[About the problem of bursting in spontaneous neuronal activity at the periphery of the frog auditory pathway]

Firing activity of 104 neurons located on the medullar dorsal nucleus (a homolog of the complex of mammalian cochlear nuclei) of immobilized common frogs (Rana temporaria) was recorded extracellularly in the absence of external auditory signals. This background activity was analyzed by using the stochastic point process characteristics, such as the variation coefficient, local coefficient of variation, interdependence of the next intervals, the interpulse interval distribution, autocorrelation, and hazard function. All these parameters were compared with the relative number of the interpulse intervals included in bursts ("bursting") that are determined by the offered technique. In neurons with the expressed refractoriness the bursting usually was lower, whereas in neurons with expressed maximum of the correlation function--higher than in the casual Poisson process. However, even in the last group of cells the number of intervals included in bursts was not decreased after casual shuffling of all interpulse intervals. As a result, we have failed to observe any real bursting background activity in the secondary order auditory neurons of the studied amphibian species. The data are compared with features of the background firing in different nuclei of the mammalian auditory pathway.