https://techcrunch.com/2023/01/31/precision-neuroscience-is-making-brain-implants-safer-smarter-and-reversible/

Brain researchers have relied on devices called microelectrode arrays for decades, but the technology behind these tools is increasingly outdated. Precision Neuroscience is building a modern alternative that’s not only an order of magnitude better, but far less invasive to put in. With a newly raised $41 million in the bank, they’re all set to embark on the complex path to market.

In order to understand what’s going on in the brain, sometimes a EEG or MRI from outside it just isn’t enough — you need to really get in there. Implanted electrodes have been used for this purpose for a long time, and arrays of them in formation are used to collect information from multiple points within the cortex at the same time.