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Cognitive functions and cerebral oxygenation changes during acute and prolonged hypoxic exposure
Karen Davranche1, Laurence Casini2, Pierrick J Arnal3
1Laboratoire de Psychologie Cognitive (LPC), UMR 7290, CNRS, Aix-Marseille Université, FR, 3C FR, 3512, Marseille, France.
Physiology & Behavior
|June 6, 2016
Summary
High altitude exposure impairs cognitive functions like reaction time and accuracy, with prefrontal cortex activity increasing initially. Prolonged exposure affects time perception, possibly due to reduced cortical arousal from hypoxia.
Area of Science:
- Altitude physiology
- Cognitive neuroscience
- Neuroimaging
Background:
- High-altitude exposure presents physiological challenges, including hypoxia.
- Cognitive function and brain activity can be affected by environmental stressors like altitude.
Purpose of the Study:
- To assess cognitive control and time perception during acute and prolonged high-altitude exposure.
- To investigate hemodynamic changes in the prefrontal cortex (PFC) using functional near-infrared spectroscopy (fNIRS).
Main Methods:
- Eleven male subjects were exposed to 4350 meters for 4 days.
- Cognitive tasks (conflict, temporal bisection) and fNIRS monitoring of PFC were conducted at sea level and at high altitude (D0, D2, D4).
Main Results:
- High altitude initially slowed reaction times and doubled decision errors.
- Increased PFC activity (fNIRS signals) was observed early on, potentially counteracting performance decline.
- Time perception was underestimated during prolonged exposure, suggesting a slowed internal clock; cognitive control remained intact.
Conclusions:
- Hypoxia at high altitude impacts cognitive processing speed and accuracy.
- Reduced cortical arousal may explain altered time perception and persistent errors.
- While cognitive control was preserved, prolonged hypoxia affects temporal judgments and overall cognitive performance.
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