Concepedia

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Changes in apparent body orientation and sensory localization induced by vibration of postural muscles: vibratory myesthetic illusions.

318

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References

1979

Year

TLDR

Vibrating postural muscles can induce illusory continuous body tilt and rotation, with the apparent pivot point modulated by touch and pressure cues, and visual motion matching the illusion when a light is present, illustrating how vibratory myesthetic sensations alter posture, sensory localization, and spatial orientation. The authors identified a “propriogyral illusion”—an illusory body and visual motion accompanied by compensatory nystagmus—that is eliminated by full illumination, shows a dissociation between displacement and velocity, and demonstrates that muscle afferent and touch‑pressure signals shape spatial orientation, visual localization, and oculomotor control.

Abstract

Illusions of continuous body tilt and rotation can be elicited by vibrating postural muscles of subjects standing in the dark. During such illusory motion, the apparent pivot point of the body can be influenced systematically by touch and pressure cues. Strong apparent movement is sometimes accompained by nystagmus of compensatory sign. If a small target light is visible during vibration, visual motion of like direction and velocity will accompany the illusory body motion. We have designated this pattern of apparent body and visual motion the "propriogyral illusion". Full room illumination abolishes both components of the propriogyral illusion. When the propriogyral illusion is being experienced, there is a dissociation between apparent displacement and apparent velocity; the extent of displacement is always less than would be expected on the basis of apparent velocity. The misconceptions of continuous body motion and the propriogyral illusion represent elements of a general set of vibratory myesthetic illusions that influence apparent posture, sensory, localization, and position sense of the body. These misconceptions demonstrate an important contribution of muscle afferent and touch-pressure information to the central mechanisms that determine apparent spatial orientation and visual localization. They also provide evidence that somatosensory information about orientation can influence oculomotor control.