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GUI Help
Head Modeling Tool
Creates customized head models for the subject and dataset selected in the Data Manager. Note, each dataset session needs a different headmodel, because the relative position of the head to the sensors may change. (See m-file help)
CHECK BOXES
FORWARD MODELING METHODS -- Source Model
| Current Dipole |
Computes the forward fields of current dipole sources. |
| Current Multipole Expansion |
Computes the forward fields of multipole sources (not implemented yet). |
| MEG/EEG |
Specify the type of dataset, MEG or EEG. |
VOLUME SOURCE GRID
| Compute |
Computes the forward matrix for a volume grid inside the brain. The volume grid will serve as a source space for scanning techniques, such as RAP-MUSIC. The Head Modeling Tool will create a file called *headmodelVolGrid in the dataset directory. |
DROPDOWN MENUS
AVAILABLE HEAD MODEL FILES(s)
| Shows the list of all available head models for the selected subject. These files reside in the selected dataset folder, specified in the Data Manager window. By selecting a headmodel, you can view its parameters in the Head Modeling Tool. |
FORWARD MODELS IN MEG
| List of Available forward modeling methods for MEG: single sphere, overlapping spheres, and BEM. |
FORWARD MODELS IN EEG
| List of Available forward modeling methods for EEG: single sphere, 3-shell sphere, 3-shell sphere (BERG), overlapping spheres, and BEM. |
EEG REFERENCE
| EEG Reference point. NAME (not index of the channel file) of the electrode that acts as the reference channel for the EEG. Hint: If data is referenced to instantaneous average (i.e. so called average-reference recording) value is 'AVERAGE REF'. |
HEAD COMPARTMENTS -- Scalp
Select a scalp surface (if available, for example BrainSuite can generate tessellated surfaces from MRI scans). It the selected headmodel type is 'Single sphere', then <best-fitting sphere> can be used. In this case, the sensor locations are used to define an approximate scalp surface. All other headmodel types (overlapping spheres, BEM, etc) require a scalp surface. |
HEAD COMPARTMENTS -- Cortex
| Select a cortical surface (if available, for example BrainSuite can generate tessellated surfaces from MRI scans). All imaging inverse methods (min-norm imaging, beamformer or MUSIC on cortical surface, etc) require a cortical surface for source support. If you don't have a cortical surface, you can only run volume source localization, by selecting the check box 'compute volume source'. |
TEXT BOXES
HEAD MODEL NAME
| Name of the current head model. |
SPACING
| Spacing in centimeters between two consecutive sources in the 3D source grid. It only defines an initial volume grid; once a source is located, a refined grid is used for better precision. |
LIST BOXES
BEST-FITTING SPHERE PARAMETERS
| Enter the center (x, y, z coordinates), radii for inner and outer skull and scalp, and conductivity for each layer for best-fitting sphere in the corresponding list boxes available. Leave it blank if you want the head model tool to automatically adjust the parameters. |
BUTTONS
VIEW
| Click to see the scalp/cortex. |
ADJUST
| First select a scalp surface. Then click to calculate the values for best-fitting sphere. |
CLOSE
| Closes the Head Modeling Tool. |
RUN
| Creates a new head model according to parameters selected in the window. |
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