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Information about Neuropixels electrode arrays
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Best way to rinse probe in tergazyme after use #9

Open weallen opened 6 years ago

weallen commented 6 years ago

Hi,

I wanted to know if anyone had tips on the best way to wash the probe in tergazyme after use (i.e. how to hold it in the beaker/vehicle for tergazyme). This has been the most error prone part of using the probes for me -- in order to be able to use my rig while the probe is cleaning, I take the probe off, put it into a manual micromanipulator, and then put the tip into the solution. During this process I've found that it's easy to accidentally bump or brush the shank while handling it, since the shank is almost invisible to me. How do other people do it?

Is this even necessary to do after each recording, or if a probe is being reused multiple times per day and there's no obvious clumps of biological matter sticking to it, can it just be done once at the end of the day?

Thanks, Will

nsteinme commented 6 years ago

I have a setup that sounds very similar to yours, and also involves taking the probe off the rig - but I do leave the probe and headstage attached to a big rod that is held by the micromanipulators. I carry the whole thing with this rod. I think this makes it reasonably straightforward to handle.

I think Dan Denman had shown some data once suggesting that over a period of weeks, and a dozen or so recordings, he had seen some subtle signal degredation - but this effect went away when he started using tergazyme to clean the probes. The conclusion there is that tergazyme does help prevent some kind of tissue build-up. I suspect it would only be on a slow timescale, though. I just do it once at the end of the day.

weallen commented 6 years ago

Yeah, if this is useful for people, we built something that holds a beaker of tergazyme right where the mouse's head was, so we don't have to remove the probe. The times when I've been responsible for breaking the electrode have generally been when I've been manually handling them, and haven't been able to see exactly where the shank is.

At this point, Nick, what would you say your mean time to breakage is (or mean number of usages), and how has it changed as you've become more experienced with them? I'd say my average right now is pretty low, but it might be useful for people to get a sense of this for planning experiments.

nsteinme commented 6 years ago

So far as my records reflect, my last broken probe was 14 months ago. But the records also say I broke six in the first three months or so that we had this version of the probe. I think it could be well-modeled as a poisson process with a mean parameter that falls off exponentially over time :) So don't worry, it gets better from here...

On Sat, Nov 4, 2017 at 6:04 PM, William E. Allen notifications@github.com wrote:

Yeah, if this is useful for people, we built something that holds a beaker of tergazyme right where the mouse's head was, so we don't have to remove the probe. The times when I've been responsible for breaking the electrode have generally been when I've been manually handling them, and haven't been able to see exactly where the shank is.

At this point, Nick, what would you say your mean time to breakage is (or mean number of usages), and how has it changed as you've become more experienced with them? I'd say my average right now is pretty low, but it might be useful for people to get a sense of this for planning experiments.

— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/cortex-lab/neuropixels/issues/9#issuecomment-341917620, or mute the thread https://github.com/notifications/unsubscribe-auth/AHPUP_qZpBQUbGoh9iY-M9pvl_MgTDTeks5szKdCgaJpZM4QR0YD .

weallen commented 6 years ago

Good to know :-) That sounds about consistent with my rate... I guess the next question would be: is there some change you made that suddenly caused you to stop breaking them?

If it's useful for other people who read this thread, my attempted solution has been to develop a protocol for doing recordings that minimizes the times when I can't visually see the electrode under a microscope and where I'm physically holding them/moving them around.

nsteinme commented 6 years ago

No, no particular change to stop breaking them, but just as you say - finding ways to handle them in safe/secure ways (or avoid handling them).