EEG Connectivity Matrix

Convenience wrapper that computes a symmetric n_channels x n_channels connectivity matrix using the specified method. Dispatches to the appropriate connectivity function and returns a named matrix suitable for visualization or graph-theoretic analysis.

Usage

eegConnectivityMatrix(
  x,
  method = c("coherence", "plv", "wpli", "dtf", "pdc"),
  band = c(8, 13),
  ...
)

Arguments

x

A PhysioExperiment object with EEG data (2D: time x channels).

method

Connectivity method: "coherence" for magnitude-squared coherence, "plv" for Phase Locking Value, "wpli" for weighted Phase Lag Index, or the directed measures "dtf" (eegDTF()) and "pdc" (eegPDC()) (default: "coherence"). For "dtf" and "pdc" the returned matrix is directed (rows = targets, columns = sources).

band

Numeric vector of length 2 specifying the frequency band in Hz (default: c(8, 13) for alpha band).

...

Additional arguments passed to the underlying connectivity function (e.g., window_sec, overlap).

Value

A named numeric matrix of dimension n_channels x n_channels with channel labels as row and column names. Diagonal elements are 1. Off-diagonal elements represent the band-averaged connectivity between channel pairs.

References

Lachaux, J. P., et al. (1999). Measuring phase synchrony in brain signals. Human Brain Mapping, 8(4), 194-208.

See also

eegCoherence(), eegPLV(), eegWPLI(), eegGrangerCausality(), eegPlotConnectivity()

Examples

pe <- make_eeg(n_time = 5000, n_channels = 4, sr = 500)
conn <- eegConnectivityMatrix(pe, method = "plv", band = c(8, 13))
print(conn)
#>           Fp1       Fp2        F7        F3
#> Fp1 1.0000000 0.9623725 0.8560568 0.9618666
#> Fp2 0.9623725 1.0000000 0.8253624 0.9497751
#> F7  0.8560568 0.8253624 1.0000000 0.8506339
#> F3  0.9618666 0.9497751 0.8506339 1.0000000