THE CEREBRUM 269 



on either side of the fissure of Rolando, to the paracentral 

 lobule, and possibly to a small area in front of the ascending 

 frontal convolution. From above downward, on either side 

 o.f the Rolandic fissure are areas presiding over the move- 

 ments of the leg, arm and face. 



More specific information as regards areas controlling 

 various movements may be obtained by reference to Fig. 86. 



Various kinds of monoplegia (crossed) are caused by 

 lesions, as hemorrhage, in localized parts of the motor area ; 

 there may be facial, brachial, crural, bracho-facial monople- 

 gia, etc. There can be no doubt that from the motor cortical 

 zone pass the fibers which constitute the pyramidal tracts of 

 the cord. 



Sensory Centers. Centers for the reception of impres- 

 sions giving rise to general sensation may exist. Fibers from 

 the temporo-sphenoidal and occipital lobes pass through the 

 posterior third of the posterior division of the internal cap- 

 sule, and it may, therefore, be assumed that these parts of 

 the cerebrum are connected with general sensation. 



Special Centers. Besides these areas for motion and gen- 

 eral sensation, special centers certainly exist. 



The Optic Center is in the occipital lobe, probably in the 

 cuneus. Removal of the right occipital lobe is followed by 

 left hemiopia and vice versa; removal of both causes total 

 blindness. 



The Olfactory Center is probably on the inner surface of 

 the anterior extremity of the uncinate gyrus (inner extrem- 

 ity of the temporal lobe). 



The Gustatory Center is supposed to be in the temporal 

 lobe very near the preceding. 



The Auditory Center is located in the superior and middle 

 convolutions of the temporo-sphenoidal lobe. 



The Center for Cutaneous Sensations cannot be strictly 

 limited, though it is said to correspond with the motor area. 



The Center for Muscular Sensations is thought to be in 

 the lower parietal region. 



