High-Field Magnetic Resonance

Magnetic Fingerprints of Thinking

Our goal is the development and application of novel magnetic resonance techniques at very high magnetic fields to specifically probe the anatomical and functional microstructure of the brain. We aim to understand how physiological processes and microstructure impact the measured resonance signal, and how these magnetic fingerprints can be used to reliably detect brain activation.

Magnetic Resonance Imaging is currently the only imaging method able to cover the entire human brain at a spatial resolution of about 1 millimeter and a temporal resolution of about 1 second (using ultra high-field systems). This roughly corresponds to a data rate of 10⁷ to 10⁸ bits/s (extracted noninvasively from the working brain), one to several orders of magnitude more than any other neuroimaging technology.
One of the major current and future challenges is to relate these magnetic resonance signals to patterns of underlying neuronal processes.

Brain activation is (sometimes) reflected in changes of the acquired magnetic resonance (MR) signal, and, depending on the selected acquisition method, may reflect underlying neuronal activation, or just very unspecific changes in local blood oxygenation or flow. The magnetic fingerprint of neuronal activation strongly depends on local physiological processes and on the underlying microscopic composition of the neuronal tissue and microvascular architecture and dynamics. An important step towards a better understanding of MR signal formation in neuronal tissue will be achieved with multimodal integrated micro devices composed of MR detectors, optical and electrical detectors with the size of only a few hundreds of micrometers. Along these lines, we also try to assess the spatial limit of functional MRI at ultra-high fields, and whether it is possible at all to reliably detect subunits of the primary cortex such as layers or columns.
We are convinced that our research will help understand and extract reliable and novel magnetic fingerprints of neuronal tissue, a prerequisite to analyze and understand the healthy and diseased human brain.

Research Fields of the Department

Fingerprints of Neuronal Activation

We work towards a more specific understanding of the measured MR signal during brain activation, the variability of this contrast across different cortical and subcortical regions, its dependence on the underlying structure and shape of the microvasculature, and the correlation of this contrast to neuronal activation as a function of spatial and temporal resolution.

Structural and Metabolic Brain Imaging

Brain activation is (sometimes) reflected in changes of the acquired MR signal, and depending on the selected acquisition method, may reflect underlying neuronal activation, or just very unspecific changes in local blood oxygenation or flow.

MR Technology

MRI at extremely high fields requires a major effort in technical developments. A significant part of our research is thus devoted to capture as much as possible of the tiny magnetic waves emitted from the excited brain.

Neuroinformatics

Since its invention more than 20 years ago, functional Magnetic Resonance Imaging (fMRI) has played a central role in cognitive neuroscience. The aim of our research is to develop new mathematical methods for the analysis of both standard fMRI data (3 Tesla) as well as ultra-high field fMRI data (≥ 7 Tesla).