Stereoscopic depth increases intersubject correlations of brain networks

Michael Gaebler,Felix Biessmann,Jan-Peter Lamke,Klaus-Robert Müller,Henrik Walter,Stefan Hetzer

doi:10.1016/j.neuroimage.2014.06.008

Abstract

Three-dimensional movies presented via stereoscopic displays have become more popular in recent years aiming at a more engaging viewing experience. However, neurocognitive processes associated with the perception of stereoscopic depth in complex and dynamic visual stimuli remain understudied. Here, we investigate the influence of stereoscopic depth on both neurophysiology and subjective experience. Using multivariate statistical learning methods, we compare the brain activity of subjects when freely watching the same movies in 2D and in 3D. Subjective reports indicate that 3D movies are more strongly experienced than 2D movies. On the neural level, we observe significantly higher intersubject correlations of cortical networks when subjects are watching 3D movies relative to the same movies in 2D. We demonstrate that increases in intersubject correlations of brain networks can serve as neurophysiological marker for stereoscopic depth and for the strength of the viewing experience.

Highlights

Because of the horizontal separation of the eyes in the head, each eye receives slightly different images of the world
In order to find brain networks of activation that are common to all subjects, we introduce the canonical intersubject correlation coefficient (CISC), a multivariate extension of the voxel-wise intersubject correlation measures previously used for analysis of brain activation evoked by complex movie stimuli (Hasson et al, 2004)
Subjective reports of immersion indicate that stereoscopic movies are experienced more strongly than the same movies in 2D

Summary

Introduction

Because of the horizontal separation of the eyes in the head, each eye receives slightly different images of the world. It enables us to perceive stereoscopic depth and to experience three-dimensional space (Parker, 2007). This perceptual phenomenon has been used to induce an illusion of depth by presenting two offset images separately to each eye (Crone, 1992; Wheatstone, 1838). The presentation of moving images increasingly employs stereoscopic depth and 3D stimuli have entered television, computer games, and cinema and professional environments for human–machine interaction. The addition of stereoscopic depth to visual stimuli aims at approximating everyday-life visual perception, that is, at increasing how realistic a stimulus is. A reduction of sensory differences between artificial stimuli and the physical environment leads to a more engaging viewing experience

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Results

Conclusion