Spatial Distribution of Changes in Oxidised Cytochrome C Oxidase During Visual Stimulation Using Broadband Near...

Area of Science:

• Neuroscience
• Biomedical Optics
• Cerebral Metabolism

Background:

• Functional hyperaemia, indicated by changes in oxyhaemoglobin [HbO2] and deoxyhaemoglobin [HHb], maps neuronal activity but not metabolic changes.
• Cerebral oxidised cytochrome c oxidase (oxCCO) redox state changes may offer a more specific marker for neuronal metabolic activity.

Purpose of the Study:

• To investigate the spatial distribution of Δ[oxCCO] responses during visual cortex activation in healthy adults.
• To reconstruct images of these metabolic changes and compare their localization with haemodynamic responses.

Main Methods:

• Multi-channel broadband near-infrared spectroscopy (NIRS) was used on four healthy volunteers.
• Spectra (780-900 nm) were analyzed to calculate Δ[HbO2], Δ[HHb], and Δ[oxCCO] using the UCLn algorithm.
• Centre of gravity analysis determined activation centers for each chromophore.

Main Results:

• All subjects exhibited Δ[oxCCO] changes alongside typical visual-evoked haemodynamic responses.
• Image reconstruction revealed clear, spatially localized activation for Δ[HbO2], Δ[HHb], and Δ[oxCCO].
• Centre of gravity analysis indicated distinct spatial localizations for Δ[HbO2], Δ[HHb], and Δ[oxCCO] in the visual cortex.

Conclusions:

• The spatial distribution of the Δ[oxCCO] response is distinct from the haemodynamic response in the human visual cortex.
• Image reconstruction of Δ[oxCCO] shows potential for visualizing regional metabolic variations in various scenarios.