Design and Construction of a Cost Effective Headstage for Simultaneous Neural Stimulation and Recording in the Water Maze

Summary

We present a low-cost method to design and construct a light headstage pre-amplifier system with simultaneous neural recording and stimulation capability. This device can be waterproofed for use in swimming animals.

Abstract

Headstage preamplifiers and source followers are commonly used to study neural activity in behavioral neurophysiology experiments. Available commercial products are often expensive, not easily customized, and not submersible. Here we describe a method to design and build a customized, integrated circuit headstage for simultaneous 4-channel neural recording and 2-channel simulation in awake, behaving animals. The headstage is designed using a free, commercially available CAD-type design package, and can be modified easily to accommodate different scales (e.g. to add channels). A customized printed circuit board is built using surface mount resistors, capacitors and operational amplifiers to construct the unity gain source follower circuit. The headstage is made water-proof with a combination of epoxy, parafilm and a synthetic rubber putty. We have successfully used this device to record local field potentials and stimulate different brain regions simultaneously via independent channels in rats swimming in a water maze. The total cost is < $30/unit and can be manufactured readily.

Protocol

1. Headstage Design and Fabrication Overview

A completed headstage pre-amplifier system consists of the following components:

1. A computer designed integrated circuit board with four channels of recording and two channels of stimulation.
2. Electrodes that relay the recordings and stimulation channels to the appropriate connectors on the animals head stage.
3. A tether cable and interface that relays the recording and stimulation channels to a slip-ring commutator.
4. Two forms of waterproofing on the head stage and on the integrated circuit.

2. Design and Layout of the....

Discussion

Water maze based behavioral tasks provide effective tools to probe animals' cognitive abilities and representations in real time ¹. The use of lightweight and cost effective headstage preamplifiers is especially critical in behavioral neurophysiology applications involving the water maze. Because escaping the cold water provides intrinsic motivation for animals in these tasks, their behavior can be tested in repeated trials without the difficulties of motivating animals on dry mazes. The low cost headstage pre.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Custom designed Integrated Circuit Board	ExpressPCB.com	Custom	2 layer double sided PCB
Surface mount Resistors	Mouser Electronics	RK73B1JTTDD156J	1/10 W, 15 M Ohm 0603, Thick film
SMD Capacitors	Newark Inc	0402YD104KAT2A	0.1 uF (0402)
SMD Operational Amplifier (quad FET)	Mouser Electronics	595-TLC2274AIPW	Quad FET - low noise
9 pin ABS socket	Ginder Scientific	GS09SKT-220	For animal connection
9-pin ABS Plug	Ginder Scientific	GS09PLG-220	To be implanted in animal
Black Delrin Ring Nut	Ginder Scientific	GS09BDN-220
Black Delrin Cap Nut	Ginder Scientific	GS09BDC-220	For protecting animal’s implant
Amphenol pins (male)	Ginder Scientific	220-P02
Amphenol pins (female)	Ginder Scientific	220-S02
5-minute epoxy	Devcon Inc.	S-208 / 20845
Poster Tack Putty	Elmer’s	026000015318
Rosin Core Solder	Radio Shack	64-009
Soldering Iron	Weller	Pyropen WSTA6	(adjustable heat)
Metal tweezers	Fine Science Tools	Size 5
Parafilm sheets	American National Can	Parafilm 4" x 250’
Magnet wire	Belden	8052	Enamel Coated
Ammeter/ Multimeter	Fluke Biomedical	77 Multimeter
Millmax Double Row Headers	Mill-Max	575 - 002101	0.05"
Solder Wick	Chemtronics	7-10L	0.75 in.