Abstract
Primary motor areas in the brain mature relatively early in development, yet the control of complex movements improves up to early adulthood. Neural oscillations in higher-order regions are refined in adolescence and contribute to executive processes important for complex motor control. How manipulations in task complexity influence the extent to which such regions are recruited in youth is unknown. Further, evidence suggests that steroid hormones may modulate cortical motor oscillations in youth, but it is unclear whether this is specific to testosterone.
Herein, we recorded magnetoencephalography during a sequential finger tapping task with two levels of complexity in 68 healthy adolescents. Significant oscillatory responses were then subjected to whole-brain statistical analyses evaluating the relationship between biological factors and motor-related oscillatory activity. In Chapter 1, repeated-measures ANCOVAs identified brain areas in which the age-related trajectory of oscillatory power differed by movement complexity (i.e., simple versus complex) and/or motor stage (i.e., planning versus execution). In Chapter 2, the same adolescents provided saliva samples for measurement of dehydroepiandrosterone (DHEA) levels as a proxy for development. Then, 2x2 mixed model ANCOVAs identified regions in which the developmental trajectory of oscillatory activity differed as a function of movement complexity, or sex, beyond the effects of age.
Overall, these novel results enhance the characterization of the developing motor system and neurodevelopmental trajectories of oscillatory activity. These analyses are the first to evaluate differences in motor oscillations by sequence complexity and identify higher-order regions that support different aspects of complex motor control and development in youth.