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

  FT_CONNECTIVITY_CANCORR computes the canonical correlation or coherence between
  multiple variables. Canonical correlation analysis (CCA) is a way of measuring the
  linear relationship between two multidimensional variables. It finds two bases, one
  for each variable, that are optimal with respect to correlations and, at the same
  time, it finds the corresponding correlations.
  Use as
    [px, py, wx, wy] = ft_connectivity_cancorr(C, x, y, ...)
  The input data C represents the Nchan*Nchan covariance or cross-spectral density
  matrix, and x and y specify the indices to the cross-spectral density making up the
  dependent and independent variable