Applying EEG phase synchronization measures to non-linearly coupled neural mass models.
BACKGROUND
Recent neuroimaging analyses aim to understand how information is integrated across brain regions that have traditionally been studied in isolation; however, detecting functional connectivity networks in experimental EEG recordings is a non-trivial task.


METHODS
We use neural mass models to simulate 10-s trials with coupling between 1-3 and 5-8s and compare how well three phase-based connectivity measures recover this connectivity pattern across a set of experimentally relevant conditions: variable oscillation frequency and power spectrum, feed forward connections with or without feedback, and simulated signals with and without volume conduction.


RESULTS
Overall, the results highlight successful detection of the onset and offset of significant synchronizations for a majority of the 28 simulated configurations; however, the tested phase measures sometimes differ in their sensitivity and specificity to the underlying connectivity.


METHODS
Prior work has shown that these phase measures perform well on signals generated by a computational model of coupled oscillators. In this work we extend previous studies by exploring the performance of these measures on a different class of computational models, and we compare the methods on 28 variations that capture a set of experimentally relevant conditions.


CONCLUSIONS
Our results underscore that no single phase synchronization measure is substantially better than all others, and experimental investigations will likely benefit from combining a set of measures together that are chosen based on both the experimental question of interest, the signal to noise ratio in the EEG data, and the approach used for statistical significance.
DRC High Performance Technologies Group, Reston, VA 20190, USA; Computational and Information Sciences Directorate, US Army Research Laboratory, Aberdeen Proving Ground, MD 21005, USA. Electronic address: mannyv@gmail.com.
M M
MM
Vindiola
Human Research and Engineering Directorate, US Army Research Laboratory, Aberdeen Proving Ground, MD 21005, USA.
J M
JM
Vettel
DCS Corporation, Alexandria, VA 22310, USA.
S M
SM
Gordon
Human Research and Engineering Directorate, US Army Research Laboratory, Aberdeen Proving Ground, MD 21005, USA.
P J
PJ
Franaszczuk
Human Research and Engineering Directorate, US Army Research Laboratory, Aberdeen Proving Ground, MD 21005, USA.
K
K
McDowell
D001921:Brain / Q000502:physiology*; D003198:Computer Simulation; D058407:Electroencephalography Phase Synchronization; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D017711:Nonlinear Dynamics; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
Imaginary coherence; Neural mass models; Phase lag index; Phase locking value; Phase synchronization