Sleep patterns predicting stress resilience are dependent on sex.

Area of Science:

• Neuroscience
• Sleep Science
• Stress Research

Background:

• Sleep disturbances and stress are linked to neuropsychiatric disorders, but the relationship is unclear.
• Non-rapid eye movement (NREM) sleep plays a causal role in maladaptive behavioral responses to stress.
• Most studies exclude females, despite their higher prevalence of affective disorders and sleep disturbances.

Purpose of the Study:

• To investigate sex differences in sleep patterns and stress responses using a social-defeat model in male-female pairs.
• To understand how NREM and REM sleep characteristics predict resilience or susceptibility to stress in both sexes.
• To identify underlying sex-specific mechanisms in sleep regulation and stress interaction.

Main Methods:

• Adapted female social-defeat stress models for simultaneous social-defeat and electroencephalography (EEG) in male-female pairs.
• Analyzed EEG recordings before and after social stress exposure to assess sleep architecture.
• Compared behavioral and sleep responses between sexes and across stress resilience/susceptibility phenotypes.

Main Results:

• Behavioral responses to social defeat were consistent across sexes.
• Pre-stress NREM and REM sleep differences were associated with sex-dependent resilience.
• Post-stress, resilient males showed increased NREM sleep, while susceptible females had longer NREM sleep bouts.
• Females exhibited sex differences in NREM sleep loss recovery, suggesting altered sleep homeostasis.

Conclusions:

• Sexual dimorphism exists in sleep characteristics predicting stress resilience and in sleep alterations induced by social stress.
• NREM sleep quality may be lower in resilient females, and REM sleep is decreased in susceptible females compared to males.
• Understanding these sex differences is crucial for developing targeted interventions for stress-related neuropsychiatric disorders.