SpmAnalysis - Meg Wiki

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Analysis of MEG Data in SPM5

  • For specific demo using data from our Neuromag MEG machine, see SpmDemo

  • For a fuller demo of other EEG/MEG analysis in SPM5 (though from a different MEG machine), including more general features (e.g, time-freq analysis, 3D statistical maps), with proper step-by-step instructions via the GUI, see: http://www.fil.ion.ucl.ac.uk/spm/data/mmfaces.html

  • For a more theoretical introduction to source localisation in SPM5, see these slides: attachment:henson-SPM-Grad08-4-meeg.ppt

Here are some relevant papers:

  • Summary of localisation approach using ReML for evoked and induced responses (mathematical; cites earlier development papers too): attachment:FristonEtAl_hbm_06.pdf

  • Basic considerations for Group Analyses (though using individual meshes; odd math typo not corrected): attachment:HensonEtAl_NI_07.pdf

  • Use of inverse-normalised canonical meshes: attachment:MattoutEtAl_JCIN_07.pdf

  • New method of Multiple Sparse Priors (MSP): attachment:FristonEtAl_inpress.pdf

Additional SPM5 functions:

  • If you are not using the version of SPM5 installed on the CBU network (ie do not have */spm5/cbu_updates on your Matlab path) - eg are an external collaborator - you will need to download the latest versions of some site-specific SPM5 functions in order to read the FIF format data files from our MEG scanner. These SPM functions can be downloaded from here: http://www.mrc-cbu.cam.ac.uk/~rh01/fif2spm.html. (You may also want to email RikHenson in case there have been further changes since.)

General advice:

  • First you will probably want to run your raw data through the [:Maxfilter:Maxfilter utility], particularly if you 1) used Active Shielding during acquisition, 2) if you want to apply SSS to remove noise, 3) if you used continuous HPI. Max Filter can also downsample (eg from 1000Hz to 200Hz) and convert the data into different datatypes (e.g, short), which will help reduce filesize and processing time.

  • Next you will need to convert your *.FIF files into Matlab and SPM format. For those using SPM5 at the CBU, this is now an option on the SPM5 GUI "convert" button (when in "EEG" mode) (utilising the function spm_eeg_rdata_FIF.m in /cbu_updates). Then you can perform averaging, filtering and other preprocessing in SPM, as well as distributed source localisation.