Brain structural connectivity during adrenarche: Associations between hormone levels and white matter microstructure

Area of Science:

• Neuroendocrinology
• Developmental Neuroscience
• Brain Imaging

Background:

• Adrenarcheal hormones, including dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), and testosterone, are implicated in behavior and mental health.
• Preclinical research suggests these hormones play a role in brain development, but their association with white matter structure during adrenarche remains unclear.

Purpose of the Study:

• To investigate the relationship between DHEA, DHEAS, and testosterone levels and white matter microstructure in children during adrenarche.
• To explore how variations in these hormones are associated with specific white matter diffusion metrics.

Main Methods:

• Studied 87 children within a narrow age range to minimize age-related confounding factors.
• Collected saliva samples upon waking to measure hormone levels.
• Utilized diffusion-weighted magnetic resonance imaging (MRI) to assess white matter microstructure.

Main Results:

• Elevated DHEA levels were associated with increased mean diffusivity (MD) in widespread white matter tracts, attributed to both radial diffusivity (RD) and axial diffusivity (AD).
• An interaction effect was observed: high testosterone levels were linked to higher fractional anisotropy (FA) and lower MD/RD when DHEA was high, but lower FA and higher MD/RD when DHEA was low.

Conclusions:

• Early exposure to DHEA and imbalances between adrenal hormones may influence white matter microstructure during adrenarche.
• These findings underscore the significance of adrenarcheal hormones in structural brain development.