Hello,
We are interested in excitability changes in the bilateral mPFCs.
We test the excitability of one side as a result of a biphasic 200uA pulse (0.1 ms per phase) in both ipsilateral and contralateral sides. The evoked potential trace always shows a large stimulation artifact that exponentially decays and takes up to hundreds of milliseconds (the artifact is present in a sanity check we did in a rat post-mortem). I attached a photo of a trial of stimulation. Is this artifact to be expected under the conditions of our experiment, or should we reconsider the quality of the acquisition?
That seems like a very long artifact. What kind of stimulator are you using? We use WPI 360 and 365, which have very fast decays (
There is a possibility of galvanic coupling between the stimulator and the amplifier. The outputs of the stimulator should be connected to the preparation directly. There should be no connection between the stimulator's outputs and the preparation ground. What stimulation electrode you are using? What is the ground configuration?
Anton Sheinin I record from a freely behaving rat inside a Faraday cage. The electrodes are custom-made with 6 Pt-Ir probes, with the reference shorted to the ground. The stimulation and recording are done via Alpha Omega system on the same head stage.
How close are the stimulation and recording electrodes to each other? Also, I would try to check for accidental short between the electrode wires.
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