S6o A MANUAL OF PHYSIOLOGY 



to the structurally differentiated area (visuo-psychic area of Camp- 

 bell), as the lower centre corresponds to his structurally differentiated 

 visuo-sensory area (Figs. 359, 360). 



Auditory Centre. On the outer surface of the temporo- 

 sphenoidal lobe, mainly in the first temporal convolution, lies 

 an area associated with the sense of hearing. Stimulation in the 

 region of the first temporal convolution may cause the animal to 



SYLVIA N 

 FISSURE 



FIG. 364. LATERAL VIEW OF LEFT HEMISPHERE WITH SENSORY AREAS : MAN. 

 The front of the brain is towards the left. 



prick up its ear on the opposite side. Destruction of this area 

 on both sides is followed by complete and irremediable loss of 

 hearing. If it is destroyed only on one side, there is partial deaf- 

 ness of the opposite ear, and also to some extent of the ear on 

 the same side. This is gradually recovered from. If it is de- 

 stroyed on the left side there is also the peculiar condition called 

 ' word- deaf ness/ which will be referred to directly (p. 864). In 

 deaf-mutes the first temporal convolution may be atrophied. 



