Browsing by Author "Hall, Judith E."

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    A Functional Magnetic Resonance Imaging Study to Investigate the Utility of a Picture Imagination Task in Investigating Neural Responses in Patients with Chronic Musculoskeletal Pain to Daily Physical Activity Photographs
    (Public Library of Science (PLoS), 2015-10-23) Taylor, Ann M.; Harris, Ashley D.; Varnava, Alice; Phillips, Rhiannon; Taylor, Justin O.; Hughes, Owen; Wilkes, Antony R.; Hall, Judith E.; Wise, Richard G.
    Pain-related anxiety and fear are associated with increased difficulties in attention, increased awareness of pain, impaired disengagement from pain, and can moderate the effects of attentional coping attempts. Accurately assessing the direct impact of pain-related anxiety and fear on pain behavior has proved difficult. Studies have demonstrated no or limited influence of pain-related fear and anxiety on behavior but this may be due to inherent problems with the scales used. Neuroimaging has improved the understanding of neural processes underlying the factors that influence pain perception. This study aimed to establish if a Picture and Imagination Task (PIT), largely developed from the Photographs of Daily Activity (PHODA) assessment tool, could help explore how people living with chronic pain process information about daily activities. Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to compare brain responses in patients with chronic musculoskeletal pain (CMSKP) (n = 15) and healthy controls (n = 15). Subjects were asked to imagine how they would feel mentally and physically if asked to perform daily activities illustrated in PIT. The results found that a number of regions involved in pain processing saw increased BOLD activation in patients compared with controls when undertaking the task and included the insula, anterior cingulate cortex, thalamus and inferior and superior parietal cortices. Similarly, increased BOLD responses in patients compared to controls in the frontal pole, paracingulate and the supplementary motor cortex may be suggestive of a memory component to the responses The amygdala, orbitofrontal cortex, substantia nigra/ventral tegmentum, putamen, thalamus, pallidum, inferior parietal (supramarginal and angular gyrus) and cingulate cortex were also seen to have greater differences in BOLD signal changes in patients compared with controls and many of these regions are also associated with general phobic responses. Therefore, we suggest that PIT is a useful task to explore pain-and movement-related anxiety and fear in fMRI studies. Regions in the Default Mode Network remained active or were less deactivated during the PIT task in patients with CMSKP compared to healthy controls supporting the contention that the DMN is abnormal in patients with CMSKP.
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    Cerebral blood flow response to acute hypoxic hypoxia
    (Wiley, 2013-10-07) Harris, Ashley D.; Murphy, Kevin; Diaz, Claris M.; Saxena, Neeraj; Hall, Judith E.; Liu, Thomas T.; Wise, Richard G.
    Hypoxic hypoxia (inspiratory hypoxia) stimulates an increase in cerebral blood flow (CBF) maintaining oxygen delivery to the brain. However, this response, particularly at the tissue level, is not well characterised. This study quantifies the CBF response to acute hypoxic hypoxia in healthy subjects. A 20-min hypoxic (mean P(ET)o(2)=52 mmHg) challenge was induced and controlled by dynamic end-tidal forcing whilst CBF was measured using pulsed arterial spin labelling perfusion MRI. The rate constant, temporal delay and magnitude of the CBF response were characterised using an exponential model for whole-brain and regional grey matter. Grey matter CBF increased from 76.1 mL/100 g/min (95% confidence interval (CI) of fitting: 75.5 mL/100 g/min, 76.7 mL/100 g/min) to 87.8 mL/100 g/min (95% CI: 86.7 mL/100 g/min, 89.6 mL/100 g/min) during hypoxia, and the temporal delay and rate constant for the response to hypoxia were 185 s (95% CI: 132 s, 230 s) and 0.0035 s(-1) (95% CI: 0.0019 s(-1), 0.0046 s(-1)), respectively. Recovery from hypoxia was faster with a delay of 20 s (95% CI: -38 s, 38 s) and a rate constant of 0.0069 s(-1) (95% CI: 0.0020 s(-1), 0.0103 s(-1)). R-2*, an index of blood oxygenation obtained simultaneously with the CBF measurement, increased from 30.33 s(-1) (CI: 30.31 s(-1), 30.34 s(-1)) to 31.48 s(-1) (CI: 31.47 s(-1), 31.49 s(-1)) with hypoxia. The delay and rate constant for changes in R-2* were 24 s (95% CI: 21 s, 26 s) and 0.0392 s(-1) (95% CI: 0.0333 s(-1), 0.045 s(-1) ), respectively, for the hypoxic response, and 12 s (95% CI: 10 s, 13 s) and 0.0921 s(-1) (95% CI: 0.0744 s(-1), 0.1098 s(-1)/) during the return to normoxia, confirming rapid changes in blood oxygenation with the end-tidal forcing system. CBF and R-2* reactivity to hypoxia differed between subjects, but only R-2* reactivity to hypoxia differed significantly between brain regions. (c) 2013 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.
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    In vivo Assessment of Human Brainstem Cerebrovascular Function: A Multi-Inversion Time Pulsed Arterial Spin Labelling Study
    (SAGE Publications, 2014-03-05) Warnert, Esther A.H.; Harris, Ashley D.; Murphy, Kevin; Saxena, Neerja; Tailor, Neeta; Jenkins, Nigel S.; Hall, Judith E.; Wise, Richard G.
    The brainstem (BS) is involved in critical physiologic processes, including control of cardiovascular and respiratory functions. This study implements a multi-inversion time pulsed arterial spin labelling (MTI PASL) imaging sequence that addresses the challenges of BS imaging and aims to measure normal and elevated BS perfusion in healthy volunteers. An initial experiment was performed to obtain the kinetic curve of the label in the BS and consequently to estimate the label arrival times and tissue perfusion in seven participants. A second experiment estimated the BS cerebral vascular reactivity (CVR) to hypercapnia in 10 participants. Images were acquired with a gradient-echo sequence with two spiral interleaves and short echo time (TE=2.7 ms). Data were analyzed with a two-compartment model, including a tissue and arterial component. In both experiments, perfusion in the BS was significantly lower than in cortical gray matter (repeated measures analysis of variance (RM-ANOVA), P<0.05), which is as expected since the BS consists of gray and white matter, the latter typically showing lower perfusion. The BS CVR found here is comparable to previous reports obtained with positron emission tomography (PET) imaging. Multi-inversion time pulsed ASL in combination with a two-compartment signal model can be used to assess BS perfusion and CVR.
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    Neural responses to a modified Stroop paradigm in patients with complex chronic musculoskeletal pain compared to matched controls: an experimental functional magnetic resonance imaging study
    (Springer Science and Business Media LLC, 2016-02-01) Taylor, Ann M.; Harris, Ashley D.; Varnava, Alice; Phillips, Rhiannon; Hughes, Owen; Wilkes, Antony R.; Hall, Judith E.; Wise, Richard G.
    Chronic musculoskeletal pain (CMSKP) is attentionally demanding, complex and multi-factorial; neuroimaging research in the population seen in pain clinics is sparse. A better understanding of the neural activity underlying attentional processes to pain related information compared to healthy controls may help inform diagnosis and management in the future.