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  • Conference paper
    Chhabra S, Underwood J, Cole JH, Waldman A, Sharp DJ, Winston A, Sabin Cet al., 2017,

    Clinical research cerebral MRI findings in HIV positive subjects and appropriate controls

    , BHIVA annual conference, Publisher: WILEY, Pages: 10-10, ISSN: 1464-2662
  • Conference paper
    Whittington A, Sharp DJ, Gunn RN, 2017,

    An automated algorithm to quantify brain amyloid load

    , 28th International Symposium on Cerebral Blood Flow, Metabolism and Function / 13th International Conference on Quantification of Brain Function with PET, Publisher: SAGE PUBLICATIONS INC, Pages: 80-80, ISSN: 0271-678X
  • Journal article
    Violante IR, Li LM, Carmichael DW, Lorenz R, Leech R, Hampshire A, Rothwell JC, Sharp DJet al., 2017,

    Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance

    , ELIFE, Vol: 6, ISSN: 2050-084X

    Cognitive functions such as working memory (WM) are emergent properties of large-scale network interactions. Synchronisation of oscillatory activity might contribute to WM by enabling the coordination of long-range processes. However, causal evidence for the way oscillatory activity shapes network dynamics and behavior in humans is limited. Here we applied transcranial alternating current stimulation (tACS) to exogenously modulate oscillatory activity in a right frontoparietal network that supports WM. Externally induced synchronization improved performance when cognitive demands were high. Simultaneously collected fMRI data reveals tACS effects dependent on the relative phase of the stimulation and the internal cognitive processing state. Specifically, synchronous tACS during the verbal WM task increased parietal activity, which correlated with behavioral performance. Furthermore, functional connectivity results indicate that the relative phase of frontoparietal stimulation influences information flow within the WM network. Overall, our findings demonstrate a link between behavioral performance in a demanding WM task and large-scale brain synchronization.

  • Journal article
    Cole JH, underwood J, Caan MWA, De Francesco D, van Zoest RA, Leech R, Wit FWNM, Portegies P, Geurtsen GJ, Schmand BA, Schim van der Loeff MF, Franceschi C, Sabin CA, Majoie CBLM, Winston A, Reiss P, Sharp DJet al., 2017,

    Increased brain-predicted ageing in treated HIV disease

    , Neurology, Vol: 88, Pages: 1349-1357, ISSN: 0028-3878

    Objective: To establish whether HIV disease is associated with abnormal levels of age-related brain atrophy, by estimating apparent “brain age” using neuroimaging and exploring whether these estimates related to HIV-status, age, cognitive performance and HIV-related clinical parameters.Methods: A large sample of virologically-suppressed HIV-positive adults (N = 162, aged 45-82 years) and highly-comparable HIV-negative controls (N = 105) were recruited as part of the COBRA collaboration. Using T1-MRI scans, a machine-learning model of healthy brain ageing was defined in an independent cohort (N = 2001, aged 18-90 years). Neuroimaging data from HIV-positive and HIV-negative individuals were then used to estimate brain-predicted age; then brain-predicted age difference (brain-PAD = brain-predicted brain age - chronological age) scores were calculated. Neuropsychological and clinical assessments were also carried out.Results: HIV-positive individuals had greater brain-PAD score (mean ± SD = 2.15 ± 7.79 years) compared to HIV-negative individuals (-0.87 ± 8.40 years; b = 3.48, p < 0.01). Increased brain-PAD score was associated with decreased performance in multiple cognitive domains (information processing speed, executive function, memory) and general cognitive performance across all participants. Brain-PAD score was not associated with age, duration of HIV-infection or other HIV-related measures.Conclusions: Increased apparent brain ageing, predicted using neuroimaging, was observed in HIV-positive adults, despite effective viral suppression. Furthermore, the magnitude of increased apparent brain ageing related to cognitive deficits. However, predicted brain age difference did not correlate with chronological age or duration of HIV-infection, suggesting that HIV disease may accentuate, rather than accelerate brain ageing.

  • Journal article
    Arshad Q, Roberts RE, Ahmad H, Lobo R, Patel M, Ham T, Sharp DJ, Seemungal BMet al., 2017,

    Patients with chronic dizziness following traumatic head injury typically have multiple diagnoses involving combined peripheral and central vestibular dysfunction

    , CLINICAL NEUROLOGY AND NEUROSURGERY, Vol: 155, Pages: 17-19, ISSN: 0303-8467
  • Journal article
    Ghajari M, Hellyer P, Sharp D, 2017,

    Computational modelling of traumatic brain injury predicts the location of chronic traumatic encephalopathy pathology

    , Brain, Vol: 140, Pages: 333-343, ISSN: 0006-8950

    Traumatic brain injury can lead to the neurodegenerative disease chronic traumatic encephalopathy. This condition has a clear neuropathological definition but the relationship between the initial head impact and the pattern of progressive brain pathology is poorly understood. We test the hypothesis that mechanical strain and strain rate are greatest in sulci, where neuropathology is prominently seen in chronic traumatic encephalopathy, and whether human neuroimaging observations converge with computational predictions. Three distinct types of injury were simulated. Chronic traumatic encephalopathy can occur after sporting injuries, so we studied a helmet-to-helmet impact in an American football game. In addition, we investigated an occipital head impact due to a fall from ground level and a helmeted head impact in a road traffic accident involving a motorcycle and a car. A high fidelity 3D computational model of brain injury biomechanics was developed and the contours of strain and strain rate at the grey matter–white matter boundary were mapped. Diffusion tensor imaging abnormalities in a cohort of 97 traumatic brain injury patients were also mapped at the grey matter–white matter boundary. Fifty-one healthy subjects served as controls. The computational models predicted large strain most prominent at the depths of sulci. The volume fraction of sulcal regions exceeding brain injury thresholds were significantly larger than that of gyral regions. Strain and strain rates were highest for the road traffic accident and sporting injury. Strain was greater in the sulci for all injury types, but strain rate was greater only in the road traffic and sporting injuries. Diffusion tensor imaging showed converging imaging abnormalities within sulcal regions with a significant decrease in fractional anisotropy in the patient group compared to controls within the sulci. Our results show that brain tissue deformation induced by head impact loading is greatest in sulcal

  • Journal article
    Su T, Mutsaerts HJMM, Caan MWA, Wit FWNM, Schouten J, Geurtsen GJ, Sharp DJ, Prins M, Richard E, Portegies P, Reiss P, Majoie CBet al., 2017,

    Cerebral blood flow and cognitive function in HI-infected men with sustained suppressed viremia on combination antiretroviral therapy

    , AIDS, Vol: 31, Pages: 847-856, ISSN: 0269-9370
  • Journal article
    Huntley JD, Hampshire A, Bor D, Owen A, Howard RJet al., 2017,

    Adaptive working memory strategy training in early Alzheimer's disease: randomised controlled trial

    , BRITISH JOURNAL OF PSYCHIATRY, Vol: 210, Pages: 61-66, ISSN: 0007-1250
  • Journal article
    Limbrick-Oldfield E, Mick I, Cocks R, McGonigle J, Sharman S, Goldstone A, Stokes P, Waldman A, Erritzoe D, Bowden-Jones H, Nutt DJ, Lingford-Hughes A, Clark Let al., 2017,

    Neural substrates of cue reactivity and craving in gambling disorder

    , Translational Psychiatry, Vol: 7, ISSN: 2158-3188

    Cue reactivity is an established procedure in addictions research for examining the subjective experience and neural basis of craving. This experiment sought to quantify cue-related brain responses in Gambling Disorder using personally tailored cues in conjunction with subjective craving, as well as a comparison with appetitive non-gambling stimuli. Participants with Gambling Disorder (n=19) attending treatment and 19 controls viewed personally tailored blocks of gambling-related cues, as well as neutral cues and highly appetitive (food) images during a functional MRI scan performed ~2-3 hours after a usual meal. fMRI analysis examined cue-related brain activity, cue-related changes in connectivity, and associations with block-by-block craving ratings. Craving ratings in the participants with Gambling Disorder increased following gambling cues compared with non-gambling cues. fMRI analysis revealed group differences in left insula and anterior cingulate cortex, with the Gambling Disorder group showing greater reactivity to the gambling cues, but no differences to the food cues. In participants with Gambling Disorder, craving to gamble correlated positively with gambling cue-related activity in the bilateral insula and ventral striatum, and negatively with functional connectivity between the ventral striatum and the medial PFC. Gambling cues, but not food cues, elicit increased brain responses in reward-related circuitry in individuals with Gambling Disorder (compared to controls), providing support for the incentive sensitisation theory of addiction. Activity in the insula co-varied with craving intensity, and may be a target for interventions.

  • Conference paper
    Sinclair M, Peressutti D, Puyol-Anton E, Bai W, Nordsletten D, Hadjicharalambous M, Kerfoot E, Jackson T, Claridge S, Rinaldi CA, Rueckert D, King APet al., 2017,

    Learning Optimal Spatial Scales for Cardiac Strain Analysis Using a Motion Atlas

    , 7th International Workshop on Statistical Atlases and Computational Models of the Heart (STACOM), Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 57-65, ISSN: 0302-9743

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