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

  FT_RESAMPLEDATA performs a resampling or downsampling of the data
  Use as
    [data] = ft_resampledata(cfg, data)
  The data should be organised in a structure as obtained from
  the FT_PREPROCESSING function. The configuration should contain
    cfg.resamplefs  = frequency at which the data will be resampled (default = 256 Hz)
    cfg.detrend     = 'no' or 'yes', detrend the data prior to resampling (no default specified, see below)
    cfg.demean      = 'no' or 'yes', baseline correct the data prior to resampling (default = 'no')    = 'no', 'text', 'textbar', 'gui' (default = 'text')
    cfg.trials      = 'all' or a selection given as a 1xN vector (default = 'all')
    cfg.sampleindex = 'no' or 'yes', add a channel with the original sample indices (default = 'no')
  Instead of specifying cfg.resamplefs, you can also specify a time axis on
  which you want the data to be resampled. This is usefull for merging data
  from two acquisition devides, after resampledata you can call FT_APPENDDATA
  to concatenate the channles from the different acquisition devices.
    cfg.time        = cell-array with one time axis per trial (i.e. from another dataset)
    cfg.method      = interpolation method, see INTERP1 (default = 'pchip')
  Previously this function used to detrend the data by default. The
  motivation for this is that the data is filtered prior to resampling
  to avoid aliassing and detrending prevents occasional edge artifacts
  of the filters. Detrending is fine for removing slow drifts in data
  priot to frequency analysis, but detrending is not good if you
  subsequenlty want to look at the evoked fields. Therefore the old
  default value 'yes' has been removed. You now explicitely have to
  specify whether you want to detrend (probably so if you want to
  keep your analysis compatible with previous analyses that you did),
  or if you do not want to detrent (recommended in most cases).
  If you observe edge artifacts after detrending, it is recommended
  to apply a baseline correction to the data.
  The following fields in the structure 'data' are modified by this function
  To facilitate data-handling and distributed computing you can use
    cfg.inputfile   =  ...
    cfg.outputfile  =  ...
  If you specify one of these (or both) the input data will be read from a *.mat
  file on disk and/or the output data will be written to a *.mat file. These mat
  files should contain only a single variable, corresponding with the
  input/output structure.