Cyclic cortical reorganization during early childhood

Area of Science:

• Neuroscience
• Developmental Psychology
• Brain Development

Background:

• Understanding the early development of hemispheric specialization is crucial for cognitive science.
• Electroencephalography (EEG) coherence offers insights into functional brain connectivity.
• The early childhood period is characterized by significant neural plasticity and organizational changes.

Purpose of the Study:

• To investigate developmental trajectories of EEG coherence in early childhood.
• To identify periods of rapid change or 'growth spurts' in brain connectivity.
• To explore the relationship between early developmental sequences and adult hemispheric function.

Main Methods:

• EEG coherence was calculated from intrahemispheric electrode pairs in 253 children (6 months to 7 years).
• The first derivative of mean coherence was used to detect rapid changes and growth spurts.
• Analysis focused on cyclical patterns of intracortical connection changes in both hemispheres.

Main Results:

• EEG coherence exhibited growth spurts lasting approximately 6 months to 1 year.
• These growth spurts involved a cyclical process: left hemisphere intracortical connections lengthened, while right hemisphere connections contracted.
• Each cycle spanned 2-4 years, including rostral-caudal expansion/contraction and lateral-to-medial rotation.

Conclusions:

• Left and right hemisphere functions are established early via complementary developmental sequences.
• These early sequences appear to mirror the differences observed in adult hemispheric specialization.
• The findings support a model of early, complementary hemispheric development shaping adult brain function.