title: Study of neurovascular coupling in humans via simultaneous magnetoencephalography and diffuse optical imaging acquisition.
abstract: By combining diffuse optical imaging (DOI) and magnetoencephalography (MEG) we investigate neurovascular coupling non-invasively in human subjects using median-nerve stimulation. Previous fMRI studies have shown a habituation effect in the hemodynamic blood oxygen level-dependent (BOLD) response for stimulation periods longer than 2 s. With DOI and MEG we can test whether this effect in hemodynamic response can be accounted for by a habituation effect in the neural response. Our experimental results show that the habituation effect in the hemodynamic response is stronger than that in the earliest cortical neural response (N20). Using a linear convolution model to predict hemodynamic responses we found that including late neural components (> or = 30 ms) improves the prediction of the hemoglobin response. This finding suggests that in addition to the initial evoked-response deflections related to the talamic afferent input, later cortical activity is needed to predict the hemodynamic response.
authors.affiliation: Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA. wanmei@mit.edu
authors.forename: Wanmei
authors.initials: W
authors.lastname: Ou
authors.forename: Ilkka
authors.initials: I
authors.lastname: Nissilä
authors.forename: Harsha
authors.initials: H
authors.lastname: Radhakrishnan
authors.forename: David A
authors.initials: DA
authors.lastname: Boas
authors.forename: Matti S
authors.initials: MS
authors.lastname: Hämäläinen
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Franceschini
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008959:Models, Neurological; D010101:Oxygen Consumption / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D055815:Young Adult