282 



INTRODUCTION TO NEUROLOGY 



results as summarized on Fig. 132 may be accepted as fully in 

 accord with the best previous experimental work, with the 

 anatomical investigations of the regional differentiation of the 

 cortex, and with the most recent clinical studies. The corre- 

 sponding areas of the human brain are seen in Fig. 133. 



Anus and vagina 



Hip 



Shoulder 

 Elbow 



Ear Eyelid , 



Noee Closure / 

 of jaw / 

 Opening of jaw 



Vocal cords 



I 



Mastication 



Sulcus centralia 



Fig. 132. Brain of a chimpanzee seen from the left side and from 

 above, upon which the cortical areas whose excitation causes bodily move- 

 ments are indicated by shading. The regions shaded by vertical lines and 

 marked " EYES " indicate the frontal and part of the occipital regions which 

 when electrically excited cause conjugate movements of the eyes. The 

 regions shaded with stipple comprise the motor projection centers from 

 which the fibers of the pyramidal tract arise. The names printed large 

 on the stippled area indicate the main regions of the motor area; the names 

 printed small outside the brain indicate broadly by their pointing lines 

 the relative topography of some of the chief subdivisions of the main 

 regions of the motor cortex. But there exists much overlapping of the 

 motor areas and of their subdivisions which the diagram does not attempt 

 to indicate. (After Griinbaum and Sherrington.) 



The electric or mechanical stimulation of each one of the 

 shaded areas of Fig. 132 is followed by the contraction of a 

 particular group of muscles on the opposite side of the body, as 



