Spatio-Temporal Interpolation Is Accomplished by Binocular Form and Motion Mechanisms

Farid I Kandil,Markus Lappe

doi:10.1371/journal.pone.0000264

Abstract

Spatio-temporal interpolation describes the ability of the visual system to perceive shapes as whole figures (Gestalts), even if they are moving behind narrow apertures, so that only thin slices of them meet the eye at any given point in time. The interpolation process requires registration of the form slices, as well as perception of the shape's global motion, in order to reassemble the slices in the correct order. The commonly proposed mechanism is a spatio-temporal motion detector with a receptive field, for which spatial distance and temporal delays are interchangeable, and which has generally been regarded as monocular. Here we investigate separately the nature of the motion and the form detection involved in spatio-temporal interpolation, using dichoptic masking and interocular presentation tasks. The results clearly demonstrate that the associated mechanisms for both motion and form are binocular rather than monocular. Hence, we question the traditional view according to which spatio-temporal interpolation is achieved by monocular first-order motion-energy detectors in favour of models featuring binocular motion and form detection.

Highlights

Spatio-temporal interpolation is one of those integrative components underlying our visual experience so perfectly that one would hardly ever think that there is a problem at all
As in the critical dichoptic condition, subjects performed at chance level, results obtained here confirm the findings in experiment 1A in that monocular motion information does not contribute to spatio-temporal interpolation
Since we show here that both motion and form detection underlying spatio-temporal interpolation are binocular, we propose that the notion of analogy between spatio-temporal interpolation mechanisms and the monocular spatio-temporal motion-energy mechanisms / Reichardt detectors needs to be revised

Summary

Introduction

Spatio-temporal interpolation is one of those integrative components underlying our visual experience so perfectly that one would hardly ever think that there is a problem at all. Rather than seeing a series of successive narrow views of the car, all emerging spatially from the same slits in the fence, what we perceive is a car interpolated in space and time, i.e. a constantly visible unsegregated whole object [e.g. refs. Spatio-temporal receptive field theory assumes the existence of receptive fields oriented in space-time. The receptive fields would place the incoming slit-views into the correct order by means of internal computations rather than external eye movements. Despite their great differences, both theories rely on the correct detection of both form (the series of views) and motion direction in order to link neighbouring views in the right order. We investigate whether the underlying mechanism is monocular or binocular by probing the motion and form information it can use

Methods

Results

Discussion

Conclusion