Continuous coloured light altered human brain haemodynamics and oxygenation assessed by systemic physiology augmented functional near-infrared spectroscopy

Metz, Andreas; Klein, Sabine D.; Scholkmann, Felix; Wolf, Ursula

doi:10.1038/s41598-017-09970-z

Cited by 32 publications

(38 citation statements)

References 58 publications

(58 reference statements)

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“…We found no changes in indicators of mental effort or vigilance following blue or green (520 nm) light. This was in line with a previous study showing that subjective alertness declined from before to after red but not blue or green (515 nm) light [15]. Accordingly, electroencephalographic experiments showed a rspb.royalsocietypublishing.org Proc.…”

Section: Discussionsupporting

confidence: 92%

Sustained effects of prior red light on pupil diameter and vigilance during subsequent darkness

et al. 2018

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Environmental light can exert potent effects on physiology and behaviour, including pupil size, vigilance and sleep. Previous work showed that these non-image forming effects can last long beyond discontinuation of -wavelength light exposure. The possible functional effects after switching off-wavelength light, however, have been insufficiently characterized. In a series of controlled experiments in healthy adult volunteers, we evaluated the effects of five minutes of intense red light on physiology and performance during subsequent darkness. As compared to prior darkness, prior red light induced a subsequent sustained pupil dilation. Prior red light also increased subsequent heart rate and heart rate variability when subjects were asked to perform a sustained vigilance task during the dark exposure. While these changes suggest an increase in the mental effort required for the task, it could not prevent a post-red slowing of response speed. The suggestion that exposure to intense red light affects vigilance during subsequent darkness, was confirmed in a controlled polysomnographic study that indeed showed a post-red facilitation of sleep onset. Our findings suggest the possibility of using red light as a nightcap.

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Section: Discussionsupporting

confidence: 92%

Sustained effects of prior red light on pupil diameter and vigilance during subsequent darkness

et al. 2018

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“…The results of our analysis demonstrate that we are able to differentiate between hemodynamic activity produced by performing tasks of varying workloads in the case of 2-vs. 3-back and for the 3-back end vs. beginning. This replicates previous findings that fNIRS is capable of determining differences in mental workload exertion induced through varying N-back levels [17][18][19]22,39,[52][53][54][55][56][57][58][59]. Additionally, we found decreased HbT concentrations in the 3-back(e) compared to the 3-back(b), along with increased behavioral responses on the 3-back(e) compared to the 3-back(b).…”

Section: Discussionsupporting

confidence: 91%

Effects of Performance and Task Duration on Mental Workload during Working Memory Task

et al. 2019

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N-back is a working memory (WM) task to study mental workload on the prefrontal cortex (PFC). We assume that the subject’s performance and changes in mental workload over time depends on the length of the experiment. The performance of the participant can change positively due to the participant’s learning process or negatively because of objective mental fatigue and/or sleepiness. In this pilot study, we examined the PFC activation of 23 healthy subjects while they performed an N-back task with two different levels of task difficulty (2-, and 3-back). The hemodynamic responses were analyzed along with the behavioral data (correct answers). A comparison was done between the hemodynamic activation and behavioral data between the two different task levels and between the beginning and end of the 3-back task. Our results show that there is a significant difference between the two task levels, which is due to the difference in task complication. In addition, a significant difference was seen between the beginning and end of the 3-back task in both behavioral data and hemodynamics due to the subject’s learning process throughout the experiment.

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“…56,57 Although our findings are in line with several studies indicating that the right cortices have a stronger response compared to the left ones, some studies have reported no hemispheric differences or even leftward regional lateralization. 33,58 Liu et al 6 demonstrated that right or left regional laterality could be observed across different brain systems depending on multiple genetic or environmental mechanisms.…”

Section: Frontal Cortex Oxygenation Asymmetrymentioning

confidence: 99%

Frontal cerebral oxygenation asymmetry: intersubject variability and dependence on systemic physiology, season, and time of day

2020

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Significance: Our study reveals that frontal cerebral oxygenation asymmetry (FCOA), i.e. a difference in the oxygenation between the right and left prefrontal cortex (PFC), is a real phenomenon in healthy human subjects at rest. Aim: To investigate FCOA, we performed a study with 134 healthy right-handed subjects with the systemic physiology augmented functional near infrared spectroscopy (SPA-fNIRS) approach. Approach: Subjects were measured 2 to 4 times on different days resulting in an unprecedented number of 518 single measurements of the absolute values of tissue oxygen saturation (StO 2) and total hemoglobin concentration ([tHb]) of the right and left PFC. Measurements were performed with frequency-domain functional near-infrared spectroscopy. In addition, the cardiorespiratory parameters were measured simultaneously. Results: We found that (i) subjects showed an FCOA (higher StO 2 on the right PFC), but not for tHb; (ii) intrasubject variability was excellent for both StO 2 and tHb, and fair for FCOA; (iii) StO 2 correlated significantly with blood CO 2 concentration, [tHb] with heart rate, respiration rate (RR), and the pulse-respiration quotient (PRQ), and FCOA with RR and PRQ; (iv) FCOA and StO 2 were dependent on season and time of day, respectively; (v) FCOA was negatively correlated with the room temperature; and (vi) StO 2 and tHb were not correlated with the subjects mood but with their chronotype, whereas FCOA was not dependent on the chronotype. Conclusion: Our study demonstrates that FCOA is real, and it provides unique insights into this remarkable phenomenon.

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Continuous coloured light altered human brain haemodynamics and oxygenation assessed by systemic physiology augmented functional near-infrared spectroscopy

Cited by 32 publications

References 58 publications

Sustained effects of prior red light on pupil diameter and vigilance during subsequent darkness

Sustained effects of prior red light on pupil diameter and vigilance during subsequent darkness

Effects of Performance and Task Duration on Mental Workload during Working Memory Task

Frontal cerebral oxygenation asymmetry: intersubject variability and dependence on systemic physiology, season, and time of day

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