title: Noninvasive assessment of changes in cytochrome-c oxidase oxidation in human subjects during visual stimulation.
abstract: In this study the authors used a whole-spectrum near-infrared spectroscopy approach to noninvasively assess changes in hemoglobin oxygenation and cytochrome-c oxidase redox state (Cyt-Ox) in the occipital cortex during visual stimulation. The system uses a white light source (halogen lamp). The light reflected from the subject's head is spectrally resolved by a spectrograph and dispersed on a cooled charge-coupled device camera. The authors showed the following using this approach: (1) Changes in cerebral hemoglobin oxygenation (increase in concentration of oxygenated hemoglobin, decrease in concentration of deoxygenated hemoglobin) in the human occipital cortex during visual stimulation can be assessed quantitatively. (2) The spectral changes during functional activation cannot be completely explained by changes in hemoglobin oxygenation solely; Cyt-Ox has to be included in the analysis. Only if Cyt-Ox is considered can the spectral changes in response to increased brain activity be explained. (3) Cytochrome-c oxidase in the occipital cortex of human subjects is transiently oxidized during visual stimulation. This allows us to measure vascular and intracellular energy status simultaneously.
authors.affiliation: Department of Neurology, Charité, Humboldt-University, Berlin, Germany.
authors.forename: H R
authors.initials: HR
authors.lastname: Heekeren
authors.forename: M
authors.initials: M
authors.lastname: Kohl
authors.forename: H
authors.initials: H
authors.lastname: Obrig
authors.forename: R
authors.initials: R
authors.lastname: Wenzel
authors.forename: W
authors.initials: W
authors.lastname: von Pannwitz
authors.forename: S J
authors.initials: SJ
authors.lastname: Matcher
authors.forename: U
authors.initials: U
authors.lastname: Dirnagl
authors.forename: C E
authors.initials: CE
authors.lastname: Cooper
authors.forename: A
authors.initials: A
authors.lastname: Villringer
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000201:enzymology*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005260:Female; D006452:Hemoglobinometry; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D010775:Photic Stimulation; D019265:Spectroscopy, Near-Infrared
chemical_list: D003576:Electron Transport Complex IV