Dear all,
I am approaching SPM12 (version: 20140806) for the first time.
I have CTF MEG data that I have analysed (using multitapers) at the sensor-level with Fieldtrip (FT). I now wish to run source statistics with SPM. I hope you can help me.
The first thing I should do is to convert. As such, I am using the spm_eeg_ft2SPM function.
The data I have (as after FT processing) has the following fields:
- Label
- Dimord
- Freq
- Time
- Powspctrm
- cumtapcnt
- Hdr
Hdr has the following fields:
- nChans
- label
- Fs (600 hz)
- nSamples
- nSamplesPre
- nTrials
- grad
Hdr.grad has the following fields:
- Pnt
- Ori
- Tra
- Label
- Unit (cm)
- Balance
When I use the batch to run spm_eeg_ft2spm on these data:
D = spm_eeg_ft2spm(DATA, outputfile)
I get the warning:
Data type is missing or incorrect, assigning default
Warning: could not determine channel type from CTF header
It does not give an error, and the resulting D has these fields:
Type: continuous
Transform: TF
1 conditions
265 channels
31 frequencies
111 samples/trial
1 trials
Sampling frequency: 33.3333 Hz
Few questions:
1. I am not sure why my sampling rate, which originally was 600 Hz, has been changed to 33.3333 Hz.
2. May you suggest a reference (tutorial?) I should follow to proceed without (many) problems?
Any advice would be greatly appreciated.
Many thanks and best regards,
Davide
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