Frequency representation in the rat cochlea.
In order to determine the place-frequency map of the rat cochlea, iontophoretic HRP-injections were made into the cochlear nucleus at electrophysiologically characterized positions. Distribution of retrograde HRP transport in cochlear spiral ganglion cells was analysed by means of a three dimensional reconstruction of the cochlea. The map was established for frequencies between 1.2 and 54 kHz, corresponding to positions between 96.5 to 2% of basilar membrane length (base = 0%). At apex of the cochlea the slope of the place-frequency map was below 0.25 mm/octave. The slope increased to a value of 2.1 mm/octave at 34% basilar membrane length, and remained almost constant towards the cochlear base. The close relationship between frequency range of highest sensitivity and maximum receptor- and innervation-density in the rat cochlea is discussed.
Müller
M
M
Zoologisches Institut der J.W. Goethe Universität, Frankfurt am Main, F.R.G.
D000161:Acoustic Stimulation; D000818:Animals; D003051:Cochlea / Q000033:anatomy & histology / Q000294:innervation / Q000502:physiology*; D006735:Horseradish Peroxidase; D007478:Iontophoresis; D051381:Rats; D011919:Rats, Inbred Strains; D013136:Spiral Ganglion / Q000033:anatomy & histology / Q000502:physiology
D006735:Horseradish Peroxidase