[FieldTrip] ft_singleplotTFR seems broken

Eelke Spaak eelke.spaak at donders.ru.nl
Wed Sep 18 13:25:32 CEST 2013


Dear Casper,

Could you maybe post a snippet online somewhere (e.g. dropbox) of data
corresponding to this plot (i.e. the output of ft_freqanalysis that
you input to ft_singleplotTFR, assuming that it's averaged over trials
and therefore small)? Then we can see whether this is reproducable on
our systems.

Best,
Eelke

On 16 September 2013 17:12, Casper van Heck <caspervanheck at gmail.com> wrote:
> 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:
> http://tinypic.com/r/zx2tqs/5|
> 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...
>
> Sincerely,
>
> Casper
>
>
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