Early in our company’s infancy, we relied on external institutions to provide, house, and care for animals while we built our own in-house animal program. In 2017, we chose to partner with the University of California, Davis’s prestigious California National Primate Research Center (CNPRC) to conduct animal based research. Over the next two and a half years we worked with the staff at UC Davis to establish the foundations of Neuralink’s research and development mission.

When starting this type of medical research, novel surgeries are typically performed first in animal cadavers and then later in terminal procedures. Cadavers are deceased animals who have been humanely euthanized due to a veterinary decision for a medical concern or euthanized as part of a previous unrelated research study.

Terminal procedures involve the humane euthanasia of an anesthetized animal at the completion of the surgery. Animals that fall into this category have been deemed by the veterinary staff to be healthy enough for one anesthetic event but may not have proper quality of life due to a pre-existing condition. Performing initial surgeries on cadavers and terminal procedures ensures that an animal does not potentially suffer post-operatively in the event the test procedure has an unexpected result.

We therefore started our first studies at UC Davis using both cadavers and terminal procedures. These animals were assigned to our project on the day of the surgery for our terminal procedure because they had a wide range of pre-existing conditions unrelated to our research.

In addition to pre-existing conditions these animals may have happened to lose digits throughout their life from conflicts with other monkeys. Missing digits are often a result of rhesus macaques resolving conflict through aggressive interactions with one another. See, for example, this article about digit trauma in rhesus troops.

No such injuries occurred at any time to animals housed at UC Davis while part of Neuralink’s project.

The initial work from these procedures allowed us to develop our novel surgical and robot procedures, establishing safer protocols for subsequent survival surgeries. Survival studies then allowed us to test the function of different generations of implanted devices as we refined them towards human use. The use of every animal was extensively planned and considered to balance scientific discovery with the ethical use of animals. As part of this work, two animals were euthanized at planned end dates to gather important histological data, and six animals were euthanized at the medical advice of the veterinary staff at UC Davis. These reasons included one surgical complication involving the use of the FDA-approved product (BioGlue), one implant's connecting hardware became loose, and four suspected infections, a risk inherent with any percutaneous medical device. In response we developed new surgical protocols and a fully implanted device design for future surgeries.

Once construction of our in-house facility was completed, we were able to bring some unimplanted macaques from UC Davis with us to Neuralink. This included Pager, who would later be implanted with our Neuralink device and go on to achieve outstanding brain-computer interface performance, while freely behaving and unrestrained, as demonstrated in the Monkey MindPong video.

All animal work done at UC Davis was approved by their Institutional Animal Care and Use Committee (IACUC) as mandated by Federal law, and all medical and post-surgical support, including endpoint decisions were overseen by their dedicated and skilled veterinary staff.

While the facilities and care at UC Davis did and continue to meet federally mandated standards, we absolutely wanted to improve upon these standards as we transitioned animals to our in-house facilities.