CEREBRAL LOCALIZATION 



both eyes turn in the same direction right or left. The two 

 internal recti, guided by a convergence nucleus, act together when 

 the eyes are directed toward a near object. At the same time 

 the pupil narrows and the ciliary muscle seeks to adjust the 

 range of vision (see p. 338). 



FUNCTIONS OR PHYSIOLOGY OF THE BRAIN AND 

 CRANIAL NERVES 



The cerebrum presides over all conscious acts, and recognizes 

 all sensations. The anterior portion of the frontal lobes is said 

 to be the region of mental activity or the seat of the intellect. 



CONCRLTE CONCEPT 



FIG. 200. THE AREAS AND CENTERS OF THE LATERAL ASPECT OF THE HUMAN 

 HEMICEREBRUM. (C. K. Mitts.) 



The cerebrum not only is the seat of volition, directing the 

 purposive movements of the body, but it also exerts a controlling 

 force, both accelerating and inhibitory, upon many reflex acts 

 which originate as involuntary in their nature. The partial con- 

 trol of respiratory movements has been already alluded to; laugh- 

 ing, weeping, micturition, defecation, and many other acts may be 

 included in the same class. 



Cerebral Localizations. Connections between cortical areas 

 and certain parts of the body have been noted, and their control 



