"Initial results show promising neuron spike detection," Musk said in a post on the social media platform X on Monday.
Spikes are activity by neurons, which the National Institute of Health describes as cells that use electrical and chemical signals to send information around the brain and to the body.
In September, Neuralink said it received approval for recruitment for the human trial.
The study uses a robot to surgically place a brain-computer interface (BCI) implant in a region of the brain that controls the intention to move, Neuralink said previously, adding that its initial goal is to enable people to control a computer cursor or keyboard using their thoughts alone.
The implants' ultra-fine threads help transmit signals in participants' brains, Neuralink has said, according to Reuters.
The first product from Neuralink would be called Telepathy, Musk said in a separate post on X.
The startup's PRIME Study is a trial for its wireless brain-computer interface to evaluate the safety of the implant and surgical robot.
MP/PR