Date Published: June 1, 2018
Publisher: Public Library of Science
Author(s): Zizheng Guo, Ruiya Chen, Xian Liu, Guozhen Zhao, Yan Zheng, Mingliang Gong, Jun Zhang, Hengyi Rao.
Mental fatigue is one of the main reasons for the decline of response inhibition. This study aimed to explore the impairing influence of mental fatigue on a driver’s response inhibition. The effects of mental fatigue on response inhibition were assessed by comparing brain activity and behavioral indices when performing a Go/NoGo task before and after a 90-min fatigue manipulation task. Participants in the driving group performed a simulated driving task, while individuals in the control group spent the same time watching movies. We found that participants in the driving group reported higher levels of mental fatigue and had a higher percentage of eye closure and larger lateral deviations from their lane positions, which indicated there was effective manipulation of mental fatigue through a prolonged simulated driving task. After manipulation of mental fatigue, we observed increased reaction time and miss rates, delayed NoGo-N2 latency and Go-P3 latency, and decreased NoGo-P3 amplitude, which indicated that mental fatigue may slow down the speed of the inhibition process, delay the evaluation of visual stimuli and reduce the availability of attentional resources. These findings revealed the underlying neurological mechanisms of how mental fatigue impaired response inhibition.
Response inhibition, which is a core component of executive function, refers to the ability to inhibit inappropriate or irrelevant responses [2–4]. Response inhibition can be roughly divided into two processes: the monitoring of conflict and the evaluation of stimuli or resource allocation . Many daily activities are associated with response inhibition. For example, when an emergent road event occurs (e.g., a lead vehicle suddenly stops), the driver has to brake sharply, and failure to do so may lead to a catastrophic accident [6–9]. Specifically, this operation consists of two processes that include inhibiting the process of stepping on the gas and initiating the process of slamming on the brakes.
This study designed a simulated driving task to induce mental fatigue and examined the impairing effects of mental fatigue on response inhibition in a visual Go/NoGo task. Participants in the driving group reported higher levels of mental fatigue after a 90-min simulated driving task, whereas individuals in the control group reported the same level of mental fatigue after a 90-min watching task. Additionally, participants in the driving group had a higher percentage of eye closure and larger lateral deviations from their lane positions in the first 30 mins compared to the last 30 mins of the 90-min simulated driving task. These results indicated there was effective manipulation of mental fatigue through a prolonged simulated driving task.
The present study demonstrated that mental fatigue deteriorated a participant’s response inhibition in a visual Go/NoGo task, which was reflected by prolonged reaction time, increased miss rates, and delayed latency for NoGo-N2 and Go-P3 and decreased amplitude for NoGo-P3. These results showed that mental fatigue not only led to fewer attentional resources allocated to the NoGo stimuli but also delayed the speed of response inhibition. These findings revealed the underlying neurological mechanisms about the impairing effects of mental fatigue on response inhibition.