Vivid Mental Imagery of Biomechanically Impossible Movements Elicited by Cortical Electrostimulation of the Central Region in an Awake Patient.

BACKGROUND: The perception we have of our own body, called 'body image,' is crucial for self-awareness. Here, we evoked reproducible mental imagery of a postural illusion by intrasurgical electrostimulation of the central cortex. CASE REPORT: A 24-year-old patient experienced seizures involving vivid mental imagery of biomechanically impossible movements of the upper limb. A right precentral low-grade glioma was diagnosed. Awake surgery with intraoperative electrostimulation sensorimotor mapping was performed. Remarkably, the same mental representations of biomechanically impossible movements of the left upper limb were repeatedly elicited during stimulation of the central cortex. These eloquent areas were preserved, even though the precentral part of the knob of the hand was removed. After a transient monoplegia, the patient recovered and resumed a normal life which included playing the guitar.
CONCLUSION: These mental experiences of a postural illusion generated by intraoperative stimulation could be related to neuroplasticity mechanisms induced by the slow growth of low-grade glioma within the knob of the hand. Such a functional reorganization may explain why this area was removed without permanent deficits. This perception of biomechanically impossible movements during surgery might be due to a transient disruption by stimulating the frontoparietal network involved in the coding of the body image.