R2 headgear

Chronic implants with silicon probes are fragile and require a protective structure (headgear) around them. Headgear provides:

• a physical barrier to protect the implant site and microdrives/probes from animals and debris,

• a physical frame to secure the high-density connectors (or headstages for Neuropixels and mini amps for Cambridge Neurotech probes) and decouple them mechanically from the microdrives,

• (optional) A Faraday cage to improve recorded signals (less important nowadays when using neural data acquisition systems that digitize the signal very close to the electrode),

• (optional) The possibility to implement head fixation of the animals.

Traditionally, headgear has been constructed manually with copper mesh and dental cement during surgery (Vandecasteele et al., 2012). The rat and mouse cap, on the other hand, have been designed so that they are constructed before the surgery from 3D printed parts. Such a construction is more flexible while saving significant surgery time.

In addition, the mouse/rat cap are relatively easy to disassemble and reassemble, making it significantly easier to recover and reuse silicon probes in multiple experiments.

Finally, the mouse/rat cap have been designed in conjunction with the other R2 system components for an integrated implantation and explantation experience.