PPT Slide
- The basis of representation of all sensory information is the topographical arrangement of the receptor epithelium. In the visual system this is the two-dimensional area of the retina, in which the light sensitive cells are located. In all mammals including men the auditory receptor epithelium in the inner ear, the cochlea, is formed by one row of sensitive cells (inner hair cells) in the organ of Corti.
- The hair cells of the organ of Corti form a one dimensional “map”, with an unequivocal topographical frequency representation for pure tones (= sinusoidal acoustic waves). Due to the mechanic properties of the inner ear pure tones of high frequency maximally activate hair cells at the base of the cochlea, while low frequencies activate hair cells at the upper end.
- The resulting cochleotopy or tonotopy is the basis of all neuronal processing in the auditory system.
- The work of G. Langner and C. Schreiner, which is part of this project, contributed to the exact description of the tonotopic
- structure of the main auditory brainstem nucleus, the Inferior Colliculus. It was found to consist of thirty to forty neuronal layers. On each of these layers there is a frequency gradient spanning about a sixth of an octave.