Dorsal and ventral stream sensitivity in normal development and hemiplegia

Area of Science:

• Neuroscience
• Developmental Psychology
• Visual Perception

Background:

• Form and motion coherence thresholds measure global visual processing in the ventral and dorsal streams, respectively.
• Understanding the developmental trajectory of these visual streams is crucial for identifying potential vulnerabilities.

Purpose of the Study:

• To assess the normal development of form and motion coherence thresholds in children.
• To investigate the dorsal stream's vulnerability in children with hemiplegic cerebral palsy.

Main Methods:

• Tested form and motion coherence thresholds in 360 typically developing children (4-11 years) and adults.
• Compared performance of 24 children with hemiplegic cerebral palsy to controls.

Main Results:

• Both tasks showed similar developmental trends, with motion coherence exhibiting more variability and a slight delay in reaching adult levels.
• Children with hemiplegic cerebral palsy performed significantly worse on motion coherence but not form coherence tasks compared to controls.
• No specific brain area was significantly associated with poorer motion coherence performance within the hemiplegic group.

Conclusions:

• Extrastriate mechanisms for form and motion coherence develop in parallel.
• The dorsal stream demonstrates a general vulnerability to early neurological impairment, as evidenced by motion coherence deficits in hemiplegic cerebral palsy.
• These findings highlight the importance of assessing dorsal stream function in developmental disorders.