Otoacoustic emissions and frequency resolution arise in the inner ear, peripheral to the synapse.

Evidence

What is now known about otoacoustic emissions indicates that they are produced in the inner ear, i.e. in the peripheral part of our processing system. Peripheral in this context means that the information still deals with AC values that can either be acoustical, mechanical (in the middle ear), hydromechanical (in the inner ear) or electrical (within the haircells). In all cases, oscillations with positive and negative values carry the information. The change from AC values into action potentials takes place in the synapses of the inner haircells, an area defined as the border between peripheral information processing and retro-cochlear information processing. This definition may be different from that used in audiology. From the information processing point of view, however, this definition is very useful. We assume that the production of otoacoustic emissions and frequency resolution are typical features of our hearing system that are located in the inner ear, i.e. peripheral. We also assume that what is called recruitment may be produced primarily within the inner ear. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1870

Categorization

• DEFINE: Defines the peripheral/retro-cochlear boundary at the inner haircell synapse, a useful information-processing framing distinct from clinical audiology.