Smoking and High-Altitude Exposure Affect Intrinsic Neural Activity: A fMRI Study of Interactive Effects

Area of Science:

• Neuroscience
• Environmental Health
• Addiction Research

Background:

• Smoking and high-altitude (HA) exposure are known risk factors for adverse health outcomes.
• While their individual effects on the brain are documented, the combined impact remains under-explored.
• Understanding these interactions is crucial for public health, especially in high-altitude communities.

Purpose of the Study:

• To investigate the interactive effects of smoking and high-altitude exposure on intrinsic brain activity.
• To utilize resting-state functional magnetic resonance imaging (rs-fMRI) and amplitude of low-frequency fluctuations (ALFF) to analyze brain activity patterns.
• To provide a neuroimaging perspective on substance addiction and adaptation in high-altitude environments.

Main Methods:

• A mixed sample design included four groups: high-altitude smokers (n=22), high-altitude non-smokers (n=22), sea-level smokers (n=26), and sea-level non-smokers (n=26).
• All 96 male participants underwent resting-state functional magnetic resonance imaging (rs-fMRI).
• Two-way analysis of variance (ANOVA) was employed to analyze the main effects of smoking and HA exposure, as well as their interaction on ALFF.

Main Results:

• Smoking significantly elevated ALFF in several frontal and cingulate regions.
• High-altitude exposure significantly elevated ALFF in the putamen, insula, and temporal regions.
• A significant interaction effect between smoking and HA exposure was identified in the right precentral gyrus, with increased ALFF observed in high-altitude groups compared to sea-level counterparts.

Conclusions:

• Both smoking and high-altitude exposure independently modulate spontaneous brain activity.
• A significant interaction between smoking and HA exposure influences brain function, particularly in the precentral gyrus.
• These findings enhance our understanding of neuroimaging correlates of substance addiction and adaptation in high-altitude populations.