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Lateralization of language to the left hemisphere is considered a key aspect of human brain organization. We used diffusion tensor MRI to perform in vivo virtual dissection of language pathways to assess the relationship between brain asymmetry and cognitive performance in the normal population. Our findings suggest interhemispheric differences in direct(More)
The purpose of this study is to create a white matter atlas of the human brain using diffusion tensor imaging (DTI) tractography and to describe the constant and variable features of the major pathways. DTI was acquired from 40 healthy right-handed adults and reconstructed tracts mapped within a common reference space (MNI). Group effect maps of each tract(More)
Individuals born before 33 weeks' gestation are at risk of brain lesions, which have the potential to disrupt subsequent neurodevelopment. As a result they manifest an increased incidence of neuromotor signs and cognitive deficits, which can still be detected in adolescence. The cerebellum is known to be involved in both the co-ordination of movement and in(More)
The N-methyl-D-aspartate (NMDA) antagonist, ketamine, produces neurobehavioural symptoms that mimic aspects of schizophrenia. Prepulse inhibition (PPI) of the startle reflex, a measure of sensorimotor gating, is decreased in chronically ill, medicated schizophrenic patients and in animals treated acutely with NMDA antagonists. We tested the hypothesis that(More)
Glutamatergic dysfunction at N-methyl-d-aspartate (NMDA) receptors has been proposed as a neurochemical model for schizophrenia. A key feature of this disorder is impairments in cognitive function. The present study sought to investigate the effects of ketamine, an NMDA antagonist, on the performance and neural correlates of verbal fluency, a task that(More)
Adolescence is a time of social and cognitive development associated with changes in brain structure and function. These developmental changes may show an altered path in individuals born before 33 weeks' gestation (very preterm; VPT). The cerebellum is affected by VPT birth, but no studies have yet assessed the adolescent development of this structure, or(More)
Disruption of facial emotion perception occurs in neuropsychiatric disorders where the expression of emotion is dulled or blunted, for example depersonalization disorder and schizophrenia. It has been suggested that, in the clinical context of emotional blunting, there is a shift in the relative contribution of brain regions subserving cognitive and(More)
Elevated plasma levels of the amino acid homocysteine have been associated with schizophrenia, particularly in young male patients. Among other factors, low folate and vitamin B12 levels have been implicated in the increase in homocysteine. In order to investigate this association, we determined plasma homocysteine, folate and B12 levels in 97 (67 males and(More)
PURPOSE To determine the locations and extent of activation in areas of the brain at functional magnetic resonance (MR) imaging with olfactory stimulation and to determine whether accommodation or amplification of brain activation occurs with sequential olfactory stimulation. MATERIALS AND METHODS Five adult men with normal senses of smell underwent(More)
Very preterm birth (before 33 weeks gestation) is associated with the white matter damage, and a common sequel is reduced size and altered shape of the corpus callosum. We used diffusion tensor MRI to assess the corpus callosum in 63 very preterm and 45 term-born young adults. Indices of white matter microstructure [fractional anisotropy (FA) and mean(More)