Abstract
Behavioral studies have shown that the human motor system recycles motor parameters of previous actions, such as movement amplitude, when programming new actions. Shifting motor plans toward a new action forms a particularly severe problem for patients with Parkinson’s disease (PD), a disorder that, in its early stage, is dominated by basal ganglia dysfunction. Here, we test whether this action selection deficit in Parkinson’s patients arises from an impaired ability to recycle motor parameters shared across subsequent actions. Parkinson’s patients off dopaminergic medication (n = 16) and matched healthy controls (n = 16) performed a task that involved moving a handheld dowel over an obstacle in the context of a sequence of aiming movements. Consistent with previous research, healthy participants continued making unnecessarily large hand movements after clearing the obstacle (defined as “hand path priming effect”), even after switching movements between hands. In contrast, Parkinson’s patients showed a reduced hand path priming effect, i.e., they performed biomechanically more efficient movements than controls, but only when switching movements between hands. This effect correlated with disease severity, such that patients with more severe motor symptoms had a smaller hand path priming effect. We propose that the basal ganglia mediate recycling of movement parameters across subsequent actions.
Footnotes
M.F., R.P.R.D.v.d.W., R.S., and I.T. declare no competing interests. R.C.H. serves on the clinical advisory board of Cadent Therapeutics and received honoraria from AbbVie. B.R.B currently serves as Associate Editor for the Journal of Parkinson’s Disease, serves on the editorial of Practical Neurology and Digital
Biomarkers, has received honoraria from serving on the scientific advisory board for Abbvie, Biogen, UCB, and Walk with Path, and has received fees for speaking at conferences from AbbVie, Zambon, Roche, GE Healthcare, and Bial.
R.C.H. was funded by the VENI grant from the Netherlands Organization for Scientific Research 91617077. The Center of Expertise for Parkinson & Movement Disorders of the Radboud university medical center was supported by a Center of Excellence Grant of the Parkinson’s Foundation. B.R.B. was supported by the Netherlands Organization for Scientific Research, the Michael J Fox Foundation, UCB, Abbvie, the Stichting Parkinson Fonds, the Hersenstichting Nederland, the Parkinson’s Foundation, Verily Life Sciences, Horizon 2020, the Topsector Life Sciences and Health, and the Parkinson Vereniging.
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