Mark R. Symms

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Functional lateralization is a feature of human brain function, most apparent in the typical left-hemisphere specialization for language. A number of anatomical and imaging studies have examined whether structural asymmetries underlie this functional lateralization. We combined functional MRI (fMRI) and diffusion-weighted imaging (DWI) with tractography to(More)
Voxel-based morphometry (VBM) has been used to analyze diffusion tensor MRI (DT-MRI) data in a number of studies. In VBM, following spatial normalization, data are smoothed to improve the validity of statistical inferences and to reduce inter-individual variation. However, the size of the smoothing filter used for VBM of DT-MRI data is highly variable(More)
This study describes a new technique for Diffusion Tensor Imaging (DTI) that acquires axial (transverse) images of the cervical spinal cord. The DTI images depict axonal fiber orientation, enable quantification of diffusion characteristics along the spinal cord, and have the potential to demonstrate the connectivity of cord white matter tracts. Because of(More)
BACKGROUND Mesial temporal lobe epilepsy (mTLE) with hippocampus sclerosis (HS) is an important cause for focal epilepsy. In this study, we explored the integrity of connecting networks using diffusion tensor imaging (DTI) and two whole-brain voxel-based methods: statistical parametric mapping (SPM) and tract-based spatial statistics (TBSS). METHODS(More)
PURPOSE To propose a new method to optimize the ordering of gradient directions in diffusion-weighted MRI so that partial scans have the best spherical coverage. MATERIALS AND METHODS Diffusion-weighted MRI often uses a spherical sampling scheme, which acquires images sequentially with diffusion-weighting gradients in unique directions distributed(More)
Malformations of cortical development (MCD) are a common cause of epilepsy. Studies of structural MRIs and PET data in patients with MCD have found widespread changes outside the visually identified lesions. The aim of this study was to investigate diffusion changes interictally in patients with MCD and to test the hypothesis that MCD would be associated(More)
Diffusion tensor imaging (DTI) was used to investigate regional white matter in vivo in patients with schizophrenia. DTI is capable of providing information about the organization of white matter tracts and has only recently been used to study schizophrenia. In this study, a voxel based analysis of DTI maps in 14 patients and 19 controls did not reveal any(More)
Functional magnetic resonance imaging can demonstrate the functional anatomy of cognitive processes. In patients with refractory temporal lobe epilepsy, evaluation of preoperative verbal and visual memory function is important as anterior temporal lobe resections may result in material specific memory impairment, typically verbal memory decline following(More)
PURPOSE Anterior temporal lobe resection (ATLR) controls seizures in up to 70% of patients with intractable temporal lobe epilepsy (TLE) but, in the language dominant hemisphere, may impair language function, particularly naming. Functional reorganization can occur within the ipsilateral and contralateral hemispheres. We investigated reorganization of(More)
EEG-triggered functional MRI (fMRI) offers the potential to localize the generators of scalp EEG events, such as interictal epileptiform discharges, using a biological measurement as opposed to relying solely on modelling techniques. Although recent studies have demonstrated these possibilities in a small number of patients, wider application has been(More)