EXPERIMENTAL STUDIES ON THE THALAMUS 21 



3. Digestion processes are normal if the animal is fed and 

 watered by hand. 



4. Body temperature, maintenance and regulation is nearly 

 normal. 



5. There are no disturbances of equilibrium, so that the bird 

 can walk and fly in a normal manner. 



6. The bird moves only when some stimulus, either external, 

 as irritation of the skin, or internal, such as hunger, thirst, or 

 defecation, disturbs it. 



7. When deprived of food and water, a characteristic periodic 

 restless walking to and fro, which ceases on feeding. 



8. The loss of all typical instinctive types of actions, such as 

 feeding, bathing, courting and mating, nesting, etc. 



After three or four months there is added to this picture a rest- 

 less type of walking whose causation is obscure. The bird may 

 be restless in the day time and 'sleep' quietly at night. Fur- 

 thermore, this alternation of walking in the day time and quiet 

 at night is not merely a matter of illumination, for the blind 

 decerebrate bird will exhibit the same type of behavior. In 

 part it is related to hunger, but not wholly, for at this stage it 

 may be independent of feeding or starvation. The writer has 

 seen this type of behavior in those birds only which have survived 

 the operation for months. This is not to be confused with a 

 type of violent, forced, continuous walking or flying movements 

 that sometimes appear when there has been some damage done to 

 the thalamus or midbrain, also of unknown causation. 



As pointed out by Bechterew, if the thalamus also be removed 

 at the time of operation, the animal differs from the preceding 

 picture. 



1. The animal stands quietly without spontaneous movements. 



2. The feathers lie flat against the body and not fluffed. This 

 is so striking as to become diagnostic. 



3. Digestion disturbances appear. Some of these are difficulty 

 in swallowing, vomiting, and an apparent diarrhea or excess 

 urination. 



4. There may be indefinite or marked disturbances in main- 

 taining body equilibrium. These may assume the most bizarre 



