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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.

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Related in: MedlinePlus

Heart rate and heart rate variance parameters during stages of the testing session. a) Heart rate and heart rate variance parameters during: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). *Heart rate during REO was lower than during CPT, GNG, and CTD tasks (p < 0.0125, n = 46, mean ± SEM). #Heart rate during GNG was higher than during the CTD task (p < 0.0125, n = 46, mean ± SEM), b) *The high frequency range during REO was greater than during the GNG task (p < 0.0125, n = 46, mean ± SEM). c) No differences were found in the low frequency range. d) No differences were found in the low frequency/high frequency ratio of heart rate variance parameters.
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Figure 6: Heart rate and heart rate variance parameters during stages of the testing session. a) Heart rate and heart rate variance parameters during: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). *Heart rate during REO was lower than during CPT, GNG, and CTD tasks (p < 0.0125, n = 46, mean ± SEM). #Heart rate during GNG was higher than during the CTD task (p < 0.0125, n = 46, mean ± SEM), b) *The high frequency range during REO was greater than during the GNG task (p < 0.0125, n = 46, mean ± SEM). c) No differences were found in the low frequency range. d) No differences were found in the low frequency/high frequency ratio of heart rate variance parameters.

Mentions: Friedman ANOVA revealed differences in heart rate during the different stages of the testing session (Chi Sqr(3,46) = 49.89, p < 0.0001) and differences in high frequency heart rate variance (Chi Sqr(3,46) = 9.77, p < 0.05; Figure 6).


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

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

Heart rate and heart rate variance parameters during stages of the testing session. a) Heart rate and heart rate variance parameters during: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). *Heart rate during REO was lower than during CPT, GNG, and CTD tasks (p < 0.0125, n = 46, mean ± SEM). #Heart rate during GNG was higher than during the CTD task (p < 0.0125, n = 46, mean ± SEM), b) *The high frequency range during REO was greater than during the GNG task (p < 0.0125, n = 46, mean ± SEM). c) No differences were found in the low frequency range. d) No differences were found in the low frequency/high frequency ratio of heart rate variance parameters.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Heart rate and heart rate variance parameters during stages of the testing session. a) Heart rate and heart rate variance parameters during: resting eyes open (REO), continuous performance task (CPT), go/no-go task (GNG), and cued target detection task (CTD). *Heart rate during REO was lower than during CPT, GNG, and CTD tasks (p < 0.0125, n = 46, mean ± SEM). #Heart rate during GNG was higher than during the CTD task (p < 0.0125, n = 46, mean ± SEM), b) *The high frequency range during REO was greater than during the GNG task (p < 0.0125, n = 46, mean ± SEM). c) No differences were found in the low frequency range. d) No differences were found in the low frequency/high frequency ratio of heart rate variance parameters.
Mentions: Friedman ANOVA revealed differences in heart rate during the different stages of the testing session (Chi Sqr(3,46) = 49.89, p < 0.0001) and differences in high frequency heart rate variance (Chi Sqr(3,46) = 9.77, p < 0.05; Figure 6).

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