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Titolo:
Linear aspects of changes in deoxygenated hemoglobin concentration and cytochrome oxidase oxidation during brain activation
Autore:
Wobst, P; Wenzel, R; Kohl, M; Obrig, H; Villringer, A;
Indirizzi:
Humboldt Univ, Charite, Dept Neurol, Berlin, Germany Humboldt Univ Berlin Germany niv, Charite, Dept Neurol, Berlin, Germany
Titolo Testata:
NEUROIMAGE
fascicolo: 3, volume: 13, anno: 2001,
pagine: 520 - 530
SICI:
1053-8119(200103)13:3<520:LAOCID>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
NEAR-INFRARED SPECTROSCOPY; CONTRAST GAIN-CONTROL; STRIATE CORTEX; OPTICAL SPECTROSCOPY; CEREBRAL BLOOD; FUNCTIONAL MRI; VISUAL-CORTEX; HUMAN HEAD; TISSUE; CAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Wobst, P Humboldt Univ, Charite, Dept Neurol, Berlin, Germany Humboldt Univ Berlin Germany ite, Dept Neurol, Berlin, Germany
Citazione:
P. Wobst et al., "Linear aspects of changes in deoxygenated hemoglobin concentration and cytochrome oxidase oxidation during brain activation", NEUROIMAGE, 13(3), 2001, pp. 520-530

Abstract

We used near infrared spectroscopy (NIRS) to investigate the vascular and metabolic response to brain activation in human primary and adjacent secondary visual cortex. NIBS is able to measure concentration changes in deoxygenated hemoglobin ([deoxy-Hb]) (which mainly contribute to the blood oxygenation level-dependent (BOLD) signal in functional magnetic resonance imaging(fMRI)) as well as concentration changes of oxygenated hemoglobin ([oxy-Rb]) and corpuscular-blood volume ([total-Hb] = [oxy-Hb] + [deoxy-Hb]) and changes in the redox status of the cytochrome c oxidase ([Cyt-Ox]), a putative parameter for cellular oxygenation. A sound understanding of the transferfunctions between stimulus parameters, neuronal activity, and vascular/metabolic parameters is important for interpretation of data acquired with indirect neuroimaging techniques like fMRI, especially in event-related designstudies. In the present study we tested whether the vascular/metabolic response to stimulation can be described as a linear and time invariant system. Since linearity is a property attributed to systems that satisfy the scaling and superposition properties, as a first simple test, superposition of the responses obtained from short duration visual stimuli was used to predict the responses of longer duration stimuli. Our results showed that the predictions of [deoxy-Hb] and [Cyt-Ox] responses to stimuli of 6- to 24-s duration were satisfactory whereas predictions of [oxy-Hb] and [total-Hb] wereinsufficient. Ina second step, a calculated convolution function of an assumed impulse response function and the stimulus function was fitted with the measured [deoxy-Hb] and [Cyt-Ox] curves to obtain amplitude, time delay, and time constant parameters. We show that predictions of cellular and vascular oxygenation responses to visual stimulation are good for 6- to 24-s stimuli duration under the assumption of a linear transfer characteristic. This model is not valid for corpuscular volume changes which affect mainly the [deoxy-Hb] response. Noninvasive NIBS is shown to be a suitable method toget more direct information about neuronal-activity-associated changes in cerebral parameters which are partly reflected in BOLD signal but are not fully understood yet. (C) 2001 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/01/20 alle ore 21:31:57