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.