Effect of interpolation on Inter-site phase clustring

Hi Mike, I am analyzing a set of resting-state EEG data. As part of preprocessing, I interpolated the bad channels (removed bad chan, ICA, interpolated bad chan). Now, I want to apply ISPC and I was wondering if this interpolation will have adverse effect on ISPC measures? And what I can do for that? I appreciate your response.

Hi Sam. Interpolation means you are re-creating one channel by a linear combination of neighboring channels, which means that the interpolated channel has no unique information. I don’t think it will have an adverse effect of ISPC; it will simply be redundant because the ISPC will be a weighted combination of neighboring channels.

Still, in many cases there are practical reasons for keeping interpolated channels, like facilitating topographical plotting and subject averaging.

Thank you, Mike! That makes a perfect sense.
May I also ask if you know of any way to pick the electrodes associated with specific brain areas in fMRI data? For example, Broca’s area is usually considered F5. How can I relate other electrodes to other brain areas?

Best,
Sam

I would not make topographical -> anatomical claims based on electrode positions. There is too much uncertainty and too volume current projection/volume conduction. I talk about this a bit more in this video.

Understood. Thank you.