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RZ5P Tech Notes

Fiber Photometry Response Data Has Oscillation Artifact

TN0991

Product: RZ5P, Synapse
Version: All
Date Added: 2019-07-12

Issue

The issue typically is seen as a low-frequency oscillation in the demodulated data streams.

Solution

Find the minimum DC Offset, as recommended per the Fiber Photometry User Guide, then make sure to at least double that value. The distortion between the signals levels off at about twice the minimum DC Offset. If you have an LED driver that has low power mode, then we recommend using this setting.

TDT recommends using attenuating patch cords between the LEDs and the Doric Minicube (or light filters). This will allow the RZ5P DACs to be driven at a higher voltage range. This is also beneficial in general because the step resolution for LED driving current is much finer.

Note that if you were not seeing any oscillatory issues before, then there was not a problem in the data. In most cases, even if some distortion was present, the effect is at least an order of magnitude smaller than typical GCaMP activity so there would be no issue in analysis.