Hi, I agree with Max Anstötz, even the lights may be turn off. It seems to be line noise. Test your ground connections.

regards

It looks like you have both biological signals (synaptic potentials and maybe action potentials, though I can't fully examine the maximally depolaized trace) and line noise.

If the microscope lamp is AC powered, that's a likely source of line noise. Unplug it and put the plug with its cord into the experimental rig. If the noise goes away, you'll need to use a DC power supply for the lamp. I've used motorcycle or car batteries for this purpose. A regulated power supply is fine too, though they used to be much more expensive than a used car battery.

You need to learn how to ground the rig properly, without ground loops, and, if you don't already have Faraday cage, you could enclose the rig with a faraday cage.

A sheet of aluminum foil grounded to your common ground can be moved around the patch clamp probe to identify the direction from which the noise is coming. if it's clearly from one direction, you could simply put a single grounded, conductive wall on that side. A flat piece of cardboard with a sheet of aluminum foil taped to one side works until you can build something more permanent.

If you have never de-noised a patch clamp rig, ask someone who has experience to show you. For whole cell recording, it should take under an hour. For single-channel recording, it can take days (!).

Hi! Such noise might also be induced by the Wi-Fi signal. Try switching off the router.

Good luck!

what Prep. are you recording from? Brain slices? Neurons in culture? Other?

if brain slices or cultures of neurons, then those are synaptic inputs. use DNQX and CPP.

please share the full picture when you depolarize to see your APs and the associated noise you are describing.

Hi Nowrin,

Lots of good advice from all those above.

First determine frequency. Is it 60 cycles? Then computer monitor of fluorescent lights. Then it will give you an idea where to ground rig, microscope , amp headstage, etc.

I originally thought you were asking about spikes on highest holding voltage on image untitled_3 which looks like patch breakdown or activation of large current channel.

Just ground away and you will get rid of the noise.

MacG

First find out what the strange noise is

Hi Norwin,

Fluorescent lights of microscope and check the grounding electrode. Sometimes it is difficult to find the noise source or where the noise is picked by the rig. Cover the headstage with aluminum foil. The pipette holder should be dry or moisture-free. Remove each BNC of connections of the light source, perfusion connections, make sure the rig has no slat bridges and loops. Relax & sit back and see definitely you will find and overcome this challenge.

All the best,