Functional magnetic resonance imaging (fMRI) of the human brain is widely used in neuroscience, but the exact relationship between measured fMRI response and the underlying changes in neuronal activity is still elusive. To obtain further information about the specific roles of synaptic (input) and spiking activity (output) for the generation of fMRI-related signals, we used an approach that combines electrophysiological and MRI measurements in the anatomically and physiologically well defined rat hippocampus. Direct electrical stimulation of the perforant pathway enabled us to control synchronized input activity to the dentate gyrus, whereas recorded population spikes from the granular cell layer indicated the dentate output activity. The perforant pathway was first stimulated with 15 identical pulse trains (10 Hz for 8 s), and evoked blood oxygenation level-dependent (BOLD) responses and population spikes were measured for each individual stimulus train. Spatial and magnitude aspects of the elicited BOLD ...

Diffusion MRI (dMRI) provides insight into microstructural brain changes with aging, especially in the white matter (WM), not obtainable with standard MRI. It is important to preprocess dMRI to improve model fit and boost sensitivity to effects of aging...

Fusional binocular divergence is required when changing binocular fixation from near to far objects, but it is also required to maintain fusion in the face of pathological mechanical or neural biases towards convergence. The superior compartment of the ...

Background: Post-mortem and imaging studies provide converging evidence that frontal lobe myelination trajectory is dysregulated in schizophrenia and suggest that, early in treatment, antipsychotic medications increase myelination and specifically intra...

We used functional magnetic resonance imaging (fMRI) to investigate the neural circuitry underlying tactile spatial acuity at the human finger pad. Stimuli were linear, three-dot arrays, applied to the immobilized right index finger pad using a computer-controlled, MRI-compatible, pneumatic stimulator. Activity specific for spatial processing was isolated by contrasting discrimination of left–right offsets of the central dot in the array with discrimination of the duration of stimulation by an array without a spatial offset. This contrast revealed activity in a distributed frontoparietal cortical network, within which the levels of activity in right posteromedial parietal cortical foci [right posterior intraparietal sulcus (pIPS) and right precuneus] significantly predicted individual acuity thresholds. Connectivity patterns were assessed using both bivariate analysis of Granger causality with the right pIPS as a reference region and multivariate analysis of Granger causality for a selected set of regions....

Precise definitions of the anatomic subdivisions of the brainstem are required for structural and functional imaging studies of the brainstem. Localization of functional activation is aided by this precise mapping of function onto structure. In addition, brainstem abnormalities may be characterized in terms of their effects on brainstem function and volume. We describe a parcellation system of the human brainstem based upon neuroanatomy and which conserves the topographic uniqueness of the individual brain. METHOD: Based upon a set of topographical landmarks, we have defined a system for parcellation of the human brainstem into well-defined, closed areas or parcellation units (PUs). To this end, 10 delimiting planes were identified. To apply this method to T-1 weighted anatomic MR images, brainstem exterior and peduncular borders were defined, planes were identified using a cross-referential morphometric tool, and brainstem subdivision was performed. The resulting segmentation served as the basis for morph...

Fatigue is an extremely debilitating condition in older adults. It is associated with increased mortality and decreased quality of life. Despite the significant negative impact of fatigue, we know very little about its actual cause. Currently, there are...

DMRI methods have shown potential to investigate the in-vivo tissue micro-structure non-invasively. Recent DMRI studies have reported systematic diffusion patterns within the cortex (McNab, J.A. et al. NeuroImage, 2013; Kleinnijenhuis M. et al. Cortex, ...

Traumatic brain injury (TBI) resulting from blast exposure is a relevant and poorly understood human condition and conventional MRI is often unable to detect brain abnormalities following blast. Diffusion MRI (dMRI) approaches are promising for their ab...

Advancements in development of effective pain-relief therapies in acute and chronic pain conditions are of utmost importance to alleviate the suffering of the patients and lift the socio-economic burden of the disorders that involve nociceptive system. ...