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

  FT_PREPARE_NEIGHBOURS finds the neighbours of the channels based on three
  different methods. Using the 'distance'-method, prepare_neighbours is
  based on a minimum neighbourhood distance (in cfg.neighbourdist). The
  'triangulation'-method calculates a triangulation based on a
  two-dimenstional projection of the sensor position. The 'template'-method
  loads a default template for the given data type. prepare_neighbours
  should be verified using ='yes' or by calling
  The positions of the channel are specified in a gradiometer or electrode configuration or
  from a layout. The sensor configuration can be passed into this function in three ways:
   (1) in a configuration field,
   (2) in a file whose name is passed in a configuration field, and that can be imported using FT_READ_SENS, or
   (3) in a data field.
  Use as
    neighbours = ft_prepare_neighbours(cfg, data)
  The configuration can contain
    cfg.method        = 'distance', 'triangulation' or 'template'
    cfg.neighbourdist = number, maximum distance between neighbouring sensors (only for 'distance')
    cfg.template      = name of the template file, e.g. CTF275_neighb.mat
    cfg.layout        = filename of the layout, see FT_PREPARE_LAYOUT       = channels for which neighbours should be found      = 'yes' or 'no' (default = 'no')
  The EEG or MEG sensor positions can be present in the data or can be specified as
    cfg.elec          = structure with electrode positions, see FT_DATATYPE_SENS
    cfg.grad          = structure with gradiometer definition, see FT_DATATYPE_SENS
    cfg.elecfile      = name of file containing the electrode positions, see FT_READ_SENS
    cfg.gradfile      = name of file containing the gradiometer definition, see FT_READ_SENS
  The output is an array of structures with the "neighbours" which is
  structured like this:
         neighbours(1).label = 'Fz';
         neighbours(1).neighblabel = {'Cz', 'F3', 'F3A', 'FzA', 'F4A', 'F4'};
         neighbours(2).label = 'Cz';
         neighbours(2).neighblabel = {'Fz', 'F4', 'RT', 'RTP', 'P4', 'Pz', 'P3', 'LTP', 'LT', 'F3'};
         neighbours(3).label = 'Pz';
         neighbours(3).neighblabel = {'Cz', 'P4', 'P4P', 'Oz', 'P3P', 'P3'};
  Note that a channel is not considered to be a neighbour of itself.