Crawling experience is related to changes in cortical organization during infancy: evidence from EEG coherence

Greenough's model of experience-expectant plasticity was used to examine EEG coherence among four groups of 8-month-old infants that varied in hands-and-knees crawling experience. Groups included prelocomotor infants, novice crawlers with 1-4 weeks experience, infants with 5-8 weeks, and long-term crawlers with 9+ weeks experience. Resting EEG was recorded from frontal, parietal, and occipital sites of both hemispheres. EEG coherence between intrahemispheric sites was computed. Novice crawlers (1-4 weeks) displayed greater coherence than either prelocomotor infants or experienced crawlers. These data suggest that the anticipation and onset of locomotion was related to an overproduction of cortico-cortical connections. Pruning of these overabundant connections may be a source of the decrease in coherence as crawling becomes more routine.