title: Eye movements induced by linear acceleration are modified by visualisation of imaginary targets.
abstract: Lateral eye movement responses to linear acceleration in the lateromedial axis of the head have been examined in normal human subjects who were seated within a cabin, free to move on a horizontal linear track. The motion stimulus was either sinusoidal (0.2-0.8 Hz) or pseudo-random (0.11-1.25 Hz) in form, with a peak acceleration of 1.5 m.s-2. In darkness, while carrying out mental arithmetic, the mean ratio of slow-phase eye velocity to linear cart velocity increased from 2.8 degrees/m at 0.2 Hz to 10.5 degrees/m at 0.8 Hz during sinusoidal stimulation. When subjects were instructed to imagine a near head-fixed target in darkness, eye velocity decreased by 25%-48% during both sinusoidal and pseudo-random stimulation. When subjects were instructed to visualise an earth-fixed target during sinusoidal stimulation eye velocity was augmented by 47% when imagining a target 3 m distant and by 175% when visualising a target 0.6 m distant. Response augmentation was not as great during pseudo-random stimulation. The results indicate that the otolith-ocular response is highly modifiable by mental set.
authors.affiliation: R.A.F. Institute of Avitation Medicine, Farnborough, Hants, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Skipper
authors.forename: G R
authors.initials: GR
authors.lastname: Barnes
mesh_terms: D000054:Acceleration; D003624:Darkness; D004585:Electrooculography; D005133:Eye Movements; D006801:Humans; D009760:Nystagmus, Physiologic; D009903:Optical Illusions; D010037:Otolithic Membrane / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular; D012444:Saccule and Utricle / Q000502:physiology*; D014796:Visual Perception