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Near‐infrared study of fluctuations in cerebral hemodynamics during rest and motor stimulation: Temporal analysis and spatial mapping
Author(s) -
Toronov Vlad,
Franceschini Maria Angela,
Filiaci Mattia,
Fantini Sergio,
Wolf Martin,
Michalos Antonios,
Gratton Enrico
Publication year - 2000
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.598943
Subject(s) - rest (music) , hemodynamics , stimulation , medicine , physical medicine and rehabilitation , neuroscience , psychology , cardiology
We have noninvasively studied the motor cortex hemodynamics in human subjects under rest and motor stimulation conditions using a multichannel near‐infrared tissue spectrometer. Our instrument measures optical maps of the cerebral cortex at two wavelengths (758 and 830 nm), with an acquisition time of 160 ms per map. We obtained optical maps of oxy‐ and deoxy‐hemoglobin concentration changes in terms of amplitudes of folding average, power spectrum and coherence at the stimulation repetition frequency, and the phase synchronization index. Under periodic motor stimulation conditions, we observed coherence and frequency or phase synchronization of the local hemodynamic changes with stimulation. Our main findings are the following: (1) The amplitude of the hemodynamic response to the motor stimulation is comparable to the amplitude of the fluctuations at rest. (2) The spatial patterns of the oxy‐ and deoxy‐hemoglobin responses to the stimulation are different. (3) The hemodynamic response to stimulation shows a spatial localization and a level of phase synchronization with the motor stimulation that depends on the stimulation period.