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Cortical neurons with similar properties are grouped in columnar structures and supplied by matching vascular networks. The hemodynamic response to neuronal activation, however, is not well described on a fine spatial scale. We investigated the spatiotemporal characteristics of microvascular responses to neuronal activation in rat barrel cortex using(More)
The goals of this study were to first determine whether the fractional anisotropy (FA) and mean diffusivity (MD) of major white matter pathways associate with schizophrenia, and secondly to characterize the extent to which differences in these metrics might reflect a genetic predisposition to schizophrenia. Differences in FA and MD were identified using a(More)
Diffusion tensor imaging (DTI) studies have demonstrated abnormal anisotropic diffusion in schizophrenia. However, examining data with low spatial resolution and/or a low number of gradient directions and limitations associated with analysis approaches sensitive to registration confounds may have contributed to mixed findings concerning the regional(More)
AIM To determine prospectively if qualitative and quantitative diffusion tensor imaging (DTI) metrics of white matter integrity are better than conventional magnetic resonance imaging (MRI) metrics for discriminating cerebellar diseases. METHODS Conventional MRI images from 31 consecutive patients with ataxia and 12 controls were interpreted by a(More)
Horizontal gaze palsy with progressive scoliosis (HGPPS) is caused by mutations in the ROBO3 gene, critical for the crossing of long ascending medial lemniscal and descending corticospinal tracts in the medulla. Diffusion tensor imaging in a patient with HGGPS revealed the absence of major pontine crossing fiber tracts and no decussation of the superior(More)
Mean diffusivity (MD), the rotationally invariant magnitude of water diffusion that is greater in cerebrospinal fluid (CSF) and smaller in organized brain tissue, has been suggested to reflect schizophrenia-associated cortical atrophy. Regional changes, associations with CSF, and the effects of genetic predisposition towards schizophrenia, however, remain(More)
Fractional anisotropy (FA), a very widely used measure of fiber integrity based on diffusion tensor imaging (DTI), is a problematic concept as it is influenced by several quantities including the number of dominant fiber directions within each voxel, each fiber's anisotropy, and partial volume effects from neighboring gray matter. High-angular resolution(More)
We introduce a fluid mechanics based tractography method for estimating the most likely connection paths between points in diffusion tensor imaging (DTI) volumes. We customize the Navier-Stokes equations to include information from the diffusion tensor and simulate an artificial fluid flow through the DTI image volume. We then estimate the most likely(More)
We introduce a fluid mechanics based tractography method that estimates the most likely connection path between points in a ten-sor distribution function (TDF) dataset. We simulated the flow of an artificial fluid whose properties are related to the underlying TDF dataset. The resulting fluid velocity was used as a metric of connection strength. We(More)
Introduction: Advances in brain imaging have provided investigators with new ways to probe the white matter architecture of the brain through diffusion tensor imaging (DTI). Prior studies have shown that white matter is under tight genetic control during embryonic development [1]. Neuroimaging studies have shown that white matter brain volume and fiber(More)