Article

The aim of the study was to evaluate in standing subjects their perception of
whole-body rotation and spatial updating, and to determine whether the brain uses
mainly angular velocity or rotational duration to re-orient the body. Ten healthy
blindfolded adults stood barefoot on a horizontal rotating platform. Participants
had to maintain their balance while being passively rotated by a platform through
45 degrees , 90 degrees , 135 degrees , 180 degrees and 360 degrees , clockwise
(CW) and counter-clockwise (CCW). At the end of platform rotation, participants
had to give their estimation of the angle. They then had to actively reproduce it
in the opposite direction. Three different conditions were applied: one which
involved different peak cosinusoidal angular velocity profiles (18 degrees /s, 35
degrees /s, 53 degrees /s, 71 degrees /s and 141 degrees /s) at constant duration
of stimulus (4 s); one which involved different stimulus durations (1.25 s, 2.5
s, 3.75 s, 5 s and 10 s) at constant peak velocity (57 degrees /s); and one where
subjects had to reproduce a specific angle without prior stimulus imposed by the
platform. In the reproduction phase, results show overestimation of stimulus from
-180 degrees to 180 degrees in all three conditions; however, +/-360 degrees
rotations were underestimated only in the first two conditions. Comparing
stimulus perception and reproduction, the perceived angle corresponded to that
reproduced in the range from -180 degrees to 180 degrees ; however, +/-360
degrees angles were correctly perceived but inaccurately reproduced. Thus, the
interconnection between movement and information via the
vestibular/proprioceptive systems is essential to evaluate the body position in
space; however, the spatial errors show the key importance of sight in correcting
the errors caused by the cue integration.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS