196 VETERINARY PHYSIOLOGY 



of the eyes, and also connected with the cerebellum through 

 the peduncle. 



While there is good evidence that a special localised area 

 of the cortex is connected with the reception of stimuli from 

 the eyes, the evidence of the existence of similar areas or 

 centres connected with the other organs of special sense is 

 not so satisfactory. 



Auditory Centre. Terrier, by removing the superior 

 temporo-sphenoidal lobe in the monkey, produced no motor 

 disturbance, but found evidence of loss of hearing in the 

 opposite ear. When the region was stimulated he found that 

 the monkey pricked up its ears, and looked to the opposite 

 side, and he considered that these observations prove the 

 existence of a special localised mechanism for the reception 

 of stimuli from the ear. Schafer has removed these con- 

 volutions from both sides in the monkey, with aseptic 

 precautions, and kept the animal alive. He failed to find 

 evidence of loss of auditory sensations. Stimulation of the 

 ear in such animals still caused the usual muscular response. 

 But since lower connections exist between the auditory 

 nuclei in the medulla and the centres for muscular move- 

 ment in the spinal cord (fig. 98), this observation cannot 

 be accepted as excluding the relationship of the superior 

 temporo-sphenoidal convolution to hearing. The existence 

 of such a relationship is strongly supported by pathological 

 evidence. Cases of epilepsy have been recorded, in which the 

 first symptom of the fit was the hearing of sounds, and in which 

 the lesion was found in this lobe. 



The limits of this centre are defined by a characteristic cell 

 distribution (fig. 101), and around it is an area with a somewhat 

 different cell arrangement, which is probably the psycho-auditory 

 region (fig. 101) the region in which the changes in the central 

 region connected with the production of simple sensation are 

 associated with the stored passed impressions to enable the 

 nature of the sensation to be comprehended. 



The central sensory area is early supplied by medullated 

 fibres (fig. lOOs). 



Taste and Smell. The intimate relationship of these senses 

 renders it probable that their centres are closely associated 

 in the cortex. 



