Ownership of an artificial limb induced by electrical brain stimulation

Abstract

Replacing the function of a missing or paralyzed limb with a prosthetic device that acts and feels like one's own limb is a major goal in applied neuroscience. Recent studies in nonhuman primates have shown that motor control and sensory feedback can be achieved by connecting sensors in a robotic arm to electrodes implanted in the brain. However, it remains unknown whether electrical brain stimulation can be used to create a sense of ownership of an artificial limb. In this study on two human subjects, we show that ownership of an artificial hand can be induced via the electrical stimulation of the hand section of the somatosensory (SI) cortex in synchrony with touches applied to a rubber hand. Importantly, the illusion was not elicited when the electrical stimulation was delivered asynchronously or to a portion of the SI cortex representing a body part other than the hand, suggesting that multisensory integration according to basic spatial and temporal congruence rules is the underlying mechanism of the illusion. These findings show that the brain is capable of integrating "natural" visual input and direct cortical-somatosensory stimulation to create the multisensory perception that an artificial limb belongs to one's own body. Thus, they serve as a proof of concept that electrical brain stimulation can be used to "bypass" the peripheral nervous system to induce multisensory illusions and ownership of artificial body parts, which has important implications for patients who lack peripheral sensory input due to spinal cord or nerve lesions.body perception | electrical brain stimulation | neuroprosthetics | multisensory integration | self

The Embodiment of Objects: Review, Analysis, and Future Directions

“…The rubber hand illusion is a well-established paradigm to study the sense of ownership in healthy individuals (Botvinick and Cohen, 1998;Ehrsson et al, 2004Ehrsson et al, , 2005Ehrsson et al, , 2008Tsakiris and Haggard, 2005;Tsakiris et al, 2006;Marasco et al, 2011;D'Alonzo and Cipriani, 2012;D'Alonzo et al, 2014;Collins et al, 2016). In the original rubber hand paradigm, participants sit with their left arm resting on a table, hidden behind a screen, and are asked to fixate on an anatomically congruent rubber hand (Botvinick and Cohen, 1998).…”

“…Is it possible to "embody" external objects, such as prosthetics or tools, that is, to treat or regard them as in some important sense actually part of our bodies? Most of the literature concludes that people can extend the borders of the physical body to temporarily incorporate different prosthetics, such as rubber hands, into their body image (i.e., their conscious beliefs regarding their bodies; see Botvinick and Cohen, 1998;Ehrsson et al, 2004Ehrsson et al, , 2005Ehrsson et al, , 2008Tsakiris and Haggard, 2005;Tsakiris et al, 2006;Marasco et al, 2011;D'Alonzo and Cipriani, 2012;D'Alonzo et al, 2014;Collins et al, 2016), and certain external objects, such as tools, into their body schema (i.e., their unconscious knowledge of their bodies and its capacities; see Cardinali et al, 2009bCardinali et al, , 2012Sposito et al, 2012;Baccarini et al, 2014;Garbarini et al, 2015). Several studies indicate that there are surprisingly few constraints on incorporating objects into either of these two kinds of body representations.…”

Time, touch and temperature affect perceived finger position and ownership in the grasp illusion

“…; see also Collins et al . ). Illusions of body ownership are typically induced by providing temporally congruent, repetitive multisensory stimuli in the presence of an artificial body part.…”

Creating a neuroprosthesis for active tactile exploration of textures

“…Therefore, it is possible that interference between feedback from natural somatosensory pathways (hand touching the joystick, proprioception) and S1 ICMS feedback made interpretation more difficult for monkey M. This indicates that further studies are necessary to determine, among other things, the best target in S1 for delivering ICMS that encodes tactile signals for future clinical neuroprosthesis. While delivering sensory feedback to an ethologically meaningful cortical area is likely important for the subject to assimilate any limb prosthesis as a natural appendage 35–37 , the use of different somatosensory regions in the cortex may facilitate the sensory-motor integration and tactile acuity. Therefore, we suggest that it may be necessary to deliver artificial sensory feedback to multiple cortical regions simultaneously to achieve the best performance of such limb prostheses.…”