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Proprioceptive weights are independent of left and right hand sensory reliabilities

On The April 25, 2016

Laura Mikula

Team Director - Denis Pélisson

Abstract :

When planning a reach movement, we have to localize not only the target but also our hand. Hand position can be provided by two sensory modalities: vision and proprioception. The brain needs to integrate both visual and proprioceptive information in order to get a precise estimate of hand location. This process is known as multi-sensory integration. The Bayesian theory states that when multiple sensory modalities provide the same information, the nervous system gives more weight to the most reliable modality (i.e. to the least variable modality). Thus, the contributions of vision and proprioception to reach planning should be weighted by their relative precisions. This statement suggests that if left and right hand sensory reliabilities are different, sensory weights should also be different for both hands. We measured the weights of vision and proprioception during reach planning, separately for left and right hand. We also measured the sensory reliabilities for both hands in order to determine whether sensory weights and sensory reliabilities are related to each other, as described by the Bayesian model. Our results show very similar sensory weights for left and right hands despite differences in proprioceptive reliabilities for the two hands. These findings suggest that the sensory weighting of hand location is independent of left and right hand sensory reliabilities.