Abstract
Vestibular-somatosensory interactions are pervasive in the brain but it remains unclear why. Here we explore the contribution of tactile flow to processing self-motion. We assessed two aspects of self-motion: timing and speed. Participants sat on an oscillating swing and either kept their hands on their laps or rested them lightly on an earth-stationary surface. They viewed a grating oscillating at the same frequency as their motion and judged its phase or, in a separate experiment, its speed relative to their perceived motion. Participants required the phase to precede body movement (with or without tactile flow) or tactile flow by ~5° (44 ms) to appear earth-stationary. Speed judgments were 4–10% faster when motion was from tactile flow, either alone or with body motion, compared to body motion alone (where speed judgments were accurate). By comparing response variances we conclude that phase and speed judgments do not reflect optimal integration of tactile flow with other cues to body motion: instead tactile flow dominates perceived self-motion – acting as an emergency override. This may explain why even minimal tactile cues are so helpful in promoting stability and suggests that providing artificial tactile cues might be a powerful aid to perceiving self-motion.
Highlights
It is important to know about our position and movement in space in order to maintain stability and to interact with the world
Placing the finger tips lightly on an oscillating bar induces body sway in a standing participant[14], which suggests a direct role for this kind of tactile flow in assessing body motion
We compared self-motion perception produced by body motion alone, self-motion perception signaled by tactile cues presented to a stationary observer, and self-motion perception produced by body motion in the presence of simultaneous tactile cues
Summary
It is important to know about our position and movement in space in order to maintain stability and to interact with the world. Many cells in the intra-parietal region of the monkey brain, an area thought to be critically involved in the perception of self-motion, receive substantial somatosensory information as well as vestibular and visual input[17, 18] Cells in this region often have large tactile receptive fields and are directionally selective for movement across the skin reminiscent of the large receptive fields of cells that process optic flow[19, 20]. The intra-parietal region is responsive to translational movement[21], the somatosensory responses of cells that are responsive to linear acceleration have not been explored Taken together, these observations suggest that tactile flow may contribute to our sense of self-motion. We measured the perceived time of reversal of sinusoidal oscillatory movement and the perceived speed of movement
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
