682 FUNCTIONS OF THE CEREBRUM [CH. XLVIII. 



opposite side of the body; excitation of the same spot is always 

 followed by the same movement in the same animal. In different 

 animals excitation of anatomically corresponding spots produces 

 similar or corresponding results. It is this which has enabled one 



B 



Fillet 



C ^'^^^ CORD 



5t 



MID. BRAIN 



FIG. 493. Degeneration after destruction of the Rolandic area of the right hemisphere. 

 (After Go were.) 



to apply the results of stimulating areas of the monkey's brain to 

 the elucidation of the function of the similar brain of man. 



If the stimulation used is too powerful the result is a movement 

 of other parts, and a considerable portion of the body may be thrown 

 into convulsive movements similar to those seen in epilepsy. 



Extirpation, or removal, of these areas produces paralysis of the 

 same muscles which are thrown into action by stimulation. 



The degeneration tracts after destruction of the Eolandic area 

 are shown in fig. 493. 



The shaded area in each case represents the injured or degenerated 

 material; A in the cortex, B in the anterior part of the posterior 

 limb of the internal capsule, C in the middle of the crusta of crus 

 and mid-brain, D in the pyramidal bundles of the pons, E in the 

 pyramid of the bulb, and F in the crossed and direct pyramidal 

 tracts of the cord. 



Sensory areas. Stimulation of these produces no direct move- 

 ments, but doubtless sets up a sensation called a subjective sensation ; 

 that is, one produced in the animal's own brain, and this indirectly 

 leads to movements which are reflex; thus on stimulating the 

 auditory area there is a pricking up of the ears ; on stimulating the 

 visual area there is a turning of the head and eyes in the direction 



