CEREBRAL FUNCTION IN LEARNING 69 



cause is in reality the loss of reinforcing or inhibiting mechanisms 

 which determine only the tonic condition of the animal. 



Before the results of training could be interpreted it was 

 necessary, therefore, to make some estimate of the relative 

 activity of normal and of partially decerebrate animals. ObserO 

 vations during training indicated that the normal animals i 

 were more given to excess activities, such as leaping over low x ^ 

 obstacles (see page 92), than were the operated ones, but 

 aside from this "f riskiness" the normals seemed in no way more 

 active than the operated animals. The latter spent little time 

 in complete inactivity, moved quickly about the restraining 

 cages, and reacted to stimuli as promptly as did normals. There "1 

 was no indication of differences in general activity which might \ 

 influence the rate of learning. 



Methods 



For a more accurate measure of the general activity of the 

 groups whose rates of learning were compared, continuous 

 records of activity for 240 hours were made for some of the 

 animals trained and for other normal ones. These records 

 were obtained by the use of a modification of the apparatus 

 designed by Slonaker ('08). Four revolving cages were arranged 

 so that their movements were recorded on a disk kymograph 

 giving continuous records over twenty-four hour periods. A 

 sample from such a record, covering six hours, is shown in figure 1. 

 The cages were pivoted so that the slightest movement of the 

 animal within them would produce a break in the continuous 

 line of the record sheet. The figure shows periods of con- 

 tinuous activity with rapid spinning of the cage (a), periods of 

 practically complete quiescence (6), and periods of slight activ- 

 ity, restlessness without active running (c). Observations on 

 the animals indicate that the periods of nearly complete inac- 

 tivity are spent in sleep. Periods of partial activity are difficult 

 to interpret and in dealing with the records statistically it seemed 

 best to include only periods of active running and periods of 

 complete quiet. The active running was computed as average ~] 



