Language processing in emergencies recruits both language and default mode networks

Effective language processing in emergencies is crucial for professionals, including firefighters, soldiers, and doctors. Substantial research has been undertaken on language processing in silence, with several studies indicating the impact of noise on language processing in non-emergencies. However, it remains unclear about the neural mechanisms involved in language processing during emergencies, especially the role of the language network (LN) and the default mode network (DMN) in such contexts. In this study, we adopted functional near-infrared spectroscopy (fNIRS) to investigate brain activities of 60 participants who were performing language processing tasks in simulated high-emergency and low-emergency scenarios. Compared to the resting state, the reading task demonstrated reduced activation in bilateral superior and middle frontal gyri (SFG/MFG), components of the DMN, alongside enhanced activation in Broca's area, left temporal lobe and left inferior parietal lobule (IPL) – key LN regions. Furthermore, the activity of the left MFG was positively correlated with the level of stress experienced by participants during the task. Additionally, a positive correlation was identified between language processing performance and activation of the left MFG, exclusively in the participants exposed to high-emergency scenarios. These results support the view that language processing during emergency relies on both the LN and DMN. The current study deepens our understanding of the neural mechanisms that underlie language processing in complex, real-life emergency scenarios.