Proprioception as a sensory root for body and motor awareness.

The primary function of proprioception is to stabilize and protect the body. However, its role may extend beyond this fundamental function. Proprioceptive signals have been hypothesized to contribute to the emergence of body awareness (i.e. sense of ownership) and motor awareness (i.e. sense of agency). However, this hypothesis has never been explicitly empirically tested in neuropsychological studies involving a large sample of patients. We investigated this assumption in the context of pathological disturbances of body and motor awareness following right-hemisphere stroke. In an observational, cross-sectional study, we tested 46 consecutive patients assessing proprioceptive abilities, disturbed sensation of ownership (DSO), and anosognosia for hemiplegia (AHP). Our findings reveal that reduced proprioceptive abilities predict both DSO and AHP for the contralesional plegic upper limb. Advanced lesion mapping indicates that the proprioceptive deficit predicting the presence of DSO and AHP is associated with lesions to the right parietal cortex and underlying white matter tracts. The lesional pattern was further detailed by bilateral disconnections between the temporal and parietal areas associated with decreased proprioceptive ability. We discuss the theoretical implications of these results in relation to the ongoing debate on the role of proprioception in bodily self-awareness.