the signals from Chip with cells and without cells are almost the same

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the signals from Chip with cells and without cells are almost the same

Post  adamyuan on Wed Mar 14, 2012 11:08 pm

Hello, everyone,

now i face a problem here, when i record a MEA with cells, then i get the signal like the below.

Peak to Peak Amplitude with cells.

screenshoot at 14s


But when i record a MEA without cells, filled with PBS, then i get almost the same signal,

Peak to Peak Amplitude without cells.

screenshoot at 35.7s


i have record 3 MEA with cells in all, and befor the experiment, between the experiment, after the experiment i used MEA with PBS to control.
they are basicly like the same, only the frequence of the coming spike are different. And i m using a shorter cable (1M), and they are all coverd with aluminum foil, they are grounding well. i m using MEA 1060Rev.C SerNo.026

is there someone can tell me what's the problem here? thank you very much.

adamyuan

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Re: the signals from Chip with cells and without cells are almost the same

Post  Thomas on Thu Mar 15, 2012 7:32 pm

Dear Adam,

thank you very much for sharing the screenshots.

It is quite obvious, that you are seeing just artifacts in your recordings.
It seems that some electrodes are either defective or the contacts are not good.

If you see the same pattern of "high noise electrodes" on multiple MEAs, please check the contact pins on the amplifier.
If you see these issues just on one particular MEA, just try to repeat this with a new MEA chip.

You might also consider testing amplifier & contacts using the test model probe.
The first step before you start looking into biological signals should be a clean baseline!

To get a feeling what to expect from spiking neurons, please see our sample files that are included on the CD you received with the system.

Greetings

Thomas

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Re: the signals from Chip with cells and without cells are almost the same

Post  adamyuan on Thu Mar 15, 2012 10:46 pm

Thomas wrote:Dear Adam,

thank you very much for sharing the screenshots.

It is quite obvious, that you are seeing just artifacts in your recordings.
It seems that some electrodes are either defective or the contacts are not good.

If you see the same pattern of "high noise electrodes" on multiple MEAs, please check the contact pins on the amplifier.
If you see these issues just on one particular MEA, just try to repeat this with a new MEA chip.

You might also consider testing amplifier & contacts using the test model probe.
The first step before you start looking into biological signals should be a clean baseline!

To get a feeling what to expect from spiking neurons, please see our sample files that are included on the CD you received with the system.

Greetings

Thomas

Hey, Thomas,

thanks a lot for your answer, what do you mean by "test model probe" here? is it Ok,wenn i use Leer MEA filled with PBS?

should i use the "Offest Correction" in this situation? or the offset from my Amplifier is too large?

Best Regards

Adam Yuan

adamyuan

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Re: the signals from Chip with cells and without cells are almost the same

Post  Thomas on Thu Mar 15, 2012 11:04 pm

Dear Adam,

I was referring to this one:
http://www.multichannelsystems.com/products/test-mea

Of course if you have a MEA on which all electrodes are ok, you can also work with that one. the advantage of the Test MEA is that you can exclude MEA related issues.

Offset correction should be used whenever you observe a stable offset.

Thomas

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Re: the signals from Chip with cells and without cells are almost the same

Post  adamyuan on Fri Mar 16, 2012 1:35 am

Thomas wrote:Dear Adam,

I was referring to this one:
http://www.multichannelsystems.com/products/test-mea

Of course if you have a MEA on which all electrodes are ok, you can also work with that one. the advantage of the Test MEA is that you can exclude MEA related issues.

Offset correction should be used whenever you observe a stable offset.

Thomas

Dear Thomas,

now i have tried a lot of things---- contact Pins of Amplifier with 100%Ethanol cleaning; cabel and Amplifier with Aluminiumfolie completly wraped ,plug cleaning----- but i can't get a clean baseline all along, what should i do now? Crying or Very sad

Yours

Adam

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Re: the signals from Chip with cells and without cells are almost the same

Post  Thomas on Fri Mar 16, 2012 1:41 am

Did you use the Test MEA?

If everything fails, please send us the Amplifier for amintenance and possible repair.

Thomas

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Re: the signals from Chip with cells and without cells are almost the same

Post  adamyuan on Fri Mar 16, 2012 1:56 am

no, but i used a complete new chip filled with PBS, it looks the same like the picture above.
i will talk to the professor about the repairing.
thank you very much!

Adam.

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Re: the signals from Chip with cells and without cells are almost the same

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