The Responsive Neurostimulator, a brain implant designed by Neuropace to detect and block the onset of seizures, can significantly reduce their frequency in people with difficult-to-treat epilepsy.

The device, which consists of a neurostimulator that’s smaller than a deck of cards, a battery, and a small computer, continuously monitors electrical activity. It’s surgically implanted into a hollowed out part of the skull, along with a set of electrical leads that can both record electrical activity and dispense jolts of electricity. The leads are placed either on the surface of the brain or deep in the brain tissue, depending on where a patient’s seizures begin.