Characteristics of the VOR in Response to Linear Acceleration

• Published in: Annals of the New York Academy of Sciences Vol. 871; no. 1; pp. 123 - 135
• Main Authors: PAIGE, GARY D., SEIDMAN, SCOTT H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.1999
• Subjects: Acceleration; Animals; Models, Biological; Posture - physiology; Reflex, Vestibulo-Ocular - physiology; Vestibule, Labyrinth - physiology; Vision, Ocular - physiology; Non-programmatic
• ISSN: 0077-8923; 1749-6632
• DOI: 10.1111/j.1749-6632.1999.tb09179.x

: The primate linear VOR (LVOR) includes two forms. First, eye‐movement responses to translation [e.g., horizontal responses to interaural (IA) motion] help maintain binocular fixation on targets, and therefore a stable bifoveal image. The translational LVOR is strongly modulated by fixation distance, and operates with high‐pass dynamics (>1 Hz). Second, other LVOR responses occur that cannot be compensatory for translation and instead seem compensatory for head tilt. This reflects an otolith response ambiguity‐that is, an inability to distinguish head translation from head tilt relative to gravity. Thus, ocular torsion is appropriately compensatory for head roll‐tilt, but also occurs during IA translation, since both stimuli entail IA acceleration. Unlike the IA‐horizontal response, IA torsion behaves with low‐pass dynamics (with respect to “tilt”), and is uninfluenced by fixation distance. Interestingly, roll‐tilt, like IA translation, also produces both horizontal (a translational reflex) and torsional (a tilt reflex) responses, further emphasizing the ambiguity problem. Early data from subjects following unilateral labyrinthectomy, which demonstrates a general immediate decline in translational LVOR responses, are also presented, followed by only modest recovery over several months. Interestingly, the usual high‐pass dynamics of these reflexes shift to an even higher cutoff. Both eyes respond roughly equally, suggesting that unilateral otolith input generates a binocularly symmetric LVOR.