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An MRI time course of 512 echo-planar images (EPI) in resting human brain obtained every 250 ms reveals fluctuations in signal intensity in each pixel that have a physiologic origin. Regions of the sensorimotor cortex that were activated secondary to hand movement were identified using functional MRI methodology (FMRI). Time courses of low frequency (< 0.1(More)
Image processing strategies for functional magnetic resonance imaging (FMRI) data sets acquired using a gradient-recalled echo-planar imaging sequence are considered. The analysis is carried out using the mathematics of vector spaces. Data sets consisting of N sequential images of the same slice of brain tissue are analyzed in the time-domain and also,(More)
Although it is being successfully implemented for exploration of the genome, discovery science has eluded the functional neuroimaging community. The core challenge remains the development of common paradigms for interrogating the myriad functional systems in the brain without the constraints of a priori hypotheses. Resting-state functional MRI (R-fMRI)(More)
The tools needed for analysis and visualization of three-dimensional human brain functional magnetic resonance image results are outlined, covering the processing categories of data storage, interactive vs batch mode operations, visualization, spatial normalization (Talairach coordinates, etc.), analysis of functional activation, integration of multiple(More)
Using gradient-echo echo-planar MRI, a local signal increase of 4.3 +/- 0.3% is observed in the human brain during task activation, suggesting a local decrease in blood deoxyhemoglobin concentration and an increase in blood oxygenation. Images highlighting areas of signal enhancement temporally correlated to the task are created.
Quantitative imaging of perfusion using a single subtraction, second version (QUIPSS II) is a pulsed arterial spin labeling (ASL) technique for improving the quantitation of perfusion imaging by minimizing two major systematic errors: the variable transit delay from the distal edge of the tagged region to the imaging slices, and the contamination by(More)
We have recently demonstrated using functional magnetic resonance imaging the presence of synchronous low-frequency fluctuations of signal intensities from the resting human brain that have a high degree of temporal correlation (p < 0.0001) both within and across the sensorimotor cortex. A statistically significant overlap between the resting-state(More)
Data obtained from functional magnetic resonance imaging are often limited by a low signal-to-noise ratio. The time-course data obtained from activated regions contain both system noise and physiological noise, primarily linked to the heart and respiratory rates, that are superimposed on task induced signals. Time averaging of a practical number of data(More)
In this study, Blood Oxygenation Level Dependent (BOLD) contrast in the detection of human brain activation was compared between spin-echo and gradient-echo echo-planar sequences at 1.5 T. Time course series of spin-echo and gradient-echo images containing the primary motor cortex were collected during rest (no finger movement) and activation (finger(More)
Regional-specific average time courses of spontaneous fluctuations in blood oxygen level dependent (BOLD) MRI contrast at 9.4T in lightly anesthetized resting rat brain are formed, and correlation coefficients between time course pairs are interpreted as measures of connectivity. A hierarchy of regional pairwise correlation coefficients (RPCCs) is observed,(More)