Imaging brain fatigue from sustained mental workload: An ASL perfusion study of the time-on-task effect

Abstract

During sustained periods of a taxing cognitive workload, humans typically display time-on-task (TOT) effects, in which performance gets steadily worse over the period of task engagement. Arterial spin labeling (ASL) perfusion functional magnetic resonance imaging (fMRI) was used in this study to investigate the neural correlates of TOT effects in a group of 15 subjects as they performed a 20-minute continuous psychomotor vigilance test (PVT). Subjects displayed significant TOT effects, as seen in progressively slower reaction times and significantly increased mental fatigue ratings after the task. Perfusion data showed that the PVT activates a right lateralized fronto-parietal attentional network in addition to the basal ganglia and sensorimotor cortices. The fronto-parietal network was less active during post-task rest compared to pre-task rest, and regional CBF decrease in this network correlated with performance decline. These results demonstrate the persistent effects of cognitive fatigue in the fronto-parietal network after a period of heavy mental work and indicate the critical role of this attentional network in mediating TOT effects. Furthermore, resting regional CBF in the thalamus and right middle frontal gyrus prior to task onset was predictive of subjects' subsequent performance decline, suggesting that resting CBF quantified by ASL perfusion fMRI may be a useful indicator of performance potential and a marker of the level of fatigue in the neural attentional system.

Electroencephalogram assessment of mental fatigue in visual search

“…There was a significant main effect of time on RT (F = 3.101, P = 0.046) but no effect on accuracy (F = 1.034, P = 0.397). In previous studies, RT measures have been associated with fatigue from sustained mental workload [21,22]. In Figure 4, RT increases in a linear fashion from the beginning to the end of task performance (R 2 = 0.69), while there is a mild decline in accuracy.…”

Working memory in middle-aged males: Age-related brain activation changes and cognitive fatigue effects

“…Studies utilizing the induced fatigue paradigm (in which elicited fatigue falls under the construct of 'primary fatigue' proposed by DeLuca, 2005b) have shown that higher-level cognitive control functions are particularly sensitive to detrimental induced fatigue effects (Lorist et al, 2000(Lorist et al, , 2005Van der Linden et al, 2003). Furthermore, sustained task performance has been shown to elicit a lasting decrease in cerebral blood flow in the fronto-parietal attention network in association with a fatigue-related reduction in performance (Lim et al, 2010). Therefore, we hypothesized middle-aged adults would show a reduction in load-related activation and an associated performance decrement (primarily at high levels of WM load) resulting from the exhaustion of cognitive resources in this age group at high levels of WM load, particularly in areas related to cognitive control.…”

An ACT-R Process Model of the Signal Duration Phenomenon of Vigilance

“…In the case of extreme fatigue, it can take as long as 30 seconds for a production to fire (Gunzelmann et al, 2009). Microlapse theory posits that these lapses occur in central cognition based on a large body of research showing the impact of fatigue on the basal ganglia -where a recent fMRI study on the neural basis of the vigilance decrement, showed that the vigilance decrement activated a right fronto-parietal attentional network that lateralized to the basal ganglia and sensorimotor cortices (Lim et al, 2010).The result of microlapses is that productions will fire less reliably as time on task increases, causing a decreased likelihood of responding to a critical stimulus over time, with larger impacts when the signal duration is short. Gunzelmann et al (2009) also proposed a compensation mechanism for these microlapses.…”