Various MRI approaches have been used to study brain anatomy and function, including novel ways to investigate the brains functional subdivision based on the spatio-temporal structure of spontaneous activity, and ways to reveal microstructural information by studying magnetic susceptibility contrast. Notably, a method to analyze spontaneous brain activity was developed and applied to a publicly available database of fMRI studies. It was demonstrated that, by clustering activity patterns at individual fMRI time frames, brain areas with a functional relationship can be revealed that escape detection by conventional methods. To identify the neurophysiological correlate of these fMRI signals, the analysis method is now being applied to electrical recordings from primate brain. Together with a several other approaches to study spontaneous brain activity, this work has let to a number of publications. AMRI has continued to study brain anatomy by exploiting magnetic susceptibility contrast. A major development over the last year has been the extraction of cellular compartment-specific information in white matter. Magnetic field modeling studies performed by AMRI and two other groups have shown that an anisotropic susceptibility of the myelin sheath will lead to distinct field effects in the various water compartments in white matter, specifically axonal, interstitial, and myelin water. These field effects lead to characteristic signal decay effects that can be observed by multi-echo MRI techniques. Using dedicated experiments on marmoset brain, we have investigated whether analysis of the signal decay curve allows recovering this compartment specific information. One of the goals of this has been to quantify axonal myelination. Promising results in marmosets have led to initial application to healthy human subjects and MS patients, a collaborative project that is ongoing. In parallel, acquisition and analysis techniques are being refined to optimize myelin quantification. One ongoing effort is the use of magnetization transfer contrast to improve the sensitivity, and develop improve understanding of the complex MRI signal generation mechanism in white matter.

Project Start
Project End
Budget Start
Budget End
Support Year
7
Fiscal Year
2013
Total Cost
$1,618,089
Indirect Cost
City
State
Country
Zip Code
van Gelderen, Peter; Jiang, Xu; Duyn, Jeff H (2016) Rapid measurement of brain macromolecular proton fraction with transient saturation transfer MRI. Magn Reson Med :
Mandelkow, Hendrik; de Zwart, Jacco A; Duyn, Jeff H (2016) Linear Discriminant Analysis Achieves High Classification Accuracy for the BOLD fMRI Response to Naturalistic Movie Stimuli. Front Hum Neurosci 10:128
Chang, Catie; Leopold, David A; Schölvinck, Marieke Louise et al. (2016) Tracking brain arousal fluctuations with fMRI. Proc Natl Acad Sci U S A 113:4518-23
Shmueli, K; Dodd, S J; van Gelderen, P et al. (2016) Investigating lipids as a source of chemical exchange-induced MRI frequency shifts. NMR Biomed :
van Gelderen, Peter; Jiang, Xu; Duyn, Jeff H (2016) Effects of magnetization transfer on T1 contrast in human brain white matter. Neuroimage 128:85-95
Chang, Catie; Raven, Erika P; Duyn, Jeff H (2016) Brain-heart interactions: challenges and opportunities with functional magnetic resonance imaging at ultra-high field. Philos Trans A Math Phys Eng Sci 374:
Duyn, Jeff H; Schenck, John (2016) Contributions to magnetic susceptibility of brain tissue. NMR Biomed :
Li, Xiaozhen; van Gelderen, Peter; Sati, Pascal et al. (2015) Detection of demyelination in multiple sclerosis by analysis of [Formula: see text] relaxation at 7 T. Neuroimage Clin 7:709-14
Liu, Xiao; Yanagawa, Toru; Leopold, David A et al. (2015) Arousal transitions in sleep, wakefulness, and anesthesia are characterized by an orderly sequence of cortical events. Neuroimage 116:222-31
Liu, Xiao; Yanagawa, Toru; Leopold, David A et al. (2015) Robust Long-Range Coordination of Spontaneous Neural Activity in Waking, Sleep and Anesthesia. Cereb Cortex 25:2929-38

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