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Published on: December 18, 2016
Broca's region: cytoarchitectonic asymmetry and developmental changes
Katrin Amunts1, Axel Schleicher, Annette Ditterich
1Institute of Medicine, Research Center Jülich, D-52425 Jülich, Germany. k.amunts@fz-juelich.de
The Journal of Comparative Neurology
|August 20, 2003
Summary
Brain structure shows language dominance develops early and changes throughout life. This study analyzed Broca's region in human brains, finding asymmetry present from infancy and evolving with age.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Comparative Anatomy
Background:
- Language specialization shows developmental changes in children and adults.
- Anatomical basis for developmental language dominance shifts remains unclear.
- Broca's region (areas 44 and 45) is implicated in language processing.
Purpose of the Study:
- Investigate developmental changes in cytoarchitectonic asymmetry in Broca's region.
- Determine anatomical correlates of language dominance development.
- Analyze lifespan changes in interhemispheric asymmetry of areas 44 and 45.
Main Methods:
- Postmortem analysis of 34 human brains (3.5 months to 85 years).
- Cytoarchitectural analysis of areas 44 and 45.
- Quantification of interhemispheric asymmetry using Euclidean distances and gray level index (GLI).
Main Results:
- Cytoarchitectonic asymmetry in areas 44 and 45 was present in infants as young as 1 year.
- Asymmetry increased with age, significantly in area 45.
- Adult-like asymmetry (left > right GLI) was reached around 5 years (area 45) and 11 years (area 44).
- Developmental trajectory differs from primary motor cortex.
- Interhemispheric asymmetry continued to change throughout adulthood.
Conclusions:
- Cytoarchitectonic asymmetry in Broca's region develops early and persists throughout life.
- Delayed maturation of Broca's region asymmetry may underlie language development and plasticity.
- Microstructural plasticity in areas 44 and 45 is evident across the lifespan.
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