116 



K. S. LASHLEY 



The ekctro-stimulable cortex of the rat 



The portion of the rat's cortex from which movements may|be 

 elicited by electrical stimulation have been described only by 

 Ferrier ( 7 76) and only in the barest outline. A more exact de- 

 termination of its extent is necessary for this comparison. I 

 have mapped the excitable cortex in about 25 animals. There 

 is a great deal of variation an account of which must be post- 

 poned until a comparison of anesthetics is possible. Figure 13 

 is a composite picture of the excitable areas of these animals. 



FIG. 13. DIAGRAM OP THE EXCITABLE CORTEX OF THE RAT 

 For the significance of the letters see text. 



a. Head turned to opposite side 

 6. Nose retracted 



c. Vibrissae moved 



d. Chewing movements 



e. Tongue protruded 

 /. Eye closed. 



g. Ear laid back 



h. Ear pricked up 



i. Shoulder drawn forward 



j. Fore-arm retracted 



k. Elbow flexed 



I. Elbow extended 



m. Wrist flexed 



n. Fore-arm rotated 



o. Back flexed to opposite side 



p. Hind leg drawn forward 



q. Homolateral leg flexed, ipselateral 



extended 



r. Ankle extended 

 s. Tail drawn to opposite side. 



All the movements elicited from all animals are shown, so that 

 the diagram includes many more movements than can be ob- 



