Hi Andie,

I have never done field recordings so my suggestions may not be helpful. First, I am assuming you're getting noise in-spite of using a Faraday cage? Have you looked at the light source aka illuminator or power source associated with the rig, such that when you turn them on or off there's change in the level of noise. Do you have a camera attached to the microscope that you turn on while running the experiment? Does the room has its own air condition? I will look at these things first and try to play with them and see if it helps. But, if the noise is coming from something in the building then that will be hard unless you find the source. Also, is your bath solution flow even without any bubbles trapped in the tubing? There are so many things that can cause noise but since I have not done field recordings I wonder if the source of noise is coming from the amplifier or the electrode are you're using. Hope you find a solution. Let me know what works.

Jimmy

did you ground your table to the main building ground? I’ll start by that, then dissect other sources of noise. Ask facilities in your institution for the main ground cable and then connect your amplifier ground to the table.

Those are all good suggestions above. There were a couple of magic words in your question: "new building" and "extend cables." The new building may have put you in the line of fire for external noise transmitters- TV stations, military radar (don't laugh, it happened to a friend of mine near the naval station in San Diego!), even large elevator motors. The longer the cables are, the more potential for introducing noise, especially if the cables are not adequately shielded. The solution is to ensure appropriate cable shielding (and grounding for that shielding), and bringing the amplifiers closer to the preparation rather than extending those cables. To block externally-generated noise, it may take shielding of portions of the entire room. Don't despair, it just takes effort. Good luck!

Ron

Hi Andie,

I want to say the same as said Jimmy I have never performed field recording, I left electrophysiology about 6 years ago to get another speciality but I want to get back soon. I hope my experience will be useful in your situation.

First of all you have to detect in which part of your system noise appears as said Jimmy and Paula. Try to check you ground with oscilloscope. For this, just connect signal input of last one to point where your ground comes and look at the signal. In ideal case you will see very high frequency noise (in range of MHz) with very low amplitude (about mV). If you will see some periodical signal of lower frequency probably it comes from some another electrical equipment in surrounded rooms.

Next step you have to check in same way signal ground of your amplifier. In ideal case you have to observe signal of same form.

If everything is good you can try to check your system with the cell model which came with your amplifier. If you don’t have one, you can make it. Basically this electrical model has to have same parameters as your real system. I don´t know what are resistance and capacitance for the field recording but for patch-clamp it use 100kOm - 1GOm resistance in parallel with capacitance about 50pF (https://www.adinstruments.com/products/model-cells-patch-clamp-amplifiers). Something similar has to be for your amplifier or you can use even this parameters to check your system. With this model you can check all the system parameters before connecting electrode to the bath.

If everything OK with parameters of noise in all previous steps than next one will be check your holder and perfusion system, ground of your cage, your microscope, manipulator.

One very important thing is all connections with ground knobs have to be very nice. If you have some paint in places of connection you have to take off this one or connected in other place.

Setup law noise recording is one task no trivial.

If you want you can send me the model of your amplifier and I will look at it, probably I can help you more.

I hope you will find solution for your problem.

Let me know how it come out.

Sometimes the problem may be in the anti-vibration table:

the table frame lies on the stove and transmits all the noise and vibration

On the other hand, the problem may be in the bad Faraday cage