Bodily self‐recognition in patients with pathological embodiment

Abstract

The ability to discriminate between one's own and others' body parts can be lost after brain damage, as in patients who misidentify someone else's hand as their own (pathological embodiment). Surprisingly, these patients do not use visual information to discriminate between the own and the alien hand. We asked whether this impaired visual discrimination emerges only in the ecological evaluation when the pathological embodiment is triggered by the physical alien hand (the examiner's one) or whether it emerges also when hand images are displayed on a screen. Forty right brain‐damaged patients, with (E+ = 20) and without (E− = 20) pathological embodiment, and 24 healthy controls underwent two tasks in which stimuli depicting self and other hands was adopted. In the Implicit task, where participants judged which of two images matched a central target, the self‐advantage (better performance with Self than Other stimuli) selectively emerges in controls, but not in patients. Moreover, E+ patients show a significantly lower performance with respect to both controls and E− patients, whereas E− patients were comparable to controls. In the Explicit task, where participants judged which stimuli belonged to themselves, both E− and E+ patients performed worst when compared to controls, but only E+ patients hyper‐attributed others' hand to themselves (i.e., false alarms) as observed during the ecological evaluation. The VLSM revealed that SLF damage was significantly associated with the tendency of committing false alarm errors. We demonstrate that, in E+ patients, the ability to visually recognize the own body is lost, at both implicit and explicit level.

Spatial perspective and identity in visual awareness of the bodily self-other distinction

“…Within a neuropsychological approach, it has been reported that brain lesions to the right hemisphere can disrupt the so-called self-advantage (i.e., the facilitation to implicitly discriminate self-versus other people's visually presented hands 16 , 17 ). Moreover, brain damages can lead also to the misattribution of the own contralesional limb to another person 18 , 19 , or even the opposite behavior, namely the misattribution of somebody else’s arms to oneself 20 – 22 . As above, also these data suggest that the stimulus identity (i.e., self or other) might be functionally dissociable.…”

Proprioception impacts body perception in healthy aging – insights from a Psychophysical and Computational Approach

“…It is worth noting that with respect to other exteroceptive sensations such as vision and hearing that track mainly stimuli related to external objects, proprioception is strongly associated with one's own body and its movements [75][76][77][78] . Previous studies in pathological conditions indicated the loss of proprioception as a necessary, although not sufficient, condition to develop pathological alterations in BO.…”