Neuralink opened the study trial for recruitment last September. The startup did not immediately respond to a Reuters request for further details. Neuralink has faced calls for scrutiny regarding its safety protocols.Reuters reported earlier this month that the company was fined for violating U.S. Department of Transportation (DOT) rules regarding the movement of hazardous materials. Last November, four U.S. lawmakers asked the U.S. Securities and Exchange Commission to investigate whether Musk committed securities fraud by allegedly misleading investors about the safety of a brain implant being developed by Neuralink.