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Template Experiments

Included with this guide are template experiments that help you set up and understand various SIM stimulation paradigms.

Choose an appropriate template based on your electrode impedance and desired current or voltage output. Use the tables below to guide you.

The templates are described in detail, and include a link to the Synapse experiment (*.synexpz) that is used. Please be sure to have your IZV10 and other appropriate hardware detected in your rig (Menu → Edit Rig → Detect) so there are no issues when importing templates.

These templates all assume at least 4 stim banks are available.

Picking a Template Based on Impedance and Desired Output

Note

The settings of each recommended templates may need to be modified depending on the desired electrode configuration (monopolar (single-ended) or bipolar). If the recommended template needs the output mode (current-mode vs voltage-mode) switched, there will be an asterix *.

For options marked as 'Not Recommended', there may be workaround solutions. Please consult with TDT tech support for possible options.

Current-controlled (Monopolar)

Choose the tab for your electrode impedance below to see the recommended templates.

>3 kΩ

Desired Current Output Voltage 20kΩ load Recommended Template
0 mA → 5mA 0 V → ± 15 V 0 V → ± 15 V Stimulating on a Single Channel Across Four Boards
5 mA → 10 mA ± 15 V ± 15 V Not Recommended
10 mA → 20 mA ± 15 V ± 15 V Not Recommended
> 20 mA ± 15 V ± 15 V Not Recommended

<3 kΩ

Desired Current Output Voltage 500 Ω load Recommended Template
0 mA → 5mA 0 V → ± 15 V 0 V → ± 2.5 V Stimulating on a Single Channel Across Four Boards
5 mA → 10 mA 0 V → ± 15 V ± 2.5 V → ± 5 V Stimulating Up to 10 mA per Voice
10 mA → 20 mA 0 V → ± 15 V ± 5 V → ± 10 V Stimulating Up to 20 mA per Voice
> 20 mA 0 V → ± 15 V ± 10 V → ± 15 V Stimulating > 20 mA Across a Monopolar Electrode

Current-controlled (Bipolar)

>3 kΩ (20kΩ example)

Desired Current Output Voltage 20kΩ load Recommended Template
0 mA → 5mA 0 V → ± 30 V 0 V → ± 30 V Stimulating on a Single Channel Across Four Boards
5 mA → 10 mA ± 30 V → ± 120 V ± 100 V → ± 120 V Stimulating > 5 mA with Impedance Loads > 3 kΩ
10 mA → 20 mA ± 60 V → ± 120 V ± 120 V Stimulating > 5 mA with Impedance Loads > 3 kΩ
> 20 mA ± 120 V ± 120 V Not Recommended

<3 kΩ (500 Ω example)

Desired Current Output Voltage 500 Ω load Recommended Template
0 mA → 5mA 0 V → ± 15 V 0 V → ± 2.5 V Stimulating on a Single Channel Across Four Boards
5 mA → 10 mA 0 V → ± 30 V ± 2.5 V → ± 5 V Stimulating Up to 10 mA per Voice
10 mA → 20 mA 0 V → ± 30 V ± 5 V → ± 10 V Stimulating > 10 mA Across a Bipolar Electrode Pair
> 20 mA 0 V → ± 30 V ± 10 V → ± 30 V Stimulating > 10 mA Across a Bipolar Electrode Pair

Recall that a bipolar configuration in current mode allows up to increase the effective voltage compliance because each phase is measured with respect to a GND in the center of the anode and cathode. However, it will not double the measured voltage across the load impedance like in Voltage Mode. As you can see, the 500 Ω examples result in the same output ranges as monopolar for current below 20 mA because V = I*R.

Voltage-controlled (Monopolar or Bipolar)

>3 kΩ (20kΩ example)

Desired Voltage Output Voltage 20kΩ load Recommended Template
0 V → 15 V 0 V → ± 15 V 0 V → ± 15 V Stimulating on a Single Channel Across Four Boards*
15 V → 30 V ± 15 V → ± 30 V ± 15 V → ± 30 V Single Bipolar Output*
30 V → 60 V ± 30 V → ± 60 V ± 30 V → ± 60 V Stimulating Up to ± 60 V in a Bipolar Configuration
> 60 V ± 60 V → ± 120 V ± 60 V → ± 120 V Stimulating Up to ± 120 V in a Bipolar Configuration

<3 kΩ (500 Ω example)

Desired Voltage Output Voltage 500 Ω load Recommended Template
0 V → 15 V 0 V → ~± 15 V 0 V → ~± 5 V Stimulating on a Single Channel Across Four Boards
15 V → 30 V 0 V → ~± 15 V ~± 5 V Not Recommended
30 V → 60 V 0 V → ~± 15 V ~± 5 V Not Recommended
> 60 V 0 V → ~± 15 V ~± 5 V Not Recommended

* Change IZV10 'Output Type' to Voltage Mode

Voltage or Current Mode

Single Channel Across Four Boards (5 mA or ± 15 V)

Single Channel Across Four Boards (5 mA or ± 15 V)

Experiment 4BankOutputRange Download Experiment
Objective Use a simple setup to stimulate on a single channel across
four boards in current mode or voltage mode. This template will also
help to understand output ranges, epoc storage of stimulus information,
and the IZV10 monitor output.
Connections

This template is covered in the Quick Start Example

Single Bipolar Output (5 mA or ± 30 V)

Single Bipolar Output (5 mA or ± 30 V)

Experiment MonitorBipolarOutput Download Experiment
Objective Use a bipolar electrode configuration and monitor the voltage output across the load
Connections

When performing bipolar stimulation, the IZV10 monitor output ('MonA') will likely not provide a meaningful readout of the stimulation across your load. The user must subtract the two bipolar channels from one another to see the voltage across their load. This is done using the following gizmos: Selector, Unary Processor, Stream Data Storage.

In this example shows the output of a 250 µA stimulation across a 20 kΩ load. The expected voltage is 5 V. 'Monr' is the output from the bipolar subtraction.

List of Channels and Parameters over a Specified Time Sequence

List of Channels and Parameters over a Specified Time Sequence

Experiment OneChan4BanksParSeq Download Experiment
Objective Use the parameter sequencer to stimulate across a list of channels with a specified time interval. This can also be used to parametrically change the stimulation amplitude, duration, pulse count, etc.
Connections

The Parameter Sequencer is a powerful gizmo that enables the user to sequentially change stimulation parameters and target channels in a well-defined timing and pattern. In this example, we are targeting random channels from all 4 banks (output range 1 - 64).

Note

You must either arm the IZV10 first or turn off safety mode before beginning your stimulation sequence. Thus, if you have both Start Seq at Run-Time and Safety Mode enabled on the Parameter Sequencer and IZV10, respectively, you will not be able to stim.

Current Mode

Stimulating Up to 10 mA per Voice

Stimulating Up to 10 mA per Voice

Experiment OneChan4BanksCurrentDoubling Download Experiment
Objective Use Current Doubling: By Two to stimulate up to 10 mA per voice on each board
Connections

Setting the IZV10 to Current Doubling: By Two allows the user to stimulate up to 10 mA per voice. This setting decreases the max Voices per Board from 4 to 2. This is because, in order to achieve current doubling, two voices are directed to the same output channel.

In this example, we are sending 10 mA across a 500 Ω load to achieve a ± 5 V biphasic voltage output across channel 1 (channel 1, board 1).

Stimulating Up to 20 mA per Voice

Stimulating Up to 20 mA per Voice

Experiment OneChan4BanksCurrentQuadrupling Download Experiment
Objective Use Current Doubling: By Four to stimulate up to 20 mA per voice on each board
Connections

Setting the IZV10 to Current Doubling: By Four allows the user to stimulate up to 20 mA per voice. This setting decreases the max Voices per Board from 4 to1. This is because, in order to achieve current doubling, four Voices are directed to the same output channel. One can only perform single-ended stimulation with the Current Doubling: By Four option since Bipolar and Local Ground require two Voices per stim signal.

In this example, we are sending 20 mA across a 500 Ω load to achieve a ± 10 V biphasic voltage output across channel 32 (channel 16, board 2).

Note

The output channels on the IZV10 'MonA' store (below) show four stimuli trains on channels 5 - 8. This is because in Current Doubling: By Four there are four Voices being played, but they target the same output channel (recall that current sources in parallel add). The range is 5 - 8 because the IZV10 monitor looks at 4 Voice monitor streams per board.

Recall from Quick Start: Understanding Stim Info that the target channel information is contained in the eS1r stream, or if you enable Epoc Storage for the Chan parameter in the eStimDriver parameter table (see eStim1 image below).

Serial Outputs

Stimulating Up to ± 60 V in a Bipolar Configuration

Stimulating Up to ± 60 V in a Bipolar Configuration

Experiment SerialMode2Banks Download Experiment
Objective Use a manual serial configuration with Voltage Mode to stimulate beyond the ± 15 V Voice voltage compliance up to ± 60 V across a load.
Connections

Serializing an output is useful for increasing the compliance voltage across a load. The user can manually configure a serialized output (as opposed to using Serial Mode) using 2 or more boards. Recall from Serial Outputs that this is a bipolar configuration, and that specific channels are shorted together to achieve the hardware configuration.

The connection diagram is showing the serial output setup. A User Input gizmo (UIn1) is used to synchronize the output timing of two eStim waveforms. The eStim1 and eStim2 waveforms are inverses of one another and are sent to either sub stimulator 1 or sub stimulator 2 of the IZV10. The Selector Unary Processor Stream Storage Gizmo is to monitor the true bipolar output. The equation in the Unary Processor reduces to the serial output equation specified earlier once the subtraction of inverse signals is accounted for: {2 * requested voltage * Nbanks}.

Here is the output from a 15 V request using channels 1 and 16 in Voltage Mode. The output is + 60 V across an open load.

Note

The load is open to demonstrate max compliance. Recall that, in Voltage Mode, for a non-infinite load impedance there is some voltage loss vs the max compliance due to the output impedance of the stim.

Stimulating Up to ± 120 V in a Bipolar Configuration

Stimulating Up to ± 120 V in a Bipolar Configuration

Experiment SerialMode4BanksVMode Download Experiment
Objective Use a manual serial configuration with Voltage Mode to stimulate beyond the ± 15 V Voice voltage compliance up to ± 120 V across a load.
Connections

The connection diagram is showing the serial output setup for four boards. The same paradigm that was used in a two-board serial configuration is applied here.

A User Input gizmo (UIn1) synchronizes the output timing of two eStim waveforms.

The eStim1 and eStim2 waveforms are inverses of one another and are sent to either sub stimulator 1, 3 or sub stimulator 2, 4 of the IZV10 to achieve the waveform setup outlined in the Serial Outputs diagram for 4 board serialization.

The Selector Unary Processor Stream Storage Gizmo is to monitor the true bipolar output. The equation in the Unary Processor reduces to the serial output equation specified earlier once the subtraction of inverse signals is accounted for: {2 * requested voltage * Nbanks}.

Here is the output from a 20 V request using channels 1 and 16 in Voltage Mode. The output is + 120 V across an open load. This is because the compliance is still + 15 V per Voice, so the 'requested voltage' here is 15 V and not 20 V.

Stimulating Beyond 5 mA with Impedance Loads Greater than 3 kΩ

Stimulating Beyond 5 mA with Impedance Loads Greater than 3 kΩ

Experiment SerialMode4BanksIMode Download Experiment
Objective Use a manual serial configuration with Current Mode to defeat the normal current compliance for high impedance loads (> 3 kΩ) by increasing the out voltage compliance to ± 120 V.
Connections

The setup is nearly identical to the Voltage Mode setup. The main difference is that the user can easily setup Current Doubling: By Two in order to increase the current compliance from 5 mA to 10 mA per Voice across the load. Recall from Current Mode that the current across the load is the requested current and not 2*requested current, so the voltage compliance increased but the voltage output is still just V = I*R.

In this output example, we are stimulating 5 mA across a 20 kΩ resistor to achieve an output voltage of 100 V. In a normal configuration, the max current we could send across a 20 kΩ load is 750 µA {V = I*R; 15 V = 750 µA * 20 kΩ}. However, because we serialized the boards together, the voltage compliance is increased to {2 * Voice voltage compliance * Nbanks}, so we can send the full Voice current limit of 5 mA across the load.

Repeated Mode

Duplicating Stim Signals On Many Banks

Duplicating Stim Signals On Many Banks

Experiment Repeated Download Experiment
Objective Duplicate a series of signals across many banks using Repeated Mode.
Connections

Repeated Mode is an easy way to send the same stimulus to identical target channels across multiple boards. In this mode, the 'Output Channel Range' is 1 - 16, even though more than one board is active in 'Number of Boards'. In Repeated Mode channels in higher board numbers are addressed as if they were on board 1. This is because the same Voice is repeated on every board in the sub stimulator.

In this example, we are repeating four different Voices on 4 boards. ChanA addresses the first Voice on boards 1 - 4, ChanB the second Voice, and so forth. The notation 'B1a', 'B2a', 'B3b', etc. refers to BoardN, Voice A - D. Chan-1 controls Voice A on boards 1 - 4, Chan-2 controls Voice B on boards 1 - 4, etc.

The LEDs on the SI-8 board indicate voltage activity during the stimulation trains. All four boards repeated the same LED activity because they had the same stimulation signals.

Parallel Outputs and Parallel Mode

Sending 16 Unique Signals to a 16 Channel Output

Sending 16 Unique Signals to a 16 Channel Output

Experiment 16ParallelMode_1x4 Download Experiment
Objective Use Parallel Mode to send 16 unique stimulation signals to a single 16 electrode output set.
Connections

The connection is showing a Parallel Mode output of 16 unique Voices over four banks. Each eStim gizmo can output four Voices and four Channel Number signals. The eight signals from each eStim gizmo are then merged to create one multi-channel signal to inform the IZV10.

The 'Output Channel Range' is limited to 16 and each board range is 16 in Parallel Mode. This is because Parallel Mode assumes the outputs from each board are physically shorted together. This makes a single output set. In this example, 16 unique voices can target 16 individual channels on an electrode array. Each channel in the parallel configuration is addressed within a range of 1 - 16 instead of 1 - 64 to make the configuration easier to understand. Channel '1' is the actual first channel for all boards in the sub stimulator, in this case, and so forth up to channel '16'. Please refer to the Parallel Outputs section for more details.

Stimulating Greater than 20 mA Across a Monopolar Electrode

Stimulating Greater than 20 mA Across a Monopolar Electrode

Experiment IMode_4Banks_SingleEnded_Parallel Download Experiment
Objective Use parallel outputs to achieve high current output across a single-ended (monopolar) electrode pair.
Connections

Some experiments may require very large current outputs (> 20 mA) which cannot be achieve through Normal output mode configurations. In this case, the user can short outputs of each board together to make a parallel current output. The easiest way to do this is to make use of Repeated Mode and Current Doubling. In this example, we are sending 7.5 mA from a Bipolar Voice repeated four times across a 500 Ω load. This provides a 30 mA current, since current sources in parallel add together.

The result is a 15 V output across our load. {7.5 mA * 4 Voices = 30 mA; 15 V = 500 Ohms * 30 mA}

Stimulating Greater than 10 mA Across a Bipolar Electrode Pair

Stimulating Greater than 10 mA Across a Bipolar Electrode Pair

Experiment IMode_4Banks_Bipolar_Parallel Download Experiment
Objective Use parallel outputs to achieve high current output across a bipolar electrode pair.
Connections

Some experiments may require a bipolar electrode configuration with currents beyond the Normal output mode limits for bipolar Voices (10 mA). In this case, the user can short outputs of each board together to make a parallel current output. The easiest way to do this is to make use of Repeated Mode and Current Doubling. In this example, we are sending 10 mA from a Bipolar Voice repeated four times across a 500 Ω load. The result is a ± 20 V output, which is a 40 mA current. Recall that a bipolar configuration allows up to increase the effective voltage compliance because each phase is only 10 V with respect to GND.