Elektra Beckum NM20600A-A, MCE manual Creating BEM files, Min dist

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Selecting the head model

 

MCE User’s Guide

Table 1

Properties of the point sets

 

 

 

 

 

Origin: xyz

Sphere model origin (in mm; head coordinates)

 

 

 

 

 

 

 

Lattice

 

The density of the points in the point set (in mm)

 

 

 

 

 

 

Min dist

The minimum distance to the sphere model origin (in

 

 

 

 

mm). Points deeper than this are excluded from the

 

 

 

 

point set. Very deep source points may lead to numer-

 

 

 

 

ical instability in the calculations.

 

 

 

 

 

 

Comment

The comment seen in the list

 

 

 

 

 

 

 

Points

 

The number of possible source points

 

 

 

 

 

 

4.3 Creating BEM files

If you have MR images of the subject, you can create fif-files describing boundary element models of the brain with MriLab and meshes2fiff programs. See the manu- als of those programs (or Source Modeling manual) for details of using those pro- grams.

When creating the meshes in Mrilab, you must save them in head coordinates in meters.

Warning: The triangle meshes used in MCE to describe the shape of the brain must be defined in head coordinates. This differs from the recommended coordi-

! nate system usage in dipole modeling program.

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2004-05-17

NM20600A-A

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Contents MCE User’s Guide Copyright and Warranty Contents Index Introduction Hazard InformationConventions and typography VersionWhat’s new? ReferencesQuitting the program Getting StartedAnalyzing data Setting the filtering and baselines Selecting the data file and pre-processingDecreasing the computing time and file sizes Effect of the baselinesBad channels and projections MCE User’s Guide Selecting the head model BEM selectionPoint set selection Point set selection dialogCreating BEM files Min distCalculating the estimates Loading a calculated estimate Selecting the time Region of interest What is ROI?What is the orientation of a ROI? Exporting ROIs Selecting a ROIROI database Predicting MEG waveforms Saving to an image file PrintingPrinting from the dialog Saving with xgifdump command Creating Html documents and Mpeg movies Creating Html documentsCreating movies MCE windows and dialogs Window menusMain window Options menuPre-processing dialog Minimum norm estimate options dialogPre-processing dialog Units Hz MEG data dialog Remove meanFull calculation dialog Select fileBatch jobs window CalculationColor display Color display of the estimateArrow display Arrow display of the estimateAmplitude window Amplitude window with total activityAmplitude scale window Amplitude scale windowColor scale window Constant color modeRelative color mode Things to remember Region of interest windowROI database window ROI databaseROI search ROI listSQL database Current ROIOther controls Html Creation Dialog Html Creation DialogMovie Creation Dialog Time periodsWindow length Index MCE User’s Guide