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Journal of Biomedical Optics • Open Access

Noninvasive detection of functional brain activity with near-infrared diffusing-wave spectroscopy
Author(s): Jun Li; Gregor Dietsche; Diana Iftime; Sergey E. Skipetrov; Georg Maret; Thomas Elbert; Brigitte Rockstroh; Thomas Gisler

Paper Abstract

We use near-infrared dynamic multiple scattering of light [diffusing-wave spectroscopy (DWS)] to detect the activation of the somato-motor cortex in 11 right-handed volunteers performing a finger opposition task separately with their right and left hands. Temporal autocorrelation functions g(1)(r,) of the scattered light field are measured during 100-s periods of motor task alternating with 100-s resting baseline periods. From an analysis of the experimental data with an analytical theory for g(1)(r,) from a three-layer geometry with optical and dynamical heterogeneity representing scalp, skull, and cortex, we obtain quantitative estimates of the diffusion coefficient in cortical regions. Consistent with earlier results, the measured cortical diffusion coefficient is found to be increased during the motor task, with a strong contralateral and a weaker ipsilateral increase consistent with the known brain hemispheric asymmetry for right-handed subjects. Our results support the interpretation of the increase of the cortical diffusion coefficient during finger opposition being due to the functional increase in cortical blood flow rate related to vasodilation.

Paper Details

Date Published: 1 July 2005
PDF: 12 pages
J. Biomed. Opt. 10(4) 044002 doi: 10.1117/1.2007987
Published in: Journal of Biomedical Optics Volume 10, Issue 4
Show Author Affiliations
Jun Li, Univ. Konstanz (Germany)
Gregor Dietsche, Univ. Konstanz (Germany)
Diana Iftime, Univ. Konstanz (Germany)
Sergey E. Skipetrov, Univ. Joseph Fourier (France)
Georg Maret, Univ. Konstanz (Germany)
Thomas Elbert, Univ. Konstanz (Germany)
Brigitte Rockstroh, Univ. Konstanz (Germany)
Thomas Gisler, Univ. Konstanz (Germany)

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