Micro-drive Array for Chronic in vivo Recording: Drive Fabrication

Summary

In this protocol we demonstrate how to fabricate a micro-drive array for chronic electrophysiological recordings in rats.

Abstract

Chronic recording of large populations of neurons is a valuable technique for studying the function of neuronal circuits in awake behaving rats. Lightweight recording devices carrying a high density array of tetrodes allow for the simultaneous monitoring of the activity of tens to hundreds of individual neurons. Here we describe a protocol for the fabrication of a micro-drive array with twenty one independently movable micro-drives. This device has been used successfully to record from hippocampal and cortical neurons in our lab. We show how to prepare a custom designed, 3-D printed plastic base that will hold the micro-drives. We demonstrate how to construct the individual micro-drives and how to assemble the complete micro-drive array. Further preparation of the drive array for surgical implantation, such as the fabrication of tetrodes, loading of tetrodes into the drive array and gold-plating, is covered in a subsequent video article.

Protocol

1. Micro-drive array overview
   
   A complete micro-drive array consists of several main components (Fig. 1):
   1. A computer designed plastic base that holds 21 independently movable micro-drives.
   2. A cannula at the bottom of the base in which a set of stationary tetrode guide tubes is collected.
   3. 21 micro-drives that each carry one tetrode and which can be individually driven using a screw.
   4. An electrode interface board for interconnection between tetrodes and pre-amplifiers.
   5. A protective cone (not shown in Fig. 1)
   6. In a fully assembled micro-drive array, the plastic base holds all micro-drives. Each micro-drive carries....

Discussion

This protocol describes the general features of the micro-drive building process. It has been successfully modified to produce drive arrays with multiple recording targets or smaller arrays for recordings in mice. In addition to recording from the hippocampus, many researchers use these drives to target cortical and sub-cortical structures. The use of longer screws may be required in order to record from deeper brain structures. With extensive modification to the drive base, motorized drives my be used in lieu of manuall.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
3D-printed plastic parts	Material	American Precision Prototyping (www.approto.com)
stainless steel tubing	Material	Small Parts (www.smallparts.com)
Dental cement powder	Material	A-M Systems (www.a-msystems.com)	525000
Dental cement solvent	Material	A-M Systems	526000
Electrode interface board	Material	Neuralynx (www.neuralynx.com)	EIB-81
micro-drive screws	Material	Advanced Machining and Tooling (www.amtmfg.com)
’Tap-Ease’ tapping lubricant	Tool	AGS Company	TA-2
Polyimide tubing	Material	IWG High Performance Conductors (www.iwghpc.com)
Cordless drill/driver	Tool	DeWalt (www.dewalt.com)	DC750KA
Variable-Speed Rotary Tool Kit with Flex-Shaft	Tool	Dremel (www.dremel.com)	3956-02
Razor blades	Tool	VWR (www.vwr.com)	55411-050
Watch glass	Tool	VWR	66112-107
Tap for custom screws	Tool	Balax	01302
Taps	Tool	Small Parts	HSBT-0172, HSBT-0080
Pin vise	Tool	Vargus	3SHC1--I
Drill bits	Tool	Small Parts
Benchtop vise	Tool	Panavise	301
No.2 Dumont forceps	Tool	Stoelting (www.stoeltingco.com)	52100-27
5-minute epoxy	Tool	Allied Electronics (www.alliedelec.com)
Accu-Tek Carbofib Tip Tweezers	Tool	Aven (www.aveninc.com)	18768 (Pattern 304)
Micro Dissecting Scissors	Tool	Biomedical Research Instruments (www.biomedinstr.com)	25-1000
Xcelite 378M Pliers	Tool	Newark	96F8903
mini pin vise	Tool	MSC Industrial Supply (www.mscdirect.com)	00920314