Cytochrome-c-oxidase redox changes during visual stimulation measured by near-infrared spectroscopy cannot be explained by a mere cross talk artefact

Uludağ, Kâmil; Steinbrink, Jens; Kohl‐Bareis, Matthias; Wenzel, Rüdiger; Villringer, Arno; Obrig, Hellmuth

doi:10.1016/j.neuroimage.2003.09.053

Cited by 40 publications

(34 citation statements)

References 28 publications

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“…It has been claimed that chromophore cross-talk, insufficient separability due to physical noise, and any concurrent changes in scattering can all give rise to spurious ∆[oxCCO] traces [12,22]. Yet, recent studies disprove these claims and establish ∆[oxCCO] as a NIRS-derived indicator of the redox state of mitochondrial cytochrome c oxidase and hence as a brain-specific optical biomarker of cerebral metabolic status [5,[8][9][10][11]14,15,32,33]. Also note that our study employs a restrictive wavelength range of 780-900 nm; exclusion of shorter wavelengths helps to enhance the contribution of cytochrome c oxidase to attenuation signals [14].…”

Section: Discussionmentioning

confidence: 99%

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

Arifler

Zhu

Madaan

et al. 2015

Biomed. Opt. Express

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Abstract:We analyze broadband near-infrared spectroscopic measurements obtained from newborn piglets subjected to hypoxia-ischemia and we aim to identify optimal wavelength combinations for monitoring cerebral tissue chromophores. We implement an optimization routine based on the genetic algorithm to perform a heuristic search for discrete wavelength combinations that can provide accurate concentration information when benchmarked against the gold standard of 121 wavelengths. The results indicate that it is possible to significantly reduce the number of measurement wavelengths used in conjunction with spectroscopic algorithms and still achieve a high performance in estimating changes in concentrations of oxyhemoglobin, deoxyhemoglobin, and oxidized cytochrome c oxidase. While the use of a 3-wavelength combination leads to mean recovery errors of up to 10%, these errors drop to less than 4% with 4 or 5 wavelengths and to even less than 2% with 8 wavelengths.

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Section: Discussionmentioning

confidence: 99%

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

Arifler

Zhu

Madaan

et al. 2015

Biomed. Opt. Express

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“…The UCLn algorithm (1) was used to convert the attenuation change measured across 108 wavelengths (from 780nm to 900nm) to concentration changes of chromophores applying the Modified Beer-Lambert Law (MBLL) [10, 30]. UCLn algorithm is a least-squares fitting procedure, finding the best fit of chromophore concentration changes based on the chromophores’ extinction coefficients and the measured attenuation changes over n number of wavelengths.…”

Section: Methodsmentioning

confidence: 99%

“…Previously, we have extensively described an optimized NIRS approach for the detection of Δ[oxCCO] using broadband spectroscopy (780 – 900nm) [7]. This approach addresses specific challenges of detecting this chromophore: 1) its concentration is less than 10% of haemoglobin concentration and 2) risk of crosstalk artefact between chromophores with overlapping spectra [8–10]. A recent review by Bale and colleagues provides details on the spectral features of CCO, the methodology, analysis techniques as well as a summary of human brain studies regarding the NIRS measurement of cerebral oxCCO in both the healthy and injured brain [11].…”

Section: Introductionmentioning

confidence: 99%

Multi-channel multi-distance broadband near-infrared spectroscopy system to measure the spatial response of cellular oxygen metabolism and tissue oxygenation

Phan¹,

Highton

Lai³

et al. 2016

Biomed. Opt. Express

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We present a multi-channel, multi-distance broadband near-infrared spectroscopy (NIRS) system with the capability of measuring changes in haemoglobin concentrations (Δ[HbO2], Δ[HHb]), oxidation state of cytochrome-c-oxidase (Δ[oxCCO]) and tissue oxygen saturation (TOI) in the adult human brain. The main components of the instrument are two customized spectrographs and two light sources. Each spectrograph is lens-based to improve light throughput, has a grating enhanced to optimise reflection in the near-infrared (NIR) spectral region and uses a front illuminated cooled CCD camera (−70° C) with a square chip dimension of 12.3 x 12.3 mm (512 x 512 pixels). Each light source uses a 50W halogen bulb with a gold plated mirror to increase the intensity of the NIR light. Each light source was connected to a custom-built bifurcated fibre bundle to create two source fibre bundles (3.2 mm diameter each). Each spectrograph received light input from another custom-built fibre bundle comprised of six individual bundles (one with 0.6 mm diameter and the other five with 1.5 mm diameter). All fibre bundles were fixed on a 3D printed optode holder (two light sources x two fibre bundles each = four probes; and two spectrographs x six fibre bundles each = 12 probes) that allowed 24 multi-distance channels across the forehead (six channels at 20 mm, three channels at 30 mm and 15 channels at 35 mm) and six TOI measurements. We demonstrated the use of the system in a cohort of nine healthy adult volunteers during prefrontal cortex functional activation using the Stroop task. We have observed functional responses identified as significant increase in Δ[HbO2], decrease in Δ[HHb] and increase in Δ[oxCCO] in five channels (out of 12), that overlay the left and right dorsolateral prefrontal cortices. There was no observable TOI functional response and we have shown small variations in TOI across different sites within the same subject and within the same site across subjects.

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“…New algorithms are being developed that can help discern the role of Cyt-Ox and its functions during cerebral activity. A recent study reported that the differential stimulation of areas rich and poor in cytochrome-c-oxidase content results in optical changes which cannot be solely explained by the presently available models of cross talk (Uludağ et al, 2004). One of the most renowned studies tackling the physiological question reported that the spectra obtained in a state of increased brain activity cannot be explained solely by the well-known changes in oxyHb and deoxyHb, but must include Cyt-Ox in the analysis.…”

Section: Cytochrome-c Oxidasementioning

confidence: 99%

Functional Near-Infrared Spectroscopy (fNIRS): Principles and Neuroscientific Applications

León-Carrión¹,

León-Domínguez²

2012

Neuroimaging - Methods

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Cytochrome-c-oxidase redox changes during visual stimulation measured by near-infrared spectroscopy cannot be explained by a mere cross talk artefact

Cited by 40 publications

References 28 publications

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

Multi-channel multi-distance broadband near-infrared spectroscopy system to measure the spatial response of cellular oxygen metabolism and tissue oxygenation

Functional Near-Infrared Spectroscopy (fNIRS): Principles and Neuroscientific Applications

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