White matter architecture rather than cortical surface area correlates with the EEG alpha rhythm

Area of Science:

• Neuroscience
• Neuroimaging
• Biophysics

Background:

• Inter-individual variability in electroencephalography (EEG) spectral properties remains poorly understood.
• Biophysical models suggest neuroanatomical factors influence EEG, but empirical evidence is limited.
• Previous studies suggested a link between head size and alpha peak frequency, but this requires re-examination.

Purpose of the Study:

• To investigate the neuroanatomical determinants of the alpha peak frequency (P(alpha)) in EEG.
• To re-examine the relationship between head size and P(alpha).
• To explore the influence of white matter architecture on P(alpha) using diffusion tensor imaging (DTI).

Main Methods:

• Correlational analysis of P(alpha) with head size and cortical surface area in 222 subjects.
• Multivariate penalized regression analysis relating P(alpha) to DTI fractional anisotropy.
• Utilized data from the Cuban Human Brain Mapping Project's EEG/MRI database.

Main Results:

• No significant relationship was found between head size/cortical area and P(alpha).
• Significant correlations between P(alpha) and white matter fractional anisotropy were identified in the corona radiata and corpus callosum.
• Specific white matter tracts, including the posterior corona radiata and posterior corpus callosum fibers, showed strong associations with P(alpha).

Conclusions:

• White matter architecture, particularly connectivity and time delays, plays a crucial role in determining alpha rhythm dynamics.
• Neocortical area is not the primary determinant of alpha frequency.
• Findings support biophysical theories linking cortico-thalamocortical cycle periods to alpha frequency modulation.