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Browsing by Author "Duffy, John R., author"

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    Large scale brain network mental workload engagement in schizophrenia
    (Colorado State University. Libraries, 2022) Duffy, John R., author; Thomas, Michael L., advisor; Rojas, Don, committee member; Blanchard, Nathanial, committee member; Tompkins, Sara Anne, committee member
    Objective: Cognitive deficits in patients diagnosed with schizophrenia are a core feature of the disorder. There are currently no treatments for these cognitive deficits. Our aim is to examine and compare patterns of increased versus decreased activity in the central executive network (CEN), salience network (SN), and default mode network (DMN) between healthy controls (HC) and patients diagnosed with schizophrenia (SZ) as well as to explore the influence of task load on these networks between HC and SZ. Method: Analyses focused on a secondary dataset comprising Blood Oxygen-Level Dependent (BOLD) data collected from 25 HC and 27 SZ who completed a working memory (WM) task (N-back) with 5 load conditions while undergoing functional magnetic resonance imaging (fMRI). Region of interest (ROI) data were analyzed using linear mixed-effects models. Dynamic causal modeling (DCM) was used in an exploratory analysis to examine working memory load input to these networks. Results: Group activation differences were found in the posterior salience network (pSN), default mode network (DMN), dorsal default mode network (dDMN), and ventral default mode network (vDMN) showing greater activity for SZ. Specifically, pSN, SMN, dDMN, and vDMN all showed increased activity in SZ compared to HC. The curve of brain activity was consistent between HC and SZ with the exception of the vDMN, where HC show greater activation at modest mental workload (quadratic curve) and SZ showed greater brain activation at lower mental workload (linear). In the CEN, there were no group differences, and the response curve was the same for both groups. In DCM analysis, working memory load acted as an input on different networks between HC and SZ. Conclusions: These group differences demonstrate network difference between HC and SZ and could show value in treatments targeting cognitive deficits in SZ from a large-scale brain network connectivity perspective. Future studies are needed to confirm these results with higher sample size in order to examine potential subtleties of interactions between these networks.
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    Multi-dimensional aspects of mindfulness: psychometric evaluation, neurobiological underpinnings, and experiential insights
    (Colorado State University. Libraries, 2024) Duffy, John R., author; Thomas, Michael L., advisor; Davalos, Deana, committee member; Graham, Dan, committee member; Stephans, Jaclyn, committee member
    Objective: This dissertation aimed to deepen our understanding of mindfulness by exploring a psychometric evaluation of self-report scales, neurobiological underpinnings, and experiential insights in a multidimensional approach. The objective encompassed three specific aims: firstly, to evaluate the psychometric effectiveness of two self-report scales; the Mindful Attention Awareness Scale (MAAS) and the Five Facet Mindfulness Questionnaire (FFMQ) within populations diagnosed with post-traumatic stress disorder (PTSD), ensuring these tools' validity and reliability while addressing the complexity of mindfulness. Secondly, the research intended to synthesize existing literature on brain networks related to mindfulness through an umbrella review (a review of reviews / metanalyses), aimed to clarify the neural mechanisms of mindfulness. Thirdly, the study used functional magnetic resonance imaging (fMRI) to compare brain activity between a control group performing a visualization task (control) and a group engaged in a guided compassion meditation (experimental). This comprehensive framework sought to advance the field of mindfulness research by integrating psychometric analysis, brain network review synthesis, and experimental neuroimaging to enhance theoretical understanding of mindfulness. Method: We employed a three-pronged methodological approach. Firstly, a psychometric evaluation of the Mindful Attention Awareness Scale (MAAS) and the Five Facet Mindfulness Questionnaire (FFMQ) to assess their reliability and validity in a PTSD-affected veteran population. Secondly, we conducted an umbrella review to synthesize existing research on brain networks and connectivity related to mindfulness to map out neural correlates and their implications. Thirdly, an experimental study using functional magnetic resonance imaging (fMRI) compared neural activation patterns between participants engaged in a visualization task and those practicing guided compassion meditation, aimed to identify distinct neural activities associated with this mindfulness practices. Results: The psychometric evaluation of the MAAS and FFMQ confirmed their validity and reliability in assessing mindfulness in PTSD populations, highlighting mindfulness as a complex, multifaceted construct. An umbrella review of existing literature demonstrated the significant impact of mindfulness on brain connectivity, particularly in the DMN, CEN, and SN networks. The experimental fMRI study revealed distinct neural activation patterns between compassion mindfulness and a visualization task, with compassion mindfulness showing decreased activity in regions involved in emotional regulation and cognitive functions, such as the medial superior prefrontal cortex and anterior cingulate cortex. Conclusions: These findings affirm the utility of MAAS and FFMQ reliability and validity, but demand more nuanced research based on a more multifaceted concept of mindfulness. The impact of mindfulness on large-scale brain networks underscores its potential to enhance cognitive and emotional regulation through neuroplasticity. However, significant methodological variability across studies calls for standardized research protocols to ensure consistency and reliability. Future research should address these limitations, explore the long-term effects of mindfulness, and include diverse populations to improve the generalizability of mindfulness-based interventions. Finally, significant differences in neural activation patterns between visualization tasks and compassion mindfulness meditation, indicate that such mindfulness practices may uniquely influence brain regions associated with emotional regulation and cognitive processes. These findings highlight the potential of compassion mindfulness to modulate brain activity in these areas, offering insights into its mechanisms and benefits.