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- Creators: Arizona State University
- Creators: Lau, Kin Hang
Description
In everyday life, mental fatigue can be detrimental across many domains including driving, learning, and working. Given the importance of understanding and accounting for the deleterious effects of mental fatigue on behavior, a growing body of literature has studied the role of executive control processes in mental fatigue. In a laboratory setup, participants complete a task that places demands on executive control processes and are later given a transfer task. Generally speaking, decrements to subsequent task performance are taken as evidence that the initial executive control task created mental fatigue through the continued engagement of executive control. Several hypotheses have been developed to account for negative transfer resulting from executive control depletion including cognitive resource depletion and task-switching. In the current study, we provide a brief literature review, specify current theoretical approaches to depletion, and provide a strong empirical test of theories for negative transfer from executive control depletion (i.e., does continued performance of an executive control task negatively transfer to that exact same task).
ContributorsLau, Kin Hang (Author) / Brewer, Gene (Thesis director) / Knight, George (Committee member) / Blais, Chris (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Department of Psychology (Contributor)
Created2014-12
Description
Sustained attention, the ability to concentrate on a stimulus or task over a prolonged period, is essential for goal pursuit and fulfillment. Sustained attention failures can have catastrophic consequences, underscoring the importance of understanding the mechanisms that underlie variability in sustained attention, and developing interventions targeting these mechanisms to reduce such failures. A growing body of research implicates the brainstem locus coeruleus (LC) as a core modulator of attention and arousal. Activation of LC afferents, such as the trigeminal nerve, may indirectly modulate the LC. The altered LC activity could theoretically be tracked via well-established psychological and physiological indicators of attention and arousal, such as performance, self-reports of attention state, and pupillary activity during attention tasks. The present study tests the hypothesis that continuous transcranial direct current stimulation (tDCS) over the trigeminal nerve of the face improves attentional state, attentional performance, and pupillary reactivity via indirect modulation of the LC. Participants received 2 mA of anodal or cathodal stimulation or sham stimulation over the dorsolateral prefrontal cortex while completing the Psychomotor Vigilance Task. Participants occasionally reported on their attentional state. Pupillary activity was recorded continuously throughout the task. To compare patterns of attention task performance, frequency of task-unrelated thoughts, and pupillary activity across time by stimulation condition, linear mixed-effects models were implemented.
The results replicate the complex interplay between attentional state, attentional performance, and pupillary activity reported in the literature. Specifically, a ubiquitous pattern of performance deterioration was observed, which coincided with an increase in task-unrelated thoughts and reduced pretrial and task-evoked pupil responses. However, tDCS over the face did not produce significant effects compared to the sham condition in attention task performance, proportion of task-unrelated thoughts, and pupillary activity that would indicate LC modulation. This study addresses the causal relations between LC activity, attentional state, attentional performance, and pupillary reactivity that are still poorly understood in human subjects. The findings reported here support the dominant theory of the role of the LC in attentional processes but fail to support hypotheses suggesting that tDCS of the trigeminal nerve influences activity of the LC and indicators of LC activity.
ContributorsTorres, Alexis Stephanie (Author) / Brewer, Gene A (Thesis advisor) / Robison, Matthew K (Committee member) / McClure, Samuel M (Committee member) / Helms Tillery, Stephen (Committee member) / Arizona State University (Publisher)
Created2022