A medical group opposed to medical animal testing plans to take legal action against Neuralink, the startup founded by Elon Musk to develop brain implants that could act as brain-computer interfaces, the group told Fortune. At the heart of the group's complaint are allegations that Neuralink and a university it worked with researched to abuse monkeys in medical experiments.

The Physicians Committee for Responsible Medicine (PCRM) said it will file an administrative lawsuit Thursday with the United States Department of Agriculture (USDA) against Neuralink and the University of California, Davis, which is helping Neuralink conduct its research into brain computation in primates. The medical group wants the USDA, which regulates animal testing under the Animal Welfare Act, to investigate multiple cases of alleged abuse of monkeys by Neuralink and UC Davis employees. This alleged animal abuse led to chronic infections caused by surgery, mental stress and "extreme suffering," according to the complaint, which cites university-maintained animal care records. The complaint asks USDA to sanction both Neuralink and UC Davis if the alleged violations are substantiated.

A spokesman for UC Davis noted that the university's Neuralink partnership ended in 2020. The spokesperson added that the university's Institutional Animal Care and Use Committee "thoroughly reviewed and approved" the research protocols for its project with Neuralink. "We strive to provide the best possible care for the animals in our care," said the UC Davis spokesman. "Animal testing is strictly regulated, and UC Davis complies with all applicable laws and regulations, including those of the US Department of Agriculture."

PCRM has publicly opposed animal testing and has filed lawsuits against various academic institutions since 2005, primarily to preserve public records of animal testing. But Neuralink is an unusually visible target: Thanks to the high public profile of its founder, its research has garnered a disproportionate amount of public attention, both positive and negative. (Call it the Elon Musk Effect.) A video of a monkey using a Neuralink brain implant to play the video game Pong, posted to YouTube last April, has already been viewed nearly 6 million times. And last year, Musk said he hopes to start testing Neuralink implants in humans by the end of 2022.

PCRM recently received animal care records related to the Neuralink research from the university, after filing a separate lawsuit in California Superior Court last May alleging that UC Davis obtained the group's records in violation of the federal law withheld.

In 2017, Neuralink signed an agreement with UC Davis, home of a renowned primate research facility, for the startup to research its brain and computer chip technology with the help of UC Davis employees. Since then, at least 23 monkeys at UC Davis have been involved in Neuralink's research on surgical implants.

Based on the university's records, PCRM believes 15 of those monkeys died or were euthanized as a result of the study, PCRM study board coordinator Jeremy Beckham told Fortune. When the research agreement between Neuralink and UC Davis ended in 2020, the university transferred seven monkeys to Neuralink, he said. (Beckham says it's unclear what happened to Monkey 23 as the record ends abruptly in November 2019.)

Although it received certain records from UC Davis, PCRM also alleges that the university withheld videos, photos and identification numbers related to the monkeys, which the group believes will provide further evidence that the primates were mistreated. The group plans to separately file an amended complaint in California on Thursday, based on its earlier May lawsuit, seeking the information it believes was withheld.

The UC Davis spokesman denied PCRM's claims of withholding information, saying, "We have fully complied with the California Public Records Act in responding to your request."

Beckham said one of the UC Davis records described a monkey "actually collapsing from exhaustion and convulsing," and that the monkey's keepers found that they were videotaping his behavior to monitor his health.

"So we know, honestly, these videos and photos are going to be disturbing," Beckham said. "We want to access these videos and show people a little more of the reality of what it's like in this Elon Musk-funded lab."

Beckham acknowledged that PCRM opposes all forms of animal testing for medical purposes, and that if you examined other academic institutions doing brain computing that lack Neuralink's high profile, "you would find some of the same problems." However, he added that PCRM believes that, as a public entity, UC Davis has an obligation to disclose the nature of its work with the startup.

"Here you have UC Davis researchers moving and operating on a whim with the private funding of a billionaire," Beckham said. "I think it raises some deeper ethical questions here about how these projects are viewed," he added of the animals.

Several brain computing experts have told Fortune that the animals involved appear to be healthy based on the public demonstrations Neuralink has released so far. For example, several sources noted that the primate in the widely viewed "MonkeyPong" video appeared strong and consistent.