DICS beamformer

Dynamic imaging of coherent sources (DICS) is the frequency-domain counterpart of the LCMV beamformer. Instead of the time-domain data covariance, it uses the cross-spectral density matrix at a frequency of interest, so it estimates source power and inter-source coherence within specific frequency bands — well suited to studying oscillatory activity and spectral connectivity.

DICS shares the beamformer family's strengths (adaptivity, spatial selectivity) and weaknesses (sensitivity to correlated sources and to cross-spectral-density estimation). It is widely used to map band-limited power and to estimate source-level coherence between regions, but source-space coherence estimates remain vulnerable to residual source leakage (the spatial spread of the filter), which can inflate apparent connectivity between nearby locations.