Certain functions require knowledge what sensors are near other sensors and should be considered as neighbours. As an example, any cluster-statistic needs to be informed which sensors are allowed to form a cluster. From August 2011 on, you as the user are obliged to define and verify the neighbours manually rather than relying on FieldTrip's internal standard. In the following will be explained what possibilities there are to achieve this.

In FieldTrip, the function ft_prepare_neighbours is computing information about what sensors are neighbours of which other sensors. Neighbourhood should be a symmetric property (if A is a neighbour of B, then B is a neighbour of A). You can get neighbours from your data as following:

  cfg.neighbours = ft_prepare_neighbours(cfg, data);

You can verify the neighbourselection by calling ft_neighbourplot

  ft_neighbourplot(cfg, data);

or by simply asking for feedback when calling ft_prepare_neighbours

  cfg.feedback = 'yes';
  cfg.neighbours = ft_prepare_neighbours(cfg, data);

There are three methods how ft_neighbourselection can define the neighbour structure for your data: 'distance', 'triangulation' and 'template'.