Neither blood oxygenation level dependent (BOLD) activation nor resting state magnetic resonance imaging (rsfMRI) signals in white matter have been well-established. However, growing evidence suggests reliable detection of white matter BOLD signals may ...

Fetal grafts show little migration after transplantation into the lesioned brain, whereas transplanted stem cells will migrate from the contralateral hemisphere to a focal ischaemic lesion. To track the migration of grafted cells, conditionally immortalized neural stem cells from the MHP36 cell line were labelled in vitro with the bifunctional contrast agent GRID which can be detected by magnetic resonance imaging (MRI) and fluorescent microscopy. Following 60 minutes of middle cerebral artery occlusion or sham surgery, rat brains were imaged by T1-, T2-, and proton density-weighted MRI in a 4.7T Varian imaging system to obtain pre-grafting coronal images of the stroke lesion. All animals were then transplanted contralaterally with 100,000 labelled stem cells in two deposits. The in vivo migration of grafted stem cells was assessed by scanning both transplanted ischaemic and control rats at 1, 7, and 14 days post-grafting. Fluorescent microscopy validated our in vivo images and indicated that some cells mi...

Because environmental information is often suboptimal, visual perception must frequently rely on the brain's reconstruction of contours absent from retinal images. Illusory contour (IC) stimuli have been used to investigate these “filling-in” processes. Intracranial recordings and neuroimaging studies show IC sensitivity in lower-tier area V2, and to a lesser extent V1. Some interpret these data as evidence for feedforward processing of IC stimuli, beginning at lower-tier visual areas. On the basis of lesion, visual evoked potentials (VEP), and neuroimaging evidence, others contend that IC sensitivity is a later, higher-order process. Whether IC sensitivity seen in lower-tier areas indexes feedforward or feedback processing remains unresolved. In a series of experiments, we addressed the spatiotemporal dynamics of IC processing. Centrally presented IC stimuli resulted in early VEP modulation (88–100 msec) over lateral–occipital (LOC) scalp—the IC effect. The IC effect followed visual response onset by 40 m...

Circadian rhythm is important in determining sleep-wake cycle and suprachiasmatic nucleus (SCN) plays a major role as a pacemaker in the brain. Recently, in the resting state functional magnetic resonance imaging (rsfMRI), several functional network hav...

Obstructive sleep apnea (OSA) is accompanied by multiple autonomic nervous system deficiencies, including muted and delayed heart rate responses to blood pressure challenges. Several autonomic regulatory sites show functional magnetic resonance imaging ...

Topographic representation in sensory systems is a well-established principle of neural organization. Retinotopic organization has been demonstrated with repeated success using functional magnetic resonance imaging (fMRI) in visual cortex, and reversals...

Recent functional magnetic resonance imaging (fMRI) data demonstrates that acupuncture modulates a distributed network of brain areas including cortical, subcortical and brainstem regions. However, although fMRI has excellent spatial resolution, it has ...

Calibrated functional magnetic resonance imaging (fMRI) combining blood oxygenation level dependent (BOLD) and arterial spin labeling (ASL) during a functional task and mild hypercapnia provides a potentially powerful experimental approach for assessing...

Both functional magnetic resonance imaging (fMRI)-constrained source analysis and independent component analysis (ICA) claim to uncover the neuronal sources of electroencephalographic (EEG) scalp signals. In fMRI-constrained source analysis, event-relat...

Prior knowledge of the probabilities concerning decision alternatives facilitates the selection of more likely alternatives to the disadvantage of others. The neural basis of prior probability (PP) integration into the decision-making process and associated preparatory processes is, however, still essentially unknown. Furthermore, trial-to-trial fluctuations in PP processing have not been considered thus far. In a previous study, we found that the amplitude of the contingent negative variation (CNV) in a precueing task is sensitive to PP information ([Scheibe et al., 2009][1]). We investigated brain regions with a parametric relationship between neural activity and PP and those regions involved in PP processing on a trial-to-trial basis in simultaneously recorded electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) data. Conventional fMRI analysis focusing on the information content of the probability precue revealed increasing activation of the posterior medial frontal cortex wit...