Article Figures & Data
Figures
- Figure 1.
Stimuli. a, Apparent motion stimulus. A sinusoidal spiral grating was counterphased at 3–4 Hz (left), allowing for perceived motion in the clockwise and counterclockwise directions. However, in addition to these definite percepts of motion direction, participants also observed mixture percepts with no distinct motion direction during prolonged transitions, depicted here by stars (right). b, Binocular rivalry stimulus. When the two eyes are confronted with images that cannot be fused, such as red and green orthogonal gratings (left), they engage in binocular rivalry. The left and right eye image alternate in perception and prolonged transitions often take the form of a traveling wave crossing the stimulus, replacing one exclusive percept with the other.
- Figure 2.
Imaging results, transition-related and transition-duration-related brain activity. a, Areas responding more strongly to transitions in bistable apparent motion than to baseline activity. b, Areas responding more strongly to bistable apparent motion transitions of longer durations than to shorter ones. These regions strongly overlap with the regions responding more to transitions than to baseline. c, Areas responding more strongly to transitions in binocular rivalry than to baseline activity. d, Areas responding more strongly to binocular rivalry transitions of longer durations than to shorter ones. These regions again show strong overlap with the regions responding more to transitions than to baseline, although this overlap does not include DLPFC or insula for this stimulus.
- Figure 3.
a, Procedure. Left, Observers reported their ongoing perception of a binocular rivalry display. Right, After a short break, the reported time course was replayed on-screen to simulated perceptual transitions in one of two ways per run: as an almost instantaneous cross-fade regardless of reported duration (instantaneous replay) or as a traveling wave transition replacing one image with the other with the duration of the previously reported transition (duration-matched replay). b, Areas responding more strongly to endogenous transitions than to simulated transitions, replayed as near-instantaneous events. These regions strongly overlap with the regions responding more to transitions than to baseline (Fig. 2c) and are very similar to previous results (Lumer et al., 1998; Sterzer and Kleinschmidt, 2007). c, Areas responding more strongly to endogenous transitions than to duration-matched simulated transitions. Areas in parietal and frontal regions respond indistinguishably to endogenous and simulated transitions. d, Event-triggered averages from right frontal cortex for endogenous perceptual transitions, instantaneous replay transitions, and duration-matched replay transitions. The reason the contrast shown in c does not show frontal and parietal areas is that these event-triggered responses are almost identical.
- Figure 4.
Event-triggered results for binocular rivalry per anatomical ROI. Figure 3d gave a summary result for all relevant areas of the right frontal cortex; here we show the same result split out into more specific anatomical regions. The conclusion of Figure 3d holds for all areas within parietal and right frontal cortex. Note, however, that the event-triggered curves for areas V1–3 may seem at odds with the BOLD contrast of Figure 3c. Whereas the event-triggered curves depicted show a stronger signal for duration-matched replay than for actual binocular rivalry, the BOLD contrast between those conditions (Fig. 3c) revealed voxels in those areas for which the opposite is true. This apparent discrepancy appears to reflect different loci in these brain areas responding differently. Specifically, the activated voxels in Figure 3c correspond to a more foveal representation than the voxels that contribute importantly to the curves of V1–3 in the present plot. Like areas V1–3, extrastriate sensory areas medial temporal (MT) and lateral occipital complex (LOC) also appear to respond more strongly to our duration-matched replay condition than during rivalry. This tendency, although nonsignificant, might reflect the fact that rivalry and replay differ in the sensory stimulation provided. Error regions indicate SEM across observers.
Tables
x y z Max Z score p value (uncorrected) Right DLPFC 44 50 10 5.72 5.3 × 10−9 Right FEF 6 −2 56 5.08 1.9 × 10−7 Right TPJ 56 −40 26 5.26 7.2 × 10−8 Right IFG 56 18 12 4.97 3.3 × 10−7 Right/left SPL 0 −70 52 4.72 1.2 × 10−6 - Table 3.
Locations of peak Z-scores in binocular rivalry for transition > baseline, rivalry transition > instantaneous replay transition, and rivalry transition > duration-matched replay transition contrasts
x y z Max Z score p value (uncorrected) Transition > baseline Right IFG 52 12 14 4.80 7.9 × 10−7 Right TPJ 58 −46 46 4.96 3.5 × 10−7 Right MT 58 −64 −10 4.09 2.1 × 10−5 Right FEF 12 −2 60 4.68 1.4 × 10−6 Right DLPFC 38 54 22 4.82 7.2 × 10−7 Left central sulcus −40 −14 46 4.91 4.6 × 10−7 Rivalry transition > instantaneous replay transition Right IPS 12 −75 52 3.72 1.0 × 10−3 Right FEF 10 2 70 5.05 2.2 × 10−7 Right IFG 54 6 10 4.15 1.7 × 10−5 Right TPJ 54 −46 34 4.04 2.7 × 10−5 Right SPL 4 −62 58 4.80 7.9 × 10−7 Right DLPFC 46 30 34 4.22 1.2 × 10−5 Left insula −56 14 −2 4.18 1.5 × 10−5 Left SPL −4 −64 44 4.72 1.2 × 10−6 Left central sulcus −36 −24 52 4.90 4.8 × 10−7 Rivalry transition > duration-matched replay transition Right occipital 10 −82 8 4.22 1.2 × 10−5 Left occipital −8 −70 −4 4.37 6.2 × 10−6
