MultiChannel | PS40W | Specifications | MultiChannel PS40W Specifications

MEA-System Manual
Information in this document is subject to change without notice.
No part of this document may be reproduced or transmitted without the express written
permission of Multi Channel Systems MCS GmbH.
While every precaution has been taken in the preparation of this document, the publisher and the
author assume no responsibility for errors or omissions, or for damages resulting from the use of
information contained in this document or from the use of programs and source code that may
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document.
© 2010 Multi Channel Systems MCS GmbH. All rights reserved.
Printed: 27.11.2009
Multi Channel Systems
MCS GmbH
Aspenhaustraße 21
72770 Reutlingen
Germany
Fon
+49-71 21-90 92 5 - 0
Fax
+49-71 21-90 92 5 -11
info@multichannelsystems.com
www.multichannelsystems.com
Microsoft and Windows are registered trademarks of Microsoft Corporation. Products that are
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these trademarks.
Table of Contents
1
Important Information and Instructions
5
1.1
Operator's Obligations
5
1.2
Guarantee and Liability
5
1.3
Important Safety Advice
6
2
Welcome to MEA-Systems
9
2.1
Basic Components ofMEA-Systems
9
2.2
System Configurations and Optional Components
10
2.2.1 Single Components for Standard-Systems
10
2.2.2 Enhanced Perfusion-System (-E)
10
2.2.3 MEA1060-BC Amplifier with Stimulus Artifact Suppression
2.2.4 MEA60 and MEA120-System
11
2.2.5 MEA Switch for Using Additional Amplifiers
11
2.3
Accessories
11
2.4
Add-ons for Stimulation
12
2.5
Setting Up the MEA-System
12
2.6
Supply Power and Recommended Setups
13
3
Extracellular Recording From MEAs
14
3.1
Introduction
14
3.2
Background
14
3.3
Signal types
15
3.3.1 Single Unit Activities
15
3.3.2 Local Field Potentials
15
3.4
15
Recording and Stimulation
3.4.1 Microelectrode Arrays (MEAs)
16
3.4.2 Signal Amplification and Filters
16
3.4.3 Data Acquisition
17
3.5
20
Using the Additional Analog Inputs
3.5.1 Recording Voice on Analog Inputs
20
3.6
20
Digital Input/Output, System Synchronization
3.6.1 Triggering the MC_Card and MC_Rack
11
20
3.6.2 Custom Switch for "Remote-Controlling" of the MC_Card
3.6.3 Triggering Other Instruments by the MC_Card
21
4
Troubleshooting
22
4.1
About Troubleshooting
22
4.2
Triggering / Digital Input Does not Work
22
4.3
Artifacts Caused by Perfusion
23
21
5
Appendix
25
5.1
Contact Information
25
5.2
Ordering Information
26
5.2.1 MEA-Systems
26
5.2.2 MEA Amplifiers
27
5.2.3 Accessories
27
5.2.4 Stimulus Generators
28
Important Information and Instructions
1
Important Information and Instructions
1.1
Operator's Obligations
The operator is obliged to allow only persons to work on the device, who

are familiar with the safety at work and accident prevention regulations and have been instructed
how to use the device;

are professionally qualified or have specialist knowledge and training and have received
instruction in the use of the device;

have read and understood the chapter on safety and the warning instructions in this manual and
confirmed this with their signature.
It must be monitored at regular intervals that the operating personnel are working safely.
Personnel still undergoing training may only work on the device under the supervision of an
experienced person.
1.2
Guarantee and Liability
The General conditions of sale and delivery of Multi Channel Systems MCS GmbH always apply.
The operator will receive these no later than on conclusion of the contract.
Multi Channel Systems MCS GmbH makes no Guarantee as to the accuracy of any and all tests and
data generated by the use of the device or the software. It is up to the user to use good
laboratory practice to establish the validity of his findings.
Guarantee and liability claims in the event of injury or material damage are excluded when they
are the result of one of the following.

Improper use of the device

Improper installation, commissioning, operation or maintenance of the device

Operating the device when the safety and protective devices are defective and/or inoperable

Non-observance of the instructions in the manual with regard to transport, storage, installation,
commissioning, operation or maintenance of the device

Unauthorized structural alterations to the device

Unauthorized modifications to the-System settings

Inadequate monitoring of device components subject to wear

Improperly executed and unauthorized repairs

Unauthorized opening of the device or its components

Catastrophic events due to the effect of foreign bodies or acts of God
5
MEA-System Manual
1.3
Important Safety Advice
Warning: ME- / MEA-Systems include several instruments as individual components. Each
instrument is shipped with a separate Manual. The information in the individual Manuals
fully apply to the complete-System. This manual is only to be understood as an additional
information. Read all Manuals thoroughly before setting up the system.
Warning: Obey always the rules of local regulations and laws. Only qualified personnel
should be allowed to perform laboratory work. Work according to good laboratory practice
to obtain best results and to minimize risks.
The product has been built to the state of the art and in accordance with recognized safety
engineering rules. The device may only

be used for its intended purpose;

be used when in a perfect condition.

Improper use could lead to serious, even fatal injuries to the user or third parties and damage to
the device itself or other material damage.
Warning: The devices and the software are not intended for medical uses and must not be
used on humans.
Malfunctions which could impair safety should be rectified immediately.
High Voltage
Electrical cords must be properly laid and installed. The length and quality of the cords must be in
accordance with local provisions.
Only qualified technicians may work on the electrical system. It is essential that the accident
prevention regulations and those of the employers' liability associations are observed.

Each time before starting up, make sure that the mains supply agrees with the specifications of
the products.

Check the power cords for damage each time the site is changed. Damaged power cords should
be replaced immediately and may never be reused.

Check the leads for damage. Damaged leads should be replaced immediately and may never be
reused.

Do not try to insert anything sharp or metallic into the vents or the case of the products.

Liquids may cause short circuits or other damage. Keep the devices and the power cords always
dry. Do not handle it with wet hands.
Electromagnetic compatibility of the MC_Card
The MC_Card data acquisition board is only intended for research work in laboratories. It belongs
to product class 0 conforming to the European Product Regulations and the CE (Conformité
Européenne) marking. The MC_Card complies with all applicable directives specified in the Council
Directive for Electromagnetic Compatibility (89/336/EU).
6
Important Information and Instructions
Requirements for the installation

The MC_Card is only suitable for extra-low voltages and shall be used only as specified.

The equipment shall be correctly earthed or connected to the ground.

The analog inputs should be closed or connected to active signals.

Connections to all inputs and outputs shall be made with screened cables specified by Multi
Channel Systems. The screen has to be connected to a solid earth or chassis connection. ESD
voltages at open lines may cause malfunction during operation.

The products shall only be operated from approved power packs (if necessary).
7
Welcome to MEA-Systems
2
Welcome to MEA-Systems
2.1
Basic Components of MEA-Systems
Multi Channel Systemss provides complete solutions for stimulation, perfusion, recording, and
data acquisition from up to 128 channels, data analysis and export. The MEA (microelectrode
array) product line is intended for extracellular electrophysiological recordings in vitro.
Applications include whole-heart preparations; acute brain, heart, and retina slices; cultured slices;
and dissociated neuronal or cardiomyocyte cell cultures.
In the following, all basic components that are part of all complete MEA-Systems are briefly
described.
A microelectrode array is an arrangement of 60 electrodes that allows the simultaneous
targeting of several sites for extracellular stimulation and recording. Cell lines or tissue slices are
placed directly on the MEA and can be cultivated for up to several months. Almost all excitable or
spontaneously active cells and tissues can be used. The temperature controller TC01/02
regulates the MEA temperature.
Raw data from the MEA electrodes are amplified by MEA1060 filter amplifiers with custom
bandwidth and gain, which are built very small and compact using SMD (Surface Mounted
Devices) technology. The small-sized MEA1060 amplifier combines the interface to the MEA probe
with the signal filtering and the amplification of the signal. The compact design reduces line pick
up and keeps the noise level down. All MEA1060 amplifiers are available either for inverted
microscopes or for upright microscopes, MEA1060-Inv and MEA1060-Up, respectively.
The analog input signals are then acquired and digitized by the MC_Card that is preinstalled on
the data acquisition computer.
68-pin MCS high grade cables C68x3M (3 meters), C68x1M (1 meter), or C68x0.5M (0.5 meter) are
used for connecting the MEA1060 amplifier, the MC_Card, and any additional devices. The
computer supplies the power for the amplifiers via the isolated power supply IPS10W (for one
amplifier and MEA60-System, or two amplifiers and MEA120-System). The supply power is
distributed to the amplifiers via the MCS high grade cable as well. Please note that you need an
external power supply if you use a MEA switch for operating multiple amplifiers.
Recorded data is graphed, analyzed, and reviewed with the powerful and easy-to-use MC_Rack
program. You can export the data in standard formats to other programs with the MC_DataTool.
9
MEA-System Manual
2.2
System Configurations and Optional Components
Multi Channel Systems provides several complete standard configurations and custom systems.
This chapter will give you an overview on different system configurations. Please see also the
handout Microelectrode Array Systems System Suggestions, which shows diagrams of
several typical setups.
Please note that you have various options for setting up your personal MEA-System configuration.
For more information about the scope of delivery of your system, please see the separate please
see the separate shipping documents.
Please see the separate documentation for information on installing and operating the individual
components of your MEA-System. All warnings and safety related information of the separate
documents apply and must be regarded.
Do not hesitate to contact MCS or your local retailer if you are interested in a particular setup or if
you have other questions.
2.2.1 Single Components for Standard Systems
The following components are part of MEA standard systems. Please make sure that you have
carefully studied the documentation on the single components before setting up your system. All
manuals can be found on the installation volume shipped with the system. Updated versions can
also be downloaded from the MCS web site.
Web link to the Manuals download page on www.multichannelsystems.com
Product
Manual / Reference
MEA probes of your choice
MEA Manual
Temperature controller TC01 or TC02
TC01/2 Manual
Perfusion cannula PH01 with programmable fluid
temperature (systems with enhanced perfusion E only)
PH01 Manual
MEA1060 amplifier(s) with custom bandwidth and
gain settings
MEA Amplifier (with Blanking Circuit) for
Upright/Inverse Microscopes Manual,
MEA_Select Help
MEA Switch (MEA60-2-Systems and MEA120-4Systems only)
MEA Switch Manual, MEA_Switch Help
Data acquisition computer with MC_Card and
integrated isolated power supply IPS10W or external
power supply PS40W
MEA-System Manual
Data acquisition and analysis software MC_Rack and
MC_DataTool
MC_Rack Manual / Help, MC_Rack
Tutorial
Complete MEA-System / Setup
MEA-System Manual, Microelectrode
Array Systems — Suggested Setups, MEA
Application Notes
2.2.2 Enhanced Perfusion System (-E)
A perfusion system is required especially for recordings from acute slices. All systems can be
upgraded with an enhanced perfusion system (indicated by the code –E), featuring a perfusion
cannula PH01 with programmable fluid temperature and a two-channel temperature controller
TC02 for controlling both the MEA culture chamber temperature and the fluid temperature in
parallel.
10
Welcome to MEA-Systems
2.2.3 MEA1060-BC Amplifier with Stimulus Artifact Suppression
All systems are available with MEA1060-BC amplifiers with blanking circuit featuring stimulus
artifact suppression. Electrodes can be selected for recording or stimulation with the MEA_Select
program.
2.2.4 MEA60- and MEA120-System
The MEA60-System is a complete system for in vitro recording from microelectrode arrays
(MEAs), temperature control, and data acquisition from up to 60 electrodes plus 3 additional
analog and 3 additional digital input bits. The data acquisition card can convert up to 64 analog
channels, or 63 analog channels and 1 digital channel in total.
The MEA120-System has a MC_Card extension that allows recording from two MEAs and two
MEA1060 amplifiers with 120 electrodes in total plus 3 additional analog and 3 additional digital
input bits. The data acquisition card can convert up to 128 analog channels, or 127 analog
channels and 1 digital channel in total.
2.2.5 MEA Switch for Using Additional Amplifiers
You can use a MEA Switch MEAS2/1 to select up to 60 channels from two MEA1060 amplifiers
with a MEA60-System. The MEA Switch is very useful for exploiting your MEA-System even more
efficiently, as often not all MEA electrodes show signals of interest. Choose any of the up to 60
(120) recording channels conveniently by mouse-click with the MEA_Switch software.
With a MEA120-System and a MEA Switch MEAS4/2, you can even record from four MEAs
simultaneously.
2.3
Accessories
MCS provides a wide range of accessories that will make your MEA-System even more efficient
and convenient to use. All accessories are perfect for use with MCS products, but are easily
adaptable to custom systems as well. Some accessories are included in complete systems, other
have to be ordered separately.

1- or 2-channel Temperature controller for MEAs and for perfusion cannula PH01

The SD-MEA Signal Divider allows you to connect any channel via BNC connector to an external
device, for example, an oscilloscope, without interrupting the data acquisition.

Digital in/out extension for connecting other devices to single digital input and output
channels of the MC_Card via BNC connectors (up to 16 inputs and 16 outputs), for example, for
synchronizing stimulation and recording, or for applying feedback.

Magnetic plates and plates with M3 threads for positioning and tightly fixing tools next to the
MEA.

External power supply PS40W for use with the MEA Switch or for custom setups.
11
MEA-System Manual
2.4
Add-ons for Stimulation
MCS provides general-purpose stimulators like the advanced 4000 series with 2, 4 or 8 channels.
The flexible MC_Stimulus software enables complex stimulus waveforms (both current and
voltage). Waveforms designed in the program or imported from an external file are converted by
the STG into pulses, which are sent to stimulating electrodes.
Stimulus isolation units are integrated in the STG for each channel. Thus, no additional
stimulus isolations units are required.
Trigger in- and outputs are available for an exact timing of stimulation and for controlling other
instruments by TTL pulses. For example, stimulation and recording can be synchronized with a
digital trigger signal (TTL) sent from the Sync Out output of the stimulus generator to the
MC_Card via digital inputs.
With the advanced MEA preamplifier with blanking circuit (BC), you will be able to ground
electrodes or select electrodes for recording and stimulation by software controls from the data
acquisition computer. Stimulus artifacts and amplifier saturation are effectively prevented with a
blanking circuit.
2.5
Setting up the MEA-System
Warning: Please read the separate manuals of all individual instruments before installation,
especially the warnings and safety information. Make sure all devices are switched off before you
connect them to the power supply. Damage to the devices and even fatal injuries may result from
improper installation or use.
See also the documentation Microelectrode Array Systems — System Suggestions with
detailed diagrams and various setup suggestions. Provide a power supply in the immediate vicinity
of the installation site.
Note: Do not mismatch the three clearly labeled digital and analog inputs. Digital inputs are for
connecting TTL sources (generally used for triggering the recording); analog inputs are for
connecting additional analog data sources that are not amplified by the MEA amplifier, for
example, for monitoring the temperature, or for recording patch-clamp data in parallel to the
MEA recording.
1. Place all devices on a stable and dry surface, where the air can circulate freely and the devices are
not exposed to direct sunlight.
2. Set up the computer.
3. Set up all system components as described in the separate manuals.
4. Connect the MEA amplifier to the MC_Card (input labeled MC_Card Ch. 01–64) with 3 m 68-pin
MCS standard cable C68x3M. If you use a MEA Switch, please connect the amplifiers to the MEA
Switch with 1 m 68-pin MCS standard cables C68x1M, and connect the MEA Switch to the
MC_Card with 3 m 68-pin MCS standard cables C68x3M.
5. If you have a MEA120-System, connect the second MEA amplifier with the 68-pin MCS standard
cable C68x3M to the input for channels 65–128 labeled MC_CX64 Ch. 65–128. If you use a MEA
Switch, please connect the amplifiers to the MEA Switch with 1 m 68-pin MCS standard cables
C68x1M, and connect the MEA Switch to the MC_Card with 3 m 68-pin MCS standard cables
C68x3M.
6. Optional: Connect other not amplified analog input sources to the BNC connectors labeled
Analog IN (1, 2, 3).
12
Welcome to MEA-Systems
7. Optional: Connect digital (TTL) input sources to the BNC connectors labeled Digital IN (Bits 0, 1, 2).
If you have only one instrument for triggering recording (for example the Sync Out of a stimulus
generator), connect it to bit 0. In MC_Rack, add a Trigger Detector to your virtual rack, and select
the Digital Data D1 input stream as the Trigger. Select the appropriate logical state (generally
HIGH) for triggering. Mask all unused bits. The standard settings of the Trigger Detector are for
using bit 0.
8. Optional: If you have a digital in / out extension, you can connect up to 16 digital input sources
and up to 16 devices that you want to be triggered by the Digital Output instrument of MC_Rack.
2.6
Supply Power and Recommended Setups
In the standard MEA-System, the isolated power supply IPS10W that is preinstalled on the data
acquisition computer delivers the power for the amplifiers, distributed via the 68-pin MCS high
grade cable. One of the limiting factors when using the IPS10W is the voltage drop of the 3 m
MCS high grade cable. The characteristic resistance of the cable is 0.3 Ohms per meter. This results
in a 1 Ohm resistance for a 3 m cable, leading to a voltage drop of 500 mV for a 500 mA current
(U = R * I = 1  * 500 mA = 500 mV). As the voltage drop limit is 500 mV, the limit for each cable is
± 500 mA, that equals 1 MEA amplifier with blanking circuit.
Warning: Follow the manufacturer’s setup recommendations. Do not use longer cables than
recommended. Do not connect other amplifiers or more amplifiers than recommended. A voltage
drop exceeding the limit of ± 500 mA can lead to improper behavior of the amplifier, or can even
melt the wire!
The following tables show you how much power the amplifiers need, and how much power the
MCS power supplies will provide.
MEA1060-INV
MEA1060-UP
MEA1060-INVBC
MEA1060-UPBC
Supply voltage
± 6 VDC to ± 9 VDC
± 6.5 VDC to ± 9 VDC
Supply current
max. 220 mA, typically ± 150 mA
± 550 mA
IPS10W (internal power supply)
PS40W (external power supply)
Output voltage
±6.3 V ± 10%
±7 V ± 10%
Output current
max. 1.2 A @ + 6.3 V or – 6.3 V
max. 2.5 A @ ±7 V
The following table shows the recommended setups regarding the power supplies that are
needed for operating these Systems. It is necessary to use an external power supply for operating
a MEA Switch (MEAS2to1 or MEAS4to2).
MEA1060INV/UP
MEA1060INV/UP-BC
MEAS2/1
MEAS4/2
1
1
2
2
2
2
4
4
IPS10W
PS40W
MEA-System
1
60
1
60
1
120
2
120
1
1
60
1
1
60
1
1
120
1
1
120
13
MEA-System Manual
3
Extracellular Recording from MEAs
3.1
Introduction
Over the last 30 years, non-invasive extracellular recording from multiple electrodes has
developed into a widely used standard method. Systems and methods have been greatly
improved, leading to more features, higher throughput, and lower costs. Almost all excitable or
electrogenic cells and tissues can be used for extracellular recording in vitro, for example, central
or peripheral neurons, heart cells, retina, or muscle cells.
3.2
Background
The semi permeable lipid bilayer cell membrane separates different ion concentrations (charges)
on the inner and outer side of the membrane. Therefore, the cell membrane has the electrical
properties of a plate capacitor. The electrochemical gradient results in a membrane potential that
can be measured directly with an intracellular electrode. When ion channels are opened due to
chemical or electrical stimulation, the corresponding ions are moving along their electrochemical
gradient. In other words, the resistance of the membrane is lowered, resulting in an inward or
outward flow of ions, measured as a transmembrane current.
The extracellular space is conductive as well, and though the resistance is very low, it is not zero.
According to Ohm's law (U=R*I), the extracellular current results in a small voltage that can be
measured with extracellular electrodes. Extracellular signals are smaller than transmembrane
potentials, depending on the distance of the signal source to the electrode. Extracellular signal
amplitudes decrease with increasing distance of the signal source to the electrode. Therefore, a
close interface between electrode and cell membrane is very important for a high signal-to-noise
ratio.
The transmembrane current and the extracellular potential follow the same time course and are
roughly equal to the first derivative of the transmembrane potential.
A microelectrode array (MEA) is an arrangement of several (typically 60) electrodes allowing
targeting several sites for stimulation or recording at once.
The following components are important for an extracellular recording system:

Signal source (cells / tissue)

Cell / sensor interface

Biosensor (MEA)

Filter amplifier (MEA1060)

Recording hardware (MC_Card) and software (MC_Rack)
14
Extracellular Recording from MEAs
3.3
Signal Types
3.3.1 Single Unit Activities
Usually several cells are plated onto a MEA. The waveform of a single unit spike depends on the
signal source, the geometry of the extracellular space, and the distance of the signal source to the
electrode. The property of a waveform derived from a single neuron is reproducible over time and
therefore specific for that neuron. That is, the differences of waveforms from separate signal
sources can be used to distinguish the activities and to sort spikes into single unit spikes. Thus, you
can acquire single unit data from multiple cells in parallel by recording from a single electrode.
You have to discriminate between independent activities and network responses. Responses of
cells on a MEA triggered by a chemical, electrical, or light stimulus can be either statistically
independent or show a specific pattern. The latter is quite interesting for studying the role of cells
and different tissues in a pathway. MEA recording allows such studies under controlled
experimental settings and is much easier and less labor intensive than an in vivo experiment.
3.3.2 Local Field Potentials
If the dendrite soma axes of the active cells are aligned, the waveforms from multiple units on a
MEA overlay and form a compound potential, or local field potential (LFP). The higher the activity,
that is, the spike rate, the higher is the amplitude of the LFP. A modulation of the stimulus results
in a higher frequency of action potentials that will result in a graded multi-unit response. LFPs
often show a high signal-to-noise ratio, which is very beneficial for the analysis.
If dendrites are arranged in a nonparallel or radial fashion forming a closed field, the waveforms
may cancel each other out, when the neurons fire in synchrony.
3.4
Recording and Stimulation
The MEA sensor is placed directly into the small-sized MEA amplifier. When the amplifier is closed,
the contact pins in the lid of the amplifier are pressed onto the MEA contact pads. The very close
location of the amplifier to the MEA sensor is very favorable concerning a high signal-to-noise
ratio. The amplifier is connected with a single cable to the data acquisition computer.
You can then simply ground bad or unwanted electrodes by toggling small switches on the
amplifier. You can also connect a stimulus generator to any electrode(s) for stimulation.
Stimulating electrodes are grounded to prevent a saturation of the amplifier.
If you use the new MEA preamplifier with blanking circuit, software controls allow you to select
any electrode on a MEA for stimulation and recording. A user defined, typically 500 μs long,
blanking signal switches off stimulating electrodes during stimulation and thus removes stimulus
artifacts.
With the MEA_Select software, it is easy to change the electrode selection during the experiment,
for example, to use stimulating electrodes for recording and vice versa. It is also possible to use
the same electrode for recording shortly after stimulation provided that you use a dedicated
biphasic pulse protocol that compensates for the slight DC offset that a stimulating electrode
always shows after stimulation.
15
MEA-System Manual
3.4.1 Microelectrode Arrays (MEAs)
The recording field of a standard MEA is a square grid of 8x8 electrodes with a total length
between 120 μm to 5 mm, in the middle of a circular (about 2 cm wide) recording / culture
chamber.
The layout of the MEA electrodes follows the scheme of a standard grid: The first digit is the
column number, and the second digit is the row number. For example, electrode 23 is positioned
in the third row of the second column. The numbering follows the standard order from left to
right, and from top to bottom. This numbering is used in the documentation of the MEAs, the
MEA1060 amplifiers, and in MC_Rack. That means, if you want to record data from electrode 23,
you choose channel 23 for setting up the channel layout map in MC_Rack. Please make sure that
the appropriate 2-dimensional data source setup 2 dim. (MEA) for a MEA60-System and MEA120System has been selected in MC_Rack. For more details, please refer to the MC_Rack Help or
Manual.
Microelectrode arrays are available in various configurations:

Different electrode layouts (8x8, 6x10, High Dense 2x(5x6), 4 Quadrants, Hexa)

Different electrode diameters and spatial resolutions

Different electrode materials (Titanium nitride, gold, platinum)

Opaque (titanium) or transparent (indium tin oxid) tracks
For more information on MEA types, electrode layouts, MEA handling, coating and cleaning,
please refer to the MEA Manual.
3.4.2 Signal Amplification and Filters
The standard MEA amplifier combines the probe interface with a band pass filter and the signal
amplification in one instrument.
The MEA1060-BC amplifier with blanking circuit is a 60-channel preamplifier with a broad
bandwidth. Filter specifications and gain are defined by the following filter amplifier.
Different filter settings are used to enhance the signal-to-noise ratio. The pass band of the filter
amplifier depends on the signal type. It is generally useful to filter the data with a cutoff at the
highest signal frequency.
For slow signals like field potentials, a bandwidth of 1 to 300 Hz is appropriate. If you like to
record fast signals like spikes, a pass band of 300 Hz to 3 kHz is suitable. Cardiac signals have fast
and slow components; therefore, you usually need a wider bandwidth of 1 Hz to 3 kHz.
Multi Channel Systems provides custom amplifiers with a bandwidth of your choice, from 0.1 Hz to
10 kHz. Please note that it is often wise to acquire the data with a broadband amplifier and use
the digital filter of the free MC_Rack program to change the pass band and filter the raw data.
This way, you are much more flexible in designing your experiments. As a further advantage, you
can see the original (not filtered) data as well. This is especially important because all filters are
known to distort signals. On the other hand, you may need a higher sampling rate to avoid
aliasing, and the signal-to-noise ratio is lower. See also the chapter "Data Acquisition" for more
information.
The standard gain of a MEA amplifier is 1200, which is fine for most applications, but MCS can
also provide amplifiers with a gain of your choice (from 100 to 5000) as well. For large signals (for
example, from heart preparations), you need a lower gain to prevent a saturation of the
amplifier. Please note that the gain is a fixed hardware property; and that you cannot change the
gain of the amplifier by software controls.
16
Extracellular Recording from MEAs
Please note that the ratio of the output signal to the input signal, that is, the gain, is not a fixed
parameter for the complete bandwidth. The gain that was specified for the amplifier, for
example, 1200, is not fully reached at the borders of the amplifier's pass band. The general rule is,
that at the lower and upper limit of the frequency band, the gain is 2 / 2 , that is approximately
70 %, of the full gain. Therefore, you should use a bandwidth that is at a safe distance of the
signals of interest. Outside the pass band, the gain decreases with the frequency and finally
approaches zero.
The low-pass filter properties of the MC_Card will affect the bandwidth of the complete system
only slightly.
For information on the gain and filters of the MEA amplifiers, please see the appropriate MEA
Amplifier Manual. For more information on gain and filters in general, please refer to standard
literature or contact your local retailer.
3.4.3 Data Acquisition
Recording from up to 128 channels is easy with the MC_Card hardware and the MC_Rack
software.
MC_Card hardware
Important: You need to have installed the latest MC_Card driver to operate the MC_Card, which is
usually preinstalled on the data acquisition computer. The installation may be invalid if the
MC_Card does not respond. Please contact Multi Channel Systems if you need the MC_Card Driver
and a description of the installation.
The MC_Card is an A / D board that converts analog signals in real time into digital data streams
at sampling rates of up to 50 kHz for all channels.
You configure the input voltage range from +/- 400 mV to +/- 4V and the sampling rate with the
software controls in the MC_Rack program. Please refer to the MC_Rack Help or Manual for more
information.
The input voltage range affects your dynamic range, that is, the lower the input voltage range,
the higher is the voltage resolution.
Please see the MC_Card data sheet for additional information on the pin layouts and the technical
specifications.
DC Offset correction
An offset correction is generally not necessary, because the intrinsic DC offsets of the MCS
amplifier outputs and the MC_Card are very low in comparison to the signals of interest. The
maximum total DC offset is +/– 3 mV (+/– 2 mV for the MC_Card, +/– 1 mV for the MEA amplifier
outputs). For a standard MEA amplifier with a standard gain of 1200, this results in a maximum
offset of only 2.5 μV (+/– 3 mV divided by 1200) with respect to the input signals.
You can use the MC_Rack offset correction feature to remove even this low offset and reset all
channels to zero. Please refer to the MC_Rack Help or Manual for more information.
Note: If you observe a large offset on any channel(s), you should contact your local retailer for
troubleshooting. The offset correction is not intended for removing large offsets, because the
offset correction will decrease the input voltage range.
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MEA-System Manual
Sampling rate
It is recommended to adjust the sampling rate according to your signals, because the higher the
sampling rate, the bigger the file size will be.
As a rule of thumb, the sampling rate should equal five times the highest signal frequency for a
good digitized representation of the continuous analog signals. If the sampling rate is too low,
you will miss signals and / or see artifacts. Considering the preceding statements about filtering
data, you would for example use a 5 kHz sampling rate when using a MEA amplifier with a cutoff
frequency of 1 kHz.
Please note that if you use a broadband amplifier and a digital filter, you may have to use an even
higher sampling rate.
This is the case because the whole amplifier bandwidth is recorded and then high frequency noise
is removed with a digital Low Pass filter after recording. Frequencies (noise) that are above half
the sampling rate (for example above 2.5 kHz at a 5 kHz sampling rate) will be transformed into
lower frequencies. This is called aliasing. This low frequency noise passes the digital Low Pass filter
and increases your noise level.
According to the Nyquist-Shannon sampling theorem, the sampling rate should equal twice the
bandwidth of the analog (hardware) Low Pass filter. The 1/2 bandwidth frequency is also called
Nyquist frequency. You may ignore this if saving hard disk space is more important for your
application than the noise level.
Aliasing
Note: The sampling frequency should be at least five times the highest signal frequency and at
least twice the bandwidth of the MEA1060 amplifier.
Example:
You have a broadband MEA1060 amplifier with a bandwidth of 0.1 Hz to 10 kHz. The expected
signals have a maximum frequency of 1 kHz. Therefore, you want to filter the data with a digital
Low Pass filter and a cutoff frequency of 1 kHz. A sampling rate of 5 kHz (five times the highest
signal frequency) would be required for faithfully reproducing the signals, but you should use a
sampling rate of at least 20 kHz because the sampling rate should equal twice the bandwidth of
the analog filter, regardless of the digital filter properties.
If you have a MEA1060 amplifier with a cutoff frequency of 1 kHz instead, no digital filter would
be required, and a sampling rate of 5 kHz would be enough.
18
Extracellular Recording from MEAs
Software package
With the high-performance data acquisition and analysis program MC_Rack, you can flexibly
manage all data streams. For example, you can display the raw data of all channels while
recording only the raw data of the channels of interest and the extracted parameters of all
channels. This saves computer performance and hard disk space.
MC_Rack is not limited to special applications, but can be flexibly adapted to a wide range of
applications.
Unlimited software licenses and support come free with the MEA-System, and free software
updates lower the costs as well.
The *.mcd data format is support by several third party programs for further analysis. You can also
easily convert recorded data to universal formats such as ASCII with the MC_DataTool program.
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MEA-System Manual
3.5
Using the Additional Analog Inputs
The additional analog inputs A1, A2, A3 are intended for recording additional information from
external devices, for example, for recording patch clamp in parallel to the MEA recording, for
monitoring the temperature, or for recording voice. You could also use the analog inputs for
triggering the MC_Card, but please note that the digital inputs are intended for accepting TTL
pulses.
As the gain is generally completely different on the electrode inputs and on the additional analog
inputs, signals on the analog channels are recorded "as is", with no respect to the gain specified
in MC_Rack.
Recording Voice on Analog Inputs
Microphones do not generate enough voltage to directly connect them to the analog inputs. You
need to use some kind of amplifier that adapts the output voltage of the microphone to the input
voltage range of the MC_Card.
You can then use the MC_Rack Sound tool for replaying the recorded voice. Please see the
MC_Rack Manual for more information.
3.6
Digital Input / Output, System Synchronization
TTL stands for Transistor-Transistor Logic. A TTL pulse is defined as a digital signal for
communication between two devices. A voltage between 0 V and 0.8 V is considered as a logical
state of 0 (LOW), and a voltage between 2 V and 5 V means 1 (HIGH).
Warning: A voltage that is higher than +5 Volts or lower than 0 Volts, that is, a negative voltage,
applied to the digital input would destroy the MC_Card. Make sure that you apply only TTL pulses
(0–5 V) to the digital inputs.
Important: In the standard configurations of the MEA-System, only 3 BNC connectors are included
for the digital input bits 0 to 2. If you want to use more bits of the 16-bit input channel or the
16-bit output channel (as described in chapter Triggering other Instruments by the MC_Card), you
have to order a digital in / out extension separately. You can also upgrade your MEA-System with
the extension later. Please contact your local retailer for details.
3.6.1 Triggering the MC_Card and MC_Rack
The digital input accepts TTL pulses. This feature can be used for triggering the MC_Card and
MC_Rack, for example, for synchronizing stimulation and data acquisition.
For example, you can connect the Sync Out of a STG (stimulus generator) to one of the digital
input bits. If you use only one instrument for triggering, connect it to bit 0. In MC_Rack, add a
Trigger Detector to your virtual rack, and select the Digital Data D1 input stream as the
Trigger. Select the appropriate logical state (generally HIGH) for triggering. Mask all unused bits.
The standard settings of the Trigger Detector are for using bit 0.
Please see the documentation on the Recorder and on the Trigger Detector instrument and on
triggered data in the MC_Rack Help or Manual for more details.
Important: It is recommended to apply TTL pulses with a duration of a to at least 200 μs. Shorter
pulses may be ignored by the MC_Card. Please mask unused (not connected) digital input channels
in the MC_Rack program to ignore undefined states of the open inputs that can cause unwanted
trigger events. Please see the MC_Rack Manual for more details.
20
Extracellular Recording from MEAs
3.6.2 Custom Switch for "Remote-Controlling" of the MC_Card
You can connect any device that produces TTL outputs, for example a switch, to one of the digital
input bits of the MC_Card. This means you can use a trigger for remote controlling the recording
with MC_Rack, or for synchronizing systems, if the data acquisition computer is not within reach
during an experiment.
You can define the time length of the cutouts that are recorded around the trigger event in
MC_Rack. Please note that it is not possible to start the recording of a continuous data file with
MC_Rack on a trigger, but you can start a new data file on the trigger event (select the Recorder
option Create New File On Trigger).
The following picture shows a suggested circuit diagram for a switch used for remote controlling.
The resistor and capacitor work as a low-pass filter on the TTL signal and are necessary to reduce
ringing of the signal.
3.6.3 Triggering other Instruments by the MC_Card
The digital output of the MC_Card sends 20 ms TTL pulses (0 V = LOW and 5 V = HIGH). This
feature can be used to apply a feedback triggered by a signal or a parameter stream.
For example, you can connect the Trigger In of a stimulus generator (STG) to the digital output via
the digital in / out extension. You can also use the digital output for a synchronization of the
MEA-System with other systems, for example, for Calcium imaging or video tracking (provided
that the other system of choice is able to receive TTL pulses).
Please see the documentation on the Digital Output instrument in the MC_Rack Help or Manual
for more details.
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MEA-System Manual
4
Troubleshooting
4.1
About Troubleshooting
The following hints are provided to solve special problems that have been reported by users. Most
problems occur seldom and only under specific circumstances. Please check the mentioned possible
causes carefully when you have any trouble with the product. In most cases, it is only a minor
problem that can be easily avoided or solved.
If the problem persists, please contact your local retailer. The highly qualified staff will be glad to
help you. Please inform your local retailer as well, if other problems that are not mentioned in this
documentation occur, even if you have solved the problem on your own. This helps other users,
and it helps MCS to optimize the instrument and the documentation.
Please pay attention to the safety and service information in the separate manuals of the related
products and in the software help. Multi Channel Systems has put all effort into making the
product fully stable and reliable, but like all high-performance products, it has to be handled with
care.
4.2
Triggering / Digital Input does not Work
You have connected a TTL source (for example, the Sync Out of a stimulus generator) to the
digital input of the MC_Card, and configured the virtual rack in MC_Rack for triggering displays or
data acquisition by the TTL source, but you do not see any sweeps.
Possible causes:
?
You have mismatched the digital input with the analog input. To test this, please add a Digital
Display to your virtual rack. You should see the trigger event as a logical state of HIGH (=1). If
you cannot see any signals, please add a Data Display to your rack and select the analog raw data
as the input stream. Make sure the channel layout map of the display shows all 3 analog input
channels (A1–A3). If you have mismatched the inputs, you will now see the (clipped) trigger
events.
 Connect the TTL source the BNC connectors labeled Digital IN (Bits 0, 1, 2). If you have only one
instrument for triggering recording (for example the Sync Out of a stimulus generator), connect it
to bit 0.
 If you use a digital in / out extension (Di/o) accessory, you can connect up to 16 digital input
sources and up to 16 devices that you want to be triggered by the Digital Output instrument of
MC_Rack.
?
The TTL source does not generate true TTL signals (5 V), or the TTL pulse is shorter than 200 μs.
 The MC_Card can only accept TTL signals (CMOS 5 V TTL level) as a digital input stream.
A minimum TTL pulse of 200 μs is recommended. Otherwise, a detection of the trigger by the
MC_Card is not guaranteed.
?
The software settings for the Trigger Detector do not match with the hardware configuration.
 In MC_Rack, add a Trigger Detector to your virtual rack, and select the Digital Data D1 input
stream as the Trigger. Check the digital inputs and make sure that the same bit input that is
connected is selected in the software. (The standard settings of the Trigger Detector are for using
bit 0.) Mask all unused bits. Select the appropriate logical state (generally HIGH) for triggering.
Please see the MC_Rack Help or Manual for more details.
22
Troubleshooting
4.3
Artifacts caused by Perfusion
You observe artifacts or an increased noise level after you started the perfusion.
Possible causes:
?
The artifacts correlate with an oscillation of the liquid level. The oscillation will cause the artifacts,
and also mechanically stress the biological sample.
 Use a bevelled tip for the perfusion in- and outlet. If the tip of the perfusion outlet has a blunt
end, there will be no continuous liquid flow, but instead, the following can be observed: The
liquid level will rise until it reaches the blunt tip; a discrete volume of liquid will be aspirated in a
short moment; the liquid level will rise again, and so on, leading to an oscillation. The tip should
be cut in an angle of about 45°. You can also use commercially available metal needles with a
bevelled tip.
?
The perfusion is not appropriately grounded.
 Connect the perfusion line to the ground of the amplifier / setup. You should consider using a
metal cannula that can directly be connected to ground for the perfusion inlet and outlet. You
could also insert a metal wire that is connected to ground into the tubing.
?
The aspiration pump is oscillating.
 MCS recommends the use of a peristaltic pump for an open perfusion system. The more rollers the
pump head has, the lower are the oscillations of the fluid flow. For a continuous perfusion in a
closed system, you can also an infusion-withdrawal syringe pump.
23
Appendix
5
Appendix
5.1
Contact Information
Local retailer
Please see the list of official MCS distributors on the MCS web site.
User forum
The Multi Channel Systems User Forum provides an excellent opportunity for you to exchange
your experience or thoughts with other users worldwide.
Web link to the User Forum
Mailing Liat
If you have subscribed to the mailing list, you will be automatically informed about new software
releases, upcoming events, and other news on the product line. You can subscribe to the list on
the contact form of the MCS web site.
www.multichannelsystems.com
25
MEA-System Manual
5.2
Ordering Information
Please contact your local retailer for pricing and ordering information.
5.2.1 MEA-Systems
Product
Product
Number
Description
MEA recording-System
for inverted microscopes,
60 electrode channels
MEA60-InvSystem
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Inv amplifier, TC01, power
supply, and accessories
MEA recording-System
for inverted microscopes,
60 electrode channels, 2
MEA amplifiers
MEA60-Inv-2System
Complete with 5 MEAs, data acquisition computer
with MC_Card, 2 x MEA1060-Inv amplifier,
MEAS2/1, TC02, power supply, and accessories
MEA recording-System
for upright microscopes,
60 electrode channels
MEA60-UpSystem
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Up amplifier, TC01, power
supply, and accessories
MEA recording-System
for upright microscopes,
60 electrode channels
MEA60-Up-2System
Complete with 5 MEAs, data acquisition computer
with MC_Card, 2 x MEA1060-Up amplifier,
MEAS2/1, TC02, power supply, and accessories
MEA recording-System
for inverted microscopes
with advanced perfusion,
60 electrode channels
MEA60-InvSystem-E
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Inv amplifier, TC02, PH01,
power supply, and accessories
MEA recording-System
for inverted microscopes
with advanced perfusion,
60 electrode channels
MEA60-Inv-2System-E
Complete with 5 MEAs, data acquisition computer
with MC_Card, 2 x MEA1060-Inv amplifier,
MEAS2/1, 2 x TC02, 2 x PH01, power supply, and
accessories
MEA recording-System
for upright microscopes
with advanced perfusion,
60 electrode channels
MEA60-UpSystem-E
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Up amplifier, TC02, PH01,
power supply, and accessories
MEA recording-System
for upright microscopes
with advanced perfusion,
60 electrode channels
MEA60-Up-2System-E
Complete with 5 MEAs, data acquisition computer
with MC_Card, 2 x MEA1060-Up amplifier, 2 x TC02,
2 x PH01, power supply, and accessories
MEA recording-System
for inverted microscopes,
120 electrode channels
MEA120-InvSystem
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Inv amplifier, TC02, power
supply, and accessories
MEA recording-System
for inverted microscopes,
120 electrode channels
MEA120-Inv4-System
Complete with 5 MEAs, data acquisition computer
with MC_Card, 4 x MEA1060-Inv amplifier,
MEAS4/2, 2 x TC02, power supply, and accessories
MEA recording-System
for upright microscopes,
120 electrode channels
MEA120-UpSystem
Complete with 5 MEAs, data acquisition computer
with MC_Card, MEA1060-Up amplifier, TC02, power
supply, and accessories
MEA recording-System
for upright microscopes,
120 electrode channels
MEA120-Up4-System
Complete with 5 MEAs, data acquisition computer
with MC_Card, 4 x MEA1060-Up amplifier,
MEAS4/2, 2 x TC02, power supply, and accessories
26
Appendix
5.2.2 MEA Amplifiers
Product
Product
Number
Description
MEA amplifier for inverted
microscopes
MEA1060-Inv
Probe interface and 60 channel pre- and filter
amplifier with custom gain and bandwidth
MEA amplifier for upright
microscopes
MEA1060-Up
MEA amplifier with
blanking circuit for
inverted microscopes
MEA1060-Inv-BC
MEA amplifier with
blanking circuit for upright
microscopes
MEA1060-Up-BC
Probe interface and 60 channel pre- and filter
amplifier with custom gain and bandwidth. The
blanking circuit prevents the amplifier from
getting saturated and thus prevents stimulus
artifacts.
5.2.3 Accessories
Product
Product
Number
Description
Holder with M3 threads
MPM3
For fixing tools with M3 threads next to the
MEA
1-Channel temperature
controller
TC01
2-Channel temperature
controller
TC02
PID based technology, set-point temperature
reached fast within 30 s to 5 minutes, control
temperature range from ambient temperature
to +50 °C
Perfusion cannula with
programmable fluid
temperature
PH01
Temperature can be programmed with the
temperature controller TC01 or TC02
Signal divider for
MEA-Systems
SD-MEA
Placed between a MEA1060 amplifier and
MC_Card, permits to select any channel, does
not interfere with the data acquisition, for
example for connecting an oscilloscope or other
devices to single channels
MEA Switch for 4
amplifiers
MEAS4/2
MEA Switch for 2
amplifiers
MEAS2/1
The MEA Switch allows you to acquire data
from 60 single channels from two MEA1060
amplifiers. If you have a 128-channel MC_Card
(MEA 120-System), you can even pick 128
channels in total from two MEA pairs with the
MEA Switch for four amplifiers MEAS4/2. The
selected channels are combined to one
Electrode Raw Data stream that is delivered to
MC_Card by a 68 pin MCS High Grade Cable.
Digital in/out extension
Di/o
For connecting other devices to single digital
input and output channels of the MC_Card via
BNC connectors (up to 16 inputs and 16 outputs),
for example for synchronizing stimulation and
recording, or for applying feedback.
Isolated power supply with
10 W power and ± 6.3 V
output voltage
IPS10W
Isolated power supply for integration into the
data acquisition computer. For supplying power
to MEA1060 amplifiers.
27
MEA-System Manual
5.2.4 Stimulus Generators
Product
Product
Number
Description
2-Channel stimulus generator
STG4002
4-Channel stimulus generator
STG4004
8-Channel stimulus generator
STG4008
4000 series: General-purpose stimulus generator for
current and voltage-driven electrical stimulation,
with integrated stimulus isolation unit for each
output channel. Operating in Download and
Streaming mode (continuous downstreaming of
pulses from connected computer). MC_Stimulus II
program with advanced features.
28
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