New features in BESA Connectivity 2.0

NOTE that BESA Connectivity 2.0 is for research use only!
Many new features are available in BESA Connectivity 2.0:

Themes and user interaction

• The colour theme can be adjusted between BESA White and the previous BESA Standard.

Time-Frequency Analysis

• BESA Connectivity 2.0 offers a batch processing mode in time-frequency projects that allows loading data sets for multiple subjects simultaneously and processes all those data sets in one project. Up to 10 different conditions are supported. For each condition, it is possible to select several data sets in the Load Data dialog.
• Grand Average views and data exports of multi-subject time-frequency analysis are available.
• A multi-taper method is introduced to the time-frequency methods. Multitaper analysis uses several tapers to decompose the signal into its frequencies. Here, Slepian Sequences are used to construct the tapers, which are then used in a time-frequency decomposition of the signal. Multitapering combines the properties of the different tapers to control the leakage and smooth the signal in the frequency domain. The multitaper transformation uses a sliding time window with a length that decreases with increasing frequency.
• Data export:
  • Export project results: Averaged time-frequency results of all decompositions and data sets are exported. They can directly be read in to BESA Statistics.
  • Averaged TF data: Selected display type options (temporal-spectral evolution (TSE) or absolute (ABS) values for amplitude or power) are considered during export.

Complex demodulation	Wavelet	Multitaper
CD offers a constant time-frequency resolution	Wavelet optimizes time-frequency resolution	Multitaper creates smooth signal at higher frequencies

Connectivity Analysis

• Batch processing: When loading a time-frequency project containing multiple conditions with multiple data files, connectivity analysis for all those data files can be computed within one project.
• Grand Average views and data exports of multi-subject connectivity analysis are available.
• New connectivity methods:
  • Phase lag index (PLI) (Stam et al. 2007)
  • Weighted phase lag index (WPLI) (Vinck et al., 2011)
  • Directed phase lag index (dPLI) (Stam and van Straaten, 2012)
• Circular Graph View: This new visualization mode places the sources (or sensors) on a circle and shows the coupling strength as connections for the selected latency & frequency bin between all combinations of sources. The channels are automatically arranged in four quadrants (left anterior / right anterior / left posterior / right posterior) to facilitate interpretation.
• Simultaneous averaging over time and frequency: when both averaging options are selected the matrix view changes to a visualization of a single tile per connection, thus enabling a connectome view for the selected time-frequency range.
• Freeze-Pane mode for TFC View: Channel labels will remain visible at the left-most column and top-most row of the matrix display even if the visualization is zoomed by the user.
• The 3D visualization takes into account the colors and sizes of the sources specified in the BESA Solution File Format (*.bsa).
• Data export:
  • Export project results: Connectivity results of all selected methods and data sets are exported. They can directly be read in to BESA Statistics.