Modulation of human visual evoked potentials in 3-dimensional perception after stimuli produced with an integral imaging method.

We investigated the neurophysiological correlates of stereoscopic 3-dimensional (3-D) depth perception by studying human visual evoked potentials (VEPs) with an integral imaging method characterized by horizontal but not vertical disparity. The VEPs were recorded in 10 healthy men under 4 conditions. In condition I, stimuli A (flat, 2-dimensional [2-D] image) and B (concave 3-D image) were presented at random. In condition II, stimuli A and C (convex 3-D image) were presented at random. In condition III, stimuli B and C were presented at random. In condition IV, stimuli A, B, and C were presented at random. The data for flat VEPs to stimulus A were combined in conditions I and II. The data for concave VEPs to stimulus B were combined in conditions I and III. The data for convex VEPs to stimulus C were combined in conditions II and III. When 2-way analysis of variance (ANOVA) for 2 factors, stimulus conditions (flat VEPs, concave VEPs, and convex VEPs) and electrode positions, was applied for VEP data, the N1 and N2 peak amplitudes differed significantly among the 3 stimulus conditions. In condition IV, the N1 peak amplitudes differed significantly among the 3 stimuli. Multiple comparisons followed by Bonferroni adjustment did not detect differences in the N1 peak amplitude between stimuli A and B, between stimuli A and C, or between stimuli B and C. We concluded that VEPs to concave or convex 3-D stimuli were significantly different from VEPs to flat 2-D stimuli. This is the first report showing modulation of human VEPs in 3-D perception with an integral imaging method.

P1 and P2 components of human visual evoked potentials are modulated by depth perception of 3-dimensional images.

OBJECTIVE: To determine the cerebral activity correlated with depth perception of 3-dimensional (3D) images, by recording of human visual evoked potentials (VEPs). METHODS: Two figures consisting of smaller and larger squares were presented alternately. VEPs were recorded in two conditions. In condition I, we used two figures which yielded flat 2-dimensional images. In condition II, we used two figures which yielded 3D images, which were concave and convex, respectively. RESULTS: P1, P2, and N1/P2 amplitude were significantly greater in condition II than in condition I. The P1/N1 amplitude tended to be greater in condition II than in condition I. P1 and N1 were predominantly distributed over the right temporo-parieto-occipital regions. P2 and N2 were distributed over bilateral parieto-occipital regions. CONCLUSIONS: The difference in P1 amplitude between two conditions can be explained by the difference between conditions, one of which yielded depth perception while the other did not, since previous studies showed that P1 and N1 are modulated by perception of images in depth. The role of P2 and the mechanism responsible for the increase in P2 amplitude during condition II remain unknown. SIGNIFICANCE: We recorded VEPs and identified electrophysiological correlates of depth perception with 3D images produced by concave/convex figures.