SENSE AREAS AND ASSOCIATION AREAS. 



213 



in spite of negative results by Schafer and others this localization 

 has been shown to be substantially correct. Entire ablation of 

 both temporal lobes is followed by complete deafness. Ablation 

 on one side, however, is followed only by impairment of hearing, 

 and in the light of the results from histology and from the clinical 

 side it seems probable that the connections of the auditory cortex 

 with the ear follow the general schema of the optical system rather 

 than that of the body senses. That is, it is probable that the 



Posterior nucleus. 



Deiters's nucleus. 



Dorsal nucleus. 

 Ventral nucleus. 



Cochlear branch. 



Vestibular branch. 



Semicircular 

 canals. 



Scarpa's ganglion. 

 Cochlea. 

 Spiral ganglion. 

 Fig. 94. The medullary nuclei of the eighth nerve. (From Poireer and Charpy.) 



auditory fibers from each ear end partly on the same side and 

 partly or mainly on the opposite side of the cerebrum. The exact 

 portion of the temporal lobe that serves as the cortical terminus 

 of the auditory tract of fibers cannot be determined with certainty, 

 but it seems probable that it lies mainly in the superior temporal 

 gyrus and the transverse gyri extending from this into the lateral 

 fissure of the cerebrum (fissure of Sylvius). 



The Histological Evidences. On the histological side the paths 

 of the auditory fibers have been followed with a large measure of 

 success, although in many details the opinions of the differ- 

 ent investigators vary considerably. The eighth cranial nerve 



