[FieldTrip] error when converting from spm to ft

["Jörn M. Horschig"]

Dear Zita,

The function seems to convert the function not correctly to a freq 
datastructure - it seems more like raw data to me.

freq data requires a .powspctrm field, which should be a matrix of 
observations x channels x freq x time. So you would need to use cell2mat 
on your .trial field. Probably you need to permute the dimensions to 
match this order. Additionally, you will need a .dimord field which 
which should be 'rpt_chan_freq_time' and you need a .freq field that 
contains the frequencies in that matrix. Please first make sure that 
your trials actually have 3 dimensions, else something else in the 
conversion went wrong.

I don't use SPM so no clue if there is a better way than doing it manually.

Best,
Jörn

On 11/14/2012 6:32 PM, Zita Eva Patai wrote:
> Hello FT-ers
>
> In the past i had no problem when converting my data from SPM (where i 
> do preprocessing and averaging) to FT (where I do my cluster-stats and 
> plotting)
>
> Currently, I am using the new way to convert (previous version seems 
> outdated 'nspm2ftrip') and I am hitting a wall: it says my data is not 
> in the right format, ie: not freq data. But i know that it is...any 
> advice would be much appreciated! Not to mention is warns me my data 
> is not epoched when it is indeed so...
>
> Thank you!
> zita
>
> *********************
> *>> D = spm_eeg_load*
> SPM M/EEG data object
> Type: evoked
> Transform: TF
> 8 conditions
> 326 channels
> 20 frequencies
> 501 samples/trial
> 8 trials
> Sampling frequency: 250 Hz
> Loaded from file  C:\Users\Eva Z 
> Patai\Documents\MATLAB\epoched_data\tf\rmtf_rs01_timecorr.mat
>
> Use the syntax D(channels, frequencies, samples, trials) to access the 
> data
> Type "methods('meeg')" for the list of methods performing other 
> operations with the object
> Type "help meeg/method_name" to get help about methods
>
> *>> data = spm2ft(D)*
>
> mapping condition label "11" to condition code 1
> mapping condition label "12" to condition code 2
> mapping condition label "21" to condition code 3
> mapping condition label "22" to condition code 4
> mapping condition label "31" to condition code 5
> mapping condition label "32" to condition code 6
> mapping condition label "41" to condition code 7
> mapping condition label "42" to condition code 8
>
> data =
>
>       fsample: 250.0000
>         label: {326x1 cell}
>          time: {1x8 cell}
>         trial: {1x8 cell}
>     trialinfo: [8x1 double]
>           cfg: [1x1 struct]
>
>
> *>> data2 = ft_checkdata(data, 'datatype', 'freq')*
> Warning: the data does not contain a trial definition, assuming that 
> the trials are consecutive segments of a continuous recording
> > In utilities\private\warning_once at 81
>   In utilities\private\fixsampleinfo at 54
>   In ft_datatype_raw at 91
>   In ft_checkdata at 170
> Error using ft_checkdata (line 288)
> This function requires freq data as input.
>
>
> -- 
>
> Zita Patai
> DPhil, Experimental Psychology
> University of Oxford
> bcl.psy.ox.ac.uk/people/zita-eva-patai/ 
> <http://bcl.psy.ox.ac.uk/people/zita-eva-patai/>
>
>
>
>
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip


-- 
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team

P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands

Contact:
E-Mail: jm.horschig at donders.ru.nl
Tel:    +31-(0)24-36-68493
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Visiting address:
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