Roy H. Sexton

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We analyzed F-18 fluoro-deoxyglucose PET scans carried out in 18 drug-free patients with Tourette's syndrome (TS) in order to evaluate relationships between cerebral metabolism and complex cognitive and behavioural features commonly associated with this disorder. These features (obsessions and compulsions, impulsivity, coprolalia, self-injurious behavior,(More)
A new method to perform rapid 3D fMRI in human brain is introduced and evaluated in normal subjects, on a standard clinical scanner at 1.5 Tesla. The method combines a highly stable gradient echo technique with a spiral scan method, to detect brain activation related changes in blood oxygenation with high sensitivity. A motor activation paradigm with a(More)
A 3-dimensional MRI method has been developed for functional mapping of the human brain, based on blood oxygenation level dependent (BOLD) contrast mechanisms. The method uses recently introduced principles of echo-shifted FLASH to acquire a single 3D data set in 20 s. The technique was tested on a conventional 1.5 Tesla clinical scanner with a standard(More)
Dynamic physiological scanning, based on temporary changes in local field homogeneity during the passage of a contrast agent bolus, has been performed hitherto with echo-planar imaging (EPI) or conventional gradient-recalled techniques (FLASH). Here, it is shown that the T2* sensitivity of conventional FLASH techniques can be improved drastically on a(More)
Behavioral responses to apomorphine and to the selective D1 and D2 dopamine receptor agonists SK&F38393 and quinpirole were evaluated in rats following ibotenic acid (IA) or sham lesion of the medial prefrontal cortex (MPFC). IA-lesioned rats showed an increased responsiveness to the postsynaptic effects of all of the dopamine agonists. Patterns of the(More)
PURPOSE To compare directly the two most widely used methods of functional magnetic resonance (MR) imaging--dynamic contrast material-enhanced MR imaging and blood oxygenation level-dependent (BOLD) MR imaging. MATERIALS AND METHODS Five healthy volunteers underwent dynamic contrast-enhanced and BOLD MR imaging with a conventional 1.5-T MR unit during(More)