Stimulus Isolator

Your Benefits:

The ISO-STIM-II in FULL configuration has four modes of operation:

• In the TIMED input mode, the output signal is generated by the built-in timing unit and triggered either by a TTL trigger at the INPUT connector or manually with the MANUAL pushbutton.
• In the GATED input mode, the output signal is generated only while the INPUT connector receives a TTL HIGH input signal.
• In the DIRECT input mode, the output signal follows exactly the input signal with the selected scaling.
• In the TIMED DIRECT input mode, the output signal follows – like in DIRECT mode – the input signal but is triggered by the input signal itself and the duration of the output stimulus is set at the ISO-STIM-II.

Frequently asked questions (FAQ):

What is a stimulus isolator?

A stimulus isolator is an electronic device that allows the application of an isolated high voltage pulse to cells or tissues.

What does “isolated” mean here?

The high voltage output signal of the stimulus isolator is not related to ground, i.e. it is floating.

How does a stimulus isolator work?

A stimulus isolator translates a digital or analog input signal (from a data acquisition system or signal generator) into an isolated high-voltage output signal.

What are the main applications of stimulus isolators?

Main application of a stimulus isolator is the excitation of a population of neurons to investigate the evoked responses.

What types of stimulus isolators are available?

Simple stimulus isolators have limited features. There are current-only versions or voltage-only versions, both with unipolar outputs.

The ISO-STIM II from npi can have current and voltage output, both as bipolar (±100 V). It can work in a TTL triggered mode where amplitude and duration is pre-set at the device. In the DIRECT mode, an analog input signal is translated into an amplified and isolated output voltage or current signal.

How do I choose the right stimulus isolator for my research?

If you already know, whether you need voltage or current and how your stimulus signal has to look like, you can choose the stimulus isolator accordingly. If you need to be more flexible, choose the ISO-STIM II with CURPOT option and FULL control options, to have all

Can stimulus isolators be used for in vivo experiments?

Stimulus isolators are used for in vivo experiments as well as in vitro experiments.

Are there any limitations to using a stimulus isolator?

When using current output, the maximum current is limited by the electrode’s impedance and the maximum output voltage according to Ohm’s law: for 10 mA output current the maximum electrode impedance is 10 kOhm. Higher impedances will lead to lower currents.

Can stimulus isolators be integrated with other electrophysiology equipment?

A stimulus isolator can receive TTL inputs or analog input signals and can be easily connected to the data acquisition system of an existing electrophysiology setup.