Limb loss experience evoked by electric cortical stimulation

Limb loss experience is a type of body illusion characterized by the sensation of a missing limb or body part. We aimed to investigate the brain areas involved in this unusual somatosensory experience evoked by electric cortical stimulation with stereo-electroencephalography electrodes. We retrospectively reviewed the data of patients with medical intractable epilepsy, from October 2015 to December 2020, who underwent stereo-electroencephalography implantation and electric cortical stimulation in order to locate the epileptogenic zone and obtain a functional map. We included patients who reported experiences of limb loss during the process of electric cortical stimulation for functional mapping. Three patients reported experiences of limb loss in the process of electric cortical stimulation. Limb loss experience (including the right hand, right upper limb and right side of the body) occurred when the cortex of the left posterior insula, posterior dorsal cingulate and parietal operculum were stimulated. Limb loss experience can be evoked by electric cortical stimulation of the posterior insula, parietal operculum, and posterior cingulate cortex, and provides additional evidence that these cortices play a role in the integration of body sensory perception.