The max of time window in MC_Rack

Dear Sir

I record some signals up to 5s, but the max of time window in MC-Rack is 2s. Are there anyway to extend the time window to 5 or 10s?

Thank you

Sincerely

Jyh-Jang Sun

sunj@uni-mainz.de

Dear Jyh-Jang Sun,

you are right, the maximum time window is indeed 5s.
However this affects just the online display. Of course you can record longer signals and display the data offline or analyse them offline by external tools (MEATools, Neuroesplorer ...)
If you like to tell us a bit more in detail how you plan to record we might be able to suggest you a way to overcome the problem. (Triggered or contionous ? What analysis you require online/offline ...)

Greetings

Thomas

Dear Thomas

Thanks for your answer.

Now I use the continuous recording mode ; I need the time window up to 5-10s. Then FFT will be applied off-line.

Another question is that could I apply current (positive 30uA-3s) via 3D MEA chip to make lesions. Any damage will occur to the MEA chip?

Thank you and have a nice day.

Jyh-Jang

sunj@uni-mainz.de

Dear Jyh-Jang Sun,

Concerning your question about current stimulation:

The safe current injection limit of platinum (0.4 mC/cm2) is much smaller than for TiN (23 mC/cm2). It results that the charge that you can inject into the electrode before faradaic reaction occurs is smaller. If you apply 30 µA for 3 s, you will be over this limit. This means that you will have some electrode dissolution.

This is mainly a problem for long-term stimulation where the electrode would be dissolved with time. If you make tihis stimulation only a few times, then it should be fine...

I would also recommend to you to apply a negative stimulation pulse right after your positive pulse (with same charge) in order to balance the charge on the electrode , i.e. avoid the electrode to remain charged for a long period of time time.

I have added a pdf document on our homepage that indicates the safe charge injection limit for all our platinum based MEA biochips at: http://www.ayanda-biosys.com/physiology.html

Greetings

Marc Heuschkel
CTO, Ayanda Biosystems SA