You are already a cyborg. You just don’t notice.
The blind man’s cane is not a tool he holds. It is an extension of his senses. The sense of touch transfers from the hand to the tip of the cane, and brain imaging studies show cortical reorganization after the use of assistive devices—the brain redraws its own maps to accommodate the new architecture of the body (Cardinali et al., 2009). The same principle applies to the surgeon’s scalpel, the driver’s steering wheel, the gamer’s controller. The brain does not distinguish between the biological hand and the tool it wields. It simply updates the body schema—the internal model of where the body ends and the world begins—to include the new effector (Maravita & Iriki, 2004).
This is not metaphor. It is neuroplasticity, and it is the foundation of every prosthetic and exoskeleton that will ever be built.
The Body Schema: A Map That Redraws Itself
The body schema is the brain’s unconscious model of the body’s position, shape, and capabilities. It is not fixed. It is continuously updated by multisensory input—vision, touch, proprioception—and it can be extended to include tools, prostheses, and even other people’s limbs. The classic demonstration is the rubber hand illusion: when a participant sees a rubber hand being stroked in synchrony with their own hidden hand, the brain resolves the multisensory conflict by incorporating the rubber hand into the body schema. The participant feels the touch on the rubber hand. They feel that the rubber hand is theirs (Botvinick & Cohen, 1998).
The neural mechanisms are now being mapped with precision. A 2024 study in Scientific Reports used somatosensory evoked fields to track cortical changes during the rubber hand illusion. The researchers found early displacement of the first cortical response at 20 milliseconds in Area 3b of the primary somatosensory cortex, and this displacement correlated with the extent of embodiment the participant reported. A second displacement at 35 milliseconds moved posteriorly toward Area 1, which is important for visual integration during touch perception. The conclusion is striking: the brain performs multiple neuroplastic processes in the somatosensory cortex to integrate artificial limbs into the body representation, and these processes last beyond the illusion itself (Isabella et al., 2024).
This is the biological substrate of prosthetic embodiment. The brain is not a passive recipient of the body it was born with. It is an active architect, constantly revising the boundaries of the self (Maravita & Iriki, 2004; Cardinali et al., 2009).
Prosthetics: From Tools to Limbs
The goal of modern prosthetics is not to replace a missing limb. It is to make the replacement feel like the original. This is the definition of prosthetic embodiment: the incorporation of a prosthesis into one’s sensory and functional body schema, such that the artificial limb is experienced as a part of the self.
The clinical reality is that this goal remains elusive. A major review in Neuroscience & Biobehavioral Reviews examined the state of prosthesis incorporation and found that while neuroscience has made progress in uncovering the basic mechanisms of bodily self-consciousness, the development of incorporated prosthetic limbs still faces substantial challenges in both basic neuroscience and clinical reality. The milestones that must be passed include the restoration of sensory feedback, the alignment of motor intention with prosthetic movement, and the resolution of the multisensory conflicts that arise when the brain receives contradictory information about the body’s state (Niedernhuber et al., 2018).
The most promising approaches combine surgical innovation with neural interfacing. Targeted muscle reinnervation (TMR) is a surgical procedure that redirects nerve pathways remaining after amputation to muscles that are still present, creating new interfaces through which neural signals can be retrieved (MedUni Vienna, 2025). When combined with implanted microelectrodes, TMR allows researchers to directly measure the activity of individual motor neurons—the nerve cells that transmit movement commands—and link their signal patterns to specific movement intentions. In a 2025 study published in Nature Biomedical Engineering, scientists at the Medical University of Vienna and Imperial College London demonstrated that complex movement intentions remain intact in the nervous system even after amputation, and can be mathematically reconstructed for precise control of bionic prostheses (Ferrante et al., 2025).
TMR also reduces postamputation pain by preventing the formation of painful neuromas, making it a critical intervention not just for prosthetic control but for quality of life (Ferrante et al., 2025). The regenerative peripheral nerve interface (RPNI) is a complementary technique that uses small muscle grafts to amplify electromyography signals and distinguish them from stochastic noise, enabling more refined prosthetic control (Vu et al., 2020).
The Brain-Computer Interface: Bypassing the Body
For patients with spinal cord injury or nerve lesions, the peripheral nervous system is not available to carry signals from the brain to the prosthesis. The solution is to bypass it entirely.
The most advanced demonstration of this approach is the double neural bypass (DNB) system, reported in Nature Medicine in 2026. The DNB links an intracortical brain-computer interface with targeted and patterned neuromodulation of the spinal cord and cortex. It allows brain signals associated with movement intention to directly control the movement of the user’s own hand in real time, while also promoting long-term sensorimotor recovery—even after the system is turned off. The system uses recurrent artificial neural networks and reinforcement learning for fine grasp control, together with patterned spinal cord stimulation and activity-informed intracortical microstimulation to promote neuroplasticity and durable recovery (Chandrasekaran et al., 2026).
In a participant with chronic C4 sensory/C5 motor complete tetraplegia, the DNB system enabled recovery of functional abilities including self-feeding and manipulation of delicate objects, while producing significant and persistent improvements in elbow flexion and wrist tactile sensation. The implications are profound: the brain can be trained to rewire the nervous system through the prosthetic itself, using the device not just as a replacement limb but as a rehabilitation tool that drives neuroplastic recovery (Chandrasekaran et al., 2026).
Intracortical microstimulation of the somatosensory cortex has also been used to restore tactile sensations in amputees. A 2016 study in Science Translational Medicine demonstrated that microstimulation within the hand region of the somatosensory cortex evokes tactile percepts that feel naturalistic, including feelings of pressure, and that these percepts can be evoked at low stimulation amplitudes and remain stable for months (Flesher et al., 2016). More recent work has used patterned microstimulation to produce complex tactile edges and motion sensations through brain stimulation, paving the way for a bionic hand that can feel the shape of objects it touches (Flesher et al., 2016).
Exoskeletons: Augmenting the Intact Body
Prosthetics replace what is missing. Exoskeletons augment what is present. The distinction matters for embodiment. A prosthesis must be integrated into the body schema as a replacement for a lost limb. An exoskeleton must be integrated as an extension of an existing limb—a wearable robot that the brain learns to treat as part of its own effector system.
The clinical evidence for exoskeleton rehabilitation is strongest for stroke and spinal cord injury. A 2025 scoping review in Physical Therapy Reviews analyzed 139 studies and found that the predominant health conditions using exoskeletons in rehabilitation were stroke and spinal cord injury, with the most common activities being indoor overground walking, balance, and transfers. The review also found a significant limitation: only 4% of studies utilized exoskeletons at home or in community settings, meaning the technology remains largely confined to clinical environments (Abery et al., 2025).
The next generation of exoskeletons is hybrid, combining robotic assistance with functional electrical stimulation (FES). A 2025 study in Nature Communications tested a hybrid system for overground gait training that integrates neuromuscular ES with a motorized exoskeleton. The hybrid condition reduced knee motor torque by 48% during swing without compromising tracking accuracy, and neurological participants rated the hybrid system as more usable than the exoskeleton alone. The mechanism is synergistic: the robot provides precise task execution, while the electrical stimulation induces muscle contractions that provide afferent feedback relevant to brain plasticity (Dell’Eva et al., 2025).
The embodiment of exoskeletons is a more complex problem than the embodiment of prosthetics. A prosthesis replaces a missing body part, so the brain’s body schema has a slot to fill. An exoskeleton wraps around an intact limb, so the brain must extend its body schema outward to include the device. Research on human-exoskeleton integration has identified neurophysiological markers of embodiment, including event-related potentials N60 and N100 that serve as indices of embodiment and cognitive load. The process through which the central nervous system integrates external devices is known as tool embodiment, and it is primarily assessed through subjective questionnaires—a limitation that the neurophysiological markers are beginning to address (Bertuccelli et al., 2025).
The Extended Mind
The implications of this research extend far beyond rehabilitation. If the brain can incorporate a prosthetic limb into its body schema, it can incorporate any tool that is used with sufficient skill and feedback. The blind man’s cane, the surgeon’s scalpel, the astronaut’s robotic arm—all become extensions of the self, not because of any philosophical stance, but because the brain’s body schema is fundamentally plastic (Maravita & Iriki, 2004).
The trajectory is clear. The prosthetics of the future will not be devices that the user controls. They will be limbs that the user inhabits. The exoskeletons of the future will not be robots that the user wears. They will be augmentations that the user becomes. The boundary between the biological body and the technological extension will blur—not because the technology becomes more human, but because the human becomes more technological.
The assembly line wants you rigid, compliant, and predictable. The extended body is flexible, adaptive, and sovereign. The tools are waiting. The brain is ready. The only question is how far the self will stretch.
References
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Botvinick, M., & Cohen, J. (1998). Rubber hands ‘feel’ touch that eyes see. Nature, 391(6669), 756.
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Ferrante, L., Boesendorfer, A., Barsakcioglu, D. Y., et al. (2025). Implanted microelectrode arrays in reinnervated muscles allow separation of neural drives from transferred polyfunctional nerves. Nature Biomedical Engineering, 10, 1485–1500.
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