Elon Musk’s neurotechnology startup Neuralink filed for permits to build an in-house machine shop and a biological testing laboratory for its facility in San Francisco last year.

The documentation on the company’s 2017 permits was retrieved by Gizmodo, which was able to access Neuralink’s public records. An excerpt of a letter submitted by Neuralink executive Jared Birchall on February 2017 to the city’s planning department gives some clues about the company’s plans for the facility’s proposed machine shop and animal testing lab.

“The tenant intends to use the 2nd floor as an interdisciplinary workroom for electrical, chemical, mechanical & materials engineering and computer science development, with a small machine shop attached, to modify prefabricated small bio-mechanical devices as well as perform 3D printing and CNC (Computer Numerical Control) milling. The machine shop is an accessory use to the workroom.

“The tenant intends to use the 3rd floor as a biological research laboratory for neurological interface testing and development. Ancillary to this use, the tenant will require a clean room for microfabricated device integration, a small operating room for in vivo testing, and a small room to house rodents. This will follow the CNC/NIH Animal Biosafety Laboratory Level 1. The use of rodents is exempt from the Animal Welfare Act. The clean room, operating room, and rodent housing uses are accessory to the laboratory use.”

Neuralink also filed for a permit from the California Department of Public Health in April 2017, directly referencing the utilization of laboratory animals. The document was submitted to the CDPH, which subsequently approved the permit in May 2017. According to a California DPH spokesperson who spoke to the publication, however, city officials have not inspected Neuralink’s facility after the permit was approved. The DPH spokesperson further added that Neuralink’s permit would expire on April 2018, but so far, the neurotech company has not filed for renewal.

Ultimately, Neuralink’s permits for its biological testing laboratory indicates, at least to some extent, that the company is making progress on its projects. In a statement to Gizmodo, Alik Widge, a psychiatrist-engineer at Massachusetts General Hospital involved in electrical and magnetic brain stimulation research, stated that testing on rodents is a valuable and inherent part of the research development process, especially for companies with goals as ambitious as Neuralink.

“When you think about the body, we’re made mostly of salt water. You can see what a year or two of that will do to a car. Now imagine what it will do to a high-precision medical device, especially one that’s putting out electric signals. The role of animal testing is to show that the risk of any of that happening is incredibly low,” Widge said.

Now more than a year old, the specifics of Neuralink’s projects are still a mystery. What is known, however, is that the startup is aimed at developing neural lace technologies, which are designed to foster links between the human brain and computers. As we noted in a previous report, these linkages, later dubbed as “wizard hats for the brain,” will likely be possible through the use of microelectromechanical systems (MEMS). MEMS are comprised of incredibly small robots that are biocompatible, which means that they would, by design, be able to proliferate throughout the human body.