MOTOR FUNCTION OF THE CEREBRAL CORTEX 



599 



cortex the stimulation of which produces definite movements of co-ordinated 

 groups of muscles of the opposite side of the body. Fritsch and Hitzig were 

 the first to show that the cerebral cortex responds to electrical irritation. 

 They employed a weak constant current in their experiments, applying a 



FIG. 400. 



FIG. 401. 



FIGS. 400 and 401. Brain of Dog, Viewed from Above and in Profile. F, Frontal 

 fissure sometimes termed crucial sulcus, corresponding to the fissure of Rolando in man; 

 S, fissure of Sylvius, around which the four longitudinal convolutions are concentrically 

 arranged; i, flexion of head on the neck, in the median line; 2, fle.xion 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.) 



pair of fine electrodes not more than one-twelfth inch apart to different parts 

 of the cerebral cortex. The results thus obtained have been confirmed and 

 extended by Ferrier and many others, stimulating chiefly with induction 

 currents. 



