Some proprioceptive influences on the perceptual representation of body shape and orientation

Perception of the surface contour of the body is generally thought to depend on topographically organized neural maps of somatosensation in the thalamus and cortex. Recent neurophysiological studies indicate that these maps are potentially modifiable through alterations in their sensory input. We present evidence that the apparent shape and orientation of the body can be changed within seconds by using muscle vibration to generate proprioceptive misinformation about limb position. Depending on the position of the hands or feet in relation to the rest of the body and to the test chamber, it is possible to generate systematic perceptual distortions of the body and changes in the apparent orientation of the body. Some implications of these observations for the maintenance of an accurate body schema, for spatial orientation, and for the encoding of ocular position are described.