The automatic updating of egocentric spatial relationships and its impairment due to right posterior cortical lesions.

The non-visual updating of body-centred spatial relationships was investigated in an experiment in which blindfolded patients had to point to previously seen targets after a body rotation in the absence of vision. Patients with lesions to the right dorsal (RD) area were impaired at updating their positions relative to non-RD patients and normal subjects: they tended to underestimate systematically the angle through which they had turned. The results are interpreted in terms of impoverished locomotor input and/or systematically biased processing or locomotor proprioception in the RD patients, which prevented accurate tracking of changes in egocentric spatial relationships.