Plasticity of the human otolith-ocular reflex

Wall, C. 3rd; Smith, T. R.; Furman, J. M.

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NASA NTRS · 20050000821

Plasticity of the human otolith-ocular reflex

Wall, C. 3rd·Smith, T. R.·Furman, J. M.

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Abstract

The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

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Non-NASA Center NASA Discipline Neuroscience Photic Stimulation Semicircular Canals/physiology Reflex, Vestibulo-Ocular/physiology Male Support, U.S. Gov't, P.H.S Rotation Female Nystagmus, Physiologic/physiology Support, U.S. Gov't, Non-P.H.S Adaptation, Physiological Adult Human Darkness Motion Sickness/physiopathology Vision/physiology Eye Movements/physiology

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Wall, C. 3rd, Smith, T. R., Furman, J. M.. 1992-01-01. Plasticity of the human otolith-ocular reflex. https://ntrs.nasa.gov/citations/20050000821

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