Functional MRI of global and local processing in children

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Previous reaction time (RT) studies show emerging hemispheric differences in children's visual processing of hierarchical forms.
• Children aged 7-14 initially show slower local element analysis without strong lateralization, developing a left hemisphere advantage for local and right for global processing with age.

Purpose of the Study:

• To investigate if developmental changes in cognitive measures of visual processing correspond to changes in functional brain activation patterns.
• To examine hemispheric biases in processing global versus local visual information in children using functional magnetic resonance imaging (fMRI).

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used on 20 children (12-14 years old) during attend-global and attend-local tasks.
• Children were grouped into immature-bilateral (IB) or mature-lateralized (ML) based on prior RT performance.
• Task-related activation in lateral temporo-occipital regions was compared between groups and conditions.

Main Results:

• Immature-bilateral (IB) children showed greater overall activation for local processing and comparable bilateral activation for global processing.
• Mature-lateralized (ML) children exhibited right hemisphere dominance for global analysis and left hemisphere dominance for local analysis.
• fMRI activation patterns directly mirrored the RT performance profiles observed in both groups.

Conclusions:

• The study demonstrates a developmental shift in visual processing from undifferentiated, bilateral activation towards specialized hemispheric lateralization.
• Functional brain activation patterns in children directly reflect their cognitive performance in processing global and local visual information.