Perinatal circadian desynchronization disrupts sleep and prefrontal cortex function in adult offspring

Study Objective

Sleep and circadian rhythms impact nearly all aspects of physiology and are critical for optimal organismal function. Disruption of the clock can lead to significant metabolic disorders, neuropsychiatric illness, and cognitive dysfunction. Our lab has shown that environmental circadian desynchronization (ECD) in adults alters the anatomical structure and neurophysiological function of prefrontal cortex (PFC) neurons, PFC-mediated behaviors, and sleep quality. As the PFC undergoes significant development in utero and early life, and maternal disturbances during this period can have significant long-term ramifications, we hypothesized that disrupting the circadian environment during the perinatal period would alter sleep and PFC function in adult offspring.

Methods

Using a mouse model of ECD, we investigated how perinatal ECD (pECD) modulates sleep quality in adult offspring. We also determined how pECD impacts PFC neural function in adult offspring using ex vivo patch-clamp electrophysiology, exploring how pECD alters synaptic function and action potential dynamics.

Results

We found that male pECD mice trended toward increased total sleep during the inactive (light) period with shorter sleep bouts during the active (dark) period, with no changes in female mice. Independent of time of day, pECD altered postsynaptic dynamics of excitatory release onto PFC pyramidal neurons. There was also a loss of time-of-day effects on cell endogenous properties in male pECD mice.

Conclusion

Thus, pECD clearly alters sleep behavior and PFC function in male mice. However, female mice appear protected against the effects of pECD. Together, these experiments form the foundation for future studies to understand the lifelong neurobehavioral impact of pECD.

Statement of Significance Disruptions to the body’s natural circadian rhythms during early development may have lasting consequences for brain function and behavior. This study demonstrates that desynchronizing rhythms during perinatal period has consequences for both sleep quality and cortical function later in adulthood, particularly in males. Male mice exposed to perinatal circadian desynchronization exhibited fragmented sleep and changes in synaptic properties of prefrontal cortex neurons, while female mice appeared resilient. These findings suggest that early life circadian disruptions could contribute to cognitive and behavioral disorders linked to cortical dysfunction, such as mental illness and learning deficits. Understanding these mechanisms is crucial in an era where artificial lighting and shift work disrupt natural sleep cycles, potentially affecting neurodevelopment and lifelong brain health.