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reference:ft_datatype_parcellation [2018/08/23 14:43] (current)
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 +=====  FT_DATATYPE_PARCELLATION =====
 +
 +Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_datatype_parcellation"​.
 +
 +<​html><​pre>​
 +  <a href=/​reference/​ft_datatype_parcellation><​font color=green>​FT_DATATYPE_PARCELLATION</​font></​a>​ describes the FieldTrip MATLAB structure for parcellated
 +  cortex-based data and atlases. A parcellation can either be indexed or probabilistic
 +  (see below).
 + 
 +  A parcellation describes the tissue types for each of the surface elements.
 +  Parcellations are often, but not always labeled. A parcellatoin can be used to
 +  estimate the activity from MEG data in a known region of interest. A surface-based
 +  atlas is basically a very detailled parcellation with an anatomical label for each
 +  vertex.
 + 
 +  An example of a surface based Brodmann parcellation looks like this
 + 
 +               pos: [8192x3] ​        ​positions of the vertices forming the cortical sheet
 +               tri: [16382x3] ​       triangles of the cortical sheet
 +          coordsys: '​ctf' ​           the (head) coordinate system in which the vertex positions are expressed
 +              unit: '​mm' ​            the units in which the coordinate system is expressed
 +          brodmann: [8192x1 uint8] ​  ​values from 1 to N, the value 0 means unknown
 +     ​brodmannlabel:​ {Nx1 cell}
 + 
 +  An alternative representation of this parcellation is
 + 
 +               pos: [8192x3] ​          ​positions of the vertices forming the cortical sheet
 +               tri: [16382x3] ​         triangles of the cortical sheet
 +          coordsys: '​ctf' ​             the (head) coordinate system in which the vertex positions are expressed
 +              unit: '​mm' ​              the units in which the coordinate system is expressed
 +   ​Brodmann_Area_1:​ [8192x1 logical] ​  ​binary map representing the voxels belonging to the specific area
 +   ​Brodmann_Area_2:​ [8192x1 logical] ​  ​binary map representing the voxels belonging to the specific area
 +   ​Brodmann_Area_3:​ [8192x1 logical] ​  ​binary map representing the voxels belonging to the specific area
 +   ...
 + 
 +  The examples above demonstrate that a parcellation can be indexed, i.e. consisting of
 +  subsequent integer numbers (1, 2, ...) or probabilistic,​ consisting of real numbers
 +  ranging from 0 to 1 that represent probabilities between 0% and 100%. An extreme case
 +  is one where the probability is either 0 or 1, in which case the probability can be
 +  represented as a binary or logical array.
 + 
 +  The only difference to the source data structure is that the parcellation structure
 +  contains the additional fields xxx and xxxlabel. See <a href=/​reference/​ft_datatype_source><​font color=green>​FT_DATATYPE_SOURCE</​font></​a>​ for further
 +  details.
 + 
 +  Required fields:
 +    - pos
 + 
 +  Optional fields:
 +    - tri, coordsys, unit
 + 
 +  Deprecated fields:
 +    - none
 + 
 +  Obsoleted fields:
 +    - none
 + 
 +  Revision history:
 +  (2012/​latest) The initial version was defined in accordance with the representation of
 +  a voxel-based segmentation.
 + 
 +  See also <a href=/​reference/​ft_datatype><​font color=green>​FT_DATATYPE</​font></​a>,​ <a href=/​reference/​ft_datatype_source><​font color=green>​FT_DATATYPE_SOURCE</​font></​a>,​ <a href=/​reference/​ft_datatype_segmentation><​font color=green>​FT_DATATYPE_SEGMENTATION</​font></​a>​
 +</​pre></​html>​