Adults who adapt to a perturbing force on their arm produced by a robotic manipulandum later show aftereffects when reaching with the robot deactivated but move accurately if they let go of the robot. This shows that what they learn about how to make goal-directed reaching movements when grasping a robotic manipulandum generating a movement-contingent force does not carry over to reaching without the robot. This is one example of a growing body of evidence indicating that we learn distinct predictive strategies for moving our own arm and for moving external objects, and we use these strategies in an appropriate self/object context. We have recently shown that this context-specific self/object distinction within the motor system is a developmental achievement that appears at about seven years of age in typically developing children. Our studies also show that there is not an absolute maturational time table for the emergence of context-specific self/object motor adaptation because it can be accelerated if appropriate experience is provided. In addition, we have exciting preliminary results from a study of children with high functioning autism (HFA) in which we are finding that they are as capable as typically developing children of learning to compensate for a perturbing robotic manipulandum (object) but are delayed in learning not to carry this over to the free reaching (self) context. Our overall aims are to confirm this preliminary finding in children with HFA and to test a hypothesis about how to accelerate self/object context-specific dynamic motor learning in typically developing children as well as in children with HFA. The outcomes of this project will provide a better understanding of the development of context-specific dynamic motor adaptation in typically developing children, a clearer understanding of motor deficits in autism, and a therapeutic method for enhancing motor learning in children with HFA - especially learning to interact with dynamic objects. A positive outcome will also open future avenues for investigating typical and disordered development of motor interactions between individuals.
We will investigate children's capacity separately adjust their neuromotor control to account for their own rapidly changing bodies and for forces imposed by novel external objects. Our studies will include typically developing children, children with autism. The outcomes will be a better understanding of motor development in typically developing children, a clearer understanding of motor deficits in autism and a potential therapy for improving the development of dynamic motor interactions. Strong preliminary results indicate positive outcomes which will open a future avenue for investigating typical and disordered development of motor interactions between individuals.
|Piovesan, Davide; Pierobon, Alberto; DiZio, Paul et al. (2012) Measuring multi-joint stiffness during single movements: numerical validation of a novel time-frequency approach. PLoS One 7:e33086|