## 4 Discussion
Under non-fatigued conditions, significant differences in RTs between task interruptions and pause interruptions were only observed in the recovery trials. The compensatory control mechanisms effectively redistributed cognitive resources in response to the attentional shifts caused by interruptions. This redistribution and accelerated processing resulted in longer RTs, but participants were able to maintain relatively high ACC. This phenomenon demonstrates that the executive control system can sustain cognitive capabilities at a relatively high level through adaptive resource allocation strategies, although its capacity for regulation is finite. In the fatigued state, the facilitation system was weakened, and complex task interruptions induced additional stress and frustration, further diminishing the system's effectiveness. Behavioral performance was more severely impaired under these conditions. Complex interruptions, which involve more information and interference factors, required participants to allocate more inhibitory resources to suppress distractions. Fatigue increased the load on the inhibition system, reducing its efficiency and impairing its ability to filter irrelevant information. This supports the conclusion that fatigue primarily disrupts the balance between the facilitation and inhibition systems. Moreover, it highlights the limited capacity of the executive control system to effectively adjust between primary and interrupting tasks, which in turn affects behavioral performance. During pause interruptions under fatigue, participants were in a relatively task-free state, which more readily activated the inhibition system. Extended pauses, often characterized by monotony and a lack of challenge, induced boredom and drowsiness [31], further diverting attention from the primary task. Combined with accumulated fatigue, the inhibition system increasingly suppressed cognitive engagement. This coordination mechanism may represent a rest signal to avoid overexertion and maintain homeostasis. As fatigue accumulated, the inhibition system's role became more pronounced, leading to further declines in task performance. Consequently, when the primary task resumed, participants required more time to reactivate relevant cognitive resources, resulting in a larger increase in RTs. In contrast, during simple task interruptions, although the interruptions themselves might have increased cognitive load, participants were able to maintain a certain level of cognitive alertness to respond to the interruption [32]. This alertness partially activated the facilitation system, helping individuals to sustain or improve task performance under resource-constrained conditions. This mitigated the negative impact of mental fatigue on cognitive abilities, allowing participants to more quickly recover primary task performance after interruptions. Thus, despite the effects of fatigue, the increase in RTs after simple task interruptions was relatively small. (2) ERP Evidence of Fatigue-Induced Cognitive Decline: P200 and P300 as Key Indicators  
The ERP analysis revealed that fatigue significantly affects the amplitude and latency of P200 and P300, leading to a decline in task processing efficiency. Following task interruptions, the increase in P200 amplitude and prolongation of its latency reflect the depletion of cognitive resources. Under fatigue conditions, the decrease in frontal P300 amplitude over the course of the experiment indicates impaired executive control, reduced attentional allocation, and diminished working memory updating capacity. Although the increase in central P300 amplitude may reflect a compensatory control mechanism, it fails to effectively offset the negative effects of fatigue. Fatigue state significantly affected the average amplitude and peak latency of the P200 component. The effects of trial type and task type on the P200 amplitude and latency were primarily observed in the frontal region.