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Mechanisms of the breathing contribution to bodily self-consciousness in healthy humans: Lessons from machine-assisted breathing?

ABSTRACT: Previous studies investigated bodily self-consciousness (BSC) by experimentally exposing subjects to multisensory conflicts (i.e., visuo-tactile, audio-tactile, visuo-cardiac) in virtual reality (VR) that involve the participant's torso in a paradigm known as the full-body illusion (FBI). Using a modified FBI paradigm, we found that synchrony of visuo-respiratory stimulation (i.e., a flashing outline surrounding an avatar in VR; the flash intensity depending on breathing), is also able to modulate BSC by increasing self-location and breathing agency toward the virtual body. Our aim was to investigate such visuo-respiratory effects and determine whether respiratory motor commands contributes to BSC, using non-invasive mechanical ventilation (i.e., machine-delivered breathing). Seventeen healthy participants took part in a visuo-respiratory FBI paradigm and performed the FBI during two breathing conditions: (a) "active breathing" (i.e., participants actively initiate machine-delivered breaths) and (b) "passive breathing" (i.e., breaths' timing was determined by the machine). Respiration rate, tidal volume, and their variability were recorded. In line with previous results, participants experienced subjective changes in self-location, breathing agency, and self-identification toward the avatar's body, when presented with synchronous visuo-respiratory stimulation. Moreover, drift in self-location was reduced and tidal volume variability were increased by asynchronous visuo-respiratory stimulations. Such effects were not modulated by breathing control manipulations. Our results extend previous FBI findings showing that visuo-respiratory stimulation affects BSC, independently from breathing motor command initiation. Also, variability of respiratory parameters was influenced by visuo-respiratory feedback and might reduce breathing discomfort. Further exploration of such findings might inform the development of respiratory therapeutic tools using VR in patients.

SUBMITTER: Betka S

PROVIDER: S-EPMC7507190 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Mechanisms of the breathing contribution to bodily self-consciousness in healthy humans: Lessons from machine-assisted breathing?

Betka Sophie S Canzoneri Elisa E Adler Dan D Herbelin Bruno B Bello-Ruiz Javier J Kannape Oliver Alan OA Similowski Thomas T Blanke Olaf O

Psychophysiology 20200312 8

Previous studies investigated bodily self-consciousness (BSC) by experimentally exposing subjects to multisensory conflicts (i.e., visuo-tactile, audio-tactile, visuo-cardiac) in virtual reality (VR) that involve the participant's torso in a paradigm known as the full-body illusion (FBI). Using a modified FBI paradigm, we found that synchrony of visuo-respiratory stimulation (i.e., a flashing outline surrounding an avatar in VR; the flash intensity depending on breathing), is also able to modula ...[more]

PMID: 32162704

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Project description:Background: Asymmetric ?-carotene, a provitamin A carotenoid, is cleaved to produce retinol (vitamin A) and ?-retinol (with negligible vitamin A activity). The vitamin A activity of ?-carotene-containing foods is likely overestimated because traditional analytic methods do not separate ?-retinol derivatives from active retinol.Objective: This study aimed to accurately characterize intestinal ?-carotene cleavage and its relative contribution to postprandial vitamin A in humans after consumption of raw carrots.Design: Healthy adults (n = 12) consumed a meal containing 300 g raw carrot (providing 27.3 mg ?-carotene and 18.7 mg ?-carotene). Triglyceride-rich lipoprotein fractions of plasma were isolated and extracted, and ?-retinyl palmitate (?RP) and retinyl palmitate were measured over 12 h postprandially via high-performance liquid chromatography-tandem mass spectrometry. The complete profile of all ?-retinyl esters and retinyl esters was measured at 6 h, and total absorption of ?- and ?-carotene was calculated.Results: ?RP was identified and quantified in every subject. No difference in preference for absorption of ?- over ?-carotene was observed (adjusting for dose, 28% higher, P = 0.103). After absorption, ?-carotene trended toward preferential cleavage compared with ?-carotene (22% higher, P = 0.084). A large range of provitamin A carotenoid conversion efficiencies was observed, with ?-carotene contributing 12-35% of newly converted vitamin A (predicted contribution = 25.5%). In all subjects, a majority of ?-retinol was esterified to palmitic acid (as compared with other fatty acids).Conclusions: ?-Retinol is esterified in the enterocyte and transported in the blood analogous to retinol. The percentage of absorption of ?-carotene from raw carrots was not significantly different from ?-carotene when adjusting for dose, although a trend toward higher cleavage of ?-carotene was observed. The results demonstrate large interindividual variability in ?-carotene conversion. The contribution of newly absorbed ?-carotene to postprandial vitamin A should not be estimated but should be measured directly to accurately assess the vitamin A capacity of ?-carotene-containing foods. This trial was registered at clinicaltrials.gov as NCT01432210.

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Mechanisms of the breathing contribution to bodily self-consciousness in healthy humans: Lessons from machine-assisted breathing?

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Mechanisms of the breathing contribution to bodily self-consciousness in healthy humans: Lessons from machine-assisted breathing?

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