Hemodynamic correlates of spontaneous neural activity measured by human whole-head resting state EEG + fNIRS

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Keles, H.O., Barbour, R.L. and Omurtag, A. ORCID: 0000-0002-3773-8506, 2016. Hemodynamic correlates of spontaneous neural activity measured by human whole-head resting state EEG + fNIRS. NeuroImage, 138, pp. 76-87. ISSN 1053-8119

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Official URL: http://doi.org/10.1016/j.neuroimage.2016.05.058

Abstract

The brains of awake, resting human subjects display spontaneously occurring neural activity patterns whose magnitude is typically many times greater than those triggered by cognitive or perceptual performance. Such resting state (RS) activity is thought to reflect the functional organization of the brain. In addition, both evoked and RS activation affect local cerebral hemodynamic properties through processes collectively referred to as neurovascular coupling. This is a major topic of interest due to its relationship with pathological conditions that include hypertension, stroke, subarachnoid hemorrhage, and traumatic brain injury. Its investigation calls for an ability to track both the neural and vascular aspects of brain function. We used scalp electroenc ephalography (EEG) which provided a measure of the electrical potentials generated by cortical postsynaptic currents. Simultaneously we utilized functional near-infrared spectroscopy (NIRS) to continuously monitor hemoglobin concentration changes in superficial cortical layers. The multi-modal signal from 18 healthy adult subjects allowed us to investigate the association of neural activity in a range of frequencies over the whole-head to local changes in hemoglobin concentrations. Our results verified the delayed alpha (8-16 Hz) modulation of hemodynamics in posterior areas known from the literature. They also indicated strong beta (16-32 Hz) modulation of hemodynamics. Analysis revealed, however, that beta modulation was likely generated by the alpha-beta coupling in EEG. Signals from the inferior electrode sites were dominated by scalp muscle related activity. Our study aimed to characterize the phenomena related to neurovascular coupling observable by practical, cost-effective, and non-invasive multi-modal techniques.

Item Type:

Journal article

Publication Title:

NeuroImage

Creators:

Keles, H.O., Barbour, R.L. and Omurtag, A.

Publisher:

Elsevier

Date:

September 2016

Volume:

138