A real explanation of induced rotary and vertical nystagmus should be definite as to the origins of the stimuli and the muscles stimulated. If such an explanation gives a consistent account of the phenomena, it may be accepted as dependable even though the exact neural connections are not yet demonstrated. In my proposed explanation, I shall start with the following assumption: Endolymph movement does occur, even though it consists in only a slight shift of the somewhat viscous fluid in the membranous semicircular canals; and such movement, bending the cupola and hair cells of the given crista toward or away from the canal, is the source of the stimulus to the eye muscle pairs which are known to contract in the slow or vestibular component of a nystagmus.
The endolymph movement theory of the production of nystagmus induced by rotation or douching gives a satisfactory account of horizontal nystagmus. No
FAVILL J. AN EXPLANATION OF THE MECHANISM OF INDUCED ROTARY AND VERTICAL NYSTAGMUS. Arch NeurPsych. 1925;13(4):479–489. doi:10.1001/archneurpsyc.1925.02200100058003
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