Utah array

A 4 mm silicon square with a 10×10 grid of needle electrodes, the longest-used implant for recording single neurons in people.

• Each of its 100 needles is about 1–1.5 mm long, reaching the cortical layers where the brain's output neurons fire.
• Developed at the University of Utah in the 1990s, it powered BrainGate trials from 2004 in which paralysed people moved robot arms and typed.
• Recording quality typically declines over months to years as scar tissue forms around the rigid needles.
• Early systems used a connector through the scalp, raising infection risk; Blackrock Neurotech makes it.