CEREBRAL FUNCTION IN THE RAT 



89 



same and their final efficiency was as great as that of any nor- 

 mals. Their quicker time on the first trials is probably due to 

 the fact that they had been handled a great deal and were more 

 accustomed to the experimenter than were the normal animals. 



2000 



1500 



1000 



500 



FIG. 5. A COMPARISON. OP THE RATE OP LEARNING THE INCLINED PLANE Box 

 BY NORMAL ANIMALS AND BY ANIMALS AFTER INJURY TO THE FRONTAL AREAS 



Six animals are included in each group. The average time in seconds per trial 

 is plotted. Normal rats : . Operated rats : . 



The extent of the lesions in these animals is shown in plate 

 II, figures 1, 3, 4, 6 and 7. The combined extent of the lesion 

 is shown in figure 6. Practically every part of the anterior 

 pole of the cortex in front of the knee of the corpus callosum 



FIG. 6. TOTAL EXTENT OF LESIONS IN ANIMALS WHICH LEARNED THE INCLINED 

 PLANE Box AFTER OPERATION 



