value export

To extract values of a set of files for statistical analysis, ....

•  open a sample data file in emegs2d. Value export is supported only for files of equal number of sensors/dipoles and equal number of points, thus the loaded file should have the same number of points and channels as all the files, you wish to export values from. Be sure to...
  

• check for the correct baseline and triggerpoint settings  in emegs2d. All files are baselinecorrected the way you specify it for the sample file. You should now  also...
•  load channelgroups to average across sensors and intervals to average across timepoints and activate  temporal and spatial filters if you wish (all are described below in more detail - the settings of all these parameters are applied to all files, that values are extracted from). Then, ...
  

• open emegs3d.
  
• Select the begin time and end time (Min. time and Max. time) of the exported data segment, and...
  

• select the number of intervals (subdivisions) in this segment or a subdivision length in ms (Dist. time). If a subdivision contains more than one data point, the value extracted is the average of the data points in the subdivision.  Instead of extracting the average across the timepoints in the subdivsion, you can extract the value of the first data point, by unchecking the Mean - radiobutton shown in Figure 1 (the MN Mean - radiobutton has a related but different function).
  

  Figure 1: Min. time, Max. time, Dist. time, Number of intervals, Total Interval and Mean/MN Mean controls

• Create a plot using the method that you wish to use for value export: Scalp, Laplacian, CorticalMap or a type of MinimumNorm. You can close this plot right after creation.
• Load a batchfile ( using the emegs3d menu \File\File matrix\Open batch file ) containing the paths (with one path per line) of all the files you wish to export values from.
  
• Select from emegs3d-Calculate-menu  
  

  Calculate\Scalp, Lap., Cort ==>  File\Save SLC to sensor configuration		for export of the Scalp signal (Potential or Magnetic field), Laplacian or CorticalMapping as SCADS binary data file. Sensor positions are the original sensor positions from the electrode configuration file.
  Calculate\Scalp, Lap., Cort ==>  File\Use all original sensors		for export of the Scalp signal (Potential or Magnetic field), Laplacian or CorticalMapping to a text file with seperate values for all channels. Sensor positions are the original sensor positions from the electrode configuration file.
  Calculate\Scalp, Lap., Cort ==>  File\Use predefined sensor groups		for export of the Scalp signal (Potential or Magnetic field), Laplacian or CorticalMapping to a text file with seperate values for each sensor group.
  Calculate\Minimum Norm  ==> File\Save MN to sensor configuration		for export of dipole activation datafrom the currently selected shell as SCADS binary data file. Dipole positions are not the equidistant original dipoles, but spherical spline interpolated positions on the actual shell, that match the theta/phi-coordinates of the  original sensor configuration ( e.g. dipoles below Cz, Fz, Pz etc....)
  Calculate\Minimum Norm  ==> File\Save MN to actual shell		for export of dipole activation data as SCADS binary data file. Dipole positions are the equidistant dipole positions of the actual shell of the 4 shell model.
  Calculate\Minimum Norm  ==> File\Save MN to analyze		for export of dipole activation data of all shells as volume (HDR/IMG-file pair in Analyze format -requires SPM99 to be in the matlab path)
  Calculate\Minimum Norm  ==> File\Use all original sensors		for export of dipole activation data to a text file.  Dipole positions are not the equidistant original dipoles, but spherical spline interpolated positions on the actual shell, that match the theta/phi-coordinates of the  original sensor configuration ( e.g. dipoles below Cz, Fz, Pz etc....)
  Calculate\Minimum Norm  ==> File\Use predefined sensor groups		for export of dipole activation data to a text file with seperate values for each dipole group

  
  

Using spatial  filters:  when activated in emegs2d using the menu-item \Calculate\Filter spatial, the spatial filter is applied to all data files before values are exported. Note that a selected filter will also be applied to data exported for an emegs anova.

Using temporal filters:  when activated in emegs2d using the menu-item \Calculate\Filter temporal, the temporal filter is applied to all data files before values are exported. Note that a selected filter will also be applied to data exported for an emegs anova.
   

Using channelgroups:  when activated in emegs2d using the menu-item \Calculate\Channel groups, average values across sensor clusters are exported. Sensors not included in the clustering will be ignored.

Using intervals: when activated in emegs2d using the menu-item \Calculate\Interval mean, average values across defined intervals are exported. Data points not included in the defined intervals will be ignored.