Neural correlates of shift work in nurses: Alterations in cortical gyrification and functional connectivity

Shift work among nurses is an indispensable part of healthcare. However, it may be accompanied by circadian rhythm disruption. This disruption has been associated with alterations in brain structure and function, and has often been observed to co-occur with sleep disorders and psychological problems. This study aimed to elucidate the neurobiological mechanisms underlying the clinical symptoms observed in night-shift nurses, with a focus on cortical morphology and functional connectivity.

Sixty-two night-shift nurses and fifty-nine day-shift nurses were included in this study. Their cognitive function, sleep quality and psychological states were systematically evaluated. Surface-based morphometric (SBM) analysis and seed-based functional connectivity (FC) analysis were conducted based on multimodal MRI data to assess brain structural and functional differences between the two groups.

Compared to day-shift nurses, night-shift nurses exhibited poorer sleep quality and higher levels of anxiety and depression. They also showed increased local gyrification index (LGI) in the right superior temporal gyrus (STG) extending to the superior temporal sulcus (STS), along with altered functional connectivity (FC): reduced STG-posterior cerebellum (PC) and increased STG-precuneus/cuneus connectivity. In the pooled data, higher LGI correlated with poorer sleep quality; decreased STG-PC connectivity with lower depression scores; and increased STG-precuneus/cuneus connectivity with higher anxiety scores and poorer sleep quality.

Night-shift nurses exhibited distinct alterations in cortical gyrification and functional connectivity, highlighting the potential neural correlates of shift work. These findings elucidate the neurobiological mechanisms underlying the clinical symptoms observed in night-shift nurses, from both structural and functional aspects of the brain.