[FieldTrip] Is dB baseline normalization following ft_freqanalysis appropriate?

Paul Dhami pdhami06 at gmail.com
Sat Sep 22 16:53:04 CEST 2018

Dear Fieldtrip community,

I am ultimately hoping to perform the cluster-based permutation testing for
comparing potential power differences between two groups.

>From my understanding, to facilitate statistical comparisons, baseline
normalization is warranted.

Would it be appropriate (if at all) to do this baseline normalization right
after  following ft_freqanalysis?

My current frequency preprocessing looks like this for a single subject:

        % frequency analysis

        cfg                 = [];

        cfg.output          = 'powandcsd';

        cfg.method          = 'mtmconvol';

        cfg.foi             = 2:1:40;

        cfg.t_ftimwin       =  2 ./ cfg.foi;

        cfg.tapsmofrq       = 0.4 *cfg.foi;

        cfg.toi             = -0.4:0.01:0.4;

        dataSPfreq = ft_freqanalysis(cfg, dataSPfreq);

        %baseline correction

        cfg = [];

        cfg.baseline = [-0.4 -0.1];

        cfg.baselinetype = 'db';

        dataSPfreq = ft_freqbaseline(cfg, dataSPfreq);

>From here, I then was hoping to submit my two structures, each containing
the single subject preprocessed data from their respective group, to

I initially thought this was fine, but when trying to use ft_singleplotTFR,
I ran into this error: Complex values are not supported, which only
occurred when I did the baseline correction (I also ran it without any
baseline correction and it worked fine).

Any insight would be greatly appreciated.

Thank you,

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