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HANDBOOK OF PHYSIOLOGY. 



The Motor areas of the Cerebral Cortex. 



The experiments upon the brains of various animals by means of 

 electrical stimulation have demonstrated that there are definite re- 



Fig. 378. 



Figs. 378 and 379. Brain of dog, viewed from above and in profile. F, frontal fissure some- 

 times termed crucial sulcus, corresponding to the fissure of Rolando in man. S, fissure of 

 Sylvius, around which the four longitudinal convolutions are concentrically arranged; 1, flexion 

 of head on the neck, in the median line ; 2, flexion of head on the neck, with rotation toward 

 the side of the stimulus ; 3, 4, flexion and extension of anterior limb ; 5, 6, flexion and extension 

 of posterior limb; 7, 8. 9, contraction of orbicularis oculi. and the facial muscles in general. 

 The unshaded part is that exposed by opening the skull. (Dalton.) 



gions of the cerebral cortex the stimulation of which produces definite 

 movements of co-ordinated groups of muscle of the opposite side of 

 the body. Fritsch and Hitzig were the first to show that the cere- 



