Visuomotor transformations affect bimanual coupling

• Published in: Experimental brain research 2003-02, Vol.148 (4), p.439-450
• Main Authors: WEIGELT, Cornelia, CARDOSO DE OLIVEIRA, Simone
• Format: Article
• Language: English
• Subjects: Acculturation; Adult; Analysis of Variance; Biological and medical sciences; Functional Laterality; Fundamental and applied biological sciences. Psychology; Generalization (Psychology); Humans; Male; Motor Activity - physiology; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Movement - physiology; Psychomotor Performance - physiology; Reaction Time; Reversal Learning - physiology; Space Perception - physiology; Spatial Behavior - physiology; Task Performance and Analysis; Time Perception; Transfer (Psychology) - physiology; Vertebrates: nervous system and sense organs; Visual Perception - physiology
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-002-1316-1

Interactions between bimanual movements may occur at two different levels: at a visually based level, where movement trajectories are programmed within the visually perceived external space, and at the executional level, through crosstalk of sensorimotor signals arising during movement execution. In order to distinguish between these sources of interactions, we investigated bimanual reversal movements under different conditions of visual feedback. A visuomotor transformation dissociated movement execution from visual appearance on a computer screen. The transformation we used made movements of the same amplitude evoke different excursions, and made movements of different amplitudes entail matched excursions on the screen. The transformed conditions allowed us to study which parameters of bimanual coupling were related to the way movements were executed and which correlated with the visual movement display. We found a clear dissociation between execution-related and visually related bimanual interactions. The assimilation of movement amplitudes was completely execution-related. Whenever movements of different amplitudes were generated, the shorter movement was lengthened, irrespective of how the movements appeared on the feedback screen. In contrast, temporal coordination at the point of movement reversal, as well as trial-by-trial correlations of movement amplitudes, also showed significant effects of the visuomotor transformation, suggesting that these parameters are influenced by visually perceived effects of movements. This dissociation confirms the idea of separate pathways for bimanual interactions and shows that a specific set of bimanual interactions occur at least partly within a visually based external reference frame.