Sensory and Motor Tracts in Encephalon. 19 



Fritsch, Hitzig and Ferrier have mapped out the following motor 

 areas : 



1 . The convolution in front of the outer end of the crucial sul- 

 cus controls the muscles of the neck. 



2. The bend of the same convolution backward, opposite the 

 outer extremity of the crucial sulcus, controls the extensors and 

 adductors of the fore limb. 



3. The convolution just behind the outer end of the crucial 

 sulcus controls the muscles which flex and rotate the fore limb. 



4. The same convolution behind the middle of the crucial fis- 

 ure controls the movements of the hind limb. 



5. The second convolution ba,ck of the crucial fissure controls 

 the muscles of the face. 



6. The anterior part of the internal (4th) parietal convolution, 

 just back of the crucial fissure, controls the lateral switching 

 movements of the tail. 



7. The posterior angle of the first post- crucial convolution 

 causes retraction and abduction of the fore limb. 



8. The outer end of the first post-crucial convolution, directly 

 behind the outer end of the sulcus, causes raising of the shoulder 

 and extension of the fore limb. 



9. The anterior end of the third parietal convolution (the 

 second from the longitudinal fissure) controls closure of the eye- 

 lids, the rolling of the eyeball upward, and narrowing of the 

 pupil. 



10. Stimulation of the anterior end of the second parietal con- 

 volution causes partial opening of the mouth with retraction and 

 elevation of its angle. 



1 1 . Stimulation of the point of union of the first and second 

 parietal convolutions anteriorly causes opening of the mouth 

 with protrusion and retraction of the tongue. 



12. Stimulation of the median part of the second parietal con- 

 volution, causes retraction and elevation of the angle of the mouth. 



13. Stimulation of the convolution directly in front of the 

 outer end of the crucial sulcus causes dilatation of the eyelids 

 and pupil while the eyes and head are turned toward the oppo- 

 site side. 



14. Stimulation of the convolution behind the crucial fissure 

 causes contraction of the muscles of the perineum. 



