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Precision and accuracy of the subjective haptic vertical in the roll plane.
BMC Neurosci. 2010 Jul 14; 11:83.BN

Abstract

BACKGROUND

When roll-tilted, the subjective visual vertical (SVV) deviates up to 40 degrees from earth-vertical and trial-to-trial variability increases with head roll. Imperfections in the central processing of visual information were postulated to explain these roll-angle dependent errors. For experimental conditions devoid of visual input, e.g. adjustments of body posture or of an object along vertical in darkness, significantly smaller errors were noted. Whereas the accuracy of verticality adjustments seems to depend strongly on the paradigm, we hypothesize that the precision, i.e. the inverse of trial-to-trial variability, is less influenced by the experimental setup and mainly reflects properties of the otoliths. Here we measured the subjective haptic vertical (SHV) and compared findings with previously reported SVV data. Twelve healthy right-handed human subjects (handedness assessed based on subjects' verbal report) adjusted a rod with the right hand along perceived earth-vertical during static head roll-tilts (0-360 degrees , steps of 20 degrees).

RESULTS

SHV adjustments showed a tendency for clockwise rod rotations to deviate counter-clockwise and for counter-clockwise rod rotations to deviate clockwise, indicating hysteresis. Clockwise rod rotations resulted in counter-clockwise shifts of perceived earth-vertical up to -11.7 degrees and an average counter-clockwise SHV shift over all roll angles of -3.3 degrees (+/- 11.0 degrees ; +/- 1 StdDev). Counter-clockwise rod rotations yielded peak SHV deviations in clockwise direction of 8.9 degrees and an average clockwise SHV shift over all roll angles of 1.8 degrees (+/- 11.1 degrees). Trial-to-trial variability was minimal in upright position, increased with increasing roll (peaking around 120-140 degrees) and decreased to intermediate values in upside-down orientation. Compared to SVV, SHV variability near upright and upside-down was non-significantly (p > 0.05) larger; both showed an m-shaped pattern of variability as a function of roll position.

CONCLUSIONS

The reduction of adjustment errors by eliminating visual input supports the notion that deviations between perceived and actual earth-vertical in roll-tilted positions arise from central processing of visual information. The shared roll-tilt dependent modulation of trial-to-trial variability for both SVV and SHV, on the other hand, indicates that the perception of earth-verticality is dominated by the same sensory signal, i.e. the otolith signal, independent of whether the line/rod setting is under visual or tactile control.

Authors+Show Affiliations

Department of Neurology, Zurich University Hospital, Zurich, Switzerland.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

20630097

Citation

Schuler, Jeanine R., et al. "Precision and Accuracy of the Subjective Haptic Vertical in the Roll Plane." BMC Neuroscience, vol. 11, 2010, p. 83.
Schuler JR, Bockisch CJ, Straumann D, et al. Precision and accuracy of the subjective haptic vertical in the roll plane. BMC Neurosci. 2010;11:83.
Schuler, J. R., Bockisch, C. J., Straumann, D., & Tarnutzer, A. A. (2010). Precision and accuracy of the subjective haptic vertical in the roll plane. BMC Neuroscience, 11, 83. https://doi.org/10.1186/1471-2202-11-83
Schuler JR, et al. Precision and Accuracy of the Subjective Haptic Vertical in the Roll Plane. BMC Neurosci. 2010 Jul 14;11:83. PubMed PMID: 20630097.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Precision and accuracy of the subjective haptic vertical in the roll plane. AU - Schuler,Jeanine R, AU - Bockisch,Christopher J, AU - Straumann,Dominik, AU - Tarnutzer,Alexander A, Y1 - 2010/07/14/ PY - 2010/02/11/received PY - 2010/07/14/accepted PY - 2010/7/16/entrez PY - 2010/7/16/pubmed PY - 2010/9/16/medline SP - 83 EP - 83 JF - BMC neuroscience JO - BMC Neurosci VL - 11 N2 - BACKGROUND: When roll-tilted, the subjective visual vertical (SVV) deviates up to 40 degrees from earth-vertical and trial-to-trial variability increases with head roll. Imperfections in the central processing of visual information were postulated to explain these roll-angle dependent errors. For experimental conditions devoid of visual input, e.g. adjustments of body posture or of an object along vertical in darkness, significantly smaller errors were noted. Whereas the accuracy of verticality adjustments seems to depend strongly on the paradigm, we hypothesize that the precision, i.e. the inverse of trial-to-trial variability, is less influenced by the experimental setup and mainly reflects properties of the otoliths. Here we measured the subjective haptic vertical (SHV) and compared findings with previously reported SVV data. Twelve healthy right-handed human subjects (handedness assessed based on subjects' verbal report) adjusted a rod with the right hand along perceived earth-vertical during static head roll-tilts (0-360 degrees , steps of 20 degrees). RESULTS: SHV adjustments showed a tendency for clockwise rod rotations to deviate counter-clockwise and for counter-clockwise rod rotations to deviate clockwise, indicating hysteresis. Clockwise rod rotations resulted in counter-clockwise shifts of perceived earth-vertical up to -11.7 degrees and an average counter-clockwise SHV shift over all roll angles of -3.3 degrees (+/- 11.0 degrees ; +/- 1 StdDev). Counter-clockwise rod rotations yielded peak SHV deviations in clockwise direction of 8.9 degrees and an average clockwise SHV shift over all roll angles of 1.8 degrees (+/- 11.1 degrees). Trial-to-trial variability was minimal in upright position, increased with increasing roll (peaking around 120-140 degrees) and decreased to intermediate values in upside-down orientation. Compared to SVV, SHV variability near upright and upside-down was non-significantly (p > 0.05) larger; both showed an m-shaped pattern of variability as a function of roll position. CONCLUSIONS: The reduction of adjustment errors by eliminating visual input supports the notion that deviations between perceived and actual earth-vertical in roll-tilted positions arise from central processing of visual information. The shared roll-tilt dependent modulation of trial-to-trial variability for both SVV and SHV, on the other hand, indicates that the perception of earth-verticality is dominated by the same sensory signal, i.e. the otolith signal, independent of whether the line/rod setting is under visual or tactile control. SN - 1471-2202 UR - https://www.unboundmedicine.com/medline/citation/20630097/Precision_and_accuracy_of_the_subjective_haptic_vertical_in_the_roll_plane_ L2 - https://bmcneurosci.biomedcentral.com/articles/10.1186/1471-2202-11-83 DB - PRIME DP - Unbound Medicine ER -