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An Exploration of the Feasibility of Functional Near-Infrared Spectroscopy as a Neurofeedback Cueing System for the Mitigation of the Vigilance Decrement
Title
An Exploration of the Feasibility of Functional Near-Infrared Spectroscopy as a Neurofeedback Cueing System for the Mitigation of the Vigilance Decrement.
Creator
Hancock, Gabriella, Szalma, James, Mouloua, Mustapha, Bohil, Corey, Hoffman, Robert, Matthews, Gerald, University of Central Florida
Abstract / Description
Vigilance is the capacity for observers to maintain attention over extended periods of time, and has most often been operationalized as the ability to detect rare and critical signals (Davies (&) Parasuraman, 1982; Parasuraman, 1979; Warm, 1984). Humans, however, have natural physical and cognitive limitations that preclude successful long-term vigilance performance and consequently, without some means of assistance, failures in operator vigilance are likely to occur. Such a decline in...
Show moreVigilance is the capacity for observers to maintain attention over extended periods of time, and has most often been operationalized as the ability to detect rare and critical signals (Davies (&) Parasuraman, 1982; Parasuraman, 1979; Warm, 1984). Humans, however, have natural physical and cognitive limitations that preclude successful long-term vigilance performance and consequently, without some means of assistance, failures in operator vigilance are likely to occur. Such a decline in monitoring performance over time has been a robust finding in vigilance experiments for decades and has been called the vigilance decrement function (Davies (&) Parasuraman, 1982; Mackworth, 1948). One of the most effective countermeasures employed to maintain effective performance has been cueing: providing the operator with a reliable prompt concerning signal onset probability. Most protocols have based such cues on task-related or environmental factors. The present dissertation examines the efficacy of cueing when nominally based on operator state (i.e., blood oxygenation of cortical tissue) in a novel vigilance task incorporating dynamic displays over three studies. Results pertaining to performance outcomes, physiological measures (cortical blood oxygenation and heart rate variability), and perceived workload and stress are interpreted via Signal Detection Theory and the Resource Theory of vigilance.
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Date Issued
2017
Identifier
CFE0006599, ucf:51286
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006599
Rumination and executive dysfunction: Risk factors for vascular depression
Title
Rumination and executive dysfunction: Risk factors for vascular depression.
Creator
Brush, David, Paulson, Daniel, Rapport, Mark, Bohil, Corey, University of Central Florida
Abstract / Description
Introduction: The widely-supported vascular depression hypothesis is underspecified with respect to cognitive mechanisms by which high cerebrovascular burden (CVB) and neuropathology relate to depressive symptoms. Integration of the vascular depression hypothesis with the CaR-FA-X model, a framework of affect regulation mechanisms, suggest that Rumination (R) and executive dysfunction (X) may increase due to altered recruitment of the dorsolateral prefrontal cortex resulting from high CVB and...
Show moreIntroduction: The widely-supported vascular depression hypothesis is underspecified with respect to cognitive mechanisms by which high cerebrovascular burden (CVB) and neuropathology relate to depressive symptoms. Integration of the vascular depression hypothesis with the CaR-FA-X model, a framework of affect regulation mechanisms, suggest that Rumination (R) and executive dysfunction (X) may increase due to altered recruitment of the dorsolateral prefrontal cortex resulting from high CVB and underlying neuropathology. This process would contribute to depressive symptomatology among older adults with high CVB. The progression of examined hypotheses included mediation models examining mechanistic relationships between predictors (CVB, DLPFC activation), cognitive correlates (rumination, executive functioning), and affective outcomes (depressive symptoms). Method: A sample of 52 community-dwelling, stroke-free, individuals over the age of 70, without history of severe mental illness, dementia, or severe cognitive impairment, completed the Ruminative Responses Scale, provided self-reported cerebrovascular burden data (cardiac disease, hypertension, diabetes, high cholesterol), and completed executive function tasks (Stroop, Flanker) while their hemodynamic response was measured using fNIRS. The Geriatric Depression Scale was used to assess depressive symptomatology. Prefrontal cortical recruitment was assessed using functional near-infrared spectroscopy (fNIRS).Results: A progression of conventional and bootstrapped regression-based models broadly supported relationships between CVB and depressive symptoms, but not between DLPFC activation and depressive symptoms. No mechanistic relationships were found, with respect to analyses testing prospective cognitive mediators.Conclusions: Primary findings from this study indicate that cerebrovascular burden predicts depressive symptomatology among older adults and is related to a reduction in inhibitory control ability. Further, these findings inform CVB measurement and mental health implications of contrasting approaches to CVB measurement. A primary contribution of this thesis is that results appear to support utilization of fNIRS, a low-cost and accessible neuroimaging paradigm, for the study of lateralized cognition among older adults.
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Date Issued
2018
Identifier
CFE0006981, ucf:51648
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006981
EVALUATING COMPETITION BETWEEN VERBAL AND IMPLICIT SYSTEMS WITH FUNCTIONAL NEAR-INFRARED SPECTROSCOPY
Title
EVALUATING COMPETITION BETWEEN VERBAL AND IMPLICIT SYSTEMS WITH FUNCTIONAL NEAR-INFRARED SPECTROSCOPY.
Creator
Schiebel, Troy A, Bohil, Corey, University of Central Florida
Abstract / Description
In category learning, explicit processes function through the prefrontal cortex (PFC) and implicit processes function through the basal ganglia. Research suggested that these two systems compete with each other. The goal of this study was to shed light on this theory. 15 undergraduate subjects took part in an event-related experiment that required them to categorize computer-generated line-stimuli, which varied in length and/or angle depending on condition. Subjects participated in an...
Show moreIn category learning, explicit processes function through the prefrontal cortex (PFC) and implicit processes function through the basal ganglia. Research suggested that these two systems compete with each other. The goal of this study was to shed light on this theory. 15 undergraduate subjects took part in an event-related experiment that required them to categorize computer-generated line-stimuli, which varied in length and/or angle depending on condition. Subjects participated in an explicit "rule-based" (RB) condition and an implicit "information-integration" (II) condition while connected to a functional near-infrared spectroscopy (fNIRS) apparatus, which measured the hemodynamic response (HR) in their PFC. Each condition contained 2 blocks. We hypothesized that the competition between explicit and implicit systems (COVIS) would be demonstrated if, by block 2, task-accuracy was approximately equal across conditions with PFC activity being comparatively higher in the II condition. This would indicate that subjects could learn the categorization task in both conditions but were only able to decipher an explicit rule in the RB condition; their PFC would struggle to do so in the II condition, resulting in perpetually high activation. In accordance with predictions, results revealed no difference in accuracy across conditions with significant difference in channel activation. There were channel trends (p<.1) which showed PFC activation decrease in the RB condition and increase in the II condition by block 2. While these results support our predictions, they are largely nonsignificant, which could be attributed to the event-related design. Future research should utilize a larger samples size for improved statistical power.
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Date Issued
2016
Identifier
CFH2000086, ucf:45502
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000086
PREDICTING COGNITIVE WORKLOAD WITH MEASURES FROM FUNCTIONAL NEAR-INFRARED SPECTROSCOPY (FNIRS) AND HEART RATE
Title
PREDICTING COGNITIVE WORKLOAD WITH MEASURES FROM FUNCTIONAL NEAR-INFRARED SPECTROSCOPY (FNIRS) AND HEART RATE.
Creator
Duany, John, Bohil, Corey, University of Central Florida
Abstract / Description
The objective of this study was to assess low to high levels of Cognitive Workload by measuring heart rate and cortical blood flow in real-time. Four conditions were implemented into a within-subjects experimental design. Two conditions of difficulty and two conditions of trial order were used to illicit different levels of workload which will be analyzed with psychophysiological equipment. Functional Near-Infrared Spectroscopy (fNIRS) has become more prominent for measuring the blood...
Show moreThe objective of this study was to assess low to high levels of Cognitive Workload by measuring heart rate and cortical blood flow in real-time. Four conditions were implemented into a within-subjects experimental design. Two conditions of difficulty and two conditions of trial order were used to illicit different levels of workload which will be analyzed with psychophysiological equipment. Functional Near-Infrared Spectroscopy (fNIRS) has become more prominent for measuring the blood oxygenation levels in the prefrontal cortex of individuals operating in hazardous work environments, students with learning disabilities, and in research for military training. This is due to the fNIR device being highly mobile, inexpensive, and able to produce a high-spatial resolution of the dorsolateral prefrontal cortex during executive functioning. Heart Rate will be measured by an Electrocardiogram, which will be used in concordance with fNIR oxygenation levels to predict if an individual is in a condition that produces low or high mental workload. Successfully utilizing heart rate and blood oxygenation data as predictors of cognitive workload may validate implementing multiple physiological devices together in real-time and may be a more accurate solution for preventing excessive workload.
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Date Issued
2013
Identifier
CFH0004478, ucf:45070
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004478