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Motor resonance is modulated by an object's weight distribution

Research output: Contribution to journalArticlepeer-review

Guy Rens, Jean Jacques Orban de Xivry, Marco Davare, Vonne van Polanen

Original languageEnglish
Article number107836
JournalNeuropsychologia
Volume156
DOIs
Published18 Jun 2021

Bibliographical note

Funding Information: We are grateful to Dr. Massimo Penta (Arsalis, Belgium) for the design of the manipulandum and Isa Vanstraelen for her help in data collection. This work was funded by a Research Foundation Flanders (FWO) Odysseus Project ( Fonds Wetenschappelijk Onderzoek , Belgium: G/0C51/13N ) awarded to MD and 12X7118N / Research Foundation Flanders (FWO) awarded to VVP. Publisher Copyright: © 2021 Elsevier Ltd

King's Authors

Abstract

Transcranial magnetic stimulation (TMS) studies showed that corticospinal excitability (CSE) is modulated during observation of object lifting, an effect termed ‘motor resonance’. Specifically, motor resonance is driven by movement features indicating object weight, such as object size or observed movement kinematics. We investigated in 16 humans (8 females) whether motor resonance is also modulated by an object's weight distribution. Participants were asked to lift an inverted T-shaped manipulandum with interchangeable center of mass after first observing an actor lift the same manipulandum. Participants and actor were instructed to minimize object roll and rely on constrained digit positioning during lifting. Constrained positioning was either collinear (i.e., fingertips on the same height) or noncollinear (i.e., fingertip on the heavy side higher than the one on the light side). The center of mass changed unpredictably before the actor's lifts and participants were explained that their weight distribution always matched the actor's one. Last, TMS was applied during both lift observation and planning of lift actions. Our results showed that CSE was similarly modulated during lift observation and planning: when participants observed or planned lifts in which the weight distribution was asymmetrically right-sided, CSE recorded from the thumb muscles was significantly increased compared to when the weight distribution was left-sided. During both lift observation and planning, this increase seemed to be primarily driven by the weight distribution and not specifically by the (observed) digit positioning or muscle contraction. In conclusion, our results indicate that complex intrinsic object properties such as weight distributions can modulate activation of the motor system during both observation and planning of lifting actions.

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