Resting spontaneous activity in the default mode network predicts performance decline during prolonged attention workload

Abstract

After continuous and prolonged cognitive workload, people typically show reduced behavioral performance and increased feelings of fatigue, which are known as “time-on-task (TOT) effects”. Although TOT effects are pervasive in modern life, their underlying neural mechanisms remain elusive. In this study, we induced TOT effects by administering a 20-minute continuous psychomotor vigilance test (PVT) to a group of 16 healthy adults and used resting-state blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine spontaneous brain activity changes associated with fatigue and performance. Behaviorally, subjects displayed robust TOT effects, as reflected by increasingly slower reaction times as the test progressed and higher self-reported mental fatigue ratings after the 20-minute PVT. Compared to pre-test measurements, subjects exhibited reduced amplitudes of low-frequency fluctuation (ALFF) in the default mode network (DMN) and increased ALFF in the thalamus after the test. Subjects also exhibited reduced anti-correlations between the posterior cingulate cortex (PCC) and right middle prefrontal cortex after the test. Moreover, pre-test resting ALFF in the PCC and medial prefrontal cortex (MePFC) predicted subjects’ subsequent performance decline; individuals with higher ALFF in these regions exhibited more stable reaction times throughout the 20-minute PVT. These results support the important role of both task-positive and task-negative networks in mediating TOT effects and suggest that spontaneous activity measured by resting-state BOLD fMRI may be a marker of mental fatigue.

Loss of frontal regulator of vigilance during sleep inertia: A simultaneous EEG‐fMRI study

“…This linkage of diminished vigilance and reduced spontaneous activity of the DMN has also been reported in previous studies (Dai et al, 2015;Song et al, 2017). Furthermore, lower BOLD activity in the DMN indicated reduced vigilance and worse performance (Gui et al, 2015). These results were consistent with reports of reduced DMN activity in decreased consciousness, such as deep sleep (Tagliazucchi & van Someren, 2017), consciousness disorders (Laureys, 2005) (Kaufmann, 2006) and the increased activity during various cognitive tasks.…”

Decreased prefrontal connectivity parallels cognitive fatigue-related performance decline after sleep deprivation. An optical imaging study

“…Task-related changes in brain activity during the ensuing resting state period (Rst) were estimated by computing the amplitude of low frequency fluctuations (ALFF; Yu-Feng et al, 2007) within the frequency range between 0.009 and 0.08 Hz of the total haemoglobin concentration. ALFF is reputed a good measure of spontaneous neural activity, appropriate to detect state-dependent resting brain changes associated with CF(Gui et al, 2015).…”

The mind-body problem; three equations and one solution represented by immaterial-material data

“…Even if there is a close connection between the mind and physical body, the mind implies a specific (intrinsic/autonomic) presence, which was described not only during attention-demanding tasks but also when an individual is awake and at rest (wakeful rest). Attentiondemanding tasks seem to be supported by task positive network of the brain, while mental presence during wakeful rest appears to be sustained by default mode network of the brain (7,8). The psychological presence (as psychological event) and the corresponding neurological support generate together internal mental existence, which is different by the physical existence of the body so that it can be compatible with analytical attention and decisions ( Figure 2).…”

“…It is unclear to what extent the selfcomponents would be supported by the brain, or they would be in fact just analytical interpretation/ products of the mind (6). At opposite end, mental impairments like autism or attention deficit hyperactivity disorder would result (according to imagistic studies) due to functional disruption of several brain networks (7)(8)(9).…”