Research output

Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMR02

Research output: Contribution to journalReview articleAcademicpeer-review

Associated researcher

Associated organisations

Abstract

Functional magnetic resonance imaging (fMRI) using the blood oxygenation level-dependent (BOLD) contrast indirectly probes neuronal activity changes via evoked cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMR02) changes. The gradient-echo BOLD signal is mostly sensitive to ascending veins in the tissue and to pial veins. Thereby, the achievable spatial specificity to neuronal activation is limited. Furthermore, the non-linear interaction of CBF, CBV and CMR02 can hamper quantitative interpretations of the BOLD signal across cortical depths with different baseline physiology. Measuring CBF, CBV or CMR02 directly on a depth-dependent level has the potential to overcome these limitations. Here, we review these candidates of physiologically well-defined contrasts with the particular focus on arterial spin labeling (ASL), vascular space occupancy (VASO) and calibrated fMRI. These methods are reviewed with respect to their fMRI sequence parameter space and the applicability for neuroscientific studies in humans. We show representative results of depth-dependent 'non-BOLD-fMRI' in humans and their spatiotemporal characteristics. We conclude that non-BOLD methods are promising alternatives compared to conventional fMRI as they can provide improved spatial specificity, quantifiability and, hence, physiological interpretability as a function of cortical depth. At submillimeter resolution with inherently low signal-to-noise ratio (SNR), however, their use is still challenging. Nevertheless, we believe that 'non-BOLD-fMRI' is a useful alternative for depth-dependent investigations, by providing valuable insights into neurovascular coupling models that facilitate the interpretability of fMRI for neuroscientific applications.

    Research areas

  • CEREBRAL BLOOD-VOLUME, HIGH-RESOLUTION FMRI, KETOGLUTARATE GLUTAMATE EXCHANGE, MAGNETIC-RESONANCE-SPECTROSCOPY, OXYGEN EXTRACTION FRACTION, CALIBRATED FUNCTIONAL MRI, CENTRAL-NERVOUS-SYSTEM, TIDAL CARBON-DIOXIDE, LAYER-DEPENDENT BOLD, SPIN-ECHO BOLD
View graph of relations

Details

Original languageEnglish
Pages (from-to)742-760
Number of pages19
JournalNeuroimage
Volume197
Early online date20 Jul 2017
DOIs
Publication statusPublished - 15 Aug 2019