Browsing by Subject "Rest"

Now showing 1 - 5 of 5
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    Altered resting-state functional connectivity of basolateral and centromedial amygdala complexes in posttraumatic stress disorder.
    (Neuropsychopharmacology, 2014-01) Brown, Vanessa M; LaBar, Kevin S; Haswell, Courtney C; Gold, Andrea L; Mid-Atlantic MIRECC Workgroup; McCarthy, Gregory; Morey, Rajendra A
    The amygdala is a major structure that orchestrates defensive reactions to environmental threats and is implicated in hypervigilance and symptoms of heightened arousal in posttraumatic stress disorder (PTSD). The basolateral and centromedial amygdala (CMA) complexes are functionally heterogeneous, with distinct roles in learning and expressing fear behaviors. PTSD differences in amygdala-complex function and functional connectivity with cortical and subcortical structures remain unclear. Recent military veterans with PTSD (n=20) and matched trauma-exposed controls (n=22) underwent a resting-state fMRI scan to measure task-free synchronous blood-oxygen level dependent activity. Whole-brain voxel-wise functional connectivity of basolateral and CMA seeds was compared between groups. The PTSD group had stronger functional connectivity of the basolateral amygdala (BLA) complex with the pregenual anterior cingulate cortex (ACC), dorsomedial prefrontal cortex, and dorsal ACC than the trauma-exposed control group (p<0.05; corrected). The trauma-exposed control group had stronger functional connectivity of the BLA complex with the left inferior frontal gyrus than the PTSD group (p<0.05; corrected). The CMA complex lacked connectivity differences between groups. We found PTSD modulates BLA complex connectivity with prefrontal cortical targets implicated in cognitive control of emotional information, which are central to explanations of core PTSD symptoms. PTSD differences in resting-state connectivity of BLA complex could be biasing processes in target regions that support behaviors central to prevailing laboratory models of PTSD such as associative fear learning. Further research is needed to investigate how differences in functional connectivity of amygdala complexes affect target regions that govern behavior, cognition, and affect in PTSD.
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    Changes in Brain Resting-state Functional Connectivity Associated with Peripheral Nerve Block: A Pilot Study.
    (Anesthesiology, 2016-08) Melton, M Stephen; Browndyke, Jeffrey N; Harshbarger, Todd B; Madden, David J; Nielsen, Karen C; Klein, Stephen M
    BACKGROUND: Limited information exists on the effects of temporary functional deafferentation (TFD) on brain activity after peripheral nerve block (PNB) in healthy humans. Increasingly, resting-state functional connectivity (RSFC) is being used to study brain activity and organization. The purpose of this study was to test the hypothesis that TFD through PNB will influence changes in RSFC plasticity in central sensorimotor functional brain networks in healthy human participants. METHODS: The authors achieved TFD using a supraclavicular PNB model with 10 healthy human participants undergoing functional connectivity magnetic resonance imaging before PNB, during active PNB, and during PNB recovery. RSFC differences among study conditions were determined by multiple-comparison-corrected (false discovery rate-corrected P value less than 0.05) random-effects, between-condition, and seed-to-voxel analyses using the left and right manual motor regions. RESULTS: The results of this pilot study demonstrated disruption of interhemispheric left-to-right manual motor region RSFC (e.g., mean Fisher-transformed z [effect size] at pre-PNB 1.05 vs. 0.55 during PNB) but preservation of intrahemispheric RSFC of these regions during PNB. Additionally, there was increased RSFC between the left motor region of interest (PNB-affected area) and bilateral higher order visual cortex regions after clinical PNB resolution (e.g., Fisher z between left motor region of interest and right and left lingual gyrus regions during PNB, -0.1 and -0.6 vs. 0.22 and 0.18 after PNB resolution, respectively). CONCLUSIONS: This pilot study provides evidence that PNB has features consistent with other models of deafferentation, making it a potentially useful approach to investigate brain plasticity. The findings provide insight into RSFC of sensorimotor functional brain networks during PNB and PNB recovery and support modulation of the sensory-motor integration feedback loop as a mechanism for explaining the behavioral correlates of peripherally induced TFD through PNB.
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    Maintenance and Representation of Mind Wandering during Resting-State fMRI.
    (Scientific reports, 2017-01-12) Chou, Ying-Hui; Sundman, Mark; Whitson, Heather E; Gaur, Pooja; Chu, Mei-Lan; Weingarten, Carol P; Madden, David J; Wang, Lihong; Kirste, Imke; Joliot, Marc; Diaz, Michele T; Li, Yi-Ju; Song, Allen W; Chen, Nan-Kuei
    Major advances in resting-state functional magnetic resonance imaging (fMRI) techniques in the last two decades have provided a tool to better understand the functional organization of the brain both in health and illness. Despite such developments, characterizing regulation and cerebral representation of mind wandering, which occurs unavoidably during resting-state fMRI scans and may induce variability of the acquired data, remains a work in progress. Here, we demonstrate that a decrease or decoupling in functional connectivity involving the caudate nucleus, insula, medial prefrontal cortex and other domain-specific regions was associated with more sustained mind wandering in particular thought domains during resting-state fMRI. Importantly, our findings suggest that temporal and between-subject variations in functional connectivity of above-mentioned regions might be linked with the continuity of mind wandering. Our study not only provides a preliminary framework for characterizing the maintenance and cerebral representation of different types of mind wandering, but also highlights the importance of taking mind wandering into consideration when studying brain organization with resting-state fMRI in the future.
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    Phobic anxiety and increased risk of mortality in coronary heart disease.
    (Psychosom Med, 2010-09) Watkins, Lana L; Blumenthal, James A; Babyak, Michael A; Davidson, Jonathan RT; McCants, Charles B; O'Connor, Christopher; Sketch, Michael H
    OBJECTIVES: To evaluate whether phobic anxiety is associated with increased risk of cardiac mortality in individuals with established coronary heart disease (CHD) and to examine the role of reduced heart rate variability (HRV) in mediating this risk. Previous findings suggest that phobic anxiety may pose increased risk of cardiac mortality in medically healthy cohorts. METHODS: We performed a prospective cohort study in 947 CHD patients recruited during hospitalization for coronary angiography. At baseline, supine recordings of heart rate for HRV were collected, and participants completed the Crown-Crisp phobic anxiety scale. Fatal cardiac events were identified over an average period of 3 years. RESULTS: Female CHD patients reported significantly elevated levels of phobic anxiety when compared with male patients (p < .001), and survival analysis showed an interaction between gender and phobic anxiety in the prediction of cardiac mortality (p = .058) and sudden cardiac death (p = .03). In women, phobic anxiety was associated with a 1.6-fold increased risk of cardiac mortality (hazard ratio, 1.56; 95% confidence interval, 1.15-2.11; p = .004) and a 2.0-fold increased risk of sudden cardiac death (hazard ratio, 2.02; 95% confidence interval, 1.16-3.52; p = .01) and was unassociated with increased mortality risk in men (p = .56). Phobic anxiety was weakly associated with reduced high-frequency HRV in female patients (r = -.14, p = .02), but reduced HRV did not alter the association between phobic anxiety on mortality. CONCLUSIONS: Phobic anxiety levels are high in women with CHD and may be a risk factor for cardiac-related mortality in women diagnosed with CHD. Reduced HRV measured during rest does not seem to mediate phobic anxiety-related risk.
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    Sources of disconnection in neurocognitive aging: cerebral white-matter integrity, resting-state functional connectivity, and white-matter hyperintensity volume.
    (Neurobiol Aging, 2017-06) Madden, David J; Parks, Emily L; Tallman, Catherine W; Boylan, Maria A; Hoagey, David A; Cocjin, Sally B; Packard, Lauren E; Johnson, Micah A; Chou, Ying-Hui; Potter, Guy G; Chen, Nan-Kuei; Siciliano, Rachel E; Monge, Zachary A; Honig, Jesse A; Diaz, Michele T
    Age-related decline in fluid cognition can be characterized as a disconnection among specific brain structures, leading to a decline in functional efficiency. The potential sources of disconnection, however, are unclear. We investigated imaging measures of cerebral white-matter integrity, resting-state functional connectivity, and white-matter hyperintensity volume as mediators of the relation between age and fluid cognition, in 145 healthy, community-dwelling adults 19-79 years of age. At a general level of analysis, with a single composite measure of fluid cognition and single measures of each of the 3 imaging modalities, age exhibited an independent influence on the cognitive and imaging measures, and the imaging variables did not mediate the age-cognition relation. At a more specific level of analysis, resting-state functional connectivity of sensorimotor networks was a significant mediator of the age-related decline in executive function. These findings suggest that different levels of analysis lead to different models of neurocognitive disconnection, and that resting-state functional connectivity, in particular, may contribute to age-related decline in executive function.