Normal development of bimanual coordination: visuomotor and interhemispheric contributions

Area of Science:

• Neuroscience
• Developmental Psychology
• Motor Control

Background:

• The corpus callosum, a major white matter tract, is among the last cortical pathways to fully myelinate, extending into childhood.
• The precise functional impact of this late maturation on bimanual motor coordination remains incompletely understood.
• Impaired bimanual coordination in children mirrors that seen in individuals with callosal agenesis or after commissurotomy, suggesting the corpus callosum's critical role.

Purpose of the Study:

• To investigate the developmental trajectory of bimanual motor coordination in typically developing children aged 6 to 15 years.
• To examine the relationship between age, unimanual motor speed, and bimanual coordination accuracy.
• To elucidate the specific contribution of interhemispheric interactions to age-related improvements in bimanual tasks.

Main Methods:

• Utilized the computerized Bimanual Coordination Test (cBCT) to assess motor performance in 67 typically developing children.
• Measured unimanual motor speed for both right and left hands.
• Analyzed accuracy on symmetric and asymmetric bimanual coordination tasks, including conditions requiring differential hand speeds.

Main Results:

• Significant negative correlations were found between age and unimanual motor speed (right hand: r = -.26; left hand: r = -.44).
• Age was significantly associated with improved accuracy in both symmetric (r = -.46) and asymmetric (r = -.50) bimanual coordination tasks.
• Accuracy on asymmetric bimanual trials, especially those demanding greater left-hand speed, uniquely predicted age-related variance, even after controlling for symmetric task performance.

Conclusions:

• Computerized Bimanual Coordination Test performance effectively reflects developmental changes in motor speed and visuomotor processing during childhood.
• Interhemispheric communication, facilitated by the corpus callosum, plays a crucial and unique role in the development of sophisticated bimanual motor skills.
• Late maturation of the corpus callosum underpins significant improvements in complex bimanual coordination throughout childhood and into adolescence.