An experimental brain implant containing tens of thousands of living neurons can form cell connections with the brains of mice. Such a device could eventually enable sophisticated control over millions of neurons on the level of individual cells – but without relying on surgically implanted electrodes that penetrate and destroy brain tissue.

The biohybrid implant, developed by California-based start-up Science Corporation, differs from many other brain-computer interface devices, which usually contain arrays of electrodes that penetrate the brain and sometimes damage cells. In comparison, Science Corporation’s implant is…