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Journal articleFagerholm ED, Hellyer PJ, Scott G, et al., 2015,
Disconnection of network hubs and cognitive impairment after traumatic brain injury.
, Brain, Vol: 138, Pages: 1696-1709, ISSN: 0006-8950Traumatic brain injury affects brain connectivity by producing traumatic axonal injury. This disrupts the function of large-scale networks that support cognition. The best way to describe this relationship is unclear, but one elegant approach is to view networks as graphs. Brain regions become nodes in the graph, and white matter tracts the connections. The overall effect of an injury can then be estimated by calculating graph metrics of network structure and function. Here we test which graph metrics best predict the presence of traumatic axonal injury, as well as which are most highly associated with cognitive impairment. A comprehensive range of graph metrics was calculated from structural connectivity measures for 52 patients with traumatic brain injury, 21 of whom had microbleed evidence of traumatic axonal injury, and 25 age-matched controls. White matter connections between 165 grey matter brain regions were defined using tractography, and structural connectivity matrices calculated from skeletonized diffusion tensor imaging data. This technique estimates injury at the centre of tract, but is insensitive to damage at tract edges. Graph metrics were calculated from the resulting connectivity matrices and machine-learning techniques used to select the metrics that best predicted the presence of traumatic brain injury. In addition, we used regularization and variable selection via the elastic net to predict patient behaviour on tests of information processing speed, executive function and associative memory. Support vector machines trained with graph metrics of white matter connectivity matrices from the microbleed group were able to identify patients with a history of traumatic brain injury with 93.4% accuracy, a result robust to different ways of sampling the data. Graph metrics were significantly associated with cognitive performance: information processing speed (R(2) = 0.64), executive function (R(2) = 0.56) and associative memory (R(2) = 0.25). These resul
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Journal articleFagerholm ED, Lorenz R, Scott G, et al., 2015,
Cascades and Cognitive State: Focused Attention Incurs Subcritical Dynamics
, Journal of Neuroscience, Vol: 35, Pages: 4626-4634, ISSN: 1529-2401 -
Journal articleVijayan R, Scott G, Ahmed F, 2015,
What is it about the number of stitches?
, BMJ (Online), Vol: 350, ISSN: 0959-8146 -
Journal articleWinder-Rhodes SE, Hampshire A, Rowe JB, et al., 2015,
Association between MAPT haplotype and memory function in patients with Parkinson's disease and healthy aging individuals
, Neurobiology of Aging, Vol: 36, Pages: 1519-1528, ISSN: 0197-4580Genetic variation is associated with differences in the function of the brain as well as its susceptibility to disease. The common H1 haplotypic variant of the microtubule-associated protein tau gene (MAPT) has been related to an increased risk for Parkinson's disease (PD). Furthermore, among PD patients, H1 homozygotes have an accelerated progression to dementia. We investigated the neurocognitive correlates of MAPT haplotypes using functional magnetic resonance imaging. Thirty-seven nondemented patients with PD (19 H1/H1, 18 H2 carriers) and 40 age-matched controls (21 H1/H1, 19 H2 carriers) were scanned during performance of a picture memory encoding task. Behaviorally, H1 homozygosity was associated with impaired picture recognition memory in PD patients and control subjects. These impairments in the H1 homozygotes were accompanied by an altered blood-oxygen level-dependent response in the medial temporal lobe during successful memory encoding. Additional age-related differences in blood-oxygen level-dependent response were observed in the medial temporal lobes of H1 homozygotes with PD. These results suggest that common variation in MAPT is not only associated with the dementia of PD but also differences in the neural circuitry underlying aspects of cognition in normal aging.
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Journal articleSam AH, Sleeth ML, Thomas EL, et al., 2015,
Circulating pancreatic polypeptide concentrations predict visceral and liver fat content
, Journal of Clinical Endocrinology and Metabolism, Vol: 100, Pages: 1048-1052, ISSN: 0021-972XContext and objective:No current biomarker can reliably predict visceral and liver fat content, both of which are risk factors for cardiovascular disease. Vagal tone has been suggested to influence regional fat deposition. Pancreatic polypeptide (PP) is secreted from the endocrine pancreas under vagal control. We investigated the utility of PP in predicting visceral and liver fat.Patients and Methods:Fasting plasma PP concentrations were measured in 104 overweight and obese subjects (46 men and 58 women). In the same subjects, total and regional adipose tissue, including total visceral adipose tissue (VAT) and total subcutaneous adipose tissue (TSAT), were measured using whole-body magnetic resonance imaging. Intrahepatocellular lipid content (IHCL) was quantified by proton magnetic resonance spectroscopy.Results:Fasting plasma PP concentrations positively and significantly correlated with both VAT (r = 0.57, P < .001) and IHCL (r = 0.51, P < .001), but not with TSAT (r = 0.02, P = .88). Fasting PP concentrations independently predicted VAT after controlling for age and sex. Fasting PP concentrations independently predicted IHCL after controlling for age, sex, body mass index (BMI), waist-to-hip ratio, homeostatic model assessment 2-insulin resistance, (HOMA2-IR) and serum concentrations of triglyceride (TG), total cholesterol (TC), and alanine aminotransferase (ALT). Fasting PP concentrations were associated with serum ALT, TG, TC, low- and high-density lipoprotein cholesterol, and blood pressure (P < .05). These associations were mediated by IHCL and/or VAT. Fasting PP and HOMA2-IR were independently significantly associated with hepatic steatosis (P < .01).Conclusions:Pancreatic polypeptide is a novel predictor of visceral and liver fat content, and thus a potential biomarker for cardiovascular risk stratification and targeted treatment of patients with ectopic fat deposition.
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Journal articleTillmann T, Gibson AR, Scott G, et al., 2015,
Systems Medicine 2.0: Potential Benefits of Combining Electronic Health Care Records With Systems Science Models
, JOURNAL OF MEDICAL INTERNET RESEARCH, Vol: 17, ISSN: 1438-8871- Author Web Link
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- Citations: 10
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Journal articleWinder-Rhodes SE, Hampshire A, Rowe JB, et al., 2015,
Association between MAPT haplotype and memory function in patients with Parkinson's disease and healthy aging individuals.
, Neurobiol Aging, Vol: 36, Pages: 1519-1528Genetic variation is associated with differences in the function of the brain as well as its susceptibility to disease. The common H1 haplotypic variant of the microtubule-associated protein tau gene (MAPT) has been related to an increased risk for Parkinson's disease (PD). Furthermore, among PD patients, H1 homozygotes have an accelerated progression to dementia. We investigated the neurocognitive correlates of MAPT haplotypes using functional magnetic resonance imaging. Thirty-seven nondemented patients with PD (19 H1/H1, 18 H2 carriers) and 40 age-matched controls (21 H1/H1, 19 H2 carriers) were scanned during performance of a picture memory encoding task. Behaviorally, H1 homozygosity was associated with impaired picture recognition memory in PD patients and control subjects. These impairments in the H1 homozygotes were accompanied by an altered blood-oxygen level-dependent response in the medial temporal lobe during successful memory encoding. Additional age-related differences in blood-oxygen level-dependent response were observed in the medial temporal lobes of H1 homozygotes with PD. These results suggest that common variation in MAPT is not only associated with the dementia of PD but also differences in the neural circuitry underlying aspects of cognition in normal aging.
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Journal articleVijayan R, Scott G, Brownlie W, et al., 2015,
How Sharp is a "Sharp Scratch"? A Mixed Methods Study of Verbal Warnings Issued Before Venipuncture
, PAIN PRACTICE, Vol: 15, Pages: 132-139, ISSN: 1530-7085- Author Web Link
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- Citations: 1
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Journal articleKweh FA, Miller JL, Sulsona CR, et al., 2015,
Hyperghrelinemia in Prader-Willi Syndrome Begins in Early Infancy Long Before the Onset of Hyperphagia
, AMERICAN JOURNAL OF MEDICAL GENETICS PART A, Vol: 167, Pages: 69-79, ISSN: 1552-4825- Author Web Link
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- Citations: 46
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BookBereket A, Kiess W, Lustig RH, et al., 2015,
Hypothalamic Obesity in Children
, Publisher: KARGER, ISBN: 978-3-318-02798-3- Author Web Link
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- Citations: 2
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