Time-dependent cortical responses to siesta disruption in male mice.

INTRODUCTION: Siestas, or daytime naps, play a critical role in relieving sleep pressure and maintaining physiological balance. However, the effects of siesta disruption remain largely unexplored. METHODS: In this study, we disrupted the natural siesta period (ZT20-23) through daily bedding changes for 2 weeks and examined its effects on overall stress levels, sleep architecture, behavior, and transcriptional responses in the frontal cortex. RESULTS: Siesta disruption during the late dark phase led to increased core body temperature, locomotor activity, and wakefulness, while having minimal effects on subsequent light phase sleep patterns, behavioral performance, or serum stress markers. Transcriptomic analysis at ZT0 and ZT12 revealed distinct time dependent responses: ZT0 was associated with the activation of stress-related and homeostatic pathways, whereas ZT12 showed enrichment of genes related to neuronal structure and intracellular transport. DISCUSSION: These findings suggest that even short-term siesta disruption induces mild but phase-specific cortical adaptations, involving early stress mitigation at ZT0 followed by synaptic remodeling at ZT12.