baseline correction on cross-spectral densities

[Mark Drakesmith]

Dear Field Trip users

I'm currently trying to obtain source coherence networks from  some MEG
data using the DICS beamformer method. I am calculating the necessary
cross-spectral densities (CSDs) using the freqanalysis function. I was
wondering is it necessary (or wise) to do baseline correction on the CSD
data? I have already applied baseline correction to the data in time
domain but I understand that the same correction still needs to be
applied in the frequency domain. The function freqbaseline does this but
it only allows you to correct non-complex power values. Is it
appropriate to manually apply baseline correction on the complex CSDs?
Or would it be more appropriate to calculate the CSDs and source
coherence for the pre- and post- stimulus data separately, and then
apply baseline correction to the coherence data?

Any advice would be greatly appreciated.

Thanks

Mark

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Mark Drakesmith
PhD Student

Neuroscience and Aphasia Research Unit (NARU)
University of Manchester

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