The authors would like to thank Angela Gomez Fonseca for the inspiration to develop the drive and all the students who ran pilot experiments with the animals, Milan Bogers, Floor van Ravenswoud, and Eva Severijnen. This work was supported by the Dutch Research Council (NWO; Crossover Program 17619 &#34;INTENSE&#34;).

Open&#45;Source Implant for Multi&#45;Region Electrophysiological Monitoring in Rats

<ol>
	<li>Deffieux, T., Demen&#233;, C., Tanter, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+Ultrasound+Imaging:+A+New+Imaging+Modality+for+Neuroscience.">Functional Ultrasound Imaging: A New Imaging Modality for Neuroscience.</a> Neuroscience. 474, 110-121 (2021).</li><li>Finn, E. S., Poldrack, R. A., Shine, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+neuroimaging+as+a+catalyst+for+integrated+neuroscience.">Functional neuroimaging as a catalyst for integrated neuroscience.</a> Nature. 623 (7986), 263-273 (2023).</li><li>Aharoni, D., Federico Guo, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aharoni-Lab/Miniscope-v4:+Release+for+generating.">Aharoni-Lab/Miniscope-v4: Release for generating.</a> GitHub. , (2023).</li><li>Takasaki, K., Abbasi-Asl, R., Waters, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superficial+bound+of+the+depth+limit+of+two-photon+imaging+in+mouse+brain.">Superficial bound of the depth limit of two-photon imaging in mouse brain.</a> eNeuro. 7 (1), (2020).</li><li>Buzs&#225;ki, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tools+for+probing+local+circuits:+High-density+silicon+probes+combined+with+optogenetics.">Tools for probing local circuits: High-density silicon probes combined with optogenetics.</a> Neuron. 86 (1), 92-105 (2015).</li><li>Lacroix, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+sleep+scoring+in+mice+reveals+human-like+stages.">Improved sleep scoring in mice reveals human-like stages.</a> bioRxi.v. , (2018).</li><li>Wilson, M. A., McNaughton, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+the+hippocampal+ensemble+code+for+space.">Dynamics of the hippocampal ensemble code for space.</a> Sci New Ser. 261 (5124), 1055-1058 (1993).</li><li>Jun, J. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fully+integrated+silicon+probes+for+high-density+recording+of+neural+activity.">Fully integrated silicon probes for high-density recording of neural activity.</a> Nature. 551 (7679), 232-236 (2017).</li><li>Headley, D. B., DeLucca, M. V., Haufler, D., Par&#233;, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incorporating+3D-printing+technology+in+the+design+of+head-caps+and+electrode+drives+for+recording+neurons+in+multiple+brain+regions.">Incorporating 3D-printing technology in the design of head-caps and electrode drives for recording neurons in multiple brain regions.</a> J Neurophysiol. 113 (7), 2721-2732 (2015).</li><li>Camba, J. D., Contero, M., Company, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parametric+CAD+modeling:+An+analysis+of+strategies+for+design+reusability.">Parametric CAD modeling: An analysis of strategies for design reusability.</a> Comput Aided Des. 74, 18-31 (2016).</li><li>Kloosterman, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro-drive+array+for+chronic+in+vivo+recording:+Drive+fabrication.">Micro-drive array for chronic in vivo recording: Drive fabrication.</a> J Vis Exp. (26), e1094 (2009).</li><li>Voigts, J., Siegle, J. H., Pritchett, D. L., Moore, C. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+flexDrive:+An+ultra-light+implant+for+optical+control+and+highly+parallel+chronic+recording+of+neuronal+ensembles+in+freely+moving+mice.">The flexDrive: An ultra-light implant for optical control and highly parallel chronic recording of neuronal ensembles in freely moving mice.</a> Front Syst Neurosci. 7, (2013).</li><li>Voigts, J., Newman, J. P., Wilson, M. A., Harnett, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+easy-to-assemble,+robust,+and+lightweight+drive+implant+for+chronic+tetrode+recordings+in+freely+moving+animals.">An easy-to-assemble, robust, and lightweight drive implant for chronic tetrode recordings in freely moving animals.</a> J Neural Eng. 17 (2), 026044 (2020).</li><li>Sheng, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+3D-printed+multi-driven+system+for+large-scale+neurophysiological+recordings+in+multiple+brain+regions.">A novel 3D-printed multi-driven system for large-scale neurophysiological recordings in multiple brain regions.</a> J Neurosci Methods. 361, 109286 (2021).</li><li>V&#246;r&#246;slakos, M., Petersen, P. C., V&#246;r&#246;slakos, B., Buzs&#225;ki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+microdrive+and+head+cap+system+for+silicon+probe+recovery+in+freely+moving+rodent.">Metal microdrive and head cap system for silicon probe recovery in freely moving rodent.</a> eLife. 10, e65859 (2021).</li><li>Mishra, A., Marzban, N., Cohen, M. X., Englitz, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamics+of+neural+microstates+in+the+VTA-striatal-prefrontal+loop+during+novelty+exploration+in+the+rat.">Dynamics of neural microstates in the VTA-striatal-prefrontal loop during novelty exploration in the rat.</a> bioRxiv. , (2020).</li><li>Allen, L. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RatHat:+A+self-targeting+printable+brain+implant+system.">RatHat: A self-targeting printable brain implant system.</a> eNeuro. 7 (2), (2020).</li><li>. Soldering Safety Available from: <a target="_blank" href="https://safety.eng.cam.ac.uk/safe-working/copy_of_soldering-safety">https://safety.eng.cam.ac.uk/safe-working/copy_of_soldering-safety</a> (2018)</li><li>. Harvard Soldering Safety Guidelines Available from: <a target="_blank" href="https://www.ehs.harvard.edu/sites/default/files/soldering_safety_guidelines.pdf">https://www.ehs.harvard.edu/sites/default/files/soldering_safety_guidelines.pdf</a> (2019)</li><li>Samanta, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CBD+lengthens+sleep+but+shortens+ripples+and+leads+to+intact+simple+but+worse+cumulative+memory.">CBD lengthens sleep but shortens ripples and leads to intact simple but worse cumulative memory.</a> iScience. 26 (11), 108327 (2023).</li><li>Machado, F., Malpica, N., Borromeo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parametric+CAD+modeling+for+open+source+scientific+hardware:+Comparing+OpenSCAD+and+FreeCAD+Python+scripts.">Parametric CAD modeling for open source scientific hardware: Comparing OpenSCAD and FreeCAD Python scripts.</a> PLOS One. 14 (12), e0225795 (2019).</li><li>Schwarz, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+head-fixed+behaving+rat:+Procedures+and+pitfalls.">The head-fixed behaving rat: Procedures and pitfalls.</a> Somatosens Mot Res. 27 (4), 131-148 (2010).</li><li>Gardiner, T. W., Toth, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereotactic+surgery+and+long-term+maintenance+of+cranial+implants+in+research+animals.">Stereotactic surgery and long-term maintenance of cranial implants in research animals.</a> Contemp Top Lab Anim Sci. 38 (1), 56-63 (1999).</li><li>Fran&#231;a, A. S. C., van Hulten, J. A., Cohen, M. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+and+versatile+electrodes+for+extracellular+chronic+recordings+in+rodents.">Low-cost and versatile electrodes for extracellular chronic recordings in rodents.</a> Heliyon. 6 (9), e04867 (2020).</li></ol>

TS and PvH are employees of 3Dneuro, Nijmegen, The Netherlands. 3Dneuro co-developed and produces the TD Drive.

Presented in this article is an adaptable implant for bilateral, symmetric multi-area wire electrode recordings for freely-moving rats.
The ability to easily adjust the implant by changing predefined parameters was one of the motivations for the creation of the TD Drive. While aiming to maximize the flexibility for changing parameters, inherent constraints in the relations between them necessarily impose limits to this adaptability. No limits are set by default for the anteroposterior paramete...

The multi-area nature of brain interactions during wake and sleep makes it difficult to exhaustively study the ongoing physiological processes. While approaches such as functional MRI (fMRI) and functional ultrasound (fUS) allow sampling of brain activity from whole brains1,2, they exploit neurovascular coupling to infer brain activity from hemodynamic activity, limiting their temporal resolution2. In addition, fMRI requires the placement of the research subject in an MRI scanner, prohibiting experiments with freely moving animals. Optical imaging of calcium dynamics with single or multiphoton imaging enables cell type-specific recordings of hundreds of neurons simultaneously3. However, head-mounted microscopes such as the Miniscope3, which do allow freely moving behavior, are usually limited to imaging superficial cortical areas in intact brains4. While the diameter of their field of view on the cortex can be in the order of 1 mm, the space requirements of these head-mounted microscopes can make it difficult to target several, especially adjacent, areas. Therefore, to capture multi-area brain dynamics in wake and sleep accurately, extracellular electrophysiology, recorded with electrodes implanted in the brain areas of interest, is one of the methods of choice due to its high temporal resolution and spatial precision5. In addition, it allows the characterization of sleep dynamics in animals compatible with analyses obtained from human EEG, increasing the translational value of this method6.
Classically, studies recording brain activity with extracellular electrodes have employed individual wire electrodes or electrode bundles, such as tetrodes7. State-of-the-art probes such as the Neuropixels probe8 allow targeting several areas simultaneously, given that they are aligned on an axis that allows implanting the probe along that axis without impairing the animal. However, accurate simultaneous recordings of multiple, spatially separated areas still remain challenging, with existing methods being either costly or time-intensive.
In recent years, additive manufacturing methods such as stereolithography have become broadly available. This allowed researchers to develop novel electrode implants that were adaptable to their experimental requirements9, for example, simplified repeatable targeting of multiple brain areas. Frequently, these implant designs are also shared with the academic community as open-source hardware, allowing other researchers to adapt them to their own purposes. The degree of adaptability of specific implants varies both as a result of how the implant is designed and how it is shared. Parametric modeling10 is a popular approach in computer-aided design, in which different components of the design are linked by interdependent parameters and a defined design history. Implementing a parametric approach for designing implants increases their reusability and adaptability10, as changing individual parameters automatically updates the complete designs without the need for complex re-modeling of the design. A consequential necessity is that the design itself is shared in an editable format that preserves the parametric relationships and design history. File formats that only represent geometric primitives, such as STL or STEP, make subsequent parametric modifications of published models unfeasible.
While tetrode hyperdrives11,12,13 enable recordings from dozens of tetrodes, their assembly and implantation are time-intensive, and their quality is largely dependent on the skill and experience of the individual researcher. In addition, they usually combine the guide tubes that direct the recording electrodes to their target location in one or two larger bundles, therefore limiting the number and spread of areas that can be targeted efficiently.
Other implants14,15 expose the complete skull and allow for the free placement of multiple individual microdrives that carry the recording electrodes. While the placement of independent microdrives16 during surgery time maximizes flexibility, it increases surgery time and can make it difficult to target multiple adjacent areas due to the space requirements of the individual microdrives. In addition, while the implants are open source, they are only published as STL files, making modification difficult.
An example of a drive with a more inherent parametric philosophy is the RatHat17. By providing a surgical stencil that covers the whole dorsal surface of the skull, it allows precise targeting of multiple brain targets without the use of a stereotactic frame during surgery. Multiple implant variations for cannulas, optrodes, or tetrodes are available. However, while the drive is free to use for academic purposes, it is not published open-source, creating a hurdle for researchers to evaluate and use the implant.
Presented in this article is the TD Drive (see Figure 1), a novel 3D-printable implant for extracellular electrode recordings in rats. The TD Drive aims to overcome some of the drawbacks of existing solutions: it allows to target multiple brain areas, mirrored across both hemispheres, with independent wire electrodes simultaneously. Due to its simple design, it can be assembled in a few hours at a relatively low cost by less experienced researchers. The TD Drive is published open-source, in easily modifiable file formats to allow researchers to adjust it to their specific needs. Incorporating a parametric 3D modeling approach from the beginning of the TD Drive&#39;s design process allows the parameters necessary to be changed to be abstracted: to change target locations, researchers can simply edit the parameters representing their dorsoventral and anteroposterior coordinates, without the need for re-designing the drive themselves. The files to modify and manufacture the TD Drive can be found at <a href="https://github.com/3Dneuro/TD_Drive">https://github.com/3Dneuro/TD_Drive</a>.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66457/66457fig01.jpg" /> 
Figure 1: Overview of the TD Drive. (A) Rendering of a TD Drive with a protective cap. (B) Rendering with inner parts shown. The TD Drive features (a)&#160;multiple, parametrically adjustable recording locations for fixed and moveable electrode wires, an EIB with (b) a high-density Omnetics connector compatible with common tethered and wireless data acquisition systems, and (c) an intuitive channel mapping optimized for recordings with Intan/Open Ephys systems (see Supplementary Figure 1) and (d) a cap to protect the implant during tethered recordings and when no headstage is connected. (C) A guide stencil on the bottom of the TD Drive facilitates the placement of guide cannulas and serves as a redundant verification of implant locations during surgery. <a href="https://www.jove.com/files/ftp_upload/66457/66457fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The implant design was piloted in n = 4, validated in n = 8, and confirmed in n= 8 Lister Hooded rats that performed different tasks. The first 4 animals were used to develop the drive and adjust parameters. Then, a full pilot was run with 8 animals (shown in results). A second cohort of 8 animals was run and included in the implant survival analysis. The implant was compatible with tethered sleep recordings and open field recordings (Object Exploration) as well as wireless recording in a large maze (HexMaze 9 m x 5 m) using two different commercial recording systems and headstages. The two cohorts of 8 were recorded with two different acquisition systems - tethered for longer sleep recordings and wireless for large maze exploration recordings. We can conclude that this simple wire drive allows for long-running experiments with larger cohorts by less experienced researchers to enable sleep stage analysis as well as oscillation analysis in multiple brain areas. This is in contrast to most electrophysiology implants to date, which, due to difficulty and time intensity, allow for smaller animal cohorts and usually need very experienced experimenters. However, with this drive, no individual neuron activity can be recorded; thus, the use is limited to investigations of local field potential (LFP) and summation activity.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.5 mm drill bit&#160;</td>
			<td>McMaster</td>
			<td>2951A38</td>
			<td></td>
		</tr>
		<tr>
			<td>1.27 mm pitch interconnected SIP/DIP socket (Mill-Max)</td>
			<td>Mouser Electronic</td>
			<td>575-003101</td>
			<td>For essembling and connection of EEG &#38; GND screws</td>
		</tr>
		<tr>
			<td>5 minute epoxy&#160;</td>
			<td>Bison</td>
			<td>Commercially available</td>
			<td>regular off-the-shelf epoxy</td>
		</tr>
		<tr>
			<td>cyanoacrylate glue</td>
			<td>Loctite</td>
			<td></td>
			<td>Super Glue-3&#160;</td>
		</tr>
		<tr>
			<td>EEG wire</td>
			<td>Science Products GmbH</td>
			<td>7SS-2T</td>
			<td></td>
		</tr>
		<tr>
			<td>Electrode wire</td>
			<td>Science Products GmbH</td>
			<td>NC7620F</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>LC</td>
			<td></td>
			<td>For standard pre-operative sterilization procedure of drive</td>
		</tr>
		<tr>
			<td>Fine forceps (5)</td>
			<td>FST</td>
			<td>91150-20</td>
			<td>For wire bundle preperation and handling</td>
		</tr>
		<tr>
			<td>Form 3B</td>
			<td>Formlabs</td>
			<td></td>
			<td>3D printer used to 3D print the self-printed parts of the TD drive</td>
		</tr>
		<tr>
			<td>Gold pins (small)</td>
			<td>Neuralynx, Inc.</td>
			<td>9885</td>
			<td>Attachment of electorde wires to EIB board</td>
		</tr>
		<tr>
			<td>Ground wire</td>
			<td>Science Products GmbH</td>
			<td>SS-3T/A</td>
			<td></td>
		</tr>
		<tr>
			<td>High-density connector&#160;</td>
			<td>LabMaker GmbH/Omnetics</td>
			<td>A79026-001</td>
			<td></td>
		</tr>
		<tr>
			<td>Lister Hodded rats</td>
			<td>Charles River Laboratories</td>
			<td>Crl:LIS</td>
			<td>we used male rats, 9-12 weeks of age at arrival</td>
		</tr>
		<tr>
			<td>M1 brass insert</td>
			<td>AliExpress</td>
			<td>Commercially available</td>
			<td>https://aliexpress.com/item/33047616164.html</td>
		</tr>
		<tr>
			<td>M1 tap</td>
			<td>McMaster</td>
			<td>2504A33</td>
			<td></td>
		</tr>
		<tr>
			<td>M1x16 screw</td>
			<td>Bossard</td>
			<td>1096613</td>
			<td></td>
		</tr>
		<tr>
			<td>M1x3 stainless steel screws&#160;</td>
			<td>Screws and More</td>
			<td>84213_14985</td>
			<td></td>
		</tr>
		<tr>
			<td>M2.5x5 polyimide screws</td>
			<td>Screws and more</td>
			<td>7985PA25S_50</td>
			<td></td>
		</tr>
		<tr>
			<td>mineral oil</td>
			<td>McMaster</td>
			<td>1244K14</td>
			<td></td>
		</tr>
		<tr>
			<td>Nail polish</td>
			<td>Etos</td>
			<td>Commercially available</td>
			<td>For color coding EEG and GND wires</td>
		</tr>
		<tr>
			<td>painter&#39;s tape</td>
			<td>Gamma</td>
			<td>Commercially available</td>
			<td>For wire bundle preperation</td>
		</tr>
		<tr>
			<td>Pin vise</td>
			<td>McMaster</td>
			<td>8455A16</td>
			<td></td>
		</tr>
		<tr>
			<td>plotting paper</td>
			<td>Canson</td>
			<td>Commercially available</td>
			<td>For wire bundle preperation</td>
		</tr>
		<tr>
			<td>polyimide tubes</td>
			<td>Amazon / Small Parts</td>
			<td>TWPT-0159-30-50</td>
			<td>AWG, 0.0159&#34; ID, 0.0219&#34; OD, 0.0030&#34; Wall, 30&#34; Length</td>
		</tr>
		<tr>
			<td>RHD 32-channel headstage with accelerometer</td>
			<td>Intan Technologies, LLC</td>
			<td>C3324</td>
			<td>For tethered recordings in the sleepbox</td>
		</tr>
		<tr>
			<td>RHD 3-ft (0.9 m) standard SPI cables</td>
			<td>Intan Technologies, LLC</td>
			<td>C3203</td>
			<td>From commutator to headstage</td>
		</tr>
		<tr>
			<td>RHD 6-ft (1.8 m) standard SPI cables</td>
			<td>Intan Technologies, LLC</td>
			<td>C3206</td>
			<td>From OpenEphys box to commutator</td>
		</tr>
		<tr>
			<td>Slip Ring with Flange</td>
			<td>Adafruit</td>
			<td>1196</td>
			<td>Commutator: 22 mm diameter, 12 wires</td>
		</tr>
		<tr>
			<td>Solder flux&#160;</td>
			<td>Griffon S-39 50 ml</td>
			<td>Commercially available</td>
			<td>For soldering EEG &#38; GND screws</td>
		</tr>
		<tr>
			<td>soldering paste</td>
			<td>Amazon</td>
			<td>B08CBZ5HC5</td>
			<td></td>
		</tr>
		<tr>
			<td>stainless steel M2 nut&#160;</td>
			<td>McMaster</td>
			<td>93935A305</td>
			<td></td>
		</tr>
		<tr>
			<td>Tethered recording setup&#160;</td>
			<td>OpenEphys</td>
			<td>Acquasition Board</td>
			<td></td>
		</tr>
		<tr>
			<td>Wireless recording logger</td>
			<td>SpikeGadgets</td>
			<td>miniLogger 32</td>
			<td>For wireless recordings in the task</td>
		</tr>
		<tr>
			<td>Wireless recording setup</td>
			<td>SpikeGadgets</td>
			<td>Main Control Unit (MCU) incl. breakout board and RF transceiver</td>
			<td>For wireless recordings in the task</td>
		</tr>
	</tbody>
</table>

the td drive: a parametric, open-source implant for multi&#45;area electrophysiological recordings in behaving and sleeping rats

Intricate interactions between multiple brain areas underlie most functions attributed to the brain. The process of learning, as well as the formation and consolidation of memories, are two examples that rely heavily on functional connectivity across the brain. In addition, investigating hemispheric similarities and/or differences goes hand in hand with these multi-area interactions. Electrophysiological studies trying to further elucidate these complex processes thus depend on recording brain activity at multiple locations simultaneously and often in a bilateral fashion. Presented here is a 3D-printable implant for rats, named TD Drive, capable of symmetric, bilateral wire electrode recordings, currently in up to ten distributed brain areas simultaneously. The open-source design was created employing parametric design principles, allowing prospective users to easily adapt the drive design to their needs by simply adjusting high-level parameters, such as anterior-posterior and mediolateral coordinates of the recording electrode locations. The implant design was validated in n = 20 Lister Hooded rats that performed different tasks. The implant was compatible with tethered sleep recordings and open field recordings (Object Exploration) as well as wireless recording in a large maze using two different commercial recording systems and headstages. Thus, presented here is the adaptable design and assembly of a new electrophysiological implant, facilitating fast preparation and implantation.

Using the instructions provided in the protocol, the TD Drive could be built easily by multiple experimenters. After drive development (n = 4), a full pilot was run with eight animals. An additional batch of eight animals was implanted, and experimental data collection was performed. As data analysis has not been completed on these animals, they have been included in the survival analysis, but not in other analyses (e.g., targeting or histology). Implant surgery was performed 2 weeks after arrival (see <strong class="xfi...

Read this Scientific Article Protocol about The TD Drive: A Parametric, Open-Source Implant for Multi-Area Electrophysiological Recordings in Behaving and Sleeping Rats at JoVE.com

Author Spotlight: Deciphering Memory and Learning Through Neural Implants for Multi&#45;Region Brain Studies

Here, we present a unique, 3D-printable implant for rats, named TD Drive, capable of symmetric, bilateral wire electrode recordings, currently in up to ten distributed brain areas simultaneously.

The TD Drive: A Parametric, Open-Source Implant for Multi&#45;Area Electrophysiological Recordings in Behaving and Sleeping Rats

Intricate interactions between multiple brain areas underlie most functions attributed to the brain. The process of learning, as well as the formation and ...

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JoVE Journal

Neuroscience

427 Views.  Radboud University. Here, we present a unique, 3D-printable implant for rats, named TD Drive, capable of symmetric, bilateral wire electrode recordings, currently in up to ten distributed brain areas simultaneously. 

Video: Author Spotlight: Deciphering Memory and Learning Through Neural Implants for Multi-Region Brain Studies

Electrophysiological Recordings from the Giant Fiber Pathway of D. melanogaster

When startled adult D. melanogaster react by jumping into the air and flying away. In many invertebrate species, including D. melanogaster, the "escape" (or "startle") response during the adult stage is mediated by the multi-component neuronal circuit called the Giant Fiber System (GFS). The comparative large size of the neurons, their distinctive morphology and simple connectivity make the GFS an attractive model system for studying neuronal circuitry. The GFS pathway is composed of two bilaterally symmetrical Giant Fiber (GF) interneurons whose axons descend from the brain along the midline into the thoracic ganglion via the cervical connective. In the mesothoracic neuromere (T2) of the ventral ganglia the GFs form electro-chemical synapses with 1) the large medial dendrite of the ipsilateral motorneuron (TTMn) which drives the tergotrochanteral muscle (TTM), the main extensor for the mesothoracic femur/leg, and 2) the contralateral peripherally synapsing interneuron (PSI) which in turn forms chemical (cholinergic) synapses with the motorneurons (DLMns) of the dorsal longitudinal muscles (DLMs), the wing depressors. The neuronal pathway(s) to the dorsovental muscles (DVMs), the wing elevators, has not yet been worked out (the DLMs and DVMs are known jointly as indirect flight muscles - they are not attached directly to the wings, but rather move the wings indirectly by distorting the nearby thoracic cuticle) (King and Wyman, 1980; Allen et al., 2006). The di-synaptic activation of the DLMs (via PSI) causes a small but important delay in the timing of the contraction of these muscles relative to the monosynaptic activation of TTM (~0.5 ms) allowing the TTMs to first extend the femur and propel the fly off the ground. The TTMs simultaneously stretch-activate the DLMs which in turn mutually stretch-activate the DVMs for the duration of the flight. The GF pathway can be activated either indirectly by applying a sensory (e.g."air-puff" or "lights-off") stimulus, or directly by a supra-threshold electrical stimulus to the brain (described here). In both cases, an action potential reaches the TTMs and DLMs solely via the GFs, PSIs, and TTM/DLM motoneurons, although the TTMns and DLMns do have other, as yet unidentified, sensory inputs. Measuring "latency response" (the time between the stimulation and muscle depolarization) and the "following to high frequency stimulation" (the number of successful responses to a certain number of high frequency stimuli) provides a way to reproducibly and quantitatively assess the functional status of the GFS components, including both central synapses (GF-TTMn, GF-PSI, PSI-DLMn) and the chemical (glutamatergic) neuromuscular junctions (TTMn-TTM and DLMn-DLM). It has been used to identify genes involved in central synapse formation and to assess CNS function.

Electrophysiological Recordings from the Giant Fiber Pathway of D. melanogaster

The Giant Fiber System is a simple neuronal circuit of adult Drosophila melanogaster containing the largest neurons in the fly. We describe the protocol for monitoring synaptic transmission through this pathway by recording post synaptic potentials in dorsal longitudinal (DLM) and tergotrochanteral (TTM) muscles following direct stimulation of the Giant Fiber interneurons.

When startled adult D. melanogaster react by jumping into the air and flying away. In many invertebrate species, including D. melanogaster, the "escape" ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

A Procedure for Implanting Organized Arrays of Microwires for Single-unit Recordings in Awake, Behaving Animals

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell level. The technique allows experimenters to examine temporally and regionally specific firing patterns in order to correlate recorded action potentials with ongoing behavior. Moreover, single-unit recordings can be combined with a plethora of other techniques in order to produce comprehensive explanations of neural function. In this article, we describe the anesthesia and preparation for microwire implantation. Subsequently, we enumerate the necessary equipment and surgical steps to accurately insert a microwire array into a target structure. Lastly, we briefly describe the equipment used to record from each individual electrode in the array. The fixed microwire arrays described are well-suited for chronic implantation and allow for longitudinal recordings of neural data in almost any behavioral preparation. We discuss tracing electrode tracks to triangulate microwire positions as well as ways to combine microwire implantation with immunohistochemical techniques in order to increase the anatomical specificity of recorded results.

Implanting organized arrays of microwires for use in single-unit electrophysiological recordings presents a number of technical challenges.&#160;Methods for performing this technique and the equipment necessary are described.&#160;Also, the beneficial use of organized microwire arrays to record from distinct neural subregions with high spatial selectivity is discussed.

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell ...

Building An Open-source Robotic Stereotaxic Instrument

This protocol includes the designs and software necessary to upgrade an existing stereotaxic instrument to a robotic (CNC) stereotaxic instrument for around $1,000 (excluding a drill), using industry standard stepper motors and CNC controlling software. Each axis has variable speed control and may be operated simultaneously or independently. The robot&#39;s flexibility and open coding system (g-code) make it capable of performing custom tasks that are not supported by commercial systems. Its applications include, but are not limited to, drilling holes, sharp edge craniotomies, skull thinning, and lowering electrodes or cannula. In order to expedite the writing of g-coding for simple surgeries, we have developed custom scripts that allow individuals to design a surgery with no knowledge of programming. However, for users to get the most out of the motorized stereotax, it would be beneficial to be knowledgeable in mathematical programming and G-Coding (simple programming for CNC machining).
The recommended drill speed is greater than 40,000 rpm. The stepper motor resolution is 1.8&#176;/Step, geared to 0.346&#176;/Step. A standard stereotax has a resolution of 2.88 &#956;m/step. The maximum recommended cutting speed is 500 &#956;m/sec. The maximum recommended jogging speed is 3,500 &#956;m/sec. The maximum recommended drill bit size is HP 2.

This protocol includes the designs and software necessary to upgrade an existing stereotaxic instrument to a robotic (computer numeric controlled; CNC) stereotaxic instrument for around $1,000 (excluding a drill).

This protocol includes the designs and software necessary to upgrade an existing stereotaxic instrument to a robotic (CNC) stereotaxic instrument for ...

Design and Fabrication of Ultralight Weight, Adjustable Multi-electrode Probes for Electrophysiological Recordings in Mice

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic targeting for microcircuit dissection and disease modeling. The introduction of optogenetics, for example, has allowed for bidirectional manipulation of genetically-identified neurons, at an unprecedented temporal resolution. To capitalize on these tools and gain insight into dynamic interactions among brain microcircuits, it is essential that one has the ability to record from ensembles of neurons deep within the brain of this small rodent, in both head-fixed and freely behaving preparations. To record from deep structures and distinct cell layers requires a preparation that allows precise advancement of electrodes towards desired brain regions. To record neural ensembles, it is necessary that each electrode be independently movable, allowing the experimenter to resolve individual cells while leaving neighboring electrodes undisturbed. To do both in a freely behaving mouse requires an electrode drive that is lightweight, resilient, and highly customizable for targeting specific brain structures.
A technique for designing and fabricating miniature, ultralight weight, microdrive electrode arrays that are individually customizable and easily assembled from commercially available parts is presented. These devices are easily scalable and can be customized to the structure being targeted; it has been used successfully to record from thalamic and cortical regions in a freely behaving animal during natural behavior.

Understanding the neural substrates of behavior requires brain circuit ensemble recording. Because of its genetic tractability, the mouse offers a model for circuit dissection and disease mimicry. Here, a method of designing and fabricating miniaturized probes is described that is suitable for targeting deep brain structure in the mouse.

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic ...

Simultaneous Long-term Recordings at Two Neuronal Processing Stages in Behaving Honeybees

In both mammals and insects neuronal information is processed in different higher and lower order brain centers. These centers are coupled via convergent and divergent anatomical connections including feed forward and feedback wiring. Furthermore, information of the same origin is partially sent via parallel pathways to different and sometimes into the same brain areas. To understand the evolutionary benefits as well as the computational advantages of these wiring strategies and especially their temporal dependencies on each other, it is necessary to have simultaneous access to single neurons of different tracts or neuropiles in the same preparation at high temporal resolution. Here we concentrate on honeybees by demonstrating a unique extracellular long term access to record multi unit activity at two subsequent neuropiles1, the antennal lobe (AL), the first olfactory processing stage and the mushroom body (MB), a higher order integration center involved in learning and memory formation, or two parallel neuronal tracts2 connecting the AL with the MB.&#160;The latter was chosen as an example and will be described in full. In the supporting video the construction and permanent insertion of flexible multi&#160;channel wire electrodes is demonstrated. Pairwise differential amplification of the micro&#160;wire electrode channels drastically reduces the noise and verifies that the source of the signal is closely related to the position of the electrode tip. The mechanical flexibility of the used wire electrodes allows stable invasive long&#160;term recordings over many hours up to days, which is a clear advantage compared to conventional extra&#160;and intracellular in vivo recording techniques.

Simultaneous extracellular long term recordings from two different brain neuropiles or two different anatomical tracts were established in honeybees. These recordings allow the investigation of temporal aspects of neuronal processing across different brain areas at the single neuron as well as at the ensemble level in a behaving animal.

In both mammals and insects neuronal information is processed in different higher and lower order brain centers. These centers are coupled via convergent ...

High-density Electroencephalographic Acquisition in a Rodent Model Using Low-cost and Open-source Resources

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network connectivity, are applicable to an expanding variety of questions in neuroscience. Performing these kinds of analyses in a rodent model requires higher electrode density than traditional screw electrodes can accomplish. While higher-density electroencephalographic montages for rodents exist, they are of limited availability to most researchers, are not robust enough for repeated experiments over an extended period of time, or are limited to use in anesthetized rodents.1-3 A proposed low-cost method for constructing a durable, high-count, transcranial electrode array, consisting of bilaterally implantable headpieces is investigated as a means to perform advanced electroencephalogram analyses in mice or rats.

Procedures for headpiece fabrication and surgical implantation necessary to produce high signal to noise, low-impedance electroencephalographic and electromyographic signals are presented. While the methodology is useful in both rats and mice, this manuscript focuses on the more challenging implementation for the smaller mouse skull. Freely moving mice are only tethered to cables via a common adapter during recording. One version of this electrode system that includes 26 electroencephalographic channels and 4 electromyographic channels is described below.

Instructions for the low-cost construction and surgical implantation of a chronic transcranial high-density electroencephalographic montage into mice are provided. Signal recording, extraction, and processing techniques are also described.

Advanced electroencephalographic analysis techniques requiring high spatial resolution, including electrical source imaging and measures of network ...

A Visual Guide to Sorting Electrophysiological Recordings Using 'SpikeSorter'

Few stand-alone software applications are available for sorting spikes from recordings made with multi-electrode arrays. Ideally, an application should be user friendly with a graphical user interface, able to read data files in a variety of formats, and provide users with a flexible set of tools giving them the ability to detect and sort extracellular voltage waveforms from different units with some degree of reliability. Previously published spike sorting methods are now available in a software program, SpikeSorter, intended to provide electrophysiologists with a complete set of tools for sorting, starting from raw recorded data file and ending with the export of sorted spikes times. Procedures are automated to the extent this is currently possible. The article explains and illustrates the use of the program. A representative data file is opened, extracellular traces are filtered, events are detected and then clustered. A number of problems that commonly occur during sorting are illustrated, including the artefactual over-splitting of units due to the tendency of some units to fire spikes in pairs where the second spike is significantly smaller than the first, and over-splitting caused by slow variation in spike height over time encountered in some units. The accuracy of SpikeSorter's performance has been tested with surrogate ground truth data and found to be comparable to that of other algorithms in current development.

The article shows how to use the program SpikeSorter to detect and sort spikes in extracellular recordings made with multi-electrode arrays.

Few stand-alone software applications are available for sorting spikes from recordings made with multi-electrode arrays. Ideally, an application should be ...

Electrophysiological Method for Whole-cell Voltage Clamp Recordings from Drosophila Photoreceptors

Whole-cell voltage clamp recordings from Drosophila melanogaster photoreceptors have revolutionized the field of invertebrate visual transduction, enabling the use of D. melanogaster molecular genetics to study inositol-lipid signaling and Transient Receptor Potential (TRP) channels at the single-molecule level. A handful of labs have mastered this powerful technique, which enables the analysis of the physiological responses to light under highly controlled conditions. This technique allows control over the intracellular and extracellular media; the membrane voltage; and the fast application of pharmacological compounds, such as a variety of ionic or pH indicators, to the intra- and extracellular media. With an exceptionally high signal-to-noise ratio, this method enables the measurement of dark spontaneous and light-induced unitary currents (i.e.&#160;spontaneous and quantum bumps) and macroscopic Light-induced Currents (LIC) from single D. melanogaster photoreceptors. This protocol outlines, in great detail, all the key steps necessary to perform this technique, which includes both electrophysiological and optical recordings. The fly retina dissection procedure for the attainment of intact and viable ex vivo isolated ommatidia in the bath chamber is described. The equipment needed to perform whole-cell and fluorescence imaging measurements are also detailed. Finally, the pitfalls in using this delicate preparation during extended experiments are explained.

Electrophysiological Method for Whole-cell Voltage Clamp Recordings from Drosophila Photoreceptors

Whole-cell recordings from Drosophila melanogaster photoreceptors enable the measurement of spontaneous dark bumps, quantum bumps, macroscopic responses to light, and current-voltage relationships under various conditions. In combination with D. melanogaster genetic manipulation tools, this method enables the study of the ubiquitous inositol-lipid signaling pathway and its target, the TRP channel.

Whole-cell voltage clamp recordings from Drosophila melanogaster photoreceptors have revolutionized the field of invertebrate visual transduction, ...

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the pathophysiological basis of these diseases, it is necessary to precisely characterize in which way the processing of information is disturbed between the different neuronal parts of the circuit. Using extracellular in vivo electrophysiological recordings, it is possible to accurately delineate neuronal activity within a neuronal network. The application of this method has several advantages over alternative techniques, e.g., functional magnetic resonance imaging and calcium imaging, as it allows a unique temporal and spatial resolution and does not rely on genetically engineered organisms. However, the use of extracellular in vivo recordings is limited since it is an invasive technique that cannot be universally applied. In this article, a simple and easy to use method is presented with which it is possible to simultaneously record extracellular potentials such as local field potentials and multiunit activity at multiple sites of a network. It is detailed how a precise targeting of subcortical nuclei can be achieved using a combination of stereotactic surgery and online analysis of multi-unit recordings. Thus, it is demonstrated, how a complete network such as the hyperdirect cortico-basal ganglia loop can be studied in anesthetized animals in vivo.

Acute In Vivo Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

In this study, the methodology is presented on how to perform multi-site in vivo electrophysiological recordings from the hyperdirect pathway under urethane anesthesia.

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the ...