COORDINATION AND SENSATION 



Fissure of Rolando 



to influence the movements of the body. But the power 

 to alter, postpone, or entirely inhibit, nervous movements 

 is but a part of the general work ascribed to the cerebrum 

 as the organ of the mind. Numerous experiments per- 

 formed upon the lower animals, together with observations 

 on man, show the cerebrum to be the seat of the mental 

 activities, and to make possible, in some way, the processes 

 of consciousness, memory, volition, imagination, emotion, 

 thought, and sensation. 



Localization of Cerebral Functions. Many experiments have been 

 performed with a view to determining whether the entire cerebrum is 

 concerned in each of its several activities or whether special functions 



belong to its different parts. 

 These experiments have been 

 made upon the lower animals 

 and the results thus obtained 

 compared with observations 

 made upon injured and im- 

 perfectly developed brains in 

 man. The results have led 

 to the conclusion that certain 

 forms of the work of the cere- 

 brum are localized and that 



FIG. 142. -Location of cerebral func- some of its P arts are con - 

 tions. Diagram of cerebrum, showing most cerned in processes different 

 of the areas whose functions are known. from those of others. 



The work of locating the 



functions of different parts of the cerebrum forms one of the most 

 interesting chapters in the history of brain physiology. The portions 

 having to do with sight, voluntary motion, speech, and hearing have 

 been rather accurately determined, while considerable evidence as to 

 the location of other functions has been secured. Much of the cerebral 

 surface, 'however, is still undetermined (Fig. 142). 



NERVOUS CONTROL OF IMPORTANT PROCESSES 



Circulation of the Blood. i. Control of the Heart. The ability to 

 contract at regular intervals has been shown to reside in the heart 



fissure of 

 SilviuS 



