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Visually guided adjustments of body posture in the roll plane.
Exp Brain Res. 2013 May; 227(1):111-20.EB

Abstract

Body position relative to gravity is continuously updated to prevent falls. Therefore, the brain integrates input from the otoliths, truncal graviceptors, proprioception and vision. Without visual cues estimated direction of gravity mainly depends on otolith input and becomes more variable with increasing roll-tilt. Contrary, the discrimination threshold for object orientation shows little modulation with varying roll orientation of the visual stimulus. Providing earth-stationary visual cues, this retinal input may be sufficient to perform self-adjustment tasks successfully, with resulting variability being independent of whole-body roll orientation. We compared conditions with informative (earth-fixed) and non-informative (body-fixed) visual cues. If the brain uses exclusively retinal input (if earth-stationary) to solve the task, trial-to-trial variability will be independent from the subject's roll orientation. Alternatively, central integration of both retinal (earth-fixed) and extra-retinal inputs will lead to increasing variability when roll-tilted. Subjects, seated on a motorized chair, were instructed to (1) align themselves parallel to an earth-fixed line oriented earth-vertical or roll-tilted 75° clockwise; (2) move a body-fixed line (aligned with the body-longitudinal axis or roll-tilted 75° counter-clockwise to it) by adjusting their body position until the line was perceived earth-vertical. At 75° right-ear-down position, variability increased significantly (p < 0.05) compared to upright in both paradigms, suggesting that, despite the earth-stationary retinal cues, extra-retinal input is integrated. Self-adjustments in the roll-tilted position were significantly (p < 0.01) more precise for earth-fixed cues than for body-fixed cues, underlining the importance of earth-stable visual cues when estimates of gravity become more variable with increasing whole-body roll.

Authors+Show Affiliations

Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland. alexander.tarnutzer@access.uzh.chNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23535837

Citation

Tarnutzer, A A., et al. "Visually Guided Adjustments of Body Posture in the Roll Plane." Experimental Brain Research, vol. 227, no. 1, 2013, pp. 111-20.
Tarnutzer AA, Bockisch CJ, Straumann D. Visually guided adjustments of body posture in the roll plane. Exp Brain Res. 2013;227(1):111-20.
Tarnutzer, A. A., Bockisch, C. J., & Straumann, D. (2013). Visually guided adjustments of body posture in the roll plane. Experimental Brain Research, 227(1), 111-20. https://doi.org/10.1007/s00221-013-3492-6
Tarnutzer AA, Bockisch CJ, Straumann D. Visually Guided Adjustments of Body Posture in the Roll Plane. Exp Brain Res. 2013;227(1):111-20. PubMed PMID: 23535837.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Visually guided adjustments of body posture in the roll plane. AU - Tarnutzer,A A, AU - Bockisch,C J, AU - Straumann,D, Y1 - 2013/03/28/ PY - 2012/09/21/received PY - 2013/03/14/accepted PY - 2013/3/29/entrez PY - 2013/3/29/pubmed PY - 2013/11/15/medline SP - 111 EP - 20 JF - Experimental brain research JO - Exp Brain Res VL - 227 IS - 1 N2 - Body position relative to gravity is continuously updated to prevent falls. Therefore, the brain integrates input from the otoliths, truncal graviceptors, proprioception and vision. Without visual cues estimated direction of gravity mainly depends on otolith input and becomes more variable with increasing roll-tilt. Contrary, the discrimination threshold for object orientation shows little modulation with varying roll orientation of the visual stimulus. Providing earth-stationary visual cues, this retinal input may be sufficient to perform self-adjustment tasks successfully, with resulting variability being independent of whole-body roll orientation. We compared conditions with informative (earth-fixed) and non-informative (body-fixed) visual cues. If the brain uses exclusively retinal input (if earth-stationary) to solve the task, trial-to-trial variability will be independent from the subject's roll orientation. Alternatively, central integration of both retinal (earth-fixed) and extra-retinal inputs will lead to increasing variability when roll-tilted. Subjects, seated on a motorized chair, were instructed to (1) align themselves parallel to an earth-fixed line oriented earth-vertical or roll-tilted 75° clockwise; (2) move a body-fixed line (aligned with the body-longitudinal axis or roll-tilted 75° counter-clockwise to it) by adjusting their body position until the line was perceived earth-vertical. At 75° right-ear-down position, variability increased significantly (p < 0.05) compared to upright in both paradigms, suggesting that, despite the earth-stationary retinal cues, extra-retinal input is integrated. Self-adjustments in the roll-tilted position were significantly (p < 0.01) more precise for earth-fixed cues than for body-fixed cues, underlining the importance of earth-stable visual cues when estimates of gravity become more variable with increasing whole-body roll. SN - 1432-1106 UR - https://www.unboundmedicine.com/medline/citation/23535837/Visually_guided_adjustments_of_body_posture_in_the_roll_plane_ L2 - https://dx.doi.org/10.1007/s00221-013-3492-6 DB - PRIME DP - Unbound Medicine ER -