Slope calculation

Dear Christine,

Could you please tell exactly how the Analyser calculates the slope? It seems to me that it directly calculates it between points marked by frames, whereas a more conventional way is to calculate it 10-90% between Max and Min points within an interval chosen. Also, is the slope expressed in uV/ms units?

I have a problem during calculation of fEPSP slopes in different channels, because depending on the distance from the stimulating electrode fEPSP peak latency is different, so it is often hard to select a region between frames that would fit several channels. Also, following LTP induction the latency changes, so sometimes the right frame happens to be behind the peak of the EPSP, rather than before it.

Many thanks,

Max

Dear Max

The slope is calculated as follows: A straight line is fitted throught the data points in the region of interest. The slope of the straight line is then calculated.

I perfectly understand your problem. Your suggestion is very good and I will add this to our to do list for MC_Rack. But unfortunately, I cannot tell you any time range when this feature will be implemented.

Meanwhile, maybe there is an external analysis program that could help? There are some programs that can directly load MC_Rack files, and you can also export MC_Rack files as ASCII with the MC_DataTool. Maybe any other forum user can add some information to this issue?

Best regards, Christine (MCS)

Dear Christine,

Is it possible to change the step of Analyser frames by a value less than 1 ms? At present, I can only move it in increments of 1 ms, i.e. the slope can be measured only betweem 2 and 4 ms; 3 and 5 but not between 2.5 and 4.5 ms.

Thank you!

>Is it possible to change the step of Analyser frames by a
>value less than 1 ms?

Dear Max

Thank you for your suggestion. In the moment, this is not possible. I will add this to our feature request list, but I cannot promise that it will be implemented in the near future.

Best regards, Christine

Dear Christine,

I have visited MCS booth at the SfN meeting and was quite impressed by the new gear, compining the amp and the stim in one box. However, even more than that I was pleased to see its new software that allows for correct estimation of the slopes. I raised this question in the past, but could you tell me if it would be possible to implement the new way of the slope calculation into newer versions of MC Rack? I mean options like 20-80% slope and liberal positioning of frames (not between unit milliseconds as it is now)?

Many thanks!

Maksym

Dear Maksym

Thank you for your feedback. We plan to implement an option for extracting a 10/90 or 20/80% slope from the region of interest for MC_Rack. The slope would be based on the trace between the maximum and minimum inside the ROI. This way, it would be much easier for the user to position the ROI frames, as the exact position would not be so important anymore. I hope that it will be possible to include this feature into the next release (early in 2006). If you subscribe to the MEA60-System Mailing list, you will be notified on the new release.

Best regards, Christine