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37. EEG MRI analysis

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Fa-Hsuan Lin edited this page Apr 21, 2024 · 27 revisions

Overview

Here are details of processing MRI and EEG data for the steady-state visual evoked potentials (SSVEP) experiment. Sample data are provided here.

Structural MRI

Reconstruct brain structure using FreeSurfer and T1-weighted MRI (MPRAGE sequence) data. Details are here.

fMRI

Follow the instruction here for fMRI data pre-processing, including the following

  • convert meas.dat into Matlab mat files
  • register between fMRI and structural MRI. See this page for details.
  • prepare fMRI data on brain surfaces

The fMRI analysis using Genearal Linear Model can be found here.

EEG

EEG pre-processing includes

  • suppress gradient and pulse artifacts.
  • calculate event-related potentials (for event-related design).

To do EEG source anaylysis, follow the procedure here.

EEG files

Each session of EEG recording use the Brain Products amplifier gave three files: .vmrk, .vhdr, and .eeg files. You need all three files to process one session of EEG. NOTE: file names cannot be arbitrarily changed because data in the file were linked to the file name.

For example, for subject `180330_SYH', SSVEP_out_1.eeg, SSVEP_out_1.vhdr, and SSVEP_out_1.eeg together completed the recording of EEG outside MRI.

In the SSVEP experiment, EEG recordings for three conditions were taken:

  • EEG recorded outside MRI: consequently no MRI gradient and pulse artifacts. This condition is coded by "outside MRI".
  • EEG recorded inside MRI bore but no MRI were taken: consequently no MRI gradient but with pulse artifacts. This condition is coded by "inside MRI".
  • EEG recorded outside MRI: consequently with both MRI gradient and pulse artifacts. This condition is coded by "SMS-InI"
Subject 180330_SYH 180401_YTH 180411_PYY
Outside MRI SSVEP_out_1 SSVEP_out_1 SSVEP_out_1
------------- ----------------------------------------- -------------------------------------------- --------------------------------------------
Inside MRI SSVEP_noMR_1, SSVEP_noMR_2, SSVEP_noMR_3 SSVEP_noMR_1, SSVEP_noMR_2, SSVEP_noMR_3 SSVEP_noMR_1, SSVEP_noMR_2, SSVEP_noMR_3
------------- ----------------------------------------- -------------------------------------------- --------------------------------------------
SMS-InI. SSVEP_sms_1, SSVEP_sms_2, SSVEP_sms_3 SSVEP_sms_1, SSVEP_sms_2, SSVEP_sms_3 SSVEP_sms_1, SSVEP_sms_2, SSVEP_sms_3
------------- ----------------------------------------- -------------------------------------------- --------------------------------------------
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