How specific is synchronous neuronal firing?

Synchronous neuronal firing has been discussed as apotential neuronal code. For testing first, if synchronousfiring exists, second if it is modulated by the behaviour,and third if it is not by chance, a large set of tools has beendeveloped. However, to test whether synchronous neuro-nal firing is really involved in information processing oneneeds a direct comparison of the amount of synchronousfiring for different factors like experimental or behav-ioural conditions. To this end we present an extended ver-sion of a previously published method NeuroXidence [1],which tests, based on a bi- and multivariate test design,whether the amount of synchronous firing above thechance level is different for different factors.