Perceived mental effort correlates with changes in tonic arousal during attentional tasks

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Perceived mental effort may be linked to arousal changes during attention tasks.
• Arousal changes can be tonic (sustained) or phasic (brief), possibly involving the locus-coeruleus norepinephrine (LC-NE) system.
• This study investigated if perceived mental effort correlates with tonic or phasic cortical arousal during attentional tasks.

Purpose of the Study:

• To determine if perceived mental effort correlates with tonic cortical arousal (EEG band power, theta/beta ratio) or phasic cortical arousal (P300 amplitude/latency).
• To examine the relationship between perceived mental effort and objective measures of tonic and phasic arousal during attention tasks.

Main Methods:

• Forty-six healthy individuals performed continuous performance, go/no-go, and cued target detection tasks.
• Tonic and phasic arousal were continuously monitored using electroencephalogram (EEG) and peripheral measures (skin conductance, heart rate).
• Participants reported perceived mental effort after each task, alongside objective arousal measurements.

Main Results:

• Arousal levels changed significantly from rest to task completion and between different attentional tasks.
• Perceived mental effort increased with task demands and correlated with left parietal beta band power.
• Higher mental effort was inversely related to theta/beta ratios during specific tasks.

Conclusions:

• Perceived mental effort during attention tasks reflects tonic, not phasic, changes in arousal.
• Findings suggest perceived mental effort may partially reflect tonic activity of the LC-NE system in healthy individuals.