Passive Coping Strategies During Repeated Social Defeat Are Associated With Long-Lasting Changes in Sleep in Rats.

Area of Science:

• Neuroscience
• Behavioral Science
• Sleep Medicine

Background:

• Severe stress can cause long-term neuropsychiatric issues and increase Posttraumatic Stress Disorder (PTSD) risk.
• Only a subset of individuals develop PTSD after trauma, and the reasons for this selective vulnerability are poorly understood.
• Sleep disturbances, like insomnia and nightmares, are common in individuals who develop PTSD.

Purpose of the Study:

• To investigate sleep changes in rats exhibiting different coping strategies (passive vs. active) following repeated social defeat stress.
• To determine if coping mechanisms influence vulnerability or resilience to stress-induced sleep disturbances.
• To explore the relationship between coping styles, sleep alterations, and potential prognostic markers for stress-related disorders.

Main Methods:

• Utilized a repeated social defeat paradigm in rats to induce stress.
• Categorized rats into passively or actively coping subpopulations based on their behavioral responses.
• Monitored and analyzed sleep patterns, including slow-wave sleep (SWS) and rapid eye movement (REM) sleep, in different coping groups post-stress.

Main Results:

• Passively coping rats exhibited significantly reduced slow-wave sleep (SWS) for at least two weeks after stress exposure, unlike control and actively coping rats.
• Actively coping rats, considered resilient, showed less motor activation upon awakening from REM sleep and reduced REM sleep fragmentation.
• These findings link passive coping behaviors to persistent sleep disturbances following social defeat stress.

Conclusions:

• A passive coping strategy is associated with enduring sleep disturbances after severe stress.
• An active coping strategy appears to confer resilience to stress-induced sleep disruptions.
• These results suggest that coping mechanisms play a critical role in the development of stress-associated neuropsychiatric disorders like PTSD and may offer prognostic and therapeutic insights.