title: The kinematic signature of voluntary actions.
abstract: Research in the field of psychology and cognitive neuroscience has begun to explore the functional underpinnings of voluntary actions and how they differ from stimulus-driven actions. From these studies one can conclude that the two action modes differ with respect to their neural and behavioural correlates. So far, however, no study has investigated whether the voluntary and stimulus-driven actions also differ in terms of motor programming. We report two experiments in which participants had to perform either voluntary or stimulus-driven reach-to-grasp actions upon the same stimulus. Using kinematic methods, in Experiment 1 we obtained evidence that voluntary actions and stimulus-driven actions translate into differential movement patterns. Results for Experiments 2 suggest that selecting what to do, when to act, and whether to act are characterized by specific kinematic signatures and affect different aspects of the reach-to-grasp movement in a selective fashion. These findings add to current models of volition suggesting that voluntary action control results from an interplay of dissociable subfunctions related to specific decision components: what action execute, when to execute an action, and whether to execute any action.
authors.affiliation: Robotics, Brain and Cognitive Sciences, Istituto Italiano di Tecnologia, Genova, Italy; Centre for Cognitive Science, Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Becchio
authors.affiliation: Department of General Psychology, University of Padova, Padova, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Zanatto
authors.affiliation: Department of General Psychology, University of Padova, Padova, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Straulino
authors.affiliation: Centre for Cognitive Science, Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cavallo
authors.affiliation: Department of General Psychology, University of Padova, Padova, Italy; Centre for Cognitive Neuroscience, University of Padova, Padova, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sartori
authors.affiliation: Department of General Psychology, University of Padova, Padova, Italy; Centre for Cognitive Neuroscience, University of Padova, Padova, Italy. Electronic address: umberto.castiello@unipd.it.
authors.forename: Umberto
authors.initials: U
authors.lastname: Castiello
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D033182:Intention; D008297:Male; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D014836:Volition; D055815:Young Adult
keywords: Kinematics; Motor control; Reach-to-grasp; Stimulus-driven actions; Voluntary actions