EEG amplitude scaling affecting coherence

Discussions
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1

Hi Brainstorm team,

We found that our sEEG data amplitude was scaled down 10x during preprocessing and are wondering if this would affect coherence calculation results. We noticed that our data were being scaled down only after we've run coherence calculations for a few participants; thus, we'd like to know if we need to run these calculations again.

As always, thank you for your time and any input you provide.

Best regards,
Adam

2

Hi Adam,

The computation of coherence is not affected by the amplitude of the signal.

3

It's not clear why coherence would affect the amplitude of the original time series. Can you post a few screenshots, please?

4

@Raymundo.Cassani thank you for your response that coherence is not influenced by amplitude.

@Sylvain I don't understand. I was asking if amplitude would affect coherence, not the other way around. What would you like screenshots of? Time series?

Thanks,
Adam

5

I understood 'data' as the time series fed into the coherence calculations.