0064 Heightened Neural Responses to Negative Words in Shift Workers Using the Stroop Task

Abstract

Abstract Introduction Shift work is known to have a negative impact on a wide range of health problems such as sleep disturbance, cognitive impairment, and emotional disorders (e.g., anxiety and depression). It is important to understand underlying mechanisms for negative impact of shift work on health problems. This study aimed to investigate psychological and neural mechanisms associated with shift work. Methods Thirty six shift workers (28 females, age = 29.9 ± 7.4) and 35 non-shift workers (20 females, age = 30.5 ± 5.5) participated in this study. They were performing the word Stroop task during fMRI scanning. This task included sleep-related words and negative words to investigate neural substrates associated with sleep-related information and emotional information processing. Neutral words were included as control stimuli. The participants also completed questionnaires assessing sleep-related problems such as Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale, and emotion-related problems such as Beck Depression Inventory and Beck Anxiety Inventory. Two-sample t-tests were conducted to find group differences in self-report measures and neural response to sleep-related words and negative words compared to neutral words. Results Relative to non-shift workers, shift workers showed greater sleep disturbance (i.e., higher PSQI), but they did not show any evidence of emotion-related problems. Shift workers also demonstrated greater neural response to negative words (vs. neutral words) in several prefrontal regions (e.g., dorsal anterior cingulate cortex and dorsolateral prefrontal cortex), anterior insula and caudate compared to non-shift workers. However, shift workers did not show significantly different neural response to sleep-related words (vs. neutral words) compared to non-shift workers. Conclusion The result from this study provides supporting evidence that shift work is associated with subjective sleep disturbance. Shift workers’ heightened neural response to negative information may reflect their increased sensitivity to negative information, that may contribute to sleep disturbance. Support Brain Research Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (Study No.: 2016M3C7A1904338 and NRF-2018R1D1A1B07049704).