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Stimulus Isolator

The MS4/MS16 Stimulus Isolator converts digital waveforms into analog current waveforms as part of a computer controlled neural microstimulator system that is capable of delivering complex microstimulation patterns simultaneously across multiple microelectrode channels.

Stimulation control waveforms are first defined on a user-programmable DSP base station, such as the RZ5 or RX7, then digitally transmitted over a fiber optic cable to the battery powered stimulus isolator. On the isolator, specialized circuitry for each electrode channel generates an analog constant-current waveform as specified by the digital stimulation control waveform.

You can generate complex arbitrary waveforms with a bandwidth of up to 10 kHz or design and deliver complex patterns of biphasic pulses with phase durations of less than 50 microseconds. The microstimulator system standard configuration is capable of delivering up to 100 µA of current simultaneously across up to 16 stimulating electrodes (impedances up to 1Mohm). The system can also incorporate a multi-channel A/D input (via one of our Medusa preamplifier) for dynamic, real-time stimulus control based on analog control signals from virtually any signal source.

A proven digital communication system optically isolates the electrical stimulator from the waveform generators to eliminate AC power surges and noise, ensuring superior safety and performance. Current limiting circuitry, a self-contained high voltage battery, and fiber optic communication combine to produce complete electrical isolation between the waveform generator and stimulus delivery system, for ultimate stimulator safety.

This system can be used with our switching headstage and a Medusa preamplifier, creating a complete stimulate and record solution.

Part Numbers:
MS4 Four-Channel Stimulus Isolator
MS16 16-Channel Stimulus Isolator
NC48 Battery Pack

Also available in the following systems:
RX7G-4 Two DSP Base Station, four channel Stimulus Isolator and battery pack
RX7G-16 Five DSP Base Station, 16 channel Stimulus Isolator and battery pack

Stimulus isolator technical specifications:

Stimulus output channels:	4 or 16 PCM D/A
Stimulus output current (max):	100 microamps max (up to 200 kOhm load)
Zero-Signal Leakage Current:	Less than 0.2% of full range setting
Digital output:	16 bits
Selectable reference:	channel or global
Stimulus Power:	NC48 rechargeable NiCad battery pack
Device power:	Rechargeable Li-Ion battery
Dimensions:	Height - 3^1/16",Width - 6", Depth - 8.5"
Weight:	796g

The NC48 battery pack:

Battery life	1000 mAmp (240 hours of continuous stimulation)
Rechargeable	Yes
Maximum impedance for delivering a 100 microAmp current	200 Kilo Ohm
Usable in 1 milliAmp mode	Yes

Customers who use silicon probes, such as the NeuroNexus probes, find that the impedances of the probes drop in the range of 100 kOhms when the probes are activated for stimulation. As a result, the NC48 works fine in most cases.

If using probes with impedance of greater than 200 kOhms and you Require 100 microamps of current, contact our Technical Sales Team for custom configuration solutions.