Changes in cognitive function and latent processes of decision-making during incremental ascent to high altitude

Lefferts, Wesley K.; DeBlois, Jacob P.; White, Corey N.; Day, Trevor A.; Heffernan, Kevin S.; Brutsaert, Tom D.

doi:10.1016/j.physbeh.2019.01.002

Cited by 26 publications

(21 citation statements)

References 39 publications

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“…It has been shown that HH can shorten escape latency and target quadrant residence time, and reduce the number of crossings of the target quadrant in the MWM, which suggests that spatial learning and memory ability are reduced. [1,3,17] In accordance with previous studies, we found that after 5 days of acquisition training, the ability of all of the rats to locate the platform had improved. However, compared with rats housed in a normobaric normoxia environment, rats exposed to HH for 4 weeks had a significantly longer escape latency ( P < 0.05), while there was no significant between-group difference in the average swimming speed.…”

Section: Discussionsupporting

confidence: 90%

“…The main factors leading to HH-induced changes in cognitive function include oxidative stress and neuronal pathology. [1–5] Magnetic resonance imaging (MRI) has been applied to investigate structural and functional changes in humans exposed to high altitudes, which can enhance our understanding of HH-related cognitive impairment and provide objective indicators for precision medicine. HH has been reported to induce changes in gray matter volume and white matter fiber bundle function, and has been associated with abnormal activity of functional brain regions.…”

Section: Introductionmentioning

confidence: 99%

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Abnormal brain activity in rats with sustained hypobaric hypoxia exposure

Yuan

Wang

Liu

et al. 2019

Chinese Medical Journal

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Background:Hypobaric hypoxia (HH) exposure at high altitudes can result in a decline in cognitive function, which may have a serious impact on the daily life of people who migrate to high altitudes. However, the specific HH-induced changes in brain function remain unclear. This study explored changes in brain activity in rats exposed to a sustained HH environment using functional magnetic resonance imaging (fMRI).Methods:Healthy male rats (8 weeks old) were randomly divided into a model group and a control group. A rat model of cognitive impairment induced by sustained HH exposure was established. The control and model groups completed training and testing in the Morris water maze (MWM). A two-sample t-test for between-group difference comparisons was performed. Repeated measures analyses of variance for within-group comparisons were performed and post-hoc comparisons were made using the Tukey test. Between-group differences in spontaneous brain activity were assessed using a voxel-wise analysis of resting-state fMRI (rs-fMRI), combined with analyses of the fractional amplitude of low frequency fluctuations (fALFF) in statistical parametric mapping.Results:In the MWM test, the escape latencies of the model group were significantly longer compared with those of the control group (control group vs. model group, day 1: 21.6 ± 3.3 s vs. 40.5 ± 3.4 s, t = –11.282; day 2: 13.5 ± 2.2 s vs. 28.7 ± 5.3 s, t = –7.492; day 3: 10.5 ± 2.8 s vs. 22.6 ± 6.1 s, t = –5.099; day 4: 9.7 ± 2.5 s vs. 18.6 ± 5.2 s, t = –4.363; day 5: 8.8 ± 2.7 s vs. 16.7 ± 5.0 s, t = –3.932; all P < 0.001). Within both groups, the escape latency at day 5 was significantly shorter than those at other time points (control group: F = 57.317, P < 0.001; model group: F = 50.718, P < 0.001). There was no within-group difference in average swimming speed (control group, F = 1.162, P = 0.956; model group, F = 0.091, P = 0.880). Within the model group, the time spent within the original platform quadrant was significantly shorter (control group vs. model group: 36.1 ± 5.7 s vs. 17.8 ± 4.3 s, t = 7.249, P < 0.001) and the frequency of crossing the original platform quadrant was significantly reduced (control group vs. model group: 6.4 ± 1.9 s vs. 2.0 ± 0.8 s, t = 6.037, P < 0.001) compared with the control group. In the rs-fMRI study, compared with the control group, rats in the model group showed widespread reductions in fALFF values throughout the brain.Conclusions:The abnormalities in spontaneous brain activity indicated by the fALFF measurements may reflect changes in brain function after HH exposure. This widespread abnormal brain activity may help to explain and to provide new insights into the mechanism underlying the impairment of brain function under sustained exposure to high altitudes.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Abnormal brain activity in rats with sustained hypobaric hypoxia exposure

Yuan

Wang

Liu

et al. 2019

Chinese Medical Journal

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“…All experimental procedures, conducted in accordance with the Declaration of Helsinki (World Medical Association, 2013), were approved by the Academic Ethical Committee of Brussels (Brussels Alliance for Research and Higher Education, B200-2014-045) and written informed signed consent was sought. Seventeen Caucasian, well educated (Lefferts et al, 2019) male subjects, naïve to high altitude were included in the study. Their mean age was 26.3 ± 8.1 years.…”

Section: Methodsmentioning

confidence: 99%

“…Literature shows mixed findings on cognition function under hyperoxic (Lafere et al, 2016; Brebeck et al, 2017; Germonpre et al, 2017) or hypobaric hypoxic conditions. This depends on duration of exposure, altitude level, individual susceptibility and/or education (Lefferts et al, 2019) and choice of battery testing. Decrease in reaction time (Li et al, 2000) or an increase in decisional errors (Davranche et al, 2016) has been reported.…”

Section: Introductionmentioning

confidence: 99%

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Variation of Cognitive Function During a Short Stay at Hypobaric Hypoxia Chamber (Altitude: 3842 M)

et al. 2019

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Objective To observe the effects of a fast-acute ascent to high altitude on brain cognitive function and transcranial doppler parameters in order to understand the physiological countermeasures of hypoxia. Methods 17 high-altitude-naïve male subjects (mean age was 26.3 ± 8.1 years) participated in the study. We measured Critical Flicker Fusion Frequency (CFFF), blood oxygen saturation, Psychology Experiment Building (PEBL) including three tests (Modified Math Processing Task, Perceptual Vigilance Task, and Time Estimation Task), as well as Cerebral Blood Flow index (CBFi), mean cerebral artery Systolic and diastolic velocities, Cerebral Pulsatility index (CPi), and heart Rate. All were measured at sea level, at least 1 h after arrival at the hypobaric hypoxia equivalent of 3842 m and 1 h after return to sea level. Results Under acute exposure to hypobaric hypoxic conditions, significant decrease in CFFF [42.1 ± 1 vs. 43.5 ± 1.7 Hz at sea level (asl), p < 0.01], CBFi (611 ± 51 vs. 665 ± 71 asl, p < 0.01) and blood oxygen saturation (83 ± 4% vs. 98 ± 1% asl, p < 0.001) as compared to pre-ascent values were observed. Physiological countermeasures to hypoxia could be involved as there was no significant change in neuropsychometric tests, Systolic and Diastolic velocities and CPi. A significant increase in Heart Rate (81 ± 15 bpm vs. 66 ± 15 bpm asl, p < 0.001) was observed. All parameters returned to their basal values 1 h after regaining sea level. Conclusion Hypoxia results in a decrease in CFFF, CBFi and oxygen saturation and in an increase in heart rate. As it decreased, Cerebral Blood Flow index does not seem to be the physiological measurement of choice to hypoxia explaining the maintenance of cognitive performance after acute exposure to hypobaric hypoxia and requires further investigation. Cerebral oxygen delivery and extraction could be one of the underlying mechanisms.

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A review of methods for assessment of cognitive function in high‐altitude hypoxic environments

Fan,

Meng,

Zhu

et al. 2024

Brain and Behavior

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Hypoxic environments like those present at high altitudes may negatively affect brain function. Varying levels of hypoxia, whether acute or chronic, are previously shown to impair cognitive function in humans. Assessment and prevention of such cognitive impairment require detection of cognitive changes and impairment using specific cognitive function assessment tools. This paper summarizes the findings of previous research, outlines the methods for cognitive function assessment used at a high altitude, elaborates the need to develop standardized and systematic cognitive function assessment tools for high‐altitude hypoxia environments.

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Changes in cognitive function and latent processes of decision-making during incremental ascent to high altitude

Cited by 26 publications

References 39 publications

Abnormal brain activity in rats with sustained hypobaric hypoxia exposure

Abnormal brain activity in rats with sustained hypobaric hypoxia exposure

Variation of Cognitive Function During a Short Stay at Hypobaric Hypoxia Chamber (Altitude: 3842 M)

A review of methods for assessment of cognitive function in high‐altitude hypoxic environments

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