Anticipating the effects of visual gravity during simulated self-motion: Estimates of time-to-passage along vertical and horizontal paths

Iole Indovina, Vincenzo Maffei, Francesco Lacquaniti

Research output: Contribution to journalArticle

Abstract

By simulating self-motion on a virtual rollercoaster, we investigated whether acceleration cued by the optic flow affected the estimate of time-to-passage (TTP) to a target. In particular, we studied the role of a visual acceleration (1 g = 9.8 m/s2) simulating the effects of gravity in the scene, by manipulating motion law (accelerated or decelerated at 1 g, constant speed) and motion orientation (vertical, horizontal). Thus, 1-g-accelerated motion in the downward direction or decelerated motion in the upward direction was congruent with the effects of visual gravity. We found that acceleration (positive or negative) is taken into account but is overestimated in module in the calculation of TTP, independently of orientation. In addition, participants signaled TTP earlier when the rollercoaster accelerated downward at 1 g (as during free fall), with respect to when the same acceleration occurred along the horizontal orientation. This time shift indicates an influence of the orientation relative to visual gravity on response timing that could be attributed to the anticipation of the effects of visual gravity on self-motion along the vertical, but not the horizontal orientation. Finally, precision in TTP estimates was higher during vertical fall than when traveling at constant speed along the vertical orientation, consistent with a higher noise in TTP estimates when the motion violates gravity constraints.

Original languageEnglish
Pages (from-to)579-586
Number of pages8
JournalExperimental Brain Research
Volume229
Issue number4
DOIs
Publication statusPublished - Sep 2013

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Gravitation
Optic Flow
Noise

Keywords

  • Gravity
  • Horizontal
  • Self-motion
  • TTP
  • Vertical
  • Visual

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Anticipating the effects of visual gravity during simulated self-motion : Estimates of time-to-passage along vertical and horizontal paths. / Indovina, Iole; Maffei, Vincenzo; Lacquaniti, Francesco.

In: Experimental Brain Research, Vol. 229, No. 4, 09.2013, p. 579-586.

Research output: Contribution to journalArticle

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