Visual processing of moving and static self body-parts.

Humans' ability to recognize static images of self body-parts can be lost following a lesion of the right hemisphere [Frassinetti, F., Maini, M., Romualdi, S., Galante, E., & Avanzi, S. (2008). Is it mine? Hemispheric asymmetries in corporeal self-recognition. Journal of Cognitive Neuroscience, 20, 1507-1516]. Here we investigated whether the visual information provided by the movement of self body-parts may be separately processed by right brain-damaged (RBD) patients and constitute a valuable cue to reduce their deficit in self body-parts processing. To pursue these aims, neurological healthy subjects and RBD patients were submitted to a matching-task of a pair of subsequent visual stimuli, in two conditions. In the dynamic condition, participants were shown movies of moving body-parts (hand, foot, arm and leg); in the static condition, participants were shown still images of the same body-parts. In each condition, on half of the trials at least one stimulus in the pair was from the participant's own body ('Self' condition), whereas on the remaining half of the trials both stimuli were from another person ('Other' condition). Results showed that in healthy participants the self-advantage was present when processing both static and dynamic body-parts, but it was more important in the latter condition. In RBD patients, however, the self-advantage was absent in the static, but present in the dynamic body-parts condition. These findings suggest that visual information from self body-parts in motion may be processed independently in patients with impaired static self-processing, thus pointing to a modular organization of the mechanisms responsible for the self/other distinction.