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

Howells FM, Stein DJ, Russell VA - Behav Brain Funct (2010)

Bottom Line: Third, increased mental effort during the go/no-go task and the cued target detection task was inversely related to theta/beta ratios.These results indicate that perceived mental effort reflects tonic rather than phasic changes in arousal during tasks of attention.We suggest that perceived mental effort may reflect in part tonic activity of the LC-NE system in healthy individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa. Fleur.Howells@uct.ac.za

ABSTRACT

Background: It has been suggested that perceived mental effort reflects changes in arousal during tasks of attention. Such changes in arousal may be tonic or phasic, and may be mediated by the locus-coeruleus norepinephrine (LC-NE) system. We hypothesized that perceived mental effort during attentional tasks would correlate with tonic changes in cortical arousal, as assessed by relative electroencephalogram (EEG) band power and theta/beta ratio, and not with phasic changes in cortical arousal, assessed by P300 amplitude and latency.

Methods: Forty-six healthy individuals completed tasks that engage the anterior and posterior attention networks (continuous performance task, go/no-go task, and cued target detection task). During completion of the three attentional tasks a continuous record of tonic and phasic arousal was taken. Cortical measures of arousal included frequency band power, theta/beta ratios over frontal and parietal cortices, and P300 amplitude and latency over parietal cortices. Peripheral measures of arousal included skin conductance responses, heart rate and heart rate variance. Participants reported their perceived mental effort during each of the three attentional tasks.

Results: First, changes in arousal were seen from rest to completion of the three attentional tasks and between the attentional tasks. Changes seen between the attentional tasks being related to the task design and the attentional network activated. Second, perceived mental effort increased when demands of the task increased and correlated with left parietal beta band power during the three tasks of attention. Third, increased mental effort during the go/no-go task and the cued target detection task was inversely related to theta/beta ratios.

Conclusion: These results indicate that perceived mental effort reflects tonic rather than phasic changes in arousal during tasks of attention. We suggest that perceived mental effort may reflect in part tonic activity of the LC-NE system in healthy individuals.

Show MeSH

Related in: MedlinePlus

Relative EEG band power during stages of the testing session. Relative EEG band power during various stages of the testing session: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). Relative band power reported: theta (θ, 4-7 Hz), alpha (α, 7-14 Hz), and beta (β, 15-30 Hz) for frontal (F3 & F4) and parietal (P3 & P4) electrodes. a) *Left frontal (F3) α band power was higher during REO and GNG than CPT and CTD. @β band power was higher during CTD than REO, CPT, and GNG. b) *Right frontal (F4) α band power was higher during REO than CPT and CTD. #α band power was higher during GNG than CTD. @β band power was higher during CTD than CPT and GNG. c) *Left parietal (P3) θ band power was lower during REO than CPT and CTD. #β band power was lower during GNG than REO, CPT, and CTD. d) *Right parietal (P4) θ band power was lower during REO than CPT and CTD. #α band power was higher during REO and GNG than during CTD (p < 0.0125, n = 46, mean ± SEM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2909988&req=5

Figure 1: Relative EEG band power during stages of the testing session. Relative EEG band power during various stages of the testing session: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). Relative band power reported: theta (θ, 4-7 Hz), alpha (α, 7-14 Hz), and beta (β, 15-30 Hz) for frontal (F3 & F4) and parietal (P3 & P4) electrodes. a) *Left frontal (F3) α band power was higher during REO and GNG than CPT and CTD. @β band power was higher during CTD than REO, CPT, and GNG. b) *Right frontal (F4) α band power was higher during REO than CPT and CTD. #α band power was higher during GNG than CTD. @β band power was higher during CTD than CPT and GNG. c) *Left parietal (P3) θ band power was lower during REO than CPT and CTD. #β band power was lower during GNG than REO, CPT, and CTD. d) *Right parietal (P4) θ band power was lower during REO than CPT and CTD. #α band power was higher during REO and GNG than during CTD (p < 0.0125, n = 46, mean ± SEM).

Mentions: Friedman ANOVAs revealed differences in stages of the testing session (rest, continuous performance task, go/no-go task, and cued target detection task) for relative alpha and beta power for frontal electrodes (F3 relative α Chi Sqr(3,46) = 17.09, p < 0.001, F3 relative β Chi Sqr(3,46) = 26.17, p < 0.0001 and F4 relative α Chi Sqr(3,46) = 10.61, p = 0.014, F4 relative β Chi Sqr(3,46) = 19.48, p < 0.0002). Differences between the stages of the testing session were also revealed for relative theta and beta power for left parietal electrode (P3) and relative theta and alpha power for right parietal electrode (P4) (Figure 1). Wilcoxon matched pairs tests revealed the following differences. Left frontal electrode (F3) relative alpha band power was higher during the resting eyes open phase and the go/no-go tasks than during the continuous performance task and the cued target detection task. Left frontal electrode (F3) relative beta band power during the cued target detection task was higher than during resting eyes open, the continuous performance task, and the go/no-go task (Figure 1a). Right frontal electrode (F4) relative alpha band power was higher during the resting eyes open phase compared to continuous performance task and the cued target detection task. Relative alpha band power was higher during the go/no-go task than during the cued target detection task. Right frontal electrode (F4) relative beta band power was higher during the cued target detection task than during the continuous performance task and the go/no-go task (Figure 1b). Left parietal electrode (P3) relative theta band power was lower during resting eyes open than during the continuous performance task and the cued target detection task. Left parietal electrode (P3) relative beta band power was lower during the go/no-go task than during resting eyes open, the continuous performance task, and the cued target detection task (Figure 1c). Right parietal electrode (P4) relative theta band power was lower during resting eyes open than during the continuous performance task and the cued target detection task. Right parietal electrode (P4) relative alpha band power during resting eyes open and the go/no-go task were higher than during the cued target detection task (Figure 1d).


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

Howells FM, Stein DJ, Russell VA - Behav Brain Funct (2010)

Relative EEG band power during stages of the testing session. Relative EEG band power during various stages of the testing session: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). Relative band power reported: theta (θ, 4-7 Hz), alpha (α, 7-14 Hz), and beta (β, 15-30 Hz) for frontal (F3 & F4) and parietal (P3 & P4) electrodes. a) *Left frontal (F3) α band power was higher during REO and GNG than CPT and CTD. @β band power was higher during CTD than REO, CPT, and GNG. b) *Right frontal (F4) α band power was higher during REO than CPT and CTD. #α band power was higher during GNG than CTD. @β band power was higher during CTD than CPT and GNG. c) *Left parietal (P3) θ band power was lower during REO than CPT and CTD. #β band power was lower during GNG than REO, CPT, and CTD. d) *Right parietal (P4) θ band power was lower during REO than CPT and CTD. #α band power was higher during REO and GNG than during CTD (p < 0.0125, n = 46, mean ± SEM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2909988&req=5

Figure 1: Relative EEG band power during stages of the testing session. Relative EEG band power during various stages of the testing session: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). Relative band power reported: theta (θ, 4-7 Hz), alpha (α, 7-14 Hz), and beta (β, 15-30 Hz) for frontal (F3 & F4) and parietal (P3 & P4) electrodes. a) *Left frontal (F3) α band power was higher during REO and GNG than CPT and CTD. @β band power was higher during CTD than REO, CPT, and GNG. b) *Right frontal (F4) α band power was higher during REO than CPT and CTD. #α band power was higher during GNG than CTD. @β band power was higher during CTD than CPT and GNG. c) *Left parietal (P3) θ band power was lower during REO than CPT and CTD. #β band power was lower during GNG than REO, CPT, and CTD. d) *Right parietal (P4) θ band power was lower during REO than CPT and CTD. #α band power was higher during REO and GNG than during CTD (p < 0.0125, n = 46, mean ± SEM).
Mentions: Friedman ANOVAs revealed differences in stages of the testing session (rest, continuous performance task, go/no-go task, and cued target detection task) for relative alpha and beta power for frontal electrodes (F3 relative α Chi Sqr(3,46) = 17.09, p < 0.001, F3 relative β Chi Sqr(3,46) = 26.17, p < 0.0001 and F4 relative α Chi Sqr(3,46) = 10.61, p = 0.014, F4 relative β Chi Sqr(3,46) = 19.48, p < 0.0002). Differences between the stages of the testing session were also revealed for relative theta and beta power for left parietal electrode (P3) and relative theta and alpha power for right parietal electrode (P4) (Figure 1). Wilcoxon matched pairs tests revealed the following differences. Left frontal electrode (F3) relative alpha band power was higher during the resting eyes open phase and the go/no-go tasks than during the continuous performance task and the cued target detection task. Left frontal electrode (F3) relative beta band power during the cued target detection task was higher than during resting eyes open, the continuous performance task, and the go/no-go task (Figure 1a). Right frontal electrode (F4) relative alpha band power was higher during the resting eyes open phase compared to continuous performance task and the cued target detection task. Relative alpha band power was higher during the go/no-go task than during the cued target detection task. Right frontal electrode (F4) relative beta band power was higher during the cued target detection task than during the continuous performance task and the go/no-go task (Figure 1b). Left parietal electrode (P3) relative theta band power was lower during resting eyes open than during the continuous performance task and the cued target detection task. Left parietal electrode (P3) relative beta band power was lower during the go/no-go task than during resting eyes open, the continuous performance task, and the cued target detection task (Figure 1c). Right parietal electrode (P4) relative theta band power was lower during resting eyes open than during the continuous performance task and the cued target detection task. Right parietal electrode (P4) relative alpha band power during resting eyes open and the go/no-go task were higher than during the cued target detection task (Figure 1d).

Bottom Line: Third, increased mental effort during the go/no-go task and the cued target detection task was inversely related to theta/beta ratios.These results indicate that perceived mental effort reflects tonic rather than phasic changes in arousal during tasks of attention.We suggest that perceived mental effort may reflect in part tonic activity of the LC-NE system in healthy individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Psychiatry and Mental Health, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa. Fleur.Howells@uct.ac.za

ABSTRACT

Background: It has been suggested that perceived mental effort reflects changes in arousal during tasks of attention. Such changes in arousal may be tonic or phasic, and may be mediated by the locus-coeruleus norepinephrine (LC-NE) system. We hypothesized that perceived mental effort during attentional tasks would correlate with tonic changes in cortical arousal, as assessed by relative electroencephalogram (EEG) band power and theta/beta ratio, and not with phasic changes in cortical arousal, assessed by P300 amplitude and latency.

Methods: Forty-six healthy individuals completed tasks that engage the anterior and posterior attention networks (continuous performance task, go/no-go task, and cued target detection task). During completion of the three attentional tasks a continuous record of tonic and phasic arousal was taken. Cortical measures of arousal included frequency band power, theta/beta ratios over frontal and parietal cortices, and P300 amplitude and latency over parietal cortices. Peripheral measures of arousal included skin conductance responses, heart rate and heart rate variance. Participants reported their perceived mental effort during each of the three attentional tasks.

Results: First, changes in arousal were seen from rest to completion of the three attentional tasks and between the attentional tasks. Changes seen between the attentional tasks being related to the task design and the attentional network activated. Second, perceived mental effort increased when demands of the task increased and correlated with left parietal beta band power during the three tasks of attention. Third, increased mental effort during the go/no-go task and the cued target detection task was inversely related to theta/beta ratios.

Conclusion: These results indicate that perceived mental effort reflects tonic rather than phasic changes in arousal during tasks of attention. We suggest that perceived mental effort may reflect in part tonic activity of the LC-NE system in healthy individuals.

Show MeSH
Related in: MedlinePlus