Here's what it's like inside the operating room when someone gets a brain implant

As the lights dimmed in an operating room at The Mount Sinai Hospital in New York City, Dr. Joshua Bederson prepared to make history.

Bederson, system chair for the Department of Neurosurgery at Mount Sinai Health System, is no stranger to long hours in an operating room. The former competitive gymnast has completed more than 6,500 procedures in his career, and he said he visualizes the steps for each one as if he's rehearsing for a routine.   

On this particular morning in April, Bederson was readying for a meningioma resection case, which meant he would be removing a benign brain tumor. Bederson said his primary focus is always on caring for the patient, but in some cases, he also gets to help advance science. 

This procedure was one such case. 

A small crowd gathered as Bederson took his seat in the operating room, his silhouette aglow from the bright white light shining on the patient in front of him. Health-care workers, scientists and CNBC craned forward – some peering through windows – to watch as Bederson placed four electrode arrays from Precision Neuroscience onto the surface of the patient's brain for the first time. 

An electrode is a small sensor that can detect and carry an electrical signal, and an array is a grid of electrodes. Neurosurgeons use electrodes during some procedures to help monitor and avoid important parts of the brain, like areas that control speech and movement.

Precision is a three-year-old startup building a brain-computer interface, or a BCI. A BCI is a system that decodes neural signals and translates them into commands for external technologies. Perhaps the best-known company in the field is Neuralink, which is owned by Tesla and SpaceX CEO Elon Musk.

Other companies like Synchron and