FURTHER RESULTS WITH THE UNIQUANTAL EPSP HYPOTHESIS

The hypothesis of Geisler (Brain Res. 212 (1981) 198-201), in which th e different spontaneous-rate classes of primary auditory neurons were accounted for by the different sizes of uniquantal EPSPs relative to t he gap between resting membrane and threshold potentials, was represen ted with an expanded model which included relative refractory effects. The spike rates generated by the expanded model, when plotted vs. est imated sound level, are qualitatively similar to those of experimental ly obtained rate-level curves. The hypothesis is also consistent with recent ultrastructural data which suggest that average quantal-release rates for any particular primary auditory neuron are inversely relate d to its spontaneous rate. The model's recovery processes following sp ike generation (hazard functions) are also similar to those observed e xperimentally. (C) 1997 Elsevier Science B.V.