Abstract #1131

Witt S, Schmidt M, Lazarus J, Meyerand M

We present for the first time evidence for differences in the activity of subcortical motor structures involved in automatic and effortful movements. In line with functional activation maps generated for the two motor conditions, effective connectivity results from structural equation modeling suggest that the putamen preferentially influences the cortical motor structures during automatic movements, while the cerebellum preferentially influences the cortical motor structures during effortful movements. The estimated path coefficients also indicate a general increase in drive of the motor cortices during effortful movements.