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RatHat: A self-targeting printable brain implant system

JANUARY 9, 2020

Leila Allen and colleagues in Tim Allen’s lab at Florida International University recently developed RatHat, a self-targeting printable brain implant system. Below they describe their project:


“There has not been a major change in how neuroscientists approach stereotaxic methods in decades. Here we present a new stereotaxic method that improves on traditional approaches by reducing costs, training, surgical time, and aiding repeatability. The RatHat brain implantation system is a 3D printable stereotaxic device for rats that is fabricated prior to surgery and fits to the shape of the skull. RatHat builds are directly implanted into the brain without the need for head-leveling or coordinate-mapping during surgery. The RatHat system can be used in conjunction with the traditional u-frame stereotaxic device, but does not require the use of a micromanipulator for successful implantations. Each RatHat system contains several primary components including the implant for mounting intracranial components, the surgical stencil for targeting drill sites, and the protective cap for impacts and debris. Each component serves a unique function and can be used together or separately. We demonstrate the feasibility of the RatHat system in four different proof-of-principle experiments: 1) a 3-pole cannula apparatus, 2) an optrode-electrode assembly, 3) a fixed-electrode array, and 4) a tetrode hyperdrive. Implants were successful, durable, and long-lasting (up to 9 months). RatHat print files are easily created, can be modified in CAD software for a variety of applications, and are easily shared, contributing to open science goals and replications. The RatHat system has been adapted to multiple experimental paradigms in our lab and should be a useful new way to conduct stereotaxic implant surgeries in rodents.

RatHat is freely available to academic researchers, achieving open science goals. Academic and non-profit researchers interested in receiving the 3D files can contact Dr. Timothy Allen (tallen@fiu.edu). We will first provide you a simple noncommercial license to be executed by your institution, and upon completion, printable and editable 3D files of the implant system. Our responses are fast, and all files are provided immediately after receiving the aforementioned document. Our goals are noncommercial, and our only interests are to share RatHat as widely as possible in support of our open science goals and to improve the pace of discovery using chronic brain implant systems for behavioral studies.”

 


The Allen lab has provided a video tutorial on how to implant RatHat, which you can view here on youtube.

 

For more details, you can check out the preprint here.

 

3D Printed Headstage Implant

June 6, 2019

Richard Pinnell from Ulrich Hofmann’s lab has three publications centered around open-source and 3D printed methods for headstage implant protection and portable / waterproof DBS and EEG to pair with water maze activity. We share details on the three studies below:


Most researchers opt to single-house rodents after rodents have undergone surgery. This helps the wound heal and prevent any issues with damage to the implant. However, there is substantial benefits to socially-housing rodents, as social isolation can create stressors for them. As a way to continue to socially-house rats, Pinnell et al. (2016a) created a novel 3D-printed headstage socket to surround an electrode connector. Rats were able to successfully be pair housed with these implants and their protective caps.

The polyamide headcap socket itself is 3D printed, and a stainless steel thimble can be screwed into it. The thimble can be removed by being unscrewed to reveal the electrode connector. This implant allows both for increased well-being of the rodent post-surgery, but also has additional benefits in that it can prevent any damage to the electrode implant during experiments and keeps the electrode implant clean as well.

The 3D printed headcap was used in a second study (Pinnell et al., 2016b) for wireless EEG recording in rats during a water maze task. The headstage socket housed the PCB electrode connector and the waterproof wireless system was attached. In this setup, during normal housing conditions, this waterproof attachment was replaced with a standard 18×9 mm stainless-steel sewing thimble, which contained 1.2 mm holes drilled at either end for attachment to the headstage socket. A PCB connector was manufactured to fit inside the socket, and contains an 18-pin zif connector, two DIP connectors, and an 18-pin Omnetics electrode connector for providing an interface between the implanted electrodes and the wireless recording system.

Finally, the implant was utilized in a third study (Pinnell et al., 2018) where the same group created a miniaturized, programmable deep-brain stimulator for use in a water maze. A portable deep brain stimulation (DBS) device was created through using a PCB design, and this was paired with the 3D printed device. The 3D printed headcap was modified from its use in Pinnell et al., 2016a to completely cover the implant and protect the PCB. The device, its battery, and housing weighs 2.7 g, and offers protection from both the environment and from other rats, and can be used in DBS studies during behavior in a water maze.

The portable stimulator, 3D printed cap .stl files, and more files from the publications can be found on https://figshare.com/s/31122e0263c47fa5dabd.


Pinnell, R. C., Almajidy, R. K., & Hofmann, U. G. (2016a). Versatile 3D-printed headstage implant for group housing of rodents. Journal of neuroscience methods, 257, 134-138.

Pinnell, R. C., Almajidy, R. K., Kirch, R. D., Cassel, J. C., & Hofmann, U. G. (2016b). A wireless EEG recording method for rat use inside the water maze. PloS one, 11(2), e0147730.