title: Lamina-dependent calibrated BOLD response in human primary motor cortex.
abstract: Disentangling neural activity at different cortical depths during a functional task has recently generated growing interest, since this would allow to separate feedforward and feedback activity. The majority of layer-dependent studies have, so far, relied on gradient-recalled echo (GRE) blood-oxygenation-level dependent (BOLD) acquisitions, which are weighted towards the large draining veins at the cortical surface. The current study aims to obtain quantitative brain activity responses in the primary motor cortex on a laminar scale without the contamination due to accompanying secondary vascular effects. Evoked oxidative metabolism was evaluated using the Davis model, to investigate its applicability, advantages, and limits in lamina-dependent fMRI. Average values for the calibration parameter, M, and for changes in the cerebral metabolic rate of oxygen consumption (CMRO2) during a unilateral finger-tapping task were (11±2)% and (30±7)%, respectively, with distinct variation features across the cortical depth. The results presented here showed an uncoupling between BOLD-based functional magnetic resonance imaging (fMRI) and metabolic changes across cortical depth, while the tight coupling between CMRO2 and CBV was conserved across cortical layers. We conclude that the Davis model can help to obtain estimates of lamina-dependent metabolic changes without contamination from large draining veins, with high consistency and reproducibility across participants.
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. Electronic address: guidi@cbs.mpg.de.
authors.forename: Maria
authors.initials: M
authors.lastname: Guidi
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Laurentius
authors.initials: L
authors.lastname: Huber
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Leonie
authors.initials: L
authors.lastname: Lampe
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Claudine J
authors.initials: CJ
authors.lastname: Gauthier
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. Electronic address: moeller@cbs.mpg.de.
authors.forename: Harald E
authors.initials: HE
authors.lastname: Möller
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001931:Brain Mapping / Q000379:methods* / Q000592:standards; D002138:Calibration; D002560:Cerebrovascular Circulation / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D010100:Oxygen
keywords: 7T MRI; Calibrated fMRI; Cortical layers; Hypercapnia; Oxygen metabolism; SS-SI-VASO