In every vertebrates inner ear highly specialised cells (Haircells) transform mecanical stimuly into electrical signals usable to the nervous system. Those haircells do not only provide input to the central nerveous (cns) system via ascending afferent conections, but are also controlled by efferent conections, descending from the cns to the inner ear. Birds and mammals have independently evolved a highly sophisticated subsystem of these of inner ear effernts, dealing with auditory signal processing. The present study describes position, number, morphology and projections from the cochlear efferent cells within the cochlear efferent cells in the barn owls and the chickens auditory brainstem. In adittion a method to distinguish betwen auditory efferent cells and efferents to other hair cell organs (vestibular) is proposed.     «

In every vertebrates inner ear highly specialised cells (Haircells) transform mecanical stimuly into electrical signals usable to the nervous system. Those haircells do not only provide input to the central nerveous (cns) system via ascending afferent conections, but are also controlled by efferent conections, descending from the cns to the inner ear. Birds and mammals have independently evolved a highly sophisticated subsystem of these of inner ear effernts, dealing with auditory signal process...     »