A pacemaker for your brain.

Discover surveys the state of the research into deep-brain stimulation (DBS), using electrical implants to treat conditions from Parkinson’s to chronic pain, OCD, depression and Alzheimer’s:

Currently, DBS is approved by the U.S. Food and Drug Administration to treat patients with movement disorders, including Parkinson’s disease, essential tremor and epilepsy. The FDA sanctioned the use of deep brain stimulation for refractory obsessive-compulsive disorder and dystonia under the Humanitarian Device Exemption. However, scientists believe that tapping into the brain could treat a wide variety of conditions and are continuing to explore DBS as a possible therapy for a range of conditions, including certain types of depression, chronic pain, Tourette syndrome and Alzheimer’s disease.

While experts are still uncertain about how exactly DBS affects the neural network, the prevailing theory is that the procedure causes what’s called an informational lesion: The networks in the brain are communicating with bad information, which causes the neurological dysfunction, but DBS delivers a constant stream of electrical impulses — between two to four milliamps — to drown out the bad information with white noise.

“It’s blocking part of the bad information from causing problems,” [Northwestern Memorial Hospital neurosurgeon Joshua] Rosenow says. “It doesn’t reestablish normal, but it cuts off some of these bad signals from causing problems and from causing symptoms.”

“Like any technology, it can be used for ill,” says Philip Starr, a neurosurgeon at UCSF Health. “There are privacy considerations. With a sensing device, can someone hack into your brain device and read brain signals? Eventually, there will probably be a way in which your brain signals can identify you, the way a retinal scan or a fingerprint identifies you.”

Starr reassures the public that the ethical questions and implications raised by the advancements in this field are important factors in how federal agencies fund neuroscience research. For example, the National Institutes of Health’s BRAIN Initiative, established in 2013, created a neuroethics division to work closely with researchers and to establish a set of ethical tenets that address the novel uses of neurostimulation and other techniques.

“We and many others are partnered with neuroethicists who are studying our patients, caregivers and clinicians to try to define, what are the ethical considerations with these devices that can change emotional state and can in principle change how you think?” Starr says. “How are we to think about the use of these devices, eventually for people who don’t have a brain disease, but just want to have improved function? Is that going to happen?”