A non-profit organisation has filed a complaint with the US Department of Agriculture (USDA) alleging animal mistreatment was committed by Elon Musk's Neuralink and the University of California, Davis.
The Physicians Committee for Responsible Medicine (PCRM) said that, based on the university’s records, it believed 15 of the 23 monkeys who were experimented on died or were euthanised, it told Fortune.
It comes just a month after the brain-chip start-up advertised for a clinical trials director who would oversee the chipping of humans.
Musk said in December 2021 that the company was hoping to implant its first devices into humans some time this year.
Geneticist Dr Adam Rutherford was forthright in his criticism of Musk's plans at the time, describing them as "absolute balls".
"This is god-level c**kwaffle, typical of the manballs beloved of these ignorant dorks," the author of the book Control: The Dark History and Troubling Present of Eugenics tweeted.
Rutherford's scepticism may be justified after the PCRM said "invasive and deadly brain experiments" were conducted on the macaque monkeys, after UC Davis received US$1.4 million from Neuralink to conduct them.
The complaint is based on around 600 pages of "disturbing documents" released after the committee, which represents 17,000 doctors, filed a public records lawsuit in 2021.
The PCRM has also filed a second public record lawsuit to compel the release of videos and photographs of the monkeys, which it said the university was withholding.
Most of the animals had "portions of their skulls removed to implant electrodes in their brains" and weren't provided with adequate veterinary care, the committee said.
"UC Davis may have handed over its publicly-funded facilities to a billionaire, but that doesn't mean it can evade transparency requirements and violate federal animal welfare laws," research advocacy coordinator Jeremy Beckham said.
"The documents reveal that monkeys had their brains mutilated in shoddy experiments and were left to suffer and die. It's no mystery why Elon Musk and the university want to keep photos and videos of this horrific abuse hidden from the public."
PCRM says an unapproved substance called 'Bioglue' was used on the macaque monkeys, and they were caged alone, had steel posts screwed to their skulls and suffered "facial trauma and seizures" after implants as well as infections at the implant sites.
The complaint calls for both Neuralink and AC Davis to be penalised if the allegations are found to be true.
Neuralink hasn't made any comment on the complaint yet, but a UC Davis spokesperson said the university's partnership with the company ended in 2020.
They said the university's Institutional Animal Care and Use Committee had "thoroughly reviewed and approved" the research protocols it used with Neuralink.
"We strive to provide the best possible care to animals in our charge," the spokesperson said.