EXCITATION OF AUDITORY RECEPTORS 573 







FIG. 10. Diagram of the innervation of the cochlea. The hair cells are indicated only in part. 

 The principal types of fibers and the bundles that they form aie: / and -', intraganglionic spiral 

 fibers; sa and 3a, internal spiral fibers; 4, external spiral fibers; j and 6, radial fibers. (Based on 

 observations of Retzius, Solovcov and Lorente de No.) Not shown are the relatively scarce un- 

 branched external radial fibers (Held). Type I is the continuation of the efferent olivocochlear 

 bundle. [From Wever (23).] 



FIG. II. Movement of the cochlear partition, based on descriptions by von Bekesy. Explanation 

 in text. [From Davis (3).] 



critical mechanical event that has been recognized in 

 the mechanism of stimulation. At this point the signif- 

 icant events apparently become electrical, for this 

 bending of the hairs seems to release energy in the 



form of biolectric potentials and these potentials are 

 in all probability the important intermediate step in 

 the mechanism of excitation of the auditory nerve 

 fibers. 



