0162 The neural bases of emotion dysregulation in rotating shift workers

Abstract Introduction Shift work is known to be associated with sleep disturbance and circadian misalignment and may contribute to alterations in the brain implicated in emotion dysregulation. In this study, we examined 1) neural correlates of emotion dysregulation, including emotional reactivity and regulation in shift workers and 2) relationships between neural correlates of emotion dysregulation, sleep disturbance, and circadian misalignment. Methods Fifty-six rotating shift workers (SW, 42 females, 30.80 ± 6.94 years old) who had non-standard shift schedules and 52 healthy controls (HC, 36 females, 31.69 ± 7.86 years old) who did not work as shift schedules participated in this study. Both SW and HC completed self-reported measures of sleep and mood problems, and wrote sleep diary and wore actigraphy to assess sleep quality and circadian rhythms. They also underwent one night polysomnography and were scanned while they were performing the emotion regulation task. We analyzed group differences in mood, sleep, circadian rhythms, and neural bases of emotional reactivity and regulation, and examined relationships between these variables. Results SW showed significant differences in actigraphy-estimated sleep (i.e., lower sleep efficiency) and circadian rhythms (e.g., greater motor activity [M10] and lower interdaily stability) compared to HC. SW also exhibited increased anterior insula (AI) activation in response to negative pictures, but reduced activation in the dorsomedial prefrontal cortex (dMPFC) and AI-dMPFC functional connectivity during emotion regulation compared to HC. AI activation and AI-dMPFC functional connectivity were significantly associated with sleep disturbance (i.e., sleep diary-estimated sleep onset latency) and circadian misalignment (e.g., M10 and interdaily stability). Furthermore, a mediation analysis revealed that shift work was associated with increased motor activity during the most active 10-hour period, which then contributed to increased AI activation in response to negative pictures. Conclusion Our findings suggest that shift work may contribute to sleep disturbance and circadian misalignment, and neural alterations associated with emotional reactivity and regulation. Furthermore, the mediation result suggests that increased motor activity along with misaligned circadian rhythm may serve as a pathway, through shift work contributes to heightened emotional reactivity to negative information. Support (if any) National Research Foundation (No. 2022R1A2C2008417, NRF-2022R1A2C1008209) and Korea Institute for Advancement of Technology (No. 20009210).