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

Area of Science:

• Neuroscience
• Cognitive Psychology
• Human Physiology

Background:

• Time-on-task (TOT) effects, characterized by reduced performance and increased fatigue after prolonged cognitive workload, are common but poorly understood at the neural level.
• Understanding the neural underpinnings of TOT effects is crucial for addressing fatigue in demanding occupations and daily life.

Purpose of the Study:

• To investigate the neural mechanisms of time-on-task effects using resting-state functional magnetic resonance imaging (fMRI).
• To identify changes in spontaneous brain activity associated with mental fatigue and performance decrements during a cognitive task.

Main Methods:

• A group of 16 healthy adults underwent a 20-minute psychomotor vigilance test (PVT) to induce time-on-task effects.
• Resting-state BOLD fMRI was used to measure spontaneous brain activity before and after the PVT.
• Amplitudes of low-frequency fluctuation (ALFF) and functional connectivity were analyzed.

Main Results:

• Behaviorally, participants showed slower reaction times and increased self-reported mental fatigue after the PVT.
• Post-test fMRI revealed reduced ALFF in the default mode network (DMN) and increased ALFF in the thalamus compared to pre-test.
• Reduced anti-correlations between the posterior cingulate cortex (PCC) and right middle prefrontal cortex were observed.
• Pre-test ALFF in the PCC and medial prefrontal cortex (MePFC) predicted subsequent performance stability.

Conclusions:

• Spontaneous brain activity, particularly within the default mode network and thalamus, changes with mental fatigue induced by prolonged cognitive workload.
• Resting-state fMRI measures of spontaneous neural activity may serve as a potential biomarker for mental fatigue and predict cognitive performance.
• Both task-positive and task-negative brain networks play a role in mediating time-on-task effects.