Multichannel Systems STG4004, STG4008 User Manual

Stimulus Generator Manual

STG 4004 and STG 4008

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 accompany it. In no event shall the publisher and the author be liable
for any loss of profit or any other commercial damage caused or alleged to have been caused
directly or indirectly by this document.

© 2013 Multi Channel Systems MCS GmbH. All rights reserved.

Printed: 04. 06. 2013

Multi Channel Systems MCS GmbH

Aspenhaustraße 21

72770 Reutlingen

Germany

Fon [phone] - 0

Fax [phone]

[e-mail]

www.multichannelsystems.com

Microsoft and Windows are registered trademarks of Microsoft Corporation. Products that
are referred to in this document may be either trademarks and / or registered trademarks
of their respective holders and should be noted as such. The publisher and the author make
no claim to these trademark.

Table of Contents

1 Introduction 1

1.1 About this Manual 1

1.2 Terms of Use for MC_Stimulus II 2

1.3 Limitation of Liability 2

2 Important Information and Instructions 3

2.1 Operator's Obligations 3

2.2 Guarantee and Liability 3

2.3 Important Safety Advice 4

3 First Use of the Stimulus Generator 5

3.1 Welcome to the STG and MC_Stimulus 5

3.2 Setting Up and Connecting the STG 8

3.3 Driver Installation 9

3.4 Installing the Software 10

4 Operating the STG 11

4.1 Operation Overview 11

4.2 Operating Multiple STGs 14

4.2.1 Operating the USB-MEA32-STIM4-System 15

5 Programming Stimulus Protocols 17

5.1 MC_Stimulus II Sample Files for STG 4000 Series 17

5.2 Neuroelectrophysiology / MEA-System 17

5.2.1 General Demo Files 18

5.3 MC_Stimulus II Worksheet 19

5.4 Pulse Types 20

5.5 Autorepeating Pulses and Protocols 22

5.6 Autocreating Entries and Editing Columns 25

5.7 Auto Sync for Autocreating Trigger Pulses 31

5.8 Adjusting the Stimulus Intensity Level 32

6 ASCII Import / Export 35

6.1 Loading Files 35

6.2 Exporting Files 36

6.3 Supported File Formats 36

7 Stimulus Display 45

7.1 Selecting Channels 45

7.2 Display Settings 45

7.3 Display Tools 45

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Stimulus Generator 4000 Series Manual

8

Downloading Stimuli 49

8.1 Downloading Stimulus Files 49

8.1.1 Download Modes 49

8.1.2 Independent Channel Download 50

8.2 Operating multiple MEA Amplifiers with one STG 51

9 General Software Features 53

9.1 Customizing the Main Window 53

9.2 Menu Bar 53

9.3 Toolbar 54

9.4 Shortcut Keys 54

9.5 File Menu 55

9.6 Settings Menu 56

10 Synchronizing Events 57

10.1 Digital Output Signals (Sync Out) 57

10.2 Triggering Stimulation (Trigger In) 58

10.3 Trigger Settings 60

10.4 Multi File Mode 63

10.5 Extended Multi File Mode 64

10.6 Batch Mode 67

11 Analog Output Signals 69

11.1 Output Modes 69

11.2 Voltage Mode 70

11.3 Current Mode 74

11.4 Measuring Output Signals with an Oscilloscope 77

11.5 Rise Time 77

11.6 Comparison of Output Signals in Current Mode 85

11.7 Capacitive Behavior of Stimulation Electrodes 91

12 Troubleshooting 93

12.1 About Troubleshooting 93

12.2 Technical Support 93

12.3 Error Messages 94

12.4 Signal terminated when using Trigger In 96

12.5 Strong Peak Artifacts 96

12.6 Output Signal Does not Match Programmed Signal 96

12.7 Signal is not Repeated / Pulse Train Fails 97

12.8 Internal Calibration Signals 97

13 Appendix 99

13.1 Technical Specifications STG4004 and STG4008 99

13.2 Pin Layout Digital I / O 100

13.3 Contact Information 101

iv

14 Index 103

1 Introduction

1.1 About this Manual

This manual comprises all important information about the installation and operation of the
stimulus generator STG4000 series and MC_Stimulus II software. It is assumed that you have
already a basic understanding of technical and software terms. No special skills are required to
read this manual.

This documentation refers only to the STG hardware and MC_Stimulus II software. For more
information on the STG's DLL functions and programming of custom programs, please read the
separate documentation in the Documentation folder in the MC_Stimulus II program directory.

If you are using the STG for the first time, please read the important safety advice before
installing the hardware and software (see Important Safety Advice, where you will find
important information about the installation and first steps).

The printed manual and Help are basically the same, so it is up to you which one you will use.
The Help offers you the advantage of scrolling through the text in a non-linear fashion, picking
up all information you need, especially if you use the Index and the Search function. If you are
going to read larger text passages, however, you may prefer the printed manual.

The device and the software are part of an ongoing developmental process. Please understand
that the provided documentation is not always up to date. Check also the MCS web site
(www.multichannelsystems.com) from time to time for downloading up-to-date manuals
and new software versions.

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Stimulus Generator 4000 Series Manual

1.2 Terms of Use for MC_Stimulus II

You are free to use MC_Stimulus II for its intended purpose. You agree that you will not
decompile, reverse engineer, or otherwise attempt to discover the source code of the software.

1.3 Limitation of Liability

Multi Channel Systems MCS GmbH makes no guarantee as to the accuracy of any and all tests and
data generated by the use the MC_Stimulus II software. It is up to the user to use good laboratory
practice to establish the validity of his findings.

To the maximum extent permitted by applicable law, in no event shall Multi Channel Systems
MCS GmbH or its suppliers be liable for any special, incidental, indirect, or consequential damages
whatsever (including, without limitation, injuries, damages for data loss, loss of business profits,
business interruption, loss of business information, or any other pecuniary loss) arising out of the
use of or inability to use MC_Stimulus II or the provision of or failure to provide Support Services,
even if Multi Channel Systems MCS GmbH has been advised of the possibility of such damages.

2

2 Important Information and Instructions

2.1 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.

2.2 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.

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Stimulus Generator 4000 Series Manual

2.3 Important Safety Advice

Warning: Make sure to read the following advice prior to install or to use the device and the
software. If you do not fulfill all requirements stated below, this may lead to malfunctions or
breakage of connected hardware, or even fatal injuries.

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 device 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 product.

 Check the power cord 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.

 Liquids may cause short circuits or other damage. Keep the device and the power cords always

dry. Do not handle it with wet hands.

Requirements for the installation

 Make sure that the device is not exposed to direct sunlight. Do not place anything on top of the

device, and do not place it on top of another heat producing device. Otherwise, the device may
overheat.

4

3 First Use of the Stimulus Generator

3.1 Welcome to the STG and MC_Stimulus

Product line overview

Stimulus generators of the 4000 series are general purpose stimulators designed for a wide
variety of applications, both in vitro and in vivo.

Flexible and easy-to-use MC_Stimulus software enables complex stimulus waveforms (both
current and voltage). Waveforms designed in the program or imported from an external ASCII
file are converted by the connected STGs into pulses, which are sent to stimulating electrodes.
Stimulus isolation units (SIU) for each channel are included. Thus, no external SIUs are required.

A trigger input and output for TTL signals allows to synchronize the stimulus generator
with other instruments. Triggering of other devices via programmable TTL pulses (Sync Out)
is possible, as well as triggering of the STG by external devices via the Trigger In input.
For example, you can synchronize stimulation and recording with a TTL signal sent from
the Sync Out output of the STG to the data acquisition system, for example, the MC_Card.

Stimulus generators are available with two, four or eight completely independent stimulation
channels (STG4002, STG4004, STG4008). Each channel is freely programmable, combination of
channels to achieve complex stimulation patterns is not necessary.

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Stimulus Generator 4000 Series Manual

4000 Series

The real-time stimulus generator of the 4000 series is an advanced version and the world's first
STG that is able to send continuous pulse streams to stimulating electrodes. In addition, you can
trigger all (up to 8) channels separately by external TTL pulses. 2 trigger inputs (Trigger In) and
2 trigger outputs (Sync Out) are shared by 2 channels in the 2-channel version. 4 trigger inputs
(Trigger In) and 4 trigger outputs (Sync Out) are shared by 4 channels in the 4-channel version,
and 8 trigger inputs (Trigger In) and 8 trigger outputs (Sync Out) are shared by 8 channels in the
8-channel version.

The STG 4000 series has two operating modes: Download mode and Streaming mode.

In Download mode, you can control the STG either by the MC_Stimulus II or by a custom
program. Stimulus protocols are created in MC_Stimulus II or the custom program; complete
protocols are downloaded onto the STG, and can after the download be executed without a
computer connection. MC_Stimulus II is downward compatible to MC_Stimulus (for controlling
the 1000 series), that means, you can load stimulus protocols generated by MC_Stimulus into
MC_Stimulus II, but not the other way round.

In the Streaming mode, you can control the STG either by the Stimulus Streamer or by a
custom program. If you use the Stimulus Streamer, you can load stimulus protocols in Mono­MP3 or binary file format of unlimited size that were generated by a custom application and are
then sent continuously from the computer to the STG in small data packets. If you use a custom
program for controlling the STG, this program can generate and send the stimulation protocols
in parallel from the computer to the STG.

Custom applications for the Download or the Streaming mode can be programmed in Matlab,
Labview, C/C++, and Visual Basic. This documentation refers only to the STG hardware and
MC_Stimulus II software. For more information on the STG's DLL functions and programming
of custom software, please read the separate documentation of the Documentation folder in
the MC_Stimulus II program directory.

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First Use of the Stimulus Generator

MC_Stimulus II

Stimuli are created user-friendly by entering the desired pulses (rectangular, ramp, or sine
waveforms) into a worksheet. Waveforms can be combined freely to create virtually any
stimulus pattern.

Created stimuli are displayed in a WYSIWYG stimulus display. All channels are set up
separately.

For even more convenience, repetitive stimulus patterns do not have to be entered separately,
but can be grouped and looped. You can also import waveforms in ASCII file format and
use them for stimulation. You can print and save stimuli and comments for later use and
documentation of your experiments.

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Stimulus Generator 4000 Series Manual

3.2 Setting Up and Connecting the STG

Note: You can use a USB hub for connecting the STG to the computer, for example, if you have
no free USB port or if you need to extend the USB cable.
Do not use a hub in Streaming mode! Please note that if you want to use the STG in Streaming
mode, you cannot connect a second device that sends or receives continuous data streams, for
example a web cam or USB speakers, to the same USB port, because the STG needs a broad
bandwidth for the data transmission.
This does not matter if you want to use the Download mode (via MC_Stimulus II or custom
program) only.

Provide a power supply and a computer with USB port in the immediate vicinity of the
installation site. Make sure the STG is switched off before you connect it to the power supply.

1. Place the STG on a stable surface, where the air can circulate freely and the STG is not exposed
to direct sunlight.

2. Connect the external power supply to the STG.

3. Connect the external power supply to the power outlet.

4. Connect the USB connector to the USB port of the computer. The computer connection
is necessary for programming the STG, but not for operating it (except in Batch mode).

5. Connect the + and - plugs of the required output channels with 2 mm plug cables to the
stimulating electrodes. Connect the appropriate ground to the ground input of the stimulation
setup, for example, to the ground input of the MEA1060 amplifier. Current and voltage driven
stimulation is generated from the same outputs.

6. (Optional) Connect the required Trigger In inputs with BNC cables to instruments that produce
TTL signals for triggering the STG.

7. (Optional) Connect the required Sync Out outputs with BNC cables to following instruments
that you want to be triggered by TTL signals from the STG, for example to one of the 16 digital
inputs of the MC_Card.

8. Switch the STG on by pressing the toggle switch on the rear panel.

Note: It is recommended to start the STG ten minutes before use to allow warming up!

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First Use of the Stimulus Generator

Illustration of the STG 4000 series front and rear panel with connectors

STG 4004 Front Panel

STG 4004 Rear Panel

STG 4008 Front Panel

STG 4008 Rear Panel

3.3 Driver Installation

The stimulus generator is a plug and play device. The driver is automatically installed together
with the MC_Stimulus II program.

The Windows operating system detects a new hardware when the stimulus generator is connected
to the computer, if the program has not been installed beforehand. Simply cancel the driver
installation and proceed with the installation of the MC_Stimulus II program.

Important: Please make sure that you have full control over your computer as an administrator.
Otherwise, it is possible that the installed hardware does not work properly.

If there are any problems, and you need to install or update the driver manually, please see
the MC_Stimulus II help for more information.

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Stimulus Generator 4000 Series Manual

3.4 Installing the Software

System requirements

Software: One of the following Microsoft Windows ® operating systems is required:
Windows 7, Vista or Windows XP (English and German versions supported).

Hardware: USB port (2.0 High Speed)

Installing the software

Please check the system requirements before you install the software. MCS cannot guarantee
that the software works properly if these requirements are not fulfilled.

Important: Please make sure that you have full control over your computer as an administrator.
Otherwise, is possible that the installed software does not work properly.

1. Double-click Setup.exe on the installation volume.
The installation assistant will show up and guide you through the installation procedure.

2. Follow the instructions of the installation assistant. Please select the appropriate maximum
number of analog output channels according to the connected STG. If you have different
STGs in use, choose the highest number.

For the devices with internal stimulation, STG3008-FA and MEA32-STIM4 separate manuals
are available.

When you have finished the installation of the MC_Stimulus II software and the STG driver,
you can now operate the STG.

10

4 Operating the STG

4.1 Operation Overview

Warning: Make sure that you do not come in contact with the cables or the connectors
of the STG after you have started the STG. The high voltage and power can lead
to injuries.

Warning: Do not start the STG if you are unsure about the channel configuration
or the nature of the downloaded file.

1. Set up your experiment.

2. Switch the STG on.

Note: It is recommended to start the STG ten minutes before use to allow warming up!

1. Set up your stimuli with the MC_Stimulus II program.

2. Send the stimulus sequence from a MC_Stimulus II file to the STG.

3. Start the STG either manually by pressing the Start / Stop button on the front panel,
with the software controls, or with an external trigger.

Creating stimuli

Stimuli are created user-friendly by entering the desired pulses (rectangular, ramp, or sine
waveforms) into a MC_Stimulus worksheet. Waveforms can be combined freely to create
virtually any stimulus pattern. Created stimuli are displayed in a WYSIWYG window.

Starting stimulation

Note: You need a computer connection only when you are using the software controls for starting
and stopping the stimulus generator. When you are using the STG interface or an external control
(trigger, you can disconnect the stimulus generator from the computer and operate
it independently. But you cannot remove the STG from the power connection.
The memory is cleared when the STG has lost power.

After the download of the stimulus file on the STG, you can start the stimulation. There are
several ways to start the STG.

MC_Stimulus
II interface:

You can start the stimulation directly after the download (with the command

Download and Start

stop stimulation with the command Stop
Start command is considered as activating all trigger inputs, that is, all channels

are started, and all Sync Out outputs are active. Likewise, all channels are
stopped when you click Stop.

or also later with the command Start . You can

. Starting the STG by using the

You can start the stimulation after download
separately. Please use the combined LED / Start / Stop buttons

. You can start and stop the stimulation manual

whenever you want by clicking the corresponding LED / Start / Stop button. The
LED indicates the status: Black means trigger off, red means trigger on. The first
button on the left side belongs to trigger 1, the second button to trigger 2, and
so on.

on up to eight trigger

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Stimulus Generator 4000 Series Manual

STG
interface:

You can start the stimulation by pressing the Start / Stop button on the front
panel of the STG. Press the button again to stop the stimulation. Starting the

STG by pressing the Start / Stop button is considered as activating all four
trigger inputs, that is, all channels are started and stopped, and all four Sync
Out outputs are active when the STG is started. Pressing the Start / Stop button
stops the stimulation if at least one channel is still active in the moment of the
trigger event (indicated by the lighting SWEEP LED). Pressing the button starts
stimulation only if no channel is active (dark SWEEP LED)

External
control:

You can start the stimulation on a trigger from an external device, for example,
a switch. You can use up to eight trigger inputs that independently trigger the
analog output channels that you have assigned to them. The trigger works in
a similar way as when you press the Start / Stop button. You can choose the
action that will be taken when one of the channels that are assigned to the
respective trigger input is still active. Either the stimulus protocols on the
triggered channels are stopped or restarted; or the trigger event is ignored.
There is also a separate Sync Out output for each Trigger In trigger input.
You can assign the Sync Outs to the trigger inputs. The default settings define
that Sync Out 1 is active when Trigger In 1 is triggered, and so on. Please see
Trigger Settings for more details.

STG status control

Three status control LEDs (light-emitting diode) are present on the front panel
of the STG to give you a quick overview on its status.

POWER

PROG

SWEEP

STG has been switched on.

Stimulus file was downloaded to STG. STG is now ready for operation.

Stimulation is running, that is, at least one output channel is active.

MC_Stimulus II status control

The top part of the MC_Stimulus II status control refers to the active instance of the MC_Stimulus
II program instance and the STG that is controlled by this instance. All information in this part
is saved on the STG. The information is updated in the MC_Stimulus II main window when the
connection to the STG is changed or interrupted.

Status light Color Meaning

Connected

Green STG is connected and switched on. The serial number serves as an ID

for the controlled STG and is displayed on the left. On the STG menu,
click Select Device to select another STG connected to a different
USB port from the drop-down list to switch STGs.

Programmed

Green Stimulus file in voltage mode has been downloaded to STG.

STG is now ready for operation. File name and path of the *.stm file
that was downloaded onto the STG are displayed on the right.

Orange Stimulus file in current mode has been downloaded to STG.

STG is now ready for operation. File name and path of the *.stm file
that was downloaded onto the STG are displayed on the right.

Sweep

Red

Indicates the active trigger (up to eight). Each stimulation channel can
be assigned to any trigger. If all eight channels are assigned to trigger
one for example, only one sweep indicator will light up, even though
all stimulation channels can be active. See also Triggering Stimulation.

12

Operating the STG

STG and Stimulus Protocol Information:

Autocalibration

During the first ten minutes after starting the STG, the device emits every minute high frequency
signals (small bursts) for internal offset calibration of the current outputs in a range of +/- 10 mV.
After warming up the STG, the calibration signals later will be delivered half-hourly.

Note: It is recommended to start the STG ten minutes before use to allow warming up!

High sensitive measuring equipments will monitor these calibration signals as artefacts which
might disturb the stimulation when using very low stimulus pulses (< 100 μA) in current mode.
Enable the option “Disable Autocalibration” in STG main menu to avoid the autocalibration.
Download the command to the STG.

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Stimulus Generator 4000 Series Manual

4.2 Operating Multiple STGs

If you have more than one STG connected to the same computer, please click under "STG" in main
menu "Select Device". In the "Select Device" dialog you can choose which STG you like to control
from the currently active MC_Stimulus II program.

 The serial number is printed on the STG's case. The serial number of the currently active STG

is displayed on the status bar of the currently active instance of the MC_Stimulus II program.

 Click Select Device under STG in main menu. Select the serial number of the desired STG from

the STG list.

 You can open multiple instances of the MC_Stimulus II program and control multiple STGs at

the same time. Please make sure that you control each STG only by one MC_Stimulus II instance.

 You can also open only one MC_Stimulus II instance and control multiple STGs one after the

other by the same instance. Simply change the settings in the Select Device dialog and select
the next STG when you have finished to program the first. The STGs can be operated without
a computer connection.

14

4.2.1 Operating the USB-MEA32-STIM4-System

The USB-MEA32-STIM4-System has an integrated four channel current stimulus generator.
For operating this kind of STG, please select the device in Select Device dialog via serial number.
To select stimulation channels, open the dialog Select Stimulation Channels in Edit menu.

Operating the STG

Select Layout: 1 x 12.

It is possible to assign stimulation channel 1 and 2 to stimulation electrodes S1 to S6. It is not
possible to select the same electrode for both channels. Stimulation electrodes S7 to S12 have
to be assigned to channel 3 and 4. If you do not need four channels for stimulation, click check
box "channel off".

For programming the stimulation channels, please use MC_Stimulus II as usual.

15

5 Programming Stimulus Protocols

5.1 MC_Stimulus II Sample Files for STG 4000 Series

These sample files are intended for demonstrating basic features of the Stimulus Generator
STG 4000 series, for basic applications with the MEA-System. If you are using an MEA-System,
please see also the MC_Rack tutorial in the MC_Rack help or the separate PDF on the installation
volume.

The sample files are automatically installed to the Examples folder in the MC_Stimulus II program
directory.

Please note: The demo files were kindly provided by STG users. MCS does not guarantee that
these files will be appropriate for your application and stimulating electrode type. For using
MEA electrodes as stimulating electrodes, MCS recommends the use of monopolar voltage pulses,
though some MEA users feel that they have better results with bipolar voltage pulses, depending
on the cell culture or tissue used.

Warning: Always obey the recommendations of the stimulating electrode manufacturer.

5.2 Neuroelectrophysiology / MEA-System

LTP-Induction.stm

 Stimulus type: Pulse train of 100 biphasic pulses for LTP induction
 Amplitude: 1.5 V
 Duration: 100 µs per phase
 Inter-Stimulus-Interval/Frequency: 10 ms / 100 Hz

LTP-Testpulse.stm

 Stimulus type: Biphasic test pulse
 Amplitude: 1.5 V
 Duration: 100 µs per phase
 Inter-Stimulus-Interval: 60 s

PairedPulse.stm

 Stimulus type: Paired biphasic test pulse for paired pulse facilitation and depression
 Amplitude: 2 V
 Duration: 100 µs per phase
 Inter-Stimulus-Interval: 20 ms between paired pulses, 10 s between pairs

IOcurve-500-3000.stm

 Stimulus type: Voltage step series with biphasic pulses for I/O analysis
 Amplitude: 500 mV to 3 V, increments of 250 mV, 3 repeats
 Duration: 100 µs per phase
 Inter-Stimulus-Interval: 10 s

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Stimulus Generator 4000 Series Manual

monophasic_voltage_1V_100μs.stm

 Stimulus type: Monophasic test pulse
 Amplitude: 1 V
 Duration: 100 µs
 Inter-Stimulus-Interval: 24 ms

biphasic_voltage_1V_100μs.stm

 Stimulus type: Biphasic test pulse
 Amplitude: 1 V
 Duration: 100 µs per phase
 Inter-Stimulus-Interval: 24 ms

ASCII-Import-Biopotential.stm

This file is not intended for a real experiment, but demonstrates the ASCII import feature.
Shown is a single spike recorded from an organotypic hippocampal culture with the MEA-System.
The spike waveform was exported as ASCII from MC_Rack and imported into the MC_Stimulus II
program. The imported file is "ASCII_Import_Biopotential.dat".

5.2.1 General Demo Files

Demo_Waveforms.stm

This file is not intended for a real experiment, but for demonstrating the capabilities of the
stimulus generator. The file includes stimuli with increasing inter-stimulus interval and with
increasing amplitude, ramps and sine waveforms.

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Programming Stimulus Protocols

5.3 MC_Stimulus II Worksheet

You can freely combine any pulse types. Use a separate row for each pulse type.

Hint: Several tools are provided for editing whole columns at once or autocreating entries.

1. Select the desired output type first. Click either Voltage or Current under Output Mode
on the file window of MC_Stimulus.

2. Click a tab to select an output channel.
The according channel worksheet is brought to front.

3. Now you can enter the pulses into the worksheet. Select a Pulse type (either rectangular,
ramp, or sine).

4. Enter the desired voltage steps and a time length for each step.

The according pulse is displayed in the WYSIWYG display at once.

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Stimulus Generator 4000 Series Manual

5.4 Pulse Types

Three basic pulse types are available in MC_Stimulus II. You can create virtually any pulse
by combining different types.

 Rectangular

 Ramp

 Sine wave

Note: The time resolution is 20 μs. When you enter time steps that are not a multiple of 20 μs,
the length of the step is internally adjusted (rounded arithmetically, that is, 249 μs would be
rounded down to 240 μs, 250 would be rounded up to 260 μs) to a valid value. The minimum
voltage resolution is 1 mV, the current resolution is 200 nA. Please regard also the minimum
and maximum output voltage / current of your STG version. If you enter voltage or current
values outside the STG's limit, the invalid value will be changed automatically when you download
the protocol. Cells with changed values will be highlighted in yellow.

Note: If you work near the resolution limits of the STG, the output pulses may differ from the

programmed pulses. In this case, you should check the output with an oscilloscope. Please see

also the "Analog Output Signals" chapter.

Please note that the memory of the STGs of 4000 series is limited (64 MB). You will get an error
message if the memory is full.

For the digital Sync channels, only TTL pulses with bit patterns of 0 (LOW) and 1 (HIGH) can be
programmed. A logical state of 1 (HIGH) results in a 3.3 V output signal, and a logical state of
0 (LOW) results in a 0 V output. Please note that the digital output is sent about 20 μs faster
than the analog output. Please see also the "Triggering Stimulation" chapter.

Rectangular pulse type

 Enter each voltage / current level and the duration of the pulse. The voltage / current jumps

directly to the specified level. In one row, you can enter up to three voltage / current levels.
Use the next row for programming more levels.

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Programming Stimulus Protocols

Ramp pulse type

 Define the starting point, end point, and the length of the ramp. The ramp is then

build according to these parameters in small single steps of 20 μs.

Sine wave pulse type

 Define the amplitude and the period of the sine wave. The sine wave is then computed

according to these parameters with a minimum resolution of 1 mV and 20 μs. If you enter
a negative amplitude, the sine wave starts with its negative alternation.

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Stimulus Generator 4000 Series Manual

5.5 Autorepeating Pulses and Protocols

For entering complex stimuli easier and faster, you can repeat rows and groups instead of
entering the pulses several times into the worksheet. You can repeat each single row. In the
preceding example, the rectangular pulse in row 1 is repeated twice. You can also group several
rows and repeat them altogether. In the example, pulses from rows 1 to 4 are grouped and
repeated three times.

Repeating rows

 Type the number of repeats into the Row Repeat cell of the appropriate row.

The pulses of the complete row are repeated the specified number of times.

Grouping and repeating groups

1. Select several cells by clicking and dragging cells in the Group Repeat column.
Selected cells are highlighted in black.

2. Point to the selected cells and right-click to open the context menu.

3. Click Group / Ungroup. The corresponding rows are grouped now.
This is indicated by a merging of the Group Repeat cells.

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Programming Stimulus Protocols

4. Type the number of repeats into the merged Group Repeat cell.

Repeating complete pulse protocols (autorepeat function), Continuous Mode

You can repeat the complete stimulus on all output channels that are triggered by the same
trigger. This means, each time when a trigger event occurs, the complete stimuli on all
corresponding output channels are repeated for the specified number of times. If the stimuli have
different lengths, the starting points are synchronized. For example, if channel 1 has a stimulus
with a length of 500 ms, and channel 2 of 1000 ms, and both are triggered by the same trigger
event, channel 1 waits 500 ms for the repeat until the output stream of channel 2 has been
finished.

Note: The Sync Out signal for the corresponding trigger is repeated as well each time the stimulus
is repeated.

Hint: You can repeat the complete stimulus protocol that is assigned to a trigger continuously
by using the Continuous Mode setting. Continuous mode can be activated in the main window
or under Trigger Settings. The STG has then to be stopped manually by the user. You can use this
feature regardless whether you use an external trigger input or not. When you press the Start
button, this is considered as if all four trigger inputs were active.

When you use Continuous Mode, the repeats entered in the Trigger Settings dialog box
are disabled.

1. On the STG menu, click Trigger Settings.

2. Enter the number of repeats for each trigger separately. 0 repeats the output signals
continuously.

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Stimulus Generator 4000 Series Manual

In the following example, the stimuli on output channels 1, 3, and 6 that are all triggered by
Trigger 1 are repeated three times after the trigger event, each time accompanied by the
Sync Out 1 output. All other stimuli are applied once after their respective trigger event.

Repeating complete pulse protocols, Gating Trigger

Repeated stimulation of complete protocols can also be controlled by a gating trigger. Channels
associated with a Trigger input will be active as long as the condition of that Trigger is 1 (HIGH)
and switched off as soon as the condition becomes 0 (LOW). Gating trigger function can be
enabled in the Trigger Settings menu.

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Programming Stimulus Protocols

5.6 Autocreating Entries and Editing Columns

Changing time units for a complete column

1. Click any Unit column header to select a column. The selected column is highlighted in black.

2. Right-click and click Change Time Unit.

3. Select the desired time unit.

All units in the column are set to the selected time unit.

Inverting pulses in a column

1. Click any Value column header to select a column.
The selected column is highlighted in black.

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Stimulus Generator 4000 Series Manual

2. Right-click and click Invert Selection.

The polarity of the signals is switched from positive to negative and vice versa.

Incrementing columns

This feature is very convenient for setting up long and complex stimuli without entering
each value manually. You can enter and edit multiple voltage values or time lengths.

You can keep all zero values unchanged with the option Keep Zero.

Apart from an absolute shift or increment factor, you can modify values by the percentage
as well.

Shifting time or voltage / current values

You enter a value, which is added arithmetically to all values in the selected column.
For example, if you enter "-50", -50 is added to all values.

1. Click any Value or Time column header to select a column. The selected column
is highlighted in black.

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