The sex-specific memory consolidation of social stimuli during sleep

• Applicant: Dr. Anuck Sawangjit
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572243859

Appropriate behavioral responses in complex environments require knowledge from widely different stimulus domains. Despite their distinct underlying neuronal networks, social and non-social memories form part of the episodic memory system integrating both types of stimuli as specific events. Sleep supports memory consolidation, a process in which newly acquired information is stabilized, particularly in the hippocampus-dependent episodic memory system. However, how the brain simultaneously processes social and non-social information during sleep is currently not well understood. Likewise, although there is growing evidence pointing to distinct sex differences in memory processing, female subjects have been largely neglected in memory research, especially in animal studies. Against this backdrop, in this project I aim to directly compare, in a rat model, memory formation during sleep for social and non-social stimuli, also taking into account possible sex differences in these processes. I hypothesize that sleep facilitates the formation of memories for both social and non-social stimuli only when integrated in a spatial-contextual episode (episodic memory), but not when the stimuli are presented as solitary items. Furthermore, I hypothesize that the effect of sleep is mediated by enhanced oscillatory activities during slow-wave sleep (SWS), specifically spindles and sharp waves-ripples (SWRs) in distinct hippocampal subregions, i.e., CA2 and CA1, respectively. Finally, I hypothesize that females and males differ with respect to the consolidation of context-independent item memory and context-dependent episodic memory, especially for social stimuli. To test these hypotheses, behavioral tasks are designed using combined social and non-social stimuli to test episodic memory formation during sleep in female and male rats. Furthermore, neurophysiological and molecular cytogenetic measurements are employed to investigate neural mechanisms underlying consolidation of social and non-social memory during sleep, and to identify memory-related neuronal activation across hippocampal and neocortical neuronal networks for different stimulus domains at single-cell resolution. Understanding sex-specific formation of social memory shall pave the way for translational approaches to ameliorate various types of social disorders, some of which show clear sex differences in their prevalence rates.

• DFG Programme: Research Grants