Impact of brain overgrowth on sensorial learning processing during the first year of life

Abstract

Macrocephaly is present in about 2–5% of the general population. It can be found as an isolated benign trait or as part of a syndromic condition. Brain overgrowth has been associated with neurodevelopmental disorders such as autism during the first year of life, however, evidence remains inconclusive. Furthermore, most of the studies have involved pathological or high-risk populations, but little is known about the effects of brain overgrowth on neurodevelopment in otherwise neurotypical infants. We investigated the impact of brain overgrowth on basic perceptual learning processes (repetition effects and change detection response) during the first year of life. We recorded high density electroencephalograms (EEG) in 116 full-term healthy infants aged between 3 and 11 months, 35 macrocephalic (14 girls) and 81 normocephalic (39 girls) classified according to the WHO head circumference norms. We used an adapted oddball paradigm, time-frequency analyses, and auditory event-related brain potentials (ERPs) to investigate differences between groups. We show that brain overgrowth has a significant impact on repetition effects and change detection response in the 10–20 Hz frequency band, and in N450 latency, suggesting that these correlates of sensorial learning processes are sensitive to brain overgrowth during the first year of life.

EEG repetition and change detection responses in infancy predict adaptive functioning in preschool age: a longitudinal study

“…On the other hand, few to no literature exists regarding exact time intervals of brain activity. The results found here and in our previous publications 40 , 43 , 61 , 62 show theta and alpha activity after a post-stimulus delay, and beta activity early after stimuli onset. Thus, for selecting time intervals, ITC maps were created for each stimulus and testing time point (visit 1 and visit 2) to assess the time–frequency windows (TFW) in which EEG activity showed greater variation in synchronization across trials and testing time points.…”