5 June 2002 Extraction of fast neuronal changes from multichannel functional near-infrared spectroscopy signals using independent component analysis
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Proceedings Volume 4623, Functional Monitoring and Drug-Tissue Interaction; (2002) https://doi.org/10.1117/12.469474
Event: International Symposium on Biomedical Optics, 2002, San Jose, CA, United States
Abstract
Fast changes in the range of milliseconds in the optical properties of cerebral tissue, which are associated with brain activity, can be detected using non-invasive near-infrared spectroscopy (NIRS). These changes in light scattering are due to an alteration in the refractive index at neuronal membranes. The aim of this study was to develop highly sensitive data analysis algorithms to detect this fast signal, which is small compared to other physiological signals. A frequency-domain tissue oximeter, whose laser diodes were modulated at 110MHz was used. The amplitude, mean intensity and phase of the modulated optical signal was measured at 96Hz sample rate. The probe consisting of 4 crossed source detector pairs was placed above the motor cortex, contralateral to the hand performing a tapping exercise consisting of alternating rest- and tapping periods of 20s each. The tapping frequency, which was set to 3.55Hz or 2.5 times the heart rate of the subject to avoid the influence of harmonics on the signal, could not be observed in any of the individual signals measured by the detectors. An adaptive filter was used to remove the arterial pulsatility from the optical signals. Independent Component Analysis allowed to separate signal components in which the tapping frequency was clearly visible.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Geert Morren, Geert Morren, Martin Wolf, Martin Wolf, Philippe Lemmerling, Philippe Lemmerling, Ursula Wolf, Ursula Wolf, Jee Hyun Choi, Jee Hyun Choi, Enrico Gratton, Enrico Gratton, Lieven De Lathauwer, Lieven De Lathauwer, Sabine Van Huffel, Sabine Van Huffel, } "Extraction of fast neuronal changes from multichannel functional near-infrared spectroscopy signals using independent component analysis", Proc. SPIE 4623, Functional Monitoring and Drug-Tissue Interaction, (5 June 2002); doi: 10.1117/12.469474; https://doi.org/10.1117/12.469474
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