title: Bimanual coupling effects during arm immobilization and passive movements.
abstract: When humans simultaneously perform different movements with both hands, each limb movement interferes with the contralateral limb movement (bimanual coupling). Previous studies on both healthy volunteers and patients with central or peripheral nervous lesions suggested that such motor constraints are tightly linked to intentional motor programs, rather than to movement execution. Here, we aim to investigate this phenomenon, by using a circles-lines task in which, when subjects simultaneously draw lines with the right hand and circles with the left hand, both the trajectories tend to become ovals (bimanual coupling effect). In a first group, we immobilized the subjects' left arm with a cast and asked them to try to perform the bimanual task. In a second group, we passively moved the subjects' left arm and asked them to perform voluntary movements with their right arm only. If the bimanual coupling arises from motor intention and planning rather than spatial movements, we would expect different results in the two groups. In the Blocked group, where motor intentionality was required but movements in space were prevented by immobilization of the arm, a significant coupling effect (i.e., a significant increase of the ovalization index for the right hand lines) was found. On the contrary, in the Passive group, where movements in space were present but motor intentionality was not required, no significant coupling effect was observed. Our results confirmed, in healthy subjects, the central role of the intentional and predictive operations, already evidenced in pathological conditions, for the occurrence of bimanual coupling.
authors: SAMBA - SpAtial, Motor & Bodily Awareness - Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy. Electronic address: francesca.garbarini@unito.it.
authors: Francesca
authors: F
authors: Garbarini
authors: Biomedical Technology Department, Found. Don Carlo Gnocchi IRCCS, 20148 Milan, Italy.
authors: Marco
authors: M
authors: Rabuffetti
authors: SAMBA - SpAtial, Motor & Bodily Awareness - Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy.
authors: Alessandro
authors: A
authors: Piedimonte
authors: SAMBA - SpAtial, Motor & Bodily Awareness - Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy.
authors: Gianluca
authors: G
authors: Solito
authors: SAMBA - SpAtial, Motor & Bodily Awareness - Research Group, Department of Psychology, University of Turin, 10123 Turin, Italy; Neuroscience Institute of Turin (NIT), University of Turin, 10043 Orbassano (To), Italy.
authors: Anna
authors: A
authors: Berti
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D001519:Behavior; D004576:Electromyography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000502:physiology*; D006236:Handwriting; D064368:Healthy Volunteers; D006801:Humans; D007103:Immobilization; D008297:Male; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D016059:Range of Motion, Articular; D012867:Skin / Q000473:pathology; D055815:Young Adult
keywords: Arm immobilization; Bimanual coupling effect; Motor control; Motor intention; Passive movements