Article Figures & Data
Figures
- Figure 1.
Binocular rivalry and its objective measures. A, Top, Left, OKN stimulus set consisting of two distinctly colored (red/green) sinusoidal gratings that drifted in opposite lateral directions (i.e., left/right). Bottom, Left, Idealized expected OKN patterns: direction of slow phase follows the perceived direction of motion. Right, Raw horizontal gaze speed (gray), smoothed OKN slow phase speed (black), and button presses (purple vertical lines) during a typical active report rivalry OKN trial. B, Top, Left, Pupil stimulus set consisting of two stationary sinusoidal gratings that differed in orientation (i.e., ±60°), color (red/green) and luminance. Bottom, Left, Example images from eye-tracking video with pupil detection, pupil size adapts to the perceived luminance. Right, Detrended pupil size (black) and button presses (purple vertical lines) during an exemplary active report rivalry pupil trial. C, D, Average OKN speed (mean and SEM over observer median traces; C) and average pupil size (D) across observers temporally aligned to the report of a perceptual transition. The horizontal black bars indicate time periods during which traces representing a perceptual switch from percept A to percept B differed significantly from traces representing a perceptual switch from percept B to percept A. The significance criterion was adjusted to an expected false discovery rate of 0.05 (Benjamini and Hochberg, 1995) to correct for multiple comparisons. E, Median dominance durations (i.e., the time period a single percept was visible until alternated for the competing percept) for OKN and pupil trials and for the different report conditions separately. sb - w, subjective with active report; ob - w, objective with active report; ob - wo, objective with passive viewing). Dominance durations indicated by both objective indicators were shorter than those indicated by subjective report. In addition, the switch rate tended to be increased when observers had to report perceptual alternations.
- Figure 2.
Binocular rivalry versus replay for active report trials. A, “Discrete subjective”: activation pattern shows neural loci that were more activated time-locked to the moment of a subjective report (i.e., button press) during rivalry trials compared with replay trials. R, right hemisphere; L, left hemisphere. B, “Discrete objective”: rivalry-related activation pattern (rivalry > replay) time locked to the moment of an objective alternation (i.e., zero-crossing of OKN or pupil size traces). C, “Continuous objective”: activation pattern indicates neural loci as revealed by the complete OKN and pupil-size traces. D, Pattern indicates neural loci where statistical power was significantly increased when using the “continuous objective” analysis compared with the “discrete subjective” analysis. Results in A–D are thresholded at a conservative cluster-extent threshold of p < 0.01, FWE corrected (voxel level threshold p < 0.001, uncorrected). All active report trials are included in the analyses regardless of whether OKN or pupil stimulus set was presented. Activation patterns were rendered onto the surface of a standard anatomical template image.
- Figure 3.
Influence of active report on the neural network underlying binocular rivalry. A, B, Activation patterns (based on the continuous objective analysis) show neural loci that were identified to be more activated time locked to a perceptual transition during rivalry compared with replay when observers actively reported their percept (A) or just passively experienced rivalry dynamics (B). Results in A and B are thresholded at a cluster-extent threshold of p < 0.01, FWE corrected (voxel level threshold p < 0.001, uncorrected). C, Pattern indicates neural loci where rivalry-related activation (i.e., rivalry > replay) was significantly higher during active report trials compared with passive viewing trials, regardless of the objective measure OKN speed or pupil size (i.e., global null conjunction analysis). Results in C are thresholded at p < 0.001, uncorrected.
Tables
- Table 1.
Coordinates and z-scores for transient rivalry-related activations (rivalry > replay) time locked to observers' button presses
Cortical region MNI coordinates z-score x y z Rivalry > replay (button presses) Right superior parietal 24 −66 46 6.03 Right superior occipital 26 −66 34 5.74 Right middle occipital 40 −82 14 5.72 Right superior frontal 28 −2 52 5.66 Right inf. oper. frontal 46 8 16 5.27 Right precentral 38 −2 50 5.23 Left middle occipital −38 −86 16 5.41 Left inferior occipital −52 −68 −8 4.83 Left cerebellum −26 −70 −24 5.05 Right inferior frontal 40 42 −4 4.47 Right middle frontal 38 36 32 4.32 Shown are loci where activation is greater during rivalry compared with replay. Only the most significant peaks within each area of activation are reported. All results are thresholded at a conservative cluster-extent threshold of p < 0.01, FWE corrected (voxel level threshold p < 0.001, uncorrected).
- Table 2.
Coordinates and z-scores show neural loci for which the continuous objective analysis revealed higher rivalry-related activations (rivalry > replay) when observers actively reported their perception compared with when they passively experienced rivalry
Cortical region MNI coordinates z-score x y z Active > passive (continuous objective analysis) Left superior frontal −20 4 60 4.31 Left suppl. motor area −6 12 50 3.74 Left middle occipital −20 −60 36 4.24 Left superior parietal −16 −58 48 3.98 Left middle frontal −36 32 24 4.24 Right insula 30 24 10 4.09 Left insula −28 22 12 4.06 Left middle temporal −44 −60 8 3.99 Right middle frontal 40 40 34 3.98 Right inferior frontal (tris.) 40 36 26 3.71 Right superior frontal 30 44 32 3.41 Left inferior parietal −52 −42 38 3.93 Right sup. medial frontal 8 24 48 3.91 Right middle occipital 32 −74 12 3.74 Right suppl. motor area 10 10 56 3.71 Right precuneus 8 −54 66 3.68 Left calcarine −26 −60 16 3.30 Loci were identified in terms of a global null conjunction analysis to control for any indicator-related artifacts. Therefore, the linear contrast “rivalry > replay” was calculated for each report and indicator condition in every observer separately. Those contrast images entered a random-effects group analysis in which the neural loci were assessed that had higher rivalry-related activation during active report compared with passive viewing trials regardless of rivalry type. Only the most significant peaks within each area of activation are reported and only clusters exceeding 20 voxels in size are reported. All results are thresholded at p < 0.001, uncorrected.
