Citation

Panic H, Panic AS, DiZio P, Lackner JR. J. Neurophysiol. 2015; 113(10): 3600-3609.

Affiliation

Brandeis University lackner@brandeis.edu.

Copyright

(Copyright © 2015, American Physiological Society)

DOI

10.1152/jn.00737.2014

PMID

25761954

Abstract

We examined whether the direction of balance rather than an otolith reference determines the perceived upright. Participants seated in a device that rotated around the roll axis used a joystick to control its motion. The device's direction of balance, the location where it would not be accelerated to either side, could be offset from the gravitational vertical, a technique introduced by Riccio, Martin, and Stoffregen (1992). Participants used the joystick to align themselves in different trials with the gravitational vertical, the direction of balance, the 'upright', or the direction that minimized oscillations. They pressed the joystick trigger whenever they thought they were at the instructed orientation. Achieved angles for the "align with gravity" and "align with the upright" conditions were not different from each other and were significantly displaced past the gravitational vertical opposite from the direction of balance. Mean indicated angles for "align with gravity" and "align with the upright" coincided with the gravitational vertical. Both mean achieved and indicated angles for the "minimize oscillations" and "align with the direction of balance" conditions were significantly deviated towards the gravitational vertical.. Three control experiments, requiring self-settings to instructed orientations only, perceptual judgments only, and perceptual judgments during passive exposure to dynamic roll profiles confirmed that perception of the upright is determined by gravity, not by the direction of balance.

Language: en