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  • Journal article
    Kranz M, Sattler B, Wust N, Deuther-Conrad W, Patt M, Meyer PM, Fischer S, Donat CK, Wunsch B, Hesse S, Steinbach J, Brust P, Sabri Oet al., 2016,

    Evaluation of the Enantiomer Specific Biokinetics and Radiation Doses of [(18)F]Fluspidine-A New Tracer in Clinical Translation for Imaging of sigma(1) Receptors

    , Molecules, Vol: 21
  • Journal article
    Hampshire A, Hellyer PJ, Parkin B, Hiebert N, MacDonald P, Owen A, Leech R, Rowe JBet al., 2015,

    Network mechanisms of intentional learning

    , Neuroimage, Vol: 127, Pages: 123-134, ISSN: 1095-9572

    The ability to learn new tasks rapidly is a prominent characteristic of human behaviour. Thisability relies on flexible cognitive systems that adapt in order to encode temporary programs forprocessing non-automated tasks. Previous functional imaging studies have revealed distinctroles for the lateral frontal cortices (LFCs) and the ventral striatum in intentional learningprocesses. However, the human LFCs are complex; they house multiple distinct sub-regions,each of which co-activates with a different functional network. It remains unclear how these LFCnetworks differ in their functions and how they coordinate with each other, and the ventralstriatum, to support intentional learning. Here, we apply a suite of fMRI connectivity methods todetermine how LFC networks activate and interact at different stages of two novel tasks, inwhich arbitrary stimulus-response rules are learnt either from explicit instruction or by trialand-error.We report that the networks activate en masse and in synchrony when novel rules arebeing learnt from instruction. However, these networks are not homogeneous in their functions;instead, the directed connectivities between them vary asymmetrically across the learningtimecourse and they disengage from the task sequentially along a rostro-caudal axis.Furthermore, when negative feedback indicates the need to switch to alternative stimulusresponserules, there is additional input to the LFC networks from the ventral striatum. Theseresults support the hypotheses that LFC networks interact as a hierarchical system duringintentional learning and that signals from the ventral striatum have a driving influence on thissystem when the internal program for processing the task is updated.
  • Journal article
    Scott G, Hellyer PJ, Ramlackhansingh AF, Brooks DJ, Matthews PM, Sharp DJet al., 2015,

    Thalamic inflammation after brain trauma is associated with thalamo-cortical white matter damage

    , Journal of Neuroinflammation, Vol: 12, ISSN: 1742-2094

    BackgroundTraumatic brain injury can trigger chronic neuroinflammation, which may predispose to neurodegeneration. Animal models and human pathological studies demonstrate persistent inflammation in the thalamus associated with axonal injury, but this relationship has never been shown in vivo.FindingsUsing [11C]-PK11195 positron emission tomography, a marker of microglial activation, we previously demonstrated thalamic inflammation up to 17 years after traumatic brain injury. Here, we use diffusion MRI to estimate axonal injury and show that thalamic inflammation is correlated with thalamo-cortical tract damage.ConclusionsThese findings support a link between axonal damage and persistent inflammation after brain injury.
  • Journal article
    Hampshire A, Sharp D, 2015,

    Inferior PFC Subregions Have Broad Cognitive Roles

    , TRENDS IN COGNITIVE SCIENCES, Vol: 19, Pages: 712-713, ISSN: 1364-6613
  • Journal article
    Goldstone AP, Miras AD, Scholtz S, Jackson S, Neff KJ, Penicaud L, Geoghegan J, Chhina N, Durighel G, Bell JD, Meillon S, le Roux CWet al., 2015,

    Link between increased satiety gut hormones and reduced food reward following gastric bypass surgery for obesity

    , Journal of Clinical Endocrinology & Metabolism, Vol: 101, Pages: 599-609, ISSN: 1945-7197

    Context: Roux-en-Y gastric bypass (RYGB) surgery is an effective long-term intervention for weightloss maintenance, reducing appetite, and also food reward, via unclear mechanisms.Objective: To investigate the role of elevated satiety gut hormones after RYGB, we examined foodhedonic-reward responses following their acute post-prandial suppression.Design: Randomised placebo-controlled double-blind cross-over experimental medicine studies.Patients: Two groups, over 5 months after RYGB for obesity (n7–11), compared with non-obesecontrols (n10), or patients after gastric banding (BAND) surgery (n9).Intervention: Studies were performed after acute administration of the somatostatin analogueOctreotide or saline. In one study, patients after RYGB, and non-obese controls, performed abehavioral progressive ratio task (PRT) for chocolate sweets. In another study, patients after RYGB,and controls after BAND surgery, performed a functional magnetic resonance imaging (fMRI) foodpicture evaluation task.Main outcome measures: Octreotide increased both appetitive food reward (breakpoint) in thePRT (n9), and food appeal (n9) and reward system blood oxygen level dependent (BOLD) signal(n7) in the fMRI task, in the RYGB group, but not in control groups.ISSN
  • Journal article
    Li LM, Leech R, Scott GT, Malhotra P, Seemungal B, Sharp DJet al., 2015,

    The effect of oppositional parietal transcranial direct current stimulation on lateralized brain functions

    , European Journal of Neuroscience, Vol: 42, Pages: 2904-2914, ISSN: 1460-9568

    Cognitive functions such as numerical processing and spatial attention show varying degrees of lateralization. Transcranial direct current stimulation (tDCS) can be used to investigate how modulating cortical excitability affects performance of these tasks. This study investigated the effect of bi-parietal tDCS on numerical processing, spatial and sustained attention. It was hypothesized that tDCS would have distinct effects on these tasks because of varying lateralization (numerical processing left, spatial attention right) and that these effects are partly mediated by modulation of sustained attention. A single-blinded, crossover, sham-controlled study was performed. Eighteen healthy right-handed participants performed cognitive tasks during three sessions of oppositional parietal tDCS stimulation: sham; right anodal with left cathodal (RA/LC); and right cathodal with left anodal (RC/LA). Participants performed a number comparison task, a modified Posner task, a choice reaction task (CRT) and the rapid visual processing task (RVP). RA/LC tDCS impaired number comparison performance compared with sham, with slower responses to numerically close numbers pairs. RA/LC and RC/LA tDCS had distinct effects on CRT performance, specifically affecting vigilance level during the final block of the task. No effect of stimulation on the Posner task or RVP was found. It was demonstrated that oppositional parietal tDCS affected both numerical performance and vigilance level in a polarity-dependent manner. The effect of tDCS on numerical processing may partly be due to attentional effects. The behavioural effects of tDCS were specifically observed under high task demands, demonstrating the consequences of an interaction between stimulation type and cognitive load.
  • Journal article
    Li L, Leech R, Seemungal B, Malhotra P, Sharp Det al., 2015,

    A SENSE OF DIRECTION: BRAIN STIMULATION IN LATERALISED BRAIN FUNCTION

    , JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY, Vol: 86, ISSN: 0022-3050
  • Conference paper
    Gorgoraptis N, Zaw-Linn J, Feeney C, Jimenez CT, Niemi M, Malik A, Ham T, Baxter D, Goldstone A, Sharp Det al., 2015,

    THE IMPACT OF TRAUMATIC BRAIN INJURY ON PATIENT-REPORTED PHYSICAL AND MENTAL HEALTH

    , Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
  • Conference paper
    Jenkins P, Fleminger J, De-Simoni S, Jolly A, Gorgoraptis N, Hampshire A, Sharp Det al., 2015,

    HOME COMPUTERISED COGNITIVE TESTING FOR TBI IS FEASIBLE AND POPULAR

    , Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050
  • Journal article
    Corbett A, Owen A, Hampshire A, Grahn J, Stenton R, Dajani S, Burns A, Howard R, Williams N, Williams G, Ballard Cet al., 2015,

    The Effect of an Online Cognitive Training Package in Healthy Older Adults: An Online Randomized Controlled Trial

    , Journal of the American Medical Directors Association, Vol: 16, Pages: 990-997, ISSN: 1525-8610

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