Vestibular Direction Detection Thresholds in the Horizontal Plane

The perception of translational movements is an important part of selfmotion perception. We investigate how our vestibular system, specifically the otoliths which are responsible for detecting linear movements, processes such motion signals. This helps us to understand how we can provide a participant with directional motion cues on a motion simulator that are either not perceived or, on the other hand, correctly perceived but with a minimum amount of actual displacement.
Participants are blindfolded and are being moved either forward, backward, left or right (Figure 1). Afterwards they are asked to state the direction in which they felt the motion. By varying the amplitude of the movement, we can measure the direction detection thresholds and understand how these depend on several parameters, such as duration and shape of the motion profile. We found that the perception is not only dependent on the amplitude of the acceleration, but also on the rate of change of acceleration, namely the jerk.
The dynamics of the otolith system can be described with a linear model based on physiological considerations. By resorting to this model, we can predict the perceptual thresholds within a certain frequency range of movements with arbitrary shapes. Our results suggest that for lower frequencies humans are more sensitive to jerky movements compared to previous studies.


Soyka F Person (August-12-2009) Invited Lecture: Does jerk have to be considered in linear motion simulation?, AIAA Modeling and Simulation Technologies Conference 2009, Chicago, IL, USA.
CiteID: 6032

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Last updated: Friday, 05.10.2012