Background: Left bundle-branch block (LBBB) and the presence of systolic dysfunction are the major indications for cardiac resynchronization therapy (CRT). Mechanical ventricular dyssynchrony on echocardiography can help identify patients responsive to CRT. Left bundle-branch block can have different morphologic patterns.
View Article and Find Full Text PDFIn recent years, diffusion MRI has become an extremely important tool for studying the morphology of living brain tissue, as it provides unique insights into both its macrostructure and microstructure. Recent applications of diffusion MRI aimed to characterize the structural connectome using tractography to infer connectivity between brain regions. In parallel to the development of tractography, additional diffusion MRI based frameworks (CHARMED, AxCaliber, ActiveAx) were developed enabling the extraction of a multitude of micro-structural parameters (axon diameter distribution, mean axonal diameter and axonal density).
View Article and Find Full Text PDFPerspective (route or survey) during the encoding of spatial information can influence recall and navigation performance. In our experiment we investigated a third type of perspective, which is a slanted view. This slanted perspective is a compromise between route and survey perspectives, offering both information about landmarks as in route perspective and geometric information as in survey perspective.
View Article and Find Full Text PDFObjective: To examine the functional neuroanatomy that could account for pure Gerstmann syndrome, which is the selective association of acalculia, finger agnosia, left-right disorientation, and agraphia.
Methods: We used structural and functional neuroimaging at high spatial resolution in healthy subjects to seek a shared cortical substrate of the Grundstörung posited by Gerstmann, ie, a common functional denominator accounting for this clinical tetrad. We construed a functional activation paradigm that mirrors each of the four clinical deficits in Gerstmann syndrome and determined cortical activation patterns.
Identifying the sequence of computations which constitute a cognitive task is a fundamental problem in neuroscience. Here we show, using functional magnetic resonance imaging (fMRI), that we can parse, at the time scale of about 100 ms, the different stages of brain activations which compose a complex sequential task. To identify timing information from the slow blood oxygen level-dependent (BOLD) signal response, we use a simple analytic method, based on periodic stimulation and an analysis of covariation of the spectral parameters (phase and power spectrum at the stimulation frequency) with the different experimental conditions.
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