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

Summary

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.

Abstract

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.

Introduction

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 brains^1,2, 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 mult....

Protocol

The present study was approved by the Dutch Central Commissie Dierproeven (CCD) and conducted according to the Experiments on Animals Act (protocol codes: 2020-0020-006 & 2020-0020-010). Male Lister Hooded rats of 9-12 weeks on arrival were used. The reagents and the equipment used in the protocol are listed in the Table of Materials. See Supplementary Figure 1 and Supplementary Figure 2 for the steps of the drive-building process.

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Discussion

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.......

Materials

Name	Company	Catalog Number	Comments
0.5 mm drill bit	McMaster	2951A38
1.27 mm pitch interconnected SIP/DIP socket (Mill-Max)	Mouser Electronic	575-003101	For essembling and connection of EEG & GND screws
5 minute epoxy	Bison	Commercially available	regular off-the-shelf epoxy
cyanoacrylate glue	Loctite		Super Glue-3
EEG wire	Science Products GmbH	7SS-2T
Electrode wire	Science Products GmbH	NC7620F
Ethanol	LC		For standard pre-operative sterilization procedure of drive
Fine forceps (5)	FST	91150-20	For wire bundle preperation and handling
Form 3B	Formlabs		3D printer used to 3D print the self-printed parts of the TD drive
Gold pins (small)	Neuralynx, Inc.	9885	Attachment of electorde wires to EIB board
Ground wire	Science Products GmbH	SS-3T/A
High-density connector	LabMaker GmbH/Omnetics	A79026-001
Lister Hodded rats	Charles River Laboratories	Crl:LIS	we used male rats, 9-12 weeks of age at arrival
M1 brass insert	AliExpress	Commercially available	https://aliexpress.com/item/33047616164.html
M1 tap	McMaster	2504A33
M1x16 screw	Bossard	1096613
M1x3 stainless steel screws	Screws and More	84213_14985
M2.5x5 polyimide screws	Screws and more	7985PA25S_50
mineral oil	McMaster	1244K14
Nail polish	Etos	Commercially available	For color coding EEG and GND wires
painter's tape	Gamma	Commercially available	For wire bundle preperation
Pin vise	McMaster	8455A16
plotting paper	Canson	Commercially available	For wire bundle preperation
polyimide tubes	Amazon / Small Parts	TWPT-0159-30-50	AWG, 0.0159" ID, 0.0219" OD, 0.0030" Wall, 30" Length
RHD 32-channel headstage with accelerometer	Intan Technologies, LLC	C3324	For tethered recordings in the sleepbox
RHD 3-ft (0.9 m) standard SPI cables	Intan Technologies, LLC	C3203	From commutator to headstage
RHD 6-ft (1.8 m) standard SPI cables	Intan Technologies, LLC	C3206	From OpenEphys box to commutator
Slip Ring with Flange	Adafruit	1196	Commutator: 22 mm diameter, 12 wires
Solder flux	Griffon S-39 50 ml	Commercially available	For soldering EEG & GND screws
soldering paste	Amazon	B08CBZ5HC5
stainless steel M2 nut	McMaster	93935A305
Tethered recording setup	OpenEphys	Acquasition Board
Wireless recording logger	SpikeGadgets	miniLogger 32	For wireless recordings in the task
Wireless recording setup	SpikeGadgets	Main Control Unit (MCU) incl. breakout board and RF transceiver	For wireless recordings in the task