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 mi BIBLIOGRAPHIC) IBRVICE, hi i-iim hi i; '.''.I 



EXPERIMENTAL STUDIES OIS rill': BRAIN STEM 



11. COMPARATIVE STUD'S OF THE RELATION OF THE CEREBRAL 

 CORTEX TO VESTIBULAR NYSTAGMUS 



A. C IVY 

 Hull Physiological Laboratory, '/'//<■ University of Chieago 



M \K FIGl l.i 



During the course of a study involving a scries of eerebral 



ablations, it was suggested by Dr. F. T. Rogers that observa 

 tious be made upon the nystagmus reaction. Wilson ami Pike 



('II, '13, 'lo) are of the opinion that the quick component of 



nystagmus is dependent upon the integrity oi a oerebral reflex 



arc. Pike ('17) reports that removal of one cerebral hemisphere 

 abolishes the quick movement when the slow movement of the 

 eyes is directed to the side of the remaining cerebral hemisphere. 

 On the other hand, llauer and I eidler t ' I I ) report that the quick 



componenl of vestibular nystagmus is not dependent upon the 

 oerebral cortex and that "extirpation of the cerebrum, thalamus, 



even extensive desl ruct ion of t he midbrain and probably with t he 

 inclusion of the oculomotor nucleus does not disturb vestibular 

 nystagmus." Hence there is quite a discrepancy between the 

 reports of the two groups of investigators whioh has stimulated 

 this study. 



METHODS 



FrOgS, turtles, pigeons, rabbits, kittens, cats, pups, and dogs 

 were studied. All operations upon mammals were done under 



aseptic conditions. Observations were made before and a1 dil 

 ferent periods following the operation. When the animals were 



comatose, or markedly depressed, or showed symptoms ol in 



oreased intracranial pressure, a notation of such a condition 



Was made. Autopsy was done upon every animal and the brain 

 w as preserved. 



1 



