Consistent differences in brain structure and functional connectivity in high-altitude native Tibetans and
Xinjuan Zhang1, Weiwei Xie2, Wenrui Du3
1Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China.
Brain Imaging and Behavior
|January 24, 2023
Summary
High-altitude environments alter brain structure and function. Both native Tibetans and acclimatized immigrants show similar brain adaptations, with Tibetans exhibiting more pronounced changes to cope with low oxygen.
Area of Science:
- Neuroscience
- Human Physiology
- Environmental Medicine
Background:
- High-altitude (HA) environments significantly impact human physiology, including the brain.
- Previous research has not fully elucidated the distinct brain adaptations in native high-altitude dwellers versus acclimatized immigrants.
Purpose of the Study:
- To investigate and compare brain structural and functional network differences between native Tibetan high-altitude dwellers, Han immigrants acclimatized to high altitude, and lowland controls.
- To explore the relationship between physiological markers, cognitive performance, and brain changes in these populations.
Main Methods:
- Magnetic resonance imaging (MRI) was used to assess cortical gray matter volume, thickness, and functional connectivity.
- Physiological measurements included oxygen saturation (SpO2), hematocrit, and hemoglobin levels.
- Cognitive function was evaluated using reaction time and accuracy in a visual movement task.
Main Results:
- Both Tibetan natives and HA immigrants exhibited decreased SpO2, increased hematocrit and hemoglobin, and enhanced performance in the visual movement task compared to lowlanders.
- Increased gray matter volume and cortical thickness were observed in the somatosensory and motor cortex for both HA groups versus lowlanders.
- Functional connectivity decreased across multiple networks (visual, default mode, subcortical, somatosensory-motor, ventral attention) in HA populations compared to lowlanders.
- Native Tibetans showed higher SpO2, lower hematocrit/hemoglobin, and greater gray matter/cortical thickness increases in specific brain regions (visual, motor, auditory) compared to immigrants.
- Visual cortex thickness positively correlated with task performance.
Conclusions:
- High-altitude acclimatization induces largely consistent structural and functional brain network adaptations in both native populations and immigrants.
- Native Tibetans demonstrate more intense brain modulation, suggesting a greater degree of adaptation to the high-altitude environment.
- These findings highlight convergent evolutionary and adaptive mechanisms for coping with hypoxic conditions at high altitudes.
