ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. G'U 



Motor and Sensory Centers. 



By observations upon the chimpanzee, Sherrington and Gruen- 

 lum have shown that the motor area is in the ascending frontal 

 (precentral) convolution and spread over its whole length. The motor 

 area did not, at any point, extend behind the fissure of Eolando (cen- 

 tral fissure) ; on the inner side of the brain they found the motor area 

 extended only a short distance downward, and not to the calloso-mar- 

 ginal fissure. In the motor area they also localized movements of the 



SuU. Central. ^ n ^ * Vagina. 



Sulccalloso 



JSute.jprecen6r.meoy. 



Fig. 280. The Motor Areas and Centers on the Mesial Aspect of the 

 Hemicerebrum of the Chimpanzee. (GRUNBAUM and SHERRINGTON.) 



ear, nostril, palate, movements of sucking, mastication, of the vocal 

 cords, of the thorax, abdomen, and the sphincters. The arrangement 

 of the representation of various regions of the muscles follows the 

 exact segmental sequence of the cranio-spinal nerve series; thus, in 

 front of the central fissure from below upward are, first, the center 

 of the face; next, centers for the upper extremity; next, those from 

 the trunk; and last, for the lower extremities. Extirpation of these 

 areas gave positive paralysis. Sherrington and Gruenbaum also 

 found in the middle and inferior frontal convolutions a center which, 

 when irritated, caused conjugate deviation of the eye of the oppo- 

 site side. 



In accordance with these facts of Sherrington, and from his 



