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ORIGINAL RESEARCH article

Front. Physiol.
Sec. Environmental, Aviation and Space Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1425302

Short-term microgravity effects simulation does not affect fNIRS measures of cerebral oxygenation changes induced by cognitive load

Provisionally accepted
Vsevolod Peysakhovich Vsevolod Peysakhovich 1*Thibault Kiehl Thibault Kiehl 1,2Lucia Vicente Martinez Lucia Vicente Martinez 3Laure Boyer Laure Boyer 2,3Mickael Causse Mickael Causse 1Alexis Paillet Alexis Paillet 2Anne Pavy-Le Traon Anne Pavy-Le Traon 3,4
  • 1 Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Toulouse, France
  • 2 Centre National d’Etudes Spatiales (CNES), Paris, France
  • 3 Medes (France), Toulouse, France
  • 4 Centre Hospitalier Universitaire de Toulouse, Toulouse, Occitanie, France

The final, formatted version of the article will be published soon.

    In the past decade, there has been a surge in interest in space exploration studies, particularly due to the prospect of exploring distant planets such as Mars. However, long-duration space missions may pose cognitive challenges resulting from spaceflight-induced perceptual and motor changes, prolonged cephalic fluid shifts, and high cognitive load. One method for monitoring cognitive activity is functional near-infrared spectroscopy (fNIRS), a technique not yet tested under prolonged microgravity conditions beyond parabolic flight periods. Since fNIRS relies on cerebral oxygenation levels, should we adjust it for the fluid shift? To address this, the study explores the impact of simulated microgravity on cerebral oxygenation measures using fNIRS during a cognitive task, employing head-down tilt at different inclination levels and the Toulouse N-back Task (assessing memory and mental calculation) with varying difficulty levels. Eighteen subjects participated in the experiment. The results indicated that increasing difficulty levels of the cognitive task led to decreased accuracy, longer response times, and higher perceived difficulty scores. The inclination levels did not affect task performance. Increased difficulty was also concomitant with increasing HbO and decreasing HbR concentrations unaffected by the head-down tilt angle variations. These promising findings suggest that fNIRS measures could be used under microgravity conditions to measure cognitive load without correction for fluid shift.

    Keywords: fNIRS, Cognitive Load, cerebral oxygenation, Head-Down Tilt, n-back

    Received: 29 Apr 2024; Accepted: 24 Jan 2025.

    Copyright: © 2025 Peysakhovich, Kiehl, Martinez, Boyer, Causse, Paillet and Pavy-Le Traon. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Vsevolod Peysakhovich, Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Toulouse, France

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