Fast cerebral functional signal in the 100-ms range detected in the visual cortex by frequency-domain near-infrared spectrophotometry

Title
Fast cerebral functional signal in the 100-ms range detected in the visual cortex by frequency-domain near-infrared spectrophotometry
Authors
최지현Martin WolfEnrico GrattonUrsula WolfVladislav ToronovL. Adelina PaunescuAntonios Michalos
Issue Date
2003-07
Publisher
Psychophysiology
Citation
VOL 40, NO 4-528
Abstract
Brain activity is associated with physiological changes, which alter the optical properties of the tissue in the near-infrared part of the spectrum. Two major types of optical signals following functional brain activation can be distinguished: a slow signal due to hemodynamic changes and a fast signal, which is directly related to neuronal activity. The fast signal is small and therefore difficult to detect. We used a specially noise-optimized frequency-domain near-infrared spectrometer with a pi-sensor, which was expected to be particularly sensitive to deeper tissue layers, to investigate the human visual cortex during visual stimulation generated by a checkerboard. We were able to detect significant fast signals in single light bundles, but not in pi-signals. The fast signals were mostly collocated with strong slow hemodynamic signals, but showed a higher degree of localization than the latter. The latencies of 40 +/- 16 ms of the fast signals were similar between locations. Our results also indicate that the brain responds differently to a single and double (forth and back) reversal of the checkerboard, with a stronger reaction upon the double reversal.
URI
http://pubs.kist.re.kr/handle/201004/70188
ISSN
0048-5772
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KIST Publication > Article
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