title: Illuminating the BOLD signal: combined fMRI-fNIRS studies.
abstract: Functional magnetic resonance imaging (fMRI) is currently combined with electrophysiological methods to identify the relationship between neuronal activity and the blood oxygenation level-dependent (BOLD) signal. Several processes like neuronal activity, synaptic activity, vascular dilation, blood volume and oxygenation changes underlie both response modalities, that is, the electrophysiological signal and the vascular response. However, accessing single process relationships is absolutely mandatory when aiming at a deeper understanding of neurovascular coupling and necessitates studies on the individual building blocks of the vascular response. Combined fMRI and functional near-infrared spectroscopy studies have been performed to validate the correlation of the BOLD signal to the hemodynamic changes in the brain. Here we review the current status of the integration of both technologies and judge these studies in the light of recent findings on neurovascular coupling.
authors: Clinic of Neurology, Charité Universitaetsmedizin, 10098 Berlin, Germany. jens.steinbrink@charite.de
authors: Jens
authors: J
authors: Steinbrink
authors: Arno
authors: A
authors: Villringer
authors: Florian
authors: F
authors: Kempf
authors: Daniel
authors: D
authors: Haux
authors: Stefanie
authors: S
authors: Boden
authors: Hellmuth
authors: H
authors: Obrig