Dear Haiteng,
I don't know why you get this error. We should try to reproduce it
here. If we can't do it with our data, possibly we'll need to look at
your data. But why do you need 60 sec trials? That's not what
'epoched' data was meant for. Having trials of this length might lead
to all kinds of problems, definitely in the reviewing tool. If you
want to analyze some specific time periods from your continuous
recording perhaps you should convert your data as continuous, but
select different time segment each time (there is an option to do it
in the 'Convert' button) and then you'll have a series of datasets
rather than a series of trials. This also won't have the limitation
that all trials should be equal in duration.
Best,
Vladimir
2009/7/6 hiten <[log in to unmask]>:
> Dear Vladimir,
> Thanks for your response.According to your guidence,when
> trialduration<60,it works well.But ,when trailduration>60,the following
> error presents:
> ??? Index exceeds matrix dimensions (2).
> Error in ==> file_array.subsasgn>subfun at 132
> mat2file(sobj,dat,va{:});
> Error in ==> file_array.subsasgn at 73
> subfun(sobj,dat1,args{:});
> Error in ==> meeg.clone at 35
> d(end, end, end) = 0;
> Error in ==> spm_eeg_epochs at 168
> Dnew = clone(D, ['e' fnamedat(D)], [D.nchannels nsampl, ntrial])
> This error I have encoutered similarly before when the converting data file
> is too big,which is fixed now.I wonder is this a time limit duration at the
> present time? It would be kind of you to give some solutions to solve this
> problem.
> Thanks again!
> haiteng
>
>
>
> --
> haiteng jiang
> Research Center for Learning Science,
> Southeast University
> Si Pai Lou 2 # , Nanjing, 210096, P.R.China
> Brain Imaging Lab
> Email: [log in to unmask]
>
> 在2009-07-06 17:05:46,"Vladimir Litvak" <[log in to unmask]> 写道:
>>Dear Haiteng,
>>
>>Since there are no events in your dataset, it is not possible to
>>define trials based on events. The error you are reporting is a little
>>bit strange, but in any case you can epoch your file using a short
>>script, something like the following:
>>
>>D = spm_eeg_load
>>
>>trialduration = 1; % sec
>>
>>trl = 1:round(D.fsample*trialduration):D.nsamples;
>>trl = trl(:);
>>trl = [trl(1:(end-1)) trl(2:end) - 1 ones(length(trl)-1, 1)];
>>
>>
>>% Epoching continuous M/EEG data
>>% FORMAT D = spm_eeg_epochs(S)
>>%
>>% S - input structure (optional)
>>% (optional) fields of S:
>>% S.D - MEEG object or filename of M/EEG mat-file with
>>% continuous data
>>%
>>% Either (to use a ready-made trial definition):
>>% S.epochinfo.trl - Nx2 or Nx3 matrix (N - number of trials)
>>% [start end offset]
>>% S.epochinfo.conditionlabels - one label or cell array of N labels
>>
>>S = [];
>>S.D = D;
>>S.epochinfo.trl = trl;
>>S.epochinfo.conditionlabels = 'Whatever';
>>
>>D = spm_eeg_epochs(S);
>>
>>
>>Best,
>>
>>
>>Vladimir
>>
>>
>>2009/7/6 hiten <[log in to unmask]>:
>>> Dear SPMers:
>>> Now ,I want to use spm8 to process resting state MEG data. The resting
>>> state is the state in which the subjects are informed to hold still ,keep
>>> their eyes closed and not think of anything in particular.So there is no
>>> trial designed.Our data collection last for 120sec. attachment is the detail
>>> information of the continuous data .when go to epoching step, the following
>>> error appears:
>>> ?? Reference to non-existent field 'offset'.
>>> Error in ==> spm_eeg_definetrial at 187
>>> trlbeg = event(sel(j)).sample - event(sel(j)).offset + trloff;
>>> Error in ==> spm_eeg_epochs at 101
>>> [epochinfo.trl, epochinfo.conditionlabels, S] =
>>> spm_eeg_definetrial(S_definetrial);
>>> ??? Error using ==> spm_eeg_epochs;
>>> Reference to non-existent field 'offset'.
>>> ??? Error while evaluating uicontrol Callback
>>> could anyone give some suggestion or fix the problem? Thanks in advance!
>>>
>>>
>>> --
>>> haiteng jiang
>>> Research Center for Learning Science,
>>> Southeast University
>>> Si Pai Lou 2 # , Nanjing, 210096, P.R.China
>>> Brain Imaging Lab
>>> Email: jianghaiteng@126com
>>>
>>>
>>> ________________________________
>>> 200万种商品,最低价格,疯狂诱惑你
>
>
> ________________________________
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