Napping improves interhemispheric functional coordination during night shifts in nurses: analysis of voxel-mirrored homotopic connectivity.

PURPOSE: Napping has been shown to improve cognitive performance in nurses working night shifts; however, the underlying mechanisms remain poorly understood. This study aims to investigate the effects of night shift napping on interhemispheric functional coordination and examine their relationship with cognitive changes in nurses. METHODS: A total of 21 female nurses participated in three sessions: Rested Wakefulness (RW), Sleep Deprivation (SD), and Napping (NAP). During the RW session, participants were allowed normal sleep; during SD, they remained awake for 24 h; and in the NAP session, a two-hour nap was allowed during their night shift. Neurocognitive assessments and resting-state functional magnetic resonance imaging were conducted after SD and NAP sessions. Voxel-mirrored homotopic connectivity (VMHC) analysis was used to assess interhemispheric functional coordination. RESULTS: Compared with RW, SD led to a significant increase in VMHC, primarily involving the bilateral temporal, occipital, and parietal cortices, sensorimotor areas, middle and inferior frontal cortices, insula, subcortical regions, and cerebellum [family-wise error (FWE)-corrected p < 0.05]. In contrast to SD, NAP resulted in a reduction of VMHC in a broad range of brain regions that exhibited increased VMHC during SD (FWE-corrected p < 0.05). The alterations in global VMHC after NAP were correlated with improved neurocognitive performance among the nurses (p < 0.05). CONCLUSION: Night shift napping appears to reorganize interhemispheric functional connections, which tentatively underpins its potential role in cognitive recovery from SD among nurses, with such neural-cognitive links necessitating further validation in expanded sample cohorts.