Recruitment of the sensorimotor cortex--a developmental FMRI study.

Introduction: The growing mastery of motor tasks is one of the most visible changes in the developing child. The cortex is known to play a central role in learning, planning, and performance of motor tasks. We investigated the age dependency of motor cortex activation using functional magnetic resonance imaging (fMRI).

Methods: Thirty-two right-handed subjects were studied: 11 children (median age 9 years, range 6 - 10 years), 10 adolescents (median age 13 years, range 11 - 15 years), and 11 adults (median age 27 years, range 23 - 42 years). The subjects performed a simple, paced unilateral motor task (repetitive squeezing of a ball with the right hand). Also, we set up a control experiment (visual stimulation using an alternating checkerboard pattern) in which no age-related differences were expected.

Results: Compared to children, adults showed significantly increased activation of the bilateral sensorimotor cortex, parietal areas, the supplementary motor area, and the cerebellum. In the visual stimulation experiment there were no age-related differences.

Conclusion: Children show a significant difference in the degree of cortical activation compared to adults when performing a simple motor task. The change in fMRI activation patterns may reflect a maturation process of primary and secondary motor areas.