We have designed an implantable metal headplate that fits into head holders for head fixation. This ensures stability during behavior, recording, and/or imaging.
Our head plate design is optimized to allow maximal access to left primary somatosensory cortex (S1), but otherwise to have maximal adhesion and stability. You may want to modify it to access other areas.
The headplate design can be stamped out of a sheet of stainless steel, or it can be cut and milled. We use a vendor called AP-Proto for simple designs like this. Their prices are very reasonable. Quality can be variable but we have found them to be responsive to our concerns. They can also make it out of titanium, but we personally question whether this is necessary to resist the kinds of forces mice can produce.
Here is the headplate design in Sketchup, STEP, IGES, and STL formats. The Sketchup format is proprietary, unfortunately, but it is easy to edit and they provide a free trial version of the software. The STL format should be easier to open in a variety of CAD programs, but may be more difficult to edit. We used a Sketchup extension to export STL files, and we used FreeCAD to convert STL to STEP and IGES. Please contact us if you can recommend a good format that is easy to edit and universally readable by a wide variety of CAD programs.
You can also order our exact head plate from AP-Proto without even providing the design file. Our contact is Georgianne Gilliam, ggilliam at approto dot com. You can request the item from Quotation 136239 and they can send you the exact same piece that we ordered. It should be about $35 each, at least if you order 10 of them at once. They are made of stainless steel and it takes about one week. You can request the "micro-cut" process which will be more expensive but more accurate, but I found this to be unnecessary.
You can also order the headplate laser cut from Laser Alliance, for a price of only $8/implant.
NOTE: this is now our preferred method- we will put up the necessary CAD file soon, or ask us for details.
Head holder 1: more constrained for greater stability
This head holder uses a notch that exactly matches the head plate in size, so that there is no freedom of rotation. We use one head holder like this on each side of the headplate to ensure ~10um stability between sessions.
You can order your own head holder at Shapeways. Use this STL file and request stainless steel. They should be about $10 each.
Head holder 2: more flexible, dovetail design
This head holder is a simple dovetail that mates with a NOGA Flex-arm, allowing maximum flexibility in the placement of the head. The dovetail has an 0-80 nut soldered to it. You simply put the head plate above the hole in the dovetail, and insert and tighten an 0-80 screw. The screw head holds the headplate in place on the head holder.
Here is a DXF file for this design.