406 BRAIN MECHANISMS AND LEARNING 



animals awoke when the anaesthetic wore oft, although two animals 

 remained iniconscious for 2 days. 



The cats were tested i to 3 days after the operation and when they were 

 wide awake. All the alimentary responses conditioned to visual stimuli 

 were absent. The orienting reaction and salivation were no longer elicited 

 by turning the light on, nor by placing the fish-clamp with food within 



ALIMENTARY 

 REFLEX 



FLEXOR REFLEX 



BEFORE 



CONDITIONING 



CONDITIONED 



AFTER 

 LESION 

 IN R.F. 



mm— 



w— .-ySr'UA^i^llgll^ 



BUZZER 



ELECTfaC SHOCK 



Fig. 9 

 This figure illustrates the disappearance of alimentary and flexor conditioned 

 responses consecutive to a lesion in the mesencephalic tegmentum. Notice that the 

 brain stem injured cat does not seem to perceive the food placed within its visual 

 field. 



the visual field of the animal at short distances from it, as illustrated in 

 Fig. 9. Only when the food was put very near its nose did the cat begin to 

 snift' and salivate, but it was unable to detect the location of the food. 

 However, when the food was placed near its mouth, the cat eagerly ate it 

 and salivated abundantly. Also in these cats the buzzer did not elicit the 

 flexion of the limb nor the generalized struggle reaction (Fig. 9). And 



