CEREBRAL FUNCTION IN THE RAT 



127 



paresis which made it easier to turn to one side than to the other. 

 They did show, however, some indications of abnormality in 

 learning not due to the motor difficulty. The development of 

 stereotyped errors in experiment number 39 and the large num- 

 ber of errors of the same type made by the rat in experiment 



500 



4-00 



300 



200 



100 



100 







tTS 



ZOO 

 trials. 



normal 

 ey.p. 35 



exp.39 



7S 



100 trials 



FIG. 13. A COMPARISON OF THE RATE OF LEARNING THE SIMPLE MAZE BY 



NORMAL ANIMALS AND BY ANIMALS AFTER DESTRUCTION OF THE 



ANTERIOR AND DORSAL SURFACES OF THE CORTEX 



38 in the second training test (table 4) are without parallel 

 in the behavior of normal animals. They indicate, perhaps, 

 an abnormal predominance of kinesthetic-motor chain reflexes 

 and a difficulty in inhibiting them in new situations. This is 

 suggestive of the perseverations sometimes seen in human 

 defectives. 



