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| + | ===== FT_CONNECTIVITY_GRANGER ===== | ||
| + | |||
| + | Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_connectivity_granger". | ||
| + | |||
| + | <html><pre> | ||
| + | <a href=/reference/ft_connectivity_granger><font color=green>FT_CONNECTIVITY_GRANGER</font></a> computes spectrally resolved granger causality. This | ||
| + | implementation is loosely based on the code used in Brovelli, et. al., PNAS 101, | ||
| + | 9849-9854 (2004). | ||
| + | |||
| + | Use as | ||
| + | [GRANGER, V, N] = <a href=/reference/ft_connectivity_granger><font color=green>FT_CONNECTIVITY_GRANGER</font></a>(H, Z, S, ...) | ||
| + | |||
| + | The input data should be | ||
| + | H = spectral transfer matrix, Nrpt x Nchan x Nchan x Nfreq (x Ntime), | ||
| + | or Nrpt x Nchancmb x Nfreq (x Ntime). Nrpt can be 1. | ||
| + | Z = the covariance matrix of the noise, Nrpt x Nchan x Nchan (x Ntime), | ||
| + | or Nrpt x Nchancmb (x Ntime). | ||
| + | S = the cross-spectral density matrix with the same dimensionality as H. | ||
| + | |||
| + | Additional optional input arguments come as key-value pairs: | ||
| + | 'dimord' = required string specifying how to interpret the input data | ||
| + | supported values are 'rpt_chan_chan_freq(_time) and | ||
| + | 'rpt_chan_freq(_time), 'rpt_pos_pos_XXX' and 'rpt_pos_XXX' | ||
| + | 'method' = 'granger' (default), or 'instantaneous', or 'total'. | ||
| + | 'hasjack' = 0 (default) is a boolean specifying whether the input | ||
| + | contains leave-one-outs, required for correct variance | ||
| + | estimate | ||
| + | 'powindx' = is a variable determining the exact computation, see below | ||
| + | |||
| + | If the inputdata is such that the channel-pairs are linearly indexed, granger | ||
| + | causality is computed per quadruplet of consecutive entries, where the convention | ||
| + | is as follows: | ||
| + | |||
| + | H(:, (k-1)*4 + 1, :, :, :) -> 'chan1-chan1' | ||
| + | H(:, (k-1)*4 + 2, :, :, :) -> 'chan1->chan2' | ||
| + | H(:, (k-1)*4 + 3, :, :, :) -> 'chan2->chan1' | ||
| + | H(:, (k-1)*4 + 4, :, :, :) -> 'chan2->chan2' | ||
| + | |||
| + | The same holds for the Z and S matrices. | ||
| + | |||
| + | Pairwise block-granger causality can be computed when the inputdata has | ||
| + | dimensionality Nchan x Nchan. In that case powindx should be specified, as a 1x2 | ||
| + | cell-array indexing the individual channels that go into each 'block'. | ||
| + | |||
| + | See also <a href=/reference/ft_connectivityanalysis><font color=green>FT_CONNECTIVITYANALYSIS</font></a> | ||
| + | </pre></html> | ||
