Multisensory integration enhances coordination: The necessity of a phasing matching between cross-modal events and movements

Recent research revealed what substrates may subserve the fascinating capacity of the brain to put together different senses, from single cell to extending networks (see for review, Driver and Noesselt, 2008; Ghazanfar and Schroeder, 2006; Sperdin et al., 2010; Stein and Stanford, 2008), and lead to interesting behavioral benefits in response to cross-modal events such as shorter reaction times, easier detections or more precise synchronization (Diederich and Colonius, 2004; Elliott et al., 2010). But what happens when a combination of multisensory perception and action is required? This is a key issue, since the organization of movements in space–time in harmony with our surrounding environment is the basis of our everdaylife. Surprisingly enough, little is known about how different senses and movement are combined dynamically. Coordination skills allow to test the effectiveness of such a combination, since external events have been shown to stabilize the coordination performance when adequately tuned (Fink et al., 2000). We then tested the modulation of the capacity of participants to produce an anti-symmetric rhythmic bimanual coordination while synchronizing with audio–tactile versus audio and tactile metronomes pacing the coordination from low to high rates of motion. Three condition of metronome structure found to stabilize the anti-symmetric mode have been handled: Simple, Double and Lateralized. We found redundant signal effects for Lateralized metronomes, but not for Simple and Double metronomes, rather explained by neural audio–tactile interactions than by a simple statistical redundancy. These results reflect the effective cortical cooperation between components in charge of the audio–tactile integration and ones sustaining the anti-symmetric coordination pattern. We will discuss the apparent necessity for cross-modal events to match the phasing of movements to greater stabilize the coordination.