  A wide variety of approaches to estimate the degree of synchrony between two
or more spike trains have been proposed. One of the most recent methods is the
ISI-distance which extracts information from the interspike intervals (ISIs) by
evaluating the ratio of the instantaneous firing rates. In contrast to most
previously proposed measures it is parameter free and time-scale independent.
However, it is not well suited to track changes in synchrony that are based on
spike coincidences. Here we propose the SPIKE-distance, a complementary measure
which is sensitive to spike coincidences but still shares the fundamental
advantages of the ISI-distance. In particular, it is easy to visualize in a
time-resolved manner and can be extended to a method that is also applicable to
larger sets of spike trains. We show the merit of the SPIKE-distance using both
simulated and real data.

Biological Physics;Computational Physics;Data Analysis, Statistics and Probability