CORPUS STRIATUM OF MAMMALS 117 



incomplete differentiation of cortical and striatal 

 mechanisms of control of behavior in these primitive 

 mammals. 



That the corpus striatum is essential for the per- 

 formance of all but the simplest reflexes in lower 

 mammals and indeed in species as highly organized 

 as the dog is indicated by the following experiments. 



In most of the decerebrate dogs described in the 

 literature some portion of the striatum was preserved. 

 In Rothmann's case (1923) the dog after a time re- 

 covered a considerable number of rather complex 

 functions. He would seek food, avoid obstacles, and 

 in general behave like a dog deprived of his higher 

 sense organs. 



In one of Rogers* opossums (1924) the cortex was 

 almost completely destroyed except for a portion of 

 the olfactory field and there was extensive injury to 

 the corpus striatum of both sides, though this was 

 not all removed. Eleven days after the operation the 

 animal showed decerebrate restlessness interrupted 

 by periods of profound stupor. There was no motor 

 paralysis. It seemed to be completely blind, and was 

 unable to avoid obstacles except by the sense of 

 touch. To cutaneous stimuli it gave the ordinary 

 avoiding reactions. It would ea:t and drink if food 

 and water were put in contact with the lips but it 

 never sought food. The picture in general was that 

 of profound imbecility, depression, and loss of certain 

 inhibitions. 



