Functional NIRS Measurement of Cytochrome-C-Oxidase Demonstrates a More Brain-Specific Marker of Frontal Lobe Activation Compared to the Haemoglobins

Isabel de Roever, Gemma Bale, Robert J Cooper, Ilias Tachtsidis, Isabel de Roever, Gemma Bale, Robert J Cooper, Ilias Tachtsidis

Abstract

Functional near-infrared spectroscopy (fNIRS) is an increasingly common neuromonitoring technique used to observe evoked haemodynamic changes in the brain in response to a stimulus. The measurement is typically in terms of concentration changes of oxy- (∆HbO2) and deoxy- (∆HHb) haemoglobin. However, noise from systemic fluctuations in the concentration of these chromophores can contaminate stimulus-evoked haemodynamic responses, leading to misinterpretation of results. Short-separation channels can be used to regress out extracerebral haemodynamics to better reveal cerebral changes, significantly improving the reliability of fNIRS. Broadband NIRS can be used to additionally monitor concentration changes of the oxidation state of cytochrome-c-oxidase (∆oxCCO). Recent studies have shown ∆oxCCO to be a depth-dependent and hence brain-specific signal. This study aims to investigate whether ∆oxCCO can produce a more robust marker of functional activation. Continuous frontal lobe NIRS measurements were collected from 17 healthy adult volunteers. Short 1 cm source-detector separation channels were regressed from longer separation channels in order to minimise the extracerebral contribution to standard fNIRS channels. Significant changes in ∆HbO2 and ∆HHb were seen at 1 cm channels but were not observed in ∆oxCCO. An improvement in the haemodynamic signals was achieved with regression of the 1 cm channel. Broadband NIRS-measured concentration changes of the oxidation state of cytochrome-c-oxidase has the potential to be an alternative and more brain-specific marker of functional activation.

Keywords: Cytochrome-c-oxidase; Functional activation; Haemodynamics; Near-infrared spectroscopy; Short-separation regression.

Figures

Fig. 19.1
Fig. 19.1
(a) Probe holdersFunctional near-infrared spectroscopy (fNIRS) with source and 4 detectors. (b) Diagram showing probe placement
Fig. 19.2
Fig. 19.2
Functional near-infrared spectroscopy (fNIRS) of mean for 17 subjects during functional activation for left and right sides (a) without regression (b) with short-separation regression. Stimulus period indicated by grey background

References

    1. Tachtsidis I, Scholkmann F (2016) False positives and false negatives in functional near-infrared spectroscopy : issues, challenges, and the way forward. Neurophotonics 3:030401–1 – 030401–6
    1. Brigadoi S, Cooper RJ (2015) How short is short? Optimum source–detector distance for short-separation channels in functional near-infrared spectroscopy. Neurophotonics 2:025005–1–02005–9
    1. Saager RB, Telleri NL, Berger AJ. Two-detector corrected near infrared spectroscopy (C-NIRS) detects hemodynamic activation responses more robustly than single-detector NIRS. NeuroImage. 2011;55:1679–1685. doi: 10.1016/j.neuroimage.2011.01.043.
    1. Bainbridge A, Tachtsidis I, Faulkner SD, et al. Brain mitochondrial oxidative metabolism during and after cerebral hypoxia-ischemia studied by simultaneous phosphorus magnetic-resonance and broadband near-infrared spectroscopy. NeuroImage. 2013;102:173–183. doi: 10.1016/j.neuroimage.2013.08.016.
    1. Bale G, Elwell CE, Tachtsidis I (2016) From Jöbsis to the present day: a review of clinical near-infrared spectroscopy measurements of cerebral cytochrome-c-oxidase. J Biomed Opt 21:091307–1–091307–18
    1. Kolyva C, Ghosh A, Tachtsidis I, et al. Cytochrome c oxidase response to changes in cerebral oxygen delivery in the adult brain shows higher brain-specificity than haemoglobin. NeuroImage. 2014;85:234–244. doi: 10.1016/j.neuroimage.2013.05.070.
    1. Bale G, Mitra S, Meek J, et al. A new broadband near-infrared spectroscopy system for in-vivo measurements of cerebral cytochrome-c-oxidase changes in neonatal brain injury. Biomed Opt Express. 2014;5:663–676. doi: 10.1364/BOE.5.003450.
    1. Gagnon L, Cooper RJ, Yücel M, et al. Short separation channel location impacts the performance of short channel regression in NIRS. NeuroImage. 2012;59:2518–2528. doi: 10.1016/j.neuroimage.2011.08.095.
    1. Tachtsidis I, Leung TS, Devoto L, et al. Measurement of frontal lobe functional activation and related systemic effects: a near infrared spectroscopy investigation. Adv Exp Med Biol. 2008;614:397–403. doi: 10.1007/978-0-387-74911-2_44.
    1. Gagnon L, Perdue K, Greve DN, et al. Improved recovery of the hemodynamic response in diffuse optical imaging using short optode separations and state-space modeling. NeuroImage. 2011;56:1362–1371. doi: 10.1016/j.neuroimage.2011.03.001.

Source: PubMed

Sponsors and Collaborators

Medical Conditions

Drug Interventions

3
Subscribe