The double subtraction for the LRP

Dear all,

I need help with the double subtraction method which is something I have never done before.

I would like to examine the Lateralized Readiness Potential for each subject evoked: One for left responses and one for right responses.

Now, I want to apply the double subtraction method (De Jong et al., 1998) to calculate the LRP but I am unsure how. I want to make the following calculation:
(C3’(t) – C4’(t)) right hand - (C3‘(t) – C4‘(t)) left hand

So, within the “right hand evoked”, I want to have the signal from the C3 minus the C4. We want to make the same difference wave within the “left hand evoked”. Then, I want to subtract the right-hand difference wave from the left-hand difference wave.

I would be grateful for any help!


Hello, would adding a new “bipolar” channel work for you? That way you could do everything very naturally without having to resort to “hacky” solutions. LMK if you need more advice / examples, I’m happy to help.

also this might be an excellent question for tomorrow’s online office hour

Best wishes,

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Thanks a lot, Richard for your help!

Yes, the new bipolar channel is a very good idea! Later, the combined_evoked function can be used for second-level subtraction.