Penny A. MacDonald

Parkinson's Disease affects the contextual control, but not the expression, of a rapid visuomotor response that initiates visually-guided reaching: Evidence for multiple, interacting motor pathways and implications for motor symptoms in Parkinson's Disease

This study shows that Parkinson's disease preserves the speed and strength of a reflexive visuomotor response but impairs its contextual modulation, suggesting distinct motor pathways are affected.

Null effects of levodopa on reward- and error-based motor adaptation, savings, and anterograde interference

This study tests if levodopa affects reward- and error-based motor adaptation, finding no significant effects on adaptation or neural responses to reward feedback.

The Effect of Aging, Parkinson’s Disease, and Exogenous Dopamine on the Neural Response Associated with Auditory Regularity Processing

This study investigates how aging, Parkinson’s disease, and dopamine treatment affect auditory regularity processing using EEG, finding age-related declines and dopaminergic therapy reducing sustained neural responses.