Proprioceptive integration and body representation: insights into dancers' expertise.

The experience of the body as a single coherent whole is based on multiple local sensory signals, integrated across different sensory modalities. We investigated how local information is integrated to form a single body representation and also compared the contribution of proprioceptive and visual information both in expert dancers and non-dancer controls. A number of previous studies have focused on individual differences in proprioceptive acuity at single joints and reported inconsistent findings. We used the established endpoint position matching task to measure absolute and directional errors in matching the position of one hand with the other. The matching performance was tested in three different conditions, which involved different information about the target position: only proprioceptive information from a 'target' hand which could be either the left or the right, only visual information, or both proprioceptive and visual information. Differences in matching errors between these sensory conditions suggested that dancers show better integration of local proprioceptive signals than non-dancers. The dancers also relied more on proprioception when both proprioceptive and visual information about hand position were present.