Modeling of Microvascular Effects in Cerebral Cortical Laminar fMRI

BMBF Project

What are the limitations of fMRI and how faithfully can it reflect neural activity? In a three-year US-German project, we will improve our ability to measure neural activity from fMRI through detailed biophysical modelling of the hemodynamic response and corresponding high-resolution MRI measurements.
The group of Jon Polimeni is currently developing the framework for generating realistic microvascular networks and dynamics to simulate hemodynamic responses to neural activity. These networks will allow us to simulate different fMRI contrasts, neuronal activation durations, cortical orientations and vascular densities.
The artificial vessel models will then be combined with real macrovascular architectures derived from very high-resolution MR images and capillary densities estimated from cerebral blood volume (CBV) measurements performed at the 9.4 T in Tübingen. To achieve high robustness against subject motion, a camera-based prospective motion correction system will be used.
Verification of the simulations based on the hybrid models is another important aspect of this project. For this purpose, functional measurements with sub-millimeter resolution will be carried out with different MRI contrasts such as BOLD and CBV and sequences during a simple motor-sensory paradigm at 9.4 T.

Synthetic BOLD predictions on a microvascular reconstruction in mouse brain. Adapted from: Gagnon et al. and Pfannmoeller et al. — Synthetic BOLD predictions on a microvascular reconstruction in mouse brain. Adapted from: Gagnon *et al.* and Pfannmoeller *et al.*

Synthetic BOLD predictions on a microvascular reconstruction in mouse brain. Adapted from: Gagnon *et al.* and Pfannmoeller *et al.*

PIs:

Jonathan R. Polimeni. Martinos Center for Biomedical Imaging, Charlestown, MA

Jonas Bause. Department High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany

Klaus Scheffler. Department High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany