Intergenerational Transmission of Frontal Alpha Asymmetry Among Mother-Infant Dyads

BACKGROUND: Frontal alpha asymmetry (FAA) is a well-established neurobiological indicator of depression risk. Reduced FAA relates to current and remitted depression in adults and is seen in offspring of mothers with depression as young as 3 months of age, suggesting a potentially transmittable mechanism of depression risk. It is unclear, however, whether direct familial associations exist for FAA. To address this gap, we evaluated the intergenerational transmission of FAA in a nonclinical cohort of mother-infant dyads. METHODS: Mothers and their 12-month-old infants (n = 34 dyads) completed parallel resting-state tasks while electroencephalography was recorded. We measured FAA across a range of putative frequency bands and calculated its reliability in mothers and infants. Finally, we evaluated the heritability of FAA based on the parent-offspring correlation. RESULTS: Mother and infant FAA convergence was strongest in the high alpha range for mothers (11-13 Hz) and broad alpha range for infants (6-9 Hz). Mother high FAA exhibited excellent split-half reliability (r(SB) = .99) and internal consistency after 80 seconds (alpha = .90); infant FAA exhibited good split-half reliability (r(SB) = .81) and fair internal consistency after 70 seconds (alpha = .74). Mother-infant FAA were moderately correlated (r = .41), which indicates narrow-sense heritability of up to 82%. CONCLUSIONS: FAA can be assessed reliably and relatively quickly in both adults and infants. There is a robust association of FAA between mothers and their infants, supporting intergenerational transmission. This finding is consistent with the possibility that reduced FAA may directly confer depression risk at the individual-family level.