FT_PREPARE_HEADMODEL

Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_prepare_headmodel”.

  FT_PREPARE_HEADMODEL constructs a volume conduction model from the geometry
  of the head. The volume conduction model specifies how currents that are
  generated by sources in the brain, e.g. dipoles, are propagated through the
  tissue and how these result in externally measureable EEG potentials or MEG
  fields.
 
  FieldTrip implements a variety of forward solutions, partially with internal
  code and some of them using external toolboxes or executables. Each of the
  forward solutions requires a set of configuration options which are listed
  below. This function takes care of all the preparatory steps in the
  construction of the volume conduction model and sets it up so that
  subsequent computations are efficient and fast.
 
  Use as
    headmodel = ft_prepare_headmodel(cfg)       or
    headmodel = ft_prepare_headmodel(cfg, mesh) with the output of FT_PREPARE_MESH or FT_READ_HEADSHAPE
    headmodel = ft_prepare_headmodel(cfg, seg)  with the output of FT_VOLUMESEGMENT
    headmodel = ft_prepare_headmodel(cfg, elec) with the output of FT_READ_SENS
    headmodel = ft_prepare_headmodel(cfg, grid) with the output of FT_PREPARE_LEADFIELD
 
  In general the input to this function is a geometrical description of the
  shape of the head and a description of the electrical conductivity. The
  geometrical description can be a set of surface points obtained from
  fT_READ_HEADSHAPE, a surface mesh that was obtained from FT_PREPARE_MESH or
  a segmented anatomical MRI that was obtained from FT_VOLUMESEGMENT.
 
  The cfg argument is a structure that can contain:
    cfg.method         string that specifies the forward solution, see below
    cfg.conductivity   a number or a vector containing the conductivities of the compartments
    cfg.tissue         a string or integer, to be used in combination with a 'seg' for the
                       second intput. If 'brain', 'skull', and 'scalp' are fields
                       present in 'seg', then cfg.tissue need not be specified, as
                       these are defaults, depending on cfg.method. Otherwise,
                       cfg.tissue should refer to which field(s) of seg should be used.
 
  For EEG the following methods are available:
    singlesphere       analytical single sphere model
    concentricspheres  analytical concentric sphere model with up to 4 spheres
    openmeeg           boundary element method, based on the OpenMEEG software
    bemcp              boundary element method, based on the implementation from Christophe Phillips
    dipoli             boundary element method, based on the implementation from Thom Oostendorp
    asa                boundary element method, based on the (commercial) ASA software
    simbio             finite element method, based on the SimBio software
    fns                finite difference method, based on the FNS software
    infinite           electric dipole in an infinite homogenous medium
    halfspace          infinite homogenous medium on one side, vacuum on the other
    besa               finite element leadfield matrix from BESA
    interpolate        interpolate the precomputed leadfield
 
  For MEG the following methods are available:
    openmeeg           boundary element method, based on the OpenMEEG software
    singlesphere       analytical single sphere model
    localspheres       local spheres model for MEG, one sphere per channel
    singleshell        realisically shaped single shell approximation, based on the implementation from Guido Nolte
    infinite           magnetic dipole in an infinite vacuum
 
  Each specific method has its own specific configuration options which are listed below.
 
  BEMCP, DIPOLI, OPENMEEG
    cfg.tissue            see above; in combination with 'seg' input
    cfg.isolatedsource    (optional)
 
  CONCENTRICSPHERES
    cfg.tissue            see above; in combination with 'seg' input
    cfg.fitind            (optional)
 
  LOCALSPHERES
    cfg.grad
    cfg.tissue            see above; in combination with 'seg' input; default options are 'brain' or 'scalp'
    cfg.feedback          (optional)
    cfg.radius            (optional)
    cfg.maxradius         (optional)
    cfg.baseline          (optional)
 
  SIMBIO
    cfg.conductivity
 
  SINGLESHELL
    cfg.tissue            see above; in combination with 'seg' input; default options are 'brain' or 'scalp'
 
  SINGLESPHERE
    cfg.tissue            see above; in combination with 'seg' input; default options are 'brain' or 'scalp'; must be only 1 value
 
  INTERPOLATE
     cfg.outputfile       (required) string, filename prefix for the output files
 
  BESA
    cfg.headmodel         (required) string, filename of precomputed FEM leadfield
    cfg.elecfile          (required) string, filename of electrode configuration for the FEM leadfield
    cfg.outputfile        (required) string, filename prefix for the output files
 
  FNS
    cfg.tissue
    cfg.tissueval
    cfg.conductivity
    cfg.elec
    cfg.grad
    cfg.transform
    cfg.unit
 
  HALFSPACE
    cfg.point
    cfg.submethod         (optional)
 
  More details for each of the specific methods can be found in the corresponding
  low-level function which is called FT_HEADMODEL_XXX where XXX is the method
  of choise.
 
  See also FT_PREPARE_SOURCEMODEL, FT_PREPARE_LEADFIELD, FT_PREPARE_MESH,
  FT_HEADMODEL_BEMCP, FT_HEADMODEL_ASA, FT_HEADMODEL_DIPOLI,
  FT_HEADMODEL_SIMBIO, FT_HEADMODEL_FNS, FT_HEADMODEL_HALFSPACE,
  FT_HEADMODEL_INFINITE, FT_HEADMODEL_OPENMEEG, FT_HEADMODEL_SINGLESPHERE,
  FT_HEADMODEL_CONCENTRICSPHERES, FT_HEADMODEL_LOCALSPHERES,
  FT_HEADMODEL_SINGLESHELL, FT_HEADMODEL_INTERPOLATE

reference/ft_prepare_headmodel.txt · Last modified: 2016/08/17 23:02 (external edit)

You are here: startreferenceft_prepare_headmodel
CC Attribution-Share Alike 3.0 Unported
www.chimeric.de Valid CSS Driven by DokuWiki do yourself a favour and use a real browser - get firefox!! Recent changes RSS feed Valid XHTML 1.0
This DokuWiki features an Anymorphic Webdesign theme, customised by Eelke Spaak and Stephen Whitmarsh.
Mobile Analytics Website Security Test