Seminar: Alicja Puscian: Neural circuits for social bonding – the role of diverse cell types in the prelimbic cortex

Abstract: Neural circuits for social bonding - the role of diverse cell types in the prelimbic cortex
Impairments in social interactions are a key feature of many neurodevelopmental disorders. Additionally,
with progressively universal internet access well-industrialized world has been undergoing the "intimacy
crisis" as real-life relationships have been replaced by their online substitutes. Now more than ever,
understanding brain mechanisms underlying attachment and social bonding, seems crucial for our ability
to address those aggravating health issues.
As studies indicate a crucial role of the prefrontal cortex in social attachment, we investigated the
contributions of the major excitatory and inhibitory cell types in its prelimbic part (PL) to this process. To
increase the ecological validity of our research we tested the behavior of group-housed mice in automated
assays, which closely follow murine ethology. Using transgenic mice and the Pharmacologically Selective
Actuator Module-based ultrapotent chemogenetic approach, we performed time-constrained manipulation
of the pyramidal neurons, parvalbumin- (PV), somatostatin-, and vasoactive intestinal peptide-expressing
inhibitory cells in the PL and tested subjects' voluntary social behavior.
We show that activation of the PV neurons in the PL selectively impairs animals' sociability expressed
towards familiar conspecifics. Specifically, it reduces spontaneous social interactions with cagemates,
diminishes animals' interest in familiar social olfactory stimuli, and decreases the time mice spend together
after separation. However, such manipulation of neuronal activity neither alters the exploration of novel
social stimuli nor does it impact social learning about aversive or appetitive stimuli. Taken together, our
findings indicate distinctive neural mechanism influencing bonding with familiar conspecifics, but not other
forms of social behavior. Notably, manipulation of other tested cell types does not lead to such distinctive
social behavioral changes.
Thus, our research reveals a specific role of the PV-expressing cells in the PL in the maintenance of the social
structure and in sustaining ongoing interest in familiar conspecifics. The presented data lays a foundation for
understanding the neural underpinnings of social attachment.