Do efferent fibres to hair cells intervene in acoustic stimulus peripheral coding?

The functional roles suggested for Olivo-Cochlear Bundle (OCB) fibres innervating auditory receptors never received a fully convincing demonstration. Assuming that efferent fibres effects, at the level of hair cells, are inhibitory with regard to single auditory nerve fibre activity, a mathematical model of the peripheral auditory system is proposed in which the presence of the descending pathway is taken into account. Computer simulation of the model accounts for most of the salient features of the patterns of activity of single cochlear nerve fibres. In the light of the model predictions, the influence of OCB fibres on peripheral receptors is assumed to act in the direction of improving the signal-to-noise ratio, as a first step of information processing.