Directional interference during bimanual coordination: is interlimb coupling mediated by afferent or efferent processes.

The role of afferent information in bimanual directional interference was studied by means of a modulation of the response-produced information in one of both limbs. In Experiment 1, visual information was either present, withdrawn, or shown with a directional transformation on a LCD screen. In Experiment 2, the technique of muscle tendon vibration was used to bias the kinesthetic afferent information associated with movement. The findings revealed strong evidence for directional interference between both limbs. Nevertheless, no evidence could be advanced that the observed interference from the right onto the left limb movement was modulated by manipulation of the afferent sources of information. It is concluded that directional interference primarily emerges at the efferent level of movement planning and organization.