals from conspecifics. For instance, olfactory signals from stressed individuals induce stress-like physiological and synaptic changes in naïve partners. Direct stress is also known to alter cognition; however, the impact of socially transmitted stress on memory processes remains unknown.

Our research shows that exposure to chemosignals produced by stressed individuals is sufficient to impair memory retrieval in unstressed male mice. This effect requires astrocytic control of olfactory bulb information processing mediated by mitochondria-associated CB1 receptors (mtCB1). Using targeted genetic manipulations, in vivo Ca²⁺ imaging, and behavioral analyses, we demonstrate that mtCB1-dependent regulation of mitochondrial Ca²⁺ dynamics is necessary for processing olfactory information from stressed partners and determining its cognitive consequences.

These findings identify olfactory bulb astrocytes as a critical link between social odors and their behavioral meaning.

11:36 Klaudia Misiołek (PhD defense planned for 2026)

Maj Institute of Pharmacology Polish Academy of Sciences

"Rethinking Dynorphin in Social Behavior"

The endogenous opioid system shapes the rewarding effects of social interaction in adolescent mice. This led us to hypothesize that the opioid system itself undergoes developmental reorganization. To explore this, we analysed the expression of endogenous opioid peptide and receptor genes in the prefrontal cortex and striatum across early, mid and late adolescence (P28, P38, P44). We found that these changes were not global, but selective to the dynorphin/KOR system, with region- and cell-type-specific alterations. To determine whether this reorganization influences social reward, we disrupted dynorphin/KOR signalling, either pharmacologically or in Pdyn knockout mice, and observed reduced social conditioned place preference (CPP) specifically in late adolescence. In adulthood, overall social CPP was lower than in late adolescence, and Pdyn knockout had no detectable effect on CPP. Under baseline (no stress) conditions, dynorphin removal altered other aspects of social behaviour, improving social memory without affecting anxiety-like behaviour. In contrast, under stress, dynorphin signalling had a broader effect on reward processing, as pharmacological KOR blockade prevented stress-induced reductions in both social and cocaine CPP. Together, these findings show that dynorphin does not simply mediate stress or aversion, but contributes to the developmental organization and context-dependent expression of social behaviour.

11:46 Netsanet Belay (PhD student)

Central Institute of Mental Health, Mannheim

"Early Life Stress in rats Induces Long-Term, Sex-Dependent Alterations in Social and Drug Reward in Rats"

Early-life stress (ELS) is a critical determinant of neurobehavioral development and may shape vulnerability to social and drug-related rewards later in life. In this work, we investigated the long-term consequences of prolonged maternal separation on social behavior and cocaine reward in rats. Rat pups were subjected to maternal separation (MS) for six hours daily from postnatal day (PD) 1 to PD21, modeling chronic early-life stress. During adolescence and adulthood, multiple dimensions of social behavior, including social interaction, sociability, social recognition, and social reward, as well as cocaine reward in the self-administration paradigm, were assessed.

Our findings reveal that MS induces persistent and sex-dependent alterations in reward-related behaviors. Adolescent male rats exposed to MS exhibited enhanced social reward, alongside increased social interest and investigation, suggesting a heightened sensitivity to social stimuli. In contrast, their female counterparts displayed a blunted cocaine intake, indicating altered sensitivity to drug reward. These results highlight a sexually divergent impact of early-life stress, with males showing increased social reward processing and females suggesting enduring alterations in the drug reward system.

Overall, this study underscores the importance of early environmental factors in shaping distinct behavioral trajectories across sexes, with implications for understanding the developmental origins of social and substance use-related disorders.