[FieldTrip] Wrong functionality/ misunderstanding with cfg.frequency field in ft_freqstatistics

jan-mathijs schoffelen jan.schoffelen at donders.ru.nl
Wed Mar 19 12:57:41 CET 2014


Hi Jim and Nietzsche,

Let me chime in here: 
Where Nietzsche typed 'ft_freqanalysis' one should read 'ft_freqstatistics' probably.
Also, cfg.frequency as option into ft_freqstatistics should be a 2-element array, specifying the lower and upper bound, contrary to Nietzsche's advice.
I just tried this quickly, and it works for me.
Jim, are you using an up to date version of FieldTrip?
Also, if the problem persists, could you provide is with example code/data for us to be able to reproduce your problem. We usually do this through our bugzilla system: bugzilla.fcdonders.nl

Best,
Jan-Mathijs


On Mar 19, 2014, at 12:52 PM, Lam, Nietzsche wrote:

> Hi Jim,
> 
> Without seeing all the code you used it's hard to determine where exactly the problem is.
> NEvertheless, two things come to mind:
> 
> (1) you need to specify the frequency of interest with "cfg.foi = 1:10".
> To be precise, it is also good to specify the numbers of steps you wish to calculate e.g., 1:1:10.
> please see here: http://fieldtrip.fcdonders.nl/tutorial/timefrequencyanalysis
> 
> Alternatively, prior to calling ft_freqanalysis, you can use the function ft_selectdata(cfg,freqdata) to select the frequency band of interest.
> 
> Hope this gets you started!
> 
> Best,
> Nietzsche 
> 
> ----- Original Message -----
>> From: "Jim Parkinson" <jimparkinson at me.com>
>> To: fieldtrip at science.ru.nl
>> Sent: Wednesday, 19 March, 2014 12:40:46 PM
>> Subject: [FieldTrip] Wrong functionality/ misunderstanding with cfg.frequency field in ft_freqstatistics
>> Hi.
>> 
>> 
>> i have some TFR data which has been analysed over 1 : .5 : 30 Hz using
>> ft_freqanalysis (MTMCONVOL), 11 subjects, 2 conditions
>> 
>> 
>> Right now I'd like to compare the two conditions using
>> ft_freqstatistics but restrain the statistics to the freq range 1:10.
>> so I've set
>> 
>> 
>> cfg.frequency = [1 10]
>> 
>> 
>> But, by the time the stats are running, the analysis is over the full
>> range produced by ft_freqanalysis (1:30 Hz), and the output stats
>> reflects this. Somewhere in ft_freqstatistics the cfg.frequency
>> setting seems to be overridden. Is this a bug, am i doing something
>> wrong, or have I misunderstood what cfg,frequency is supposed to be
>> doing?
>> 
>> 
>> thanks for any help!
>> 
>> 
>> --
>> 
>> 
>> 
>> Dr Jim Parkinson, D.Phil
>> 
>> j.m.parkinson at sussex.ac.uk
>> _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
>> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> 
> -- 
> Nietzsche H.L. Lam, MSc 
> PhD Candidate 
> 
> Max Planck Institute for Psycholinguistics 
> Wundtlaan 1, 6525 XD Nijmegen, The Netherlands 
> 
> Donders Institute for Brain, Cognition and Behaviour, 
> Centre for Cognitive Neuroimaging, 
> Kapittelweg 29, 6525EN Nijmegen, The Netherlands 
> 
> n.lam at fcdonders.ru.nl 
> +31-24-3668219 
> 
> 
> neurobiologyoflanguage.com 
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

Jan-Mathijs Schoffelen, MD PhD 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging,
Radboud University Nijmegen, The Netherlands

Max Planck Institute for Psycholinguistics,
Nijmegen, The Netherlands

J.Schoffelen at donders.ru.nl
Telephone: +31-24-3614793

http://www.hettaligebrein.nl

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