A5009625091- Advanced MRI Techniques and Applications
- Functional Brain Connectivity Studies
- Atomic and Subatomic Physics Research
- Advanced Neuroimaging Techniques and Applications
- Advanced NMR Techniques and Applications
- Medical Imaging Techniques and Applications
- Neural dynamics and brain function
- MRI in cancer diagnosis
- Electron Spin Resonance Studies
- Epilepsy research and treatment
- Neuroscience and Neuropharmacology Research
- Cardiac Imaging and Diagnostics
- Microwave Imaging and Scattering Analysis
- Electrical and Bioimpedance Tomography
- Neurological disorders and treatments
- Ultrasound Imaging and Elastography
- Motor Control and Adaptation
- Neurobiology of Language and Bilingualism
- Visual perception and processing mechanisms
- Wireless Body Area Networks
- Reading and Literacy Development
- Transcranial Magnetic Stimulation Studies
- Cognitive and developmental aspects of mathematical skills
- EEG and Brain-Computer Interfaces
- NMR spectroscopy and applications
University of Minnesota
2015-2024
Resonance Research (United States)
2015-2024
University of Minnesota System
2019-2022
Utrecht University
2020
Rigshospitalet
2020
University Medical Center Utrecht
2020
Copenhagen University Hospital
2020
W. M. Keck Foundation
2019
Twin Cities Orthopedics
2006-2014
University of Minnesota Medical Center
2012
In this study, we used functional MRI (fMRI) at high field (3T) to track the time course of activation in entire basal ganglia circuitry, as well other motor-related structures, during explicit learning a sequence finger movements over month training. Fourteen right-handed healthy volunteers had practice 15 min daily eight moves using left hand. sessions were performed on days 1, 14 and 28. both putamen, decreased with rostrodorsal (associative) regions. contrast, there was significant...
FUNCTIONAL magnetic resonance imaging was used to assess inter-subject variability in the cortical representation of language comprehension processes. Moderately fluent French-English bilinguals were scanned while they listened stories their first (L1 = French) or a second (L2 English) acquired at school after age seven. In all subjects, listening L1 always activated similar set areas left temporal lobe, clustered along superior sulcus. Listening L2, however, highly variable network and...
Abstract We measured cerebral activation with functional magnetic resonance imaging at 3 Tesla while eight healthy volunteers performed various number processing tasks known to be dissociable in brain-lesioned patients: naming, comparing, multiplying, or subtracting single digits. The results revealed the of a circuit comprising bilateral intraparietal, prefrontal, and anterior cingulate components. extension lateralization this was modulated by task demands. intraparietal prefrontal more...
Abstract A landmark of corticostriatal connectivity in nonhuman primates is that cortical connections are organized into a set discrete circuits. Each circuit assumed to perform distinct behavioral functions. In animals, most studies performed using invasive tracing methods, which nonapplicable humans. To test the proposal as multiple circuits humans, we used diffusion tensor imaging axonal tracking, new magnetic resonance technique allows demonstration fiber tracts noninvasive manner....
Abstract This article describes experimental studies performed to demonstrate the feasibility of BOLD fMRI using echo‐planar imaging (EPI) at 7 T and characterize response in humans this ultrahigh magnetic field. Visual stimulation were normal subjects high‐resolution multishot EPI sequences. Changes R arising from visual experimentally determined measurements obtained multiple echo times. The results compared those 4 T. Experimental data indicate that can be reliably field strength both...
RF behavior in the human head becomes complex at ultrahigh magnetic fields. A bright center and a weak periphery are observed images obtained with volume coils, while surface coils provide strong signal periphery. Intensity patterns reported often loosely referred to as "dielectric resonances," modeling studies ascribe them superposition of traveling waves greatly dampened lossy brain tissues, raising questions regarding usage this term. Here we address question experimentally, taking full...
Abstract Transceive array coils, capable of RF transmission and independent signal reception, were developed for parallel, 1 H imaging applications in the human head at 7 T (300 MHz). The coils combine advantages high‐frequency properties lines with classic MR coil design. Because short wavelength frequency 300 MHz, these straightforward to build decouple. sensitivity profiles individual highly asymmetric, as expected this high frequency; however, summed images from all relatively uniform...
High-quality prostate images were obtained with transceiver arrays at 7T after performing subject-dependent local transmit B(1) (B(1) (+)) shimming to minimize (+) losses resulting from destructive interferences. was performed by altering the input phase of individual RF channels based on relative maps rapidly in vivo for each channel an eight-element stripline coil. The phases needed maximize coherence within a limited region around greatly differed those dictated coil geometry and highly...
Neuropsychological studies have revealed different subtypes of dyscalculia, including dissociations between exact calculation and approximation abilities, an impact number size on performance. To understand the origins these effects, we measured cerebral activity with functional MRI at 3 Tesla event-related potentials while healthy volunteers performed approximate tasks small large numbers. Bilateral intraparietal, precentral, dorsolateral superior prefrontal regions showed greater...
Abstract The Hahn spin‐echo (HSE)‐based BOLD effect at high magnetic fields is expected to provide functional images that originate exclusively from the microvasculature. blood contribution dominates HSE contrast low (e.g., 1.5 T), and degrades specificity, highly attenuated because apparent T 2 of venous in an experiment decreases quadratically with increasing field. In contrast, believed arise microvasculature increase supralinearly field strength. this work we report results detailed...
The ability of the right hemisphere to sustain acquisition or recovery language after extensive damage left has been essentially related age at time injury. Better abilities are acquired when insult occurs in early childhood (perinatal insults) compared with later occurrence. However, while previous studies have described neuropsychological pattern development typical cases, neural bases such plasticity remain unexplored. Non-invasive functional MRI (fMRI) is a unique tool assess correlates...
Abstract This work reports the preliminary results of first human images at new high‐field benchmark 9.4T. A 65‐cm‐diameter bore magnet was used together with an asymmetric 40‐cm‐diameter head gradient and shim set. multichannel transmission line (transverse electromagnetic (TEM)) coil driven by a programmable parallel transceiver to control relative phase magnitude each channel independently. These RF field methods facilitated compensation for artifacts attributed destructive interference...
To date, functional 1 H NMR spectroscopy has been utilized to report the time courses of few metabolites, primarily lactate. Benefiting from sensitivity offered by ultra-high magnetic field (7 T), concentrations 17 metabolites were measured in human visual cortex during two paradigms stimulation lasting 5.3 and 10.6 mins. Significant concentration changes approximately 0.2 μmol/g observed for several metabolites: lactate increased 23% ± 5% ( P < 0.0005), glutamate 3% 1% 0.01), whereas...
OBJECTIVE: Although the brain areas involved in emotional response and recognition of others' emotions have been reported, neural bases individual differences affective style remain to be elucidated. Alexithymia, i.e., impairment ability identify communicate one's state, influences how are regulated. Alexithymia has hypothesized involve anterior cingulate dysfunction. Therefore, authors searched for differential cerebral regional activation stimuli subjects with alexithymia. METHOD: Two...
In this study, we examined how the motor, premotor and associative basal ganglia territories process movement parameters such as complexity frequency of movement. Twelve right-handed volunteers were studied using EPI BOLD contrast (3 T) while performing audio-paced finger tapping tasks designed to differentiate territories. Tasks varied (repetitive index tapping, simple sequence movements complex 10 moves) (from 0.5 3 Hz). Activation maps coregistered onto a 3-D brain atlas derived from...
Abstract In functional magnetic resonance imaging (fMRI), it is known that physiological influences such as cardiac pulsation, respiration, and brain motion can induce fluctuations in signal intensity phase. Some of the mechanisms potentially involved those phenomena are expected to be amplified at higher fields. This study addresses issue B 0 induced by susceptibility changes during respiration attributed movements chest diaphragm, variations oxygen concentration. It demonstrated...
In functional magnetic resonance imaging, a rapid method such as echo-planar (EPI) or spiral is used to collect dynamic series of images. These techniques are sensitive changes in frequency which can arise from respiration and more significant at high fields. To decrease the noise respiration-induced phase fluctuations, simple correction "dynamic off-resonance k-space" (DORK) was developed. The uses information center k-space navigator echo illustrated with scans single-shot segmented EPI...
The present study has investigated interaction at the cortical level in human between two major components of flavor perception, pure chemical gustatory and lingual somatosensory perception. Twelve subjects participated a functional magnetic resonance imaging tasted six stimuli, applied on whole tongue, among which four were stimuli (NaCl, aspartame, quinine HCl, pH 2.4 or 2.2) both taste i.e. somato-gustatory (HCl, 1.6 1.5, aluminum potassium sulfate). Functional images acquired with an...