Abstract
This study aims to assess the vigilance task-related change in connectivity in healthy adults using wavelet phase coherence (WPCO) analysis of near-infrared spectroscopy signals (NIRS). NIRS is a non-invasive neuroimaging technique for assessing brain activity. Continuous recordings of the NIRS signals were obtained from the prefrontal cortex (PFC) and sensorimotor cortical areas of 20 young healthy adults (24.9 ± 3.3 years) during a 10-min resting state and a 20-min vigilance task state. The vigilance task was used to simulate driving mental load by judging three random numbers (i.e., whether odd numbers). The task was divided into two sessions: the first 10 min (Task t1) and the second 10 min (Task t2). The WPCO of six channel pairs were calculated in five frequency intervals: 0.6–2 Hz (I), 0.145–0.6 Hz (II), 0.052–0.145 Hz (III), 0.021–0.052 Hz (IV), and 0.0095–0.021 Hz (V). The significant WPCO formed global connectivity (GC) maps in intervals I and II and functional connectivity (FC) maps in intervals III to V. Results show that the GC levels in interval I and FC levels in interval III were significantly lower in the Task t2 than in the resting state (p < 0.05), particularly between the left PFC and bilateral sensorimotor regions. Also, the reaction time (RT) shows an increase in Task t2 compared with that in Task t1. However, no significant difference in WPCO was found between Task t1 and resting state. The results showed that the change in FC at the range of 0.6–2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors. The findings suggest that the decreased attention level might be partly attributed to the reduced GC levels between the left prefrontal region and sensorimotor area. The present results provide a new insight into the vigilance task-related brain activity.
Highlights
A high-level attention cannot constantly be maintained during a cognitively demanding task, such as driving; the level of attention progressively diminishes as time elapses, thereby affecting task performance negatively (Derosière et al, 2014)
The present results indicate that the vigilance task leads to a decreased synchronization between the prefrontal cortex (PFC) and bilateral sensorimotor regions when subjects transitioned from rest to the task
This study confirmed that the functional connectivity (FC) would decrease in the attention state, and the significant decrease was only found in the latter half of the task (Task t2). This suggests that the change in global connectivity (GC) at the range of 0.6–2 Hz was not attributed to the vigilance task per se, but the interaction effect of vigilance task and time factors
Summary
A high-level attention cannot constantly be maintained during a cognitively demanding task, such as driving; the level of attention progressively diminishes as time elapses, thereby affecting task performance negatively (Derosière et al, 2014). Attention decrements may lead to workrelated injuries (Grandjean, 1979; Czeisler et al, 2005) and traffic accidents Driving a vehicle requires the ability to make decisions, planning, and visual attention. Driver attention level decreases after a long time of driving. Understanding the cognitive state of a driver in real-time can assist in the design of in-vehicle interfaces. Clarifying the relationship between driver attention state and brain activity, including recognition and judgment, is necessary
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
