CbuSpmParameters - Meg Wiki

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CBU-specific SPM5 parameters for MEG/EEG

Some further details for CBU MEG/EEG data...

MEG/EEG montages (layout or CTF files)

  • SPM needs a "layout" or "CTF" file that simply tells it how to display the channels in the Graphics window when displaying EEG or MEG data (and when writing space-time sensor images). This file is stored in D.channels.ctf. The file is selected when you read the raw data using spm_eeg_rdata_FIF.m.
  • There is a standard one for our Neuromag MEG channels in /imaging/local/spm/spm5/EEGtemplates/FIF306_setup.mat, which you should probably use.

  • However, there have been several changes to our EEG montages in the MEG laboratory. For our old caps, you can try these montages in that directory: cbu_meg_70eeg_montage_old.mat and cbu_meg_124eeg_montage_old.mat (depending on your number of channels.

  • For the new caps (summer 2008; contact YuryShytrov), you should use cbu_meg_70eeg_montage.mat if you have <=70 channels, or contact RikHenson to create a new one for a 128 channel recording.

  • A final alternative offered by spm_eeg_rdata_FIF.m is for it to create a new CTF file for each dataset read (to be stored in a local directory of yours). It creates them simply be guessing Cz as the channel with maximal Z, and then projecting onto a flat 2D surface using a spherical projection. This will be fine for displaying data (though there may not be optimal coverage of your Graphics window), but you should double-check these if you plan to do space-time sensor SPMs across subjects).
  • In the EEGtemplates directory, you will also see some EEG montages for the CBU's EEG Neuroscan lab, ie cnt74_cbu.mat and cnt128.mat.

  • For more help, please contact RikHenson.