[FieldTrip] ft_singleplotTFR seems broken

Casper van Heck caspervanheck at gmail.com
Mon Sep 16 17:12:53 CEST 2013

Dear Fieldtrippers,

I've been doing some exploratory plotting of a dataset where several
subjects were exposed to a continuous stimulus (CPM) over the course of
three minutes. One of the things that was asked was a time-frequency plot,
over those three minutes. While I'm not quite sure a TFR can be used on
that scale without problems, I went ahead with it just to see what
Fieldtrip would do. What I got, was this:
And I have no idea what went wrong (note that this specific subject only
got a 60s stimulus). Quality of the picture and the validity of the
analysis aside, I have a severe problem with the axes, which seem to be all
over the place.

I simply read the data using ft_preprocessing (no filters or anything,
since the student in charge already used a 10Hz high-pass and a 150Hz
low-pass filter).
The only field in 'cfg' is 'headerfile'.

Next, I call ft_freqanalysis with:
*    cfg.output = 'pow';*
*    cfg.method = 'wavelet'; % default; Morlet wavelet*
*    cfg.taper = 'hanning';
*    cfg.tapsmofrq = 4;*
*    cfg.channel = 'Cz';*
*    cfg.foi = [20:0.5:30];*
*    cfg.t_ftimwin = ones(length(cfg.foi),1).*0.25;*
*    cfg.toi = 0:0.5:60;*

And finally, I end up with the monstrocity shown earlier. This problem only
presents itself with Fieldtrip-related functions, the normal Matlab-plots
work as well as they've ever done, so I'm thinking it's something in
Fieldtrip that's causing this.

My hope is that someone has encountered this problem before, and knows how
to solve it...


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