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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Cognitive control modulates pain during effortful goal-directed behaviour

Heydari, Sepideh 10 September 2020 (has links)
Many theories of decision-making consider pain, monetary loss, and other forms of punishment to be interchangeable quantities that are processed by the same neural system. For example, standard reinforcement learning models utilize a single reinforcement term to represent both monetary losses and pain signals. By contrast, I propose that 1) pain signals present unique computational challenges, 2) these challenges are addressed in humans and other animals by anterior cingulate cortex (ACC), and 3) pain is regulated by cognitive control during goal-directed tasks, using principles of the hierarchical reinforcement learning model of the ACC (HRL-ACC). To show this, I conducted 3 studies. In Study 1, I conducted an electrophysiological study to investigate the effect of task goals on event-related brain potentials (ERPs) during conditions where pain and reward are used. Specifically, I investigated whether feedback stimuli predicting forthcoming pain would elicit the reward positivity, an ERP component that is more positive-going to positive feedback than to negative feedback, when the goal of the task is to find electrical shocks. Contrary to my predictions, a standard reward positivity was not elicited by pain feedback in this task. In Study 2, I conducted three behavioral experiments wherein the subjective costs of mild electrical shocks were equated with monetary losses for each individual participant using a calibration procedure. I hypothesized that decision-making behavior in face of painful events and decision making behavior in the face of monetary losses would be different from each other despite the outcomes (pain vs. monetary loss) being equated for their subjective costs. This prediction was confirmed, demonstrating that the costs associated with pain and monetary losses differ in more than just magnitude. In Study 3, to explain these results, I developed an extension to an existing computational framework, the HRL-ACC model. The present model provides insight into choice behaviour in the pain and monetary loss (ML) conditions by showing that cognitive control levels converge to an average level across trials. In the pain condition, cognitive control fluctuates from trial to trial in a systematic fashion, causing trials with low shock levels to be over-valued and shocks with high-shock levels to be undervalued. By contrast, in the ML condition cognitive wanes across trials because it is not needed and the model displays normative behavior. These findings are in line with psychological approaches to pain treatment and provide neuro-cognitive explanations that underlie their mechanisms. In line with the HRL-ACC theory, I propose that the ACC regulates pain by motivating good performance in the face of physical punishments (but not monetary losses) in order to achieve long-term goals that are produced by ACC. / Graduate / 2021-08-18
82

Behavioral and neural correlates of chronic blast-related mild traumatic brain injury

Miller, Danielle 15 June 2016 (has links)
Blast-related mild traumatic brain injury (mTBI) is a common injury among Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans due to the frequent use of improvised explosive devices (IEDs). A significant minority of veterans with blast-related mTBI complain of postconcussion symptoms (PCS) and cognitive difficulties, even years after the injury. Studies have suggested that these behavioral sequelae are primarily linked to mental health disorders such as posttraumatic stress disorder (PTSD). However, mTBI is associated with neural changes and the impact of these changes on behavioral sequelae is unclear. As such, this dissertation had three goals. First, this dissertation assessed whether the severity of PCS in blast-exposed individuals is associated with the extent of mTBI-related neural injury. Results revealed that individuals with mTBI with loss of consciousness (LOC) had significantly more white matter abnormalities than no-TBI controls and that these white matter abnormalities were spatially variable across individuals. Importantly, the extent of white matter abnormality was associated with physical PCS severity and mediated the relationship between mTBI with LOC and physical PCS. Second, this dissertation examined whether these white matter abnormalities were also associated with overall cognitive impairment. In light of the observed variability in white matter injury, a measure of overall cognitive status that takes into account heterogeneity of cognitive impairment was used. Results showed that the extent of white matter abnormality was associated with cognitive status and mediated the relationship between mTBI with LOC and cognitive impairment. Third, this dissertation examined performance and brain function in the context of an experimental measure of cognitive control known to be sensitive to residual effects of mTBI. Results revealed that although behavioral performance was similar across groups, the mTBI group had enhanced functional connectivity between brain networks important for task performance, suggesting a potential compensatory mechanism in mTBI. Together, the findings of this dissertation suggest that mTBI is associated with structural and functional connectivity alterations years after the injury. Further, this dissertation suggests that whereas structural connectivity changes may have negative behavioral consequences, changes in functional connectivity may serve as a compensatory mechanism for successful performance.
83

Effects of Binge Drinking and Depression on Cognitive-Control Processes During an Emotional Go/No-Go Task in College Aged Adults

Magee, Kelsey Elise 29 January 2019 (has links)
No description available.
84

Heart Rate Variability at Rest and During Worry in Chronic Worriers

Free, Matthew Lee 28 August 2019 (has links)
No description available.
85

Establishing Predictors of Insight Problem Solving In Children: Age, Not Cognitive Control or Socioeconomic Status, Determines Immunity to Functional Fixedness

Ershadi, Mahsa January 2021 (has links)
Thesis advisor: Ellen Winner / Cognitive control, the ability to limit attention to goal-relevant information, subserves higher-order cognitive functions such as reasoning, attention, planning and organization. Counterintuitively, deficits in these functions have proven advantageous in certain contexts: low cognitive control means less filtering of attention, and such unfiltered attention leads to novel solutions in insight problem solving contexts. Insight is the clear and often sudden discernment of a solution to a problem by means that are not obvious, and it plays an indispensable role in creative thinking. This study examined whether insight problem solving is a compensatory advantage for children of low socioeconomic status because of their known deficits in cognitive control. One hundred and forty-eight children ages 4 to 11 years old, each completed two insight problem solving tasks (the Box Problem and the Pencil Problem) and a cognitive control task (the Flanker/Reverse Flanker). In addition, their parents completed a sociodemographic questionnaire, which was used as a measure of their socioeconomic status and child rearing values of obedience versus independence. No association was found between children’s socioeconomic status and their ability to use insight to solve a problem. Results did show that older children exhibited less cognitive flexibility than did to younger children, and that diminished cognitive flexibility correlated with older children’s ability to solve the Box Problem; however, this effect did not hold when age, sex, race, socioeconomic status, and parental report of obedience versus independence, were accounted for. Ultimately, age was the only significant predictor of children’s insight problem solving ability, such that older children were significantly more likely to solve the Box Problem and to arrive at a solution more quickly for the Pencil Problem compared to younger children. Findings from this study are explained using evidence from research on children’s tool innovation showing that young children are poor at inventing tools, and that older children’s ability to use objects for atypical functions may be the result of their greater exposure to and experience with tools. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology.
86

Imaging and Behavioral Correlates of the Anterior Cingulate in Pediatric Traumatic Brain Injury

Merkley, Tricia L. 25 February 2012 (has links) (PDF)
The anterior cingulate has been implicated in a number of cognitive processes that are at risk following traumatic brain injury (TBI), such as executive function and emotional processing. While the cingulate is believed to play a role in the above-mentioned cognitive processes, the relative roles of gray and white matter in functional outcomes post-TBI are not fully understood. The current study investigated various quantifiable brain properties (e.g., cortical thickness and volume, volume of underlying white matter, and white matter integrity) of the caudal anterior cingulate (CAC) gyrus and their relationships with behavioral measures of cognitive control following pediatric TBI. Parent ratings at three months post-injury indicated that TBI children demonstrated greater difficulty inhibiting inappropriate behavior and effectively transitioning between tasks. Reductions of CAC white matter integrity were observed in TBI participants, in the absence of significant morphometric group differences in this region. Neither CAC morphometrics nor fractional anisotropy (FA) were associated with experimental measures of cognitive control. The current findings indicate that DTI metrics may be more sensitive to brain changes in the region of the CAC following TBI. While strong relationships were not observed between CAC properties and measures of cognitive control, it is possible that study limitations may have obscured potential findings.
87

DUAL MECHANISMS OF METACONTROL: FROM NEURAL SYSTEMS TO INTERACTIVE FEATURES

Moon Sun Kang (11688955) 20 March 2024 (has links)
<p dir="ltr">Metacontrol describes outsourcing cognitive control to environmental cues, allowing for efficient instantiation of appropriate cognitive control. While recent years have seen many studies characterizing metacontrol in behavioral terms, relatively little effort has been made to characterize the neural mechanisms underlying metacontrol. Thus, the current dissertation project aimed to investigate the neural systems and interactive features of metacontrol, more specifically, proactive and reactive metacontrol that exert context-appropriate control states in preparatory and just-in-time manners, respectively. Specifically, Study 1 employed a functional magnetic resonance imaging technique and identified brain regions activated under proactive and reactive metacontrol operations. Importantly, the study revealed that the two metacontrol modes were supported by distinct neural systems. Building on the premise that distinct neural systems supporting the two metacontrol modes would enable the concurrent operation of both modes, Study 2 tested whether a preparatory metacontrol mode, proactive metacontrol, can coexist with a just-in-time metacontrol mode, reactive metacontrol. Using electroencephalography, Study 2 revealed that the two metacontrol modes can operate in parallel. Lastly, extending Study 2, Study 3 investigated how proactive metacontrol interacts with reactive metacontrol. Study 3 observed that high preparatory control states during proactive metacontrol benefit reactive metacontrol. Specifically, reactive metacontrol was observed only when penalties were at stake, which promoted heightened preparatory control states. In summary, Study 1 demonstrated that the two metacontrol modes are not only operationally distinctive but also characterized by separate neural systems underlying them. This aligns with the observation from Study 2 showing that the parallel operation of two metacontrol modes is feasible. Lastly, Study 3 suggests that despite the two metacontrol modes being supported by distinct neural systems (as shown in Study 1), they are not entirely independent and can interact with each other. Collectively, these findings reveal the relationship between the two metacontrol modes and elucidate their intricate interactions, thereby deepening our understanding of the neurocognitive mechanisms underlying metacontrol.</p>
88

The Interaction of Mobile Technology Use with Social Facets of Self-Regulatory Control and Common Executive Function

Chiu, Michelle, 0000-0002-5892-4893 January 2022 (has links)
Widespread availability of digital tools has changed the daily lives of college students. Yet, the intricacies underlying these digital ecosystems and their relationship to psychological functioning, particularly among these younger ‘digital native’ age cohorts, are still unclear. A growing body of work points to associations between digital media behaviors and the capacity for top-down self-regulatory control over thoughts, emotions, and behavior. Behavioral scientists often subdivide this skillset into separate psychological constructs with different labels (e.g., cognitive control, executive functioning, emotion regulation), and use a varied array of tasks and surveys to index its subcomponents. The general finding from across behavioral studies is that groups (and individuals) with weaker executive functioning (EF) skills also tend to exhibit heavier and more problematic digital media habits (e.g., excessive, or addiction-like use). This is presumably because the inability to reliably exert control makes one more prone to impulsive engagement with digital media (e.g., frequent phone-checking), greater attentional distractibility in response to media-associated cues (e.g., notifications), and more difficulty with sustaining goal-relevant behaviors in the presence of digital media. However, there has also been empirical work suggesting null and even positive or nonlinear relationships between digital media use and EF. The current study aimed to address these seemingly opposing sets of findings by examining how, and to what extent, individual differences in one’s self- and mobile-reported smartphone habits relate with specific facets of higher-order cognition. In our examination of the interplay between these factors, we found consistent patterns emerge between subjective measures of everyday and problematic smartphone use and common non-social executive functioning skills. Furthermore, we also found evidence indicating an overlapping pattern of findings highlighting the relationships between one’s cognizance toward their actual mobile usage habits and specific facets of socially oriented self-regulation. / Psychology
89

A ventral stream-prefrontal cortex processing cascade enables working memory gating dynamics

Yu, Shijing, Rempel, Sarah, Gholamipourbarogh, Negin, Beste, Christian 27 February 2024 (has links)
The representation of incoming information, goals and the flexible processing of these are required for cognitive control. Efficient mechanisms are needed to decide when it is important that novel information enters working memory (WM) and when these WM ‘gates’ have to be closed. Compared to neural foundations of maintaining information in WM, considerably less is known about what neural mechanisms underlie the representational dynamics during WM gating. Using different EEG analysis methods, we trace the path of mental representations along the human cortex during WM gate opening and closing. We show temporally nested representational dynamics during WM gate opening and closing depending on multiple independent neural activity profiles. These activity profiles are attributable to a ventral stream-prefrontal cortex processing cascade. The representational dynamics start in the ventral stream during WM gate opening and WM gate closing before prefrontal cortical regions are modulated. A regional specific activity profile is shown within the prefrontal cortex depending on whether WM gates are opened or closed, matching overarching concepts of prefrontal cortex functions. The study closes an essential conceptual gap detailing the neural dynamics underlying how mental representations drive the WM gate to open or close to enable WM functions such as updating and maintenance.
90

Cognitive Control and Context Maintenance in Individuals with Obsessive-Compulsive Disorder (OCD)

Fruehauf, Lindsay Morgan 01 June 2019 (has links)
Context maintenance, an aspect of cognitive control, is the internal representation and utilization of task-relevant information that helps achieve task goals. Alterations in context maintenance may be responsible for the cognitive difficulties seen in people with obsessive-compulsive disorder (OCD). We used two tasks designed to measure context maintenance: a) the cued-Stroop, a single-trial version of Golden’s Stroop test that varies the cue for each trial (color-naming or word-reading), and b) the AX-CPT task, a continuous performance task that has participants respond to an “A” only when followed by an “X,” with all other non-target trials labeled as AY, BX, and BY (and “Y” and “B” representing all non-X and non-A letters, respectively). Participants included 31 people with OCD and 30 psychiatrically-healthy controls that completed a neuropsychological test battery, self-report questionnaires measuring mood and symptom severity, and the computerized cued-Stroop and AX-CPT tasks. There was a 1s or 5s delay between the cue and probe for both tasks so as to vary the duration of context maintenance. We conducted a 2 (Group) x 2 (Delay) x 3 (Trial Type) repeated measures ANOVA for the cued-Stroop and a 2 (Group) x 2 (Delay) x 4 (Trial Type) repeated measures ANOVA for the AX-CPT. Dependent measures included median reaction times (RT) and mean error rates (ER). Both groups showed a congruency effect for the cued-Stroop, with slower RTs and greater ERs for the incongruent trials than the neutral and congruent trials, as well as lower ERs for BY trials compared to BX and AY trials of the AX-CPT task. There were no significant differences in RTs or ERs between groups for delay or condition for the cued-Stroop (ps > .45) or for the AX-CPT (ps > .07). The present study shows that people with OCD did not show deficits in context maintenance in two separate tasks. Limitations include low power, higher functioning participants with OCD, and the presence of comorbid depression and anxiety in some participants with OCD.

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