i6o 



BRAINS OF RATS AND MEN 



slightly accentuated in the brain of the rat, and no- 

 where is typical "motor" cortex as we see it in high- 

 er animals anatomically demonstrable. Area n ap- 



FiG. 40. — Lateral and dorsal views of the cerebral hemisphere of the 

 rat, indicating the electrically stimulable cortical points. After Lashley. 

 tf, head turned to opposite side; b, nose retracted; c, vibrissae moved; d, 

 chewing movements; e^ tongue protruded;/, eye closed;^, ear adducted; 

 /z, ear erected; /, shoulder drawn forward; y, forearm retracted; ky elbow 

 flexed; /, elbow extended; w, wrist flexed; «, forearm rotated; 0, back 

 flexed to opposite side; />, hind leg drawn forward; y, contralateral leg 

 flexed, homolateral extended; r, ankle extended; J, tail drawn to opposite 

 side. All movements are contralateral to the hemisphere stimulated 

 except where indicated. 



proaches this type more nearly than any other cor- 

 tical field/ 



The margins of area/ are excitable, but this area 

 as a whole seems to lie outside the excitable field. In 



^ Even in monkeys the motor cortex as determined physiologically is 

 less clearly defined in anatomical structure than in man and at the mar- 

 gins there is gradual transition to the cortical patterns of adjoining 

 fields (Nafiagas, 1922). 



