BESA | Brain Electrical Source Analysis

SOURCE COHERENCE AND TIME-FREQUENCY DISPLAY

Source coherence analysis reveals the functional connectivity between brain regions. This is achieved by transforming the surface signals into brain activity using brain source montages derived from multiple source models. The new Source Coherence Module provides an extremely fast and user-friendly implementation of time-frequency analysis based on complex demodulation. Users can create event-related time-frequency displays of power, amplitude, or event-related (de)synchronization and coherence for the current montage using brain sources or surface channels. Induced and evoked activities can be separated.

Time-frequency analysis

Time-frequency diagrams based on surface or source channels
Display of absolute power or spectral amplitude
Display of event-related spectral perturbation (ERD / ERS) in percent
Temporal-spectral information optimized by complex demodulation
Visualization of inter-trial phase locking
Variable setting of time-frequency resolution
Separation of evoked and induced activity by subtraction of the averaged evoked activity from single trials
Direct comparison of two conditions
3D Imaging of oscillatory activity using the BESA Mulitple Source Beamformer (MSBF)

Source coherence

Oscillatory coupling between brain regions analyzed directly in brain source space using source montages
Calculation of cross-spectral matrices between any combination of source (and / or surface) channels
Event-related coherence displayed in time-frequency space
Coherence analysis based on power and phase locking
Computation and display of phase delay and latency difference between channels

Statistical analysis

Statistical probability maps based on resampling of the single trial data
Statistics available for all time-frequency displays (absolute amplitude, TSE, coherence, comparison of conditions)
Export of displayed data for offline statistics across subjects (e.g. in MATLAB)