Developmental Changes in Resting Gamma Power from Age Three Months to Five Years Are Modulated by Infant Diet

Abstract

Gamma band activity (30–50 Hz) is a significant EEG component related to intelligence, memory and language processes, but there is limited information regarding the early development of this activity and none considering how infant diet may influence this development. The present study examined changes in gamma power from 3 months through 5 years in 497 healthy children who were breast‐fed (BF: 168, 84 boys), or fed milk formula (MF: 169, 89 boys), or soy formula (SF: 160, 90 boys) as infants. Recordings of resting EEG (5 min; eyes open) were obtained quarterly during infancy and then yearly. We used ANOVAs adjusted for relevant growth and environmental factors (gender, head circumference, gestation, birth and visit weight, SES and mother's IQ) to compare group, age, and group by age changes in gamma EEG power from 44 homologous sites distributed over frontal, central, temporal, parietal and occipital scalp regions. Across sites and groups, gamma power was lowest at 3 months (all p < .001), and across age gamma power was consistently higher at frontal than other sites (all p < .05). From 3 to 6 months gamma power increased dramatically at all sites for all groups [all p < .001; mean increase >100% for all sites, greatest for central‐parietal regions (187% mean increase across groups)]. After 6 months, gamma power generally increased across sites until a time after which significant (p < .05) decreases became evident relative to preceding peak levels. The ages after which decreases became evident varied within and across brain regions, with site‐specific time points of change ranging from 1 to 4 years and occurring later (after 3–4 years) in anterior frontal than other regions. Temporal sites differed from others in showing sharp decreases both early (after 9 months or 1 year) and later (after 3 years). Group variations in site‐related time points of change were most evident for frontal and occipital regions. Infant diet‐related effects were evident at 3 months [BF < MF, SF (p ≤ .001) and were generally sustained across age‐‐ particularly at parietal‐occipital sites where BF < MF differences (p < .05) were most prominent. These findings provide new information regarding the regional development of EEG gamma activity from infancy to the onset of middle childhood, and show that this development is modified by infant diet. Previous reports of negative associations between resting gamma and measures of language skills and intelligence suggest potential developmental advantages for breastfed infants.Support or Funding InformationFunded by USDA‐ARS Project 6026‐51000‐010‐05S