Measuring synchronization: An overview of the most frequently used methods
Summary
From the moment gamma-band synchronization has been proposed to
be a mechanism for the integration of neuronal populations in functional
areas widely distributed over the brain, there has been a need
for a reliable and robust method to measure this synchronization. This
method could then be applied to noninvasive measurements, performed
by MEG or EEG, on the human brain in order to study synchronization
between di erent brain areas. In the past two decades several
types of measures have been introduced and have been applied mainly
to EEG and MEG studies on subjects performing simple tasks during
the measurement and epileptic patients, with results giving an insight
into some of the neuronal processes going on in the brain. Despite
the interesting results, often spurious synchronizations is measured,
the result is spoiled by the large amount of noise present or measures
are applied to noncorresponding situations, such as stationary measures
being applied in nonstationary situations. An overview of the
most often used measures to detect synchronization is presented and
commented here.