Elsevier

Neuroscience

Volume 90, Issue 2, 22 February 1999, Pages 395-401
Neuroscience

Vestibular and vestibulo-proprioceptive perception of motion in the horizontal plane in blindfolded man—II. Estimations of rotations about the earth-vertical axis

https://doi.org/10.1016/S0306-4522(98)00449-7Get rights and content

Abstract

Perception of angular displacement in the horizontal plane was studied in blindfolded human subjects. Subjects sitting on a rotating chair were turned and turned themselves about the earth-vertical axis. Magnitudes of left- and rightward directed rotations were in steps of 30° and overlapped an entire circle. The averaged relative angular error in estimation of passive turns was 0.19±0.014 (M±m), that of active turns 0.16±0.011. Passively rotated subjects tended to overestimate turns with an increase in the rotation magnitude. Estimations of passive turns were linearly related to the turn magnitude (Y=−0.357+1.065X; R2=0.864). When turning themselves, subjects tended to overestimate rotations of lower magnitudes and underestimate those of higher magnitudes. Linearity was observed between estimations of active turns and their magnitude (Y=26.456+0.862X; R2=0.857). Turn estimation is regarded as a geometrical task, which associates subjectively defined angular and linear parameters of circular motion.

It is proposed that during rotation blindfolded subjects perceive the horizontal plane as a heterometric space, the extent of which depends on the estimation of a turn.

Section snippets

Experimental procedures

Eight subjects, 20–44-years old, six male and two female, without history of vestibular disease, participated in these experiments. Experiments were performed in a soundproof room immediately following the estimations of linear displacements in the horizontal plane described in a concomitant paper.

Blindfolded subjects, sitting upright on a turnable chair, were rotated about the earth-vertical axis (passive turn). The head, positioned on the axis, was supported by the back of the chair and

Estimations of passive turns

Data from passive turn estimations of all subjects in all trials are given in Fig. 1A, as a function of the turn magnitude. The regression line of this function revealed that in the range of rotations overlapping 360° a subjective turn estimation was related linearly to the turn magnitude with a fairly high coefficient of determination (R2=0.864). The intercept of this line had a negative value of −0.36, indicating only a slight tendency to underestimate turns with a decrease in their

Discussion

When perceiving rotation about the earth-vertical axis, the blindfolded subjects were not precise in their angular estimations. Errors in estimations of passive and active turns were not random, but revealed certain trends.

Passively rotated subjects tended to overestimate turns. It can be assumed the blindfolded subjects use subjective vestibular units of turn perception, which are greater than a real one. From the linear equation of the functional relationship between passive turn estimations

Conclusion

It can be proposed that angular errors in estimation of rotation about the earth-vertical axis have as a consequence an erroneous estimation of the linear parameters of the horizontal plane. In the case of a perfectly functioning detector of angular movement during rotation, subject should perceive the horizontal plane as a homogenous space extending uniformly in each direction, i.e. irrespective of the turn magnitude, subject has to estimate an aggregate of equidistant points in the horizontal

Acknowledgements

The author gratefully acknowleges technical assistance of Mrs Olga Sidorenko and is very grateful to Mrs Judith Dames for correction of the English text.

References (26)

  • C Gianna et al.

    Thresholds for detection of motion direction during passive lateral whole-body acceleration in normal subjects and patients with bilateral loss of labyrinthine function

    Brain Res. Bull.

    (1996)
  • F Hlavacka et al.

    Interaction of vestibular and proprioceptive inputs for human self-motion perception

    Neurosci. Lett.

    (1992)
  • J.S Barlow

    Inertial navigation as a basis for animal navigation

    Theor. Biol.

    (1964)
  • Benson A. J. (1974) Modification of the response to angular acceleration by linear accelerations. In Vestibular System,...
  • A.J Benson et al.

    European vestibular experiments on the Spacelab-1 mission: 4. Thresholds of perception of whole-body linear oscillation

    Expl Brain Res.

    (1986)
  • J Bloomberg et al.

    Adaptive modification of vestibularly perceived rotation

    Expl Brain Res.

    (1991)
  • J Bloomberg et al.

    Vestibular-contingent voluntary saccades based on cognitive estimates of remembered vestibular information

    Adv. Oto-rhino-lar.

    (1988)
  • J Blouin et al.

    Encoding the position of a flashed visual target after passive body rotations

    NeuroReport

    (1995)
  • G.A Bush et al.

    Encoding of head acceleration in vestibular neurons. I Spatiotemporal properties to linear acceleration

    J. Neurophysiol.

    (1993)
  • Guedry F. E. (1974) Psychophysics of vestibular sensation. In Vestibular System, Part 2: Psychophysics, Applied Aspects...
  • F.E Guedry et al.

    Comparison of subjective responses to semicircular canal stimulation produced by rotation about different axes

    Acta otolar.

    (1971)
  • F.E Guedry et al.

    Use of triangular waveforms of angular velocity in the study of vestibular function

    Acta otolar.

    (1970)
  • Igarashi M. (1966) Dimensional study of the vestibular end-organ apparatus. In 2nd Symposium on the Role of the...

    • Cited by (0)

    View full text
    Copyright © 1999 IBRO. Published by Elsevier Ltd. All rights reserved.