Brain Implant

What is a Brain Implant?

A brain implant is a device surgically placed in or on the brain to record neural activity, stimulate it, or both. Uses include treatment of neurological disorders and research on controlling external devices from brain signals. General cognitive enhancement remains a research aim, not an established benefit.

The terms are not interchangeable. Neural implants are a broader category that includes devices elsewhere in the nervous system. A brain-machine interface can use an implant, but it can also use non-invasive sensors outside the head.

Examples of Brain Implants

Deep Brain Stimulation (DBS)

DBS uses implanted electrodes to deliver electrical stimulation to specific brain regions. It is used for movement disorders such as Parkinson's disease, essential tremor, and dystonia, and has been investigated for psychiatric conditions including obsessive-compulsive disorder and depression. The NIMH guide to brain stimulation therapies explains the approaches and their clinical limits. Evidence and authorization apply to particular devices and conditions.

Motor Cortex Implants

These implants record activity from the motor cortex so that a computer can translate signals into commands for a cursor or robotic limb. In Hochberg and colleagues' robotic-arm study, two people with tetraplegia used implanted recordings to control reaching and grasping. Controlling an external arm is useful, but it does not mean movement has returned to the person's own arm.

Related Neural Implants

Cochlear Implants

Cochlear implants act in the inner ear, bypassing damaged structures to stimulate the auditory nerve. They combine external components, including a microphone and processor, with an implanted electrode array. They can provide a sense of sound to people with severe hearing loss, although they do not recreate normal hearing. The NIDCD cochlear implant guide describes how they work. Their location makes them neural prostheses, not brain implants.

Retinal Implants

Retinal implants are placed in the eye. They are designed to stimulate remaining retinal cells in people with retinal degeneration and send visual information through the optic nerve. They belong to the wider field of neural prostheses, but they are not implanted in the brain.