Neck muscle vibration in full cues affects pointing
Poster Presentation

Sarah McIntyre
School of Psychology, University of Sydney

Tatjana Seizova-Cajic
School of Psychology, University of Sydney

     Abstract ID Number: 3
     Full text: Not available
     Last modified: May 30, 2007
     Presentation date: 07/07/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
Vibration of the dorsolateral neck stimulates proprioceptors that are normally active during horizontal head movement; this induces a visual illusion of contralateral motion and displacement of a stationary target. Previous studies established that illusory motion occurs if the target is seen against a homogenous background, but absent or much reduced in a structured field; this surprisingly suggests that neck proprioception signals are suppressed in the normal environment. An alternative explanation is that previous research failed to find positive evidence due to experimental artifacts. We reasoned that the structured field that suppresses the motion illusion would not affect a body-centric localization task, because proprioceptive input is necessary for the transformation from a retinal into a body-centric reference frame. In the present study, vibration was applied to either side of the neck while observers pointed at the visual target with an unseen hand. Vibration of each side of the neck induced a contralateral pointing bias; importantly, this was the case in light as well as in darkness. Our results reveal the workings of a multimodal spatial constancy mechanism that takes into account neck proprioceptive signals to guide arm movements in full cues.