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

  FT_PREPROC_STANDARDIZE performs a z-transformation or standardization
  of the data. The standardized data will have a zero-mean and a unit
  standard deviation.
  Use as
    [dat] = ft_preproc_standardize(dat, begsample, endsample)
    dat        data matrix (Nchans dat Ntime)
    begsample  index of the begin sample for the mean and stdev estimate
    endsample  index of the end sample for the mean and stdev estimate
  If no begin and end sample are specified, it will be estimated on the
  complete data.
  See also PREPROC