Perceptual Integration for Qualitatively Different 3-D Cues in the Human Brain

Abstract

The visual system's flexibility in estimating depth is remarkable: we readily perceive threedimensional (3D) structure under diverse conditions from the seemingly random dots of a 'magic eye' stereogram to the aesthetically beautiful, but obviously flat, canvasses of the Old Masters. Yet, 3D perception is often enhanced when different cues specify the same depth. This perceptual process is understood as Bayesian inference that improves sensory estimates. Despite considerable behavioral support for this theory, insights into the cortical circuits involved are limited. Moreover, extant work tested quantitatively similar cues, reducing some of the challenges associated with integrating computationally and qualitatively different signals. Here we address this challenge by measuring functional MRI responses to depth structures defined by shading, binocular disparity and their combination. We quantified information about depth configurations (convex 'bumps' vs. concave 'dimples') in different visual cortical areas using patternclassification analysis. We found that fMRI responses in dorsal visual area V3B/KO were more discriminable when disparity and shading concurrently signaled depth, in line with the predictions of cue integration. Importantly, by relating fMRI and psychophysical tests of integration, we observed a close association between depth judgments and activity in this area. Finally, using a cross-cue transfer test, we found that fMRI responses evoked by one cue afford classification of responses evoked by the other. This reveals a generalized depth representation in dorsal visual cortex that combines qualitatively different information in line with 3D perception.

Effects of surface reflectance on local second order shape estimation in dynamic scenes

“…Large inter-observer variability in shape perception studies has been pointed out before (Wagemans, van Doorn, & Koenderink, 2010;Dövencioglu et al, 2013) and has, in part, been explained by differences in observers' priors (e.g. light from above Mamassian & Goutcher, 2001;Sun & Perona, 1998;Ramachandran, 1988;or convexity Langer & Bulthoff, 2001) 5 .…”

The Human Brain in Depth: How We See in 3D

“…V3B/KO shows evidence for fusion. (d ) Stimuli and results from Dövencioglu et al (2013). V3B/KO was again implicated in fusion, with perceptual differences between participants reflected in differences in patterns of brain activity.…”

“…They found that V3B/KO produced fMRI responses that matched the expectations of cue fusion: When disparity and texture both signaled slant performance they exceeded the quadratic sum prediction, and this result was specific to congruent combinations of cues (Figure 10c). Dövencioglu et al (2013) examined the combination of shading and disparity cues that depicted curved surfaces. They again found evidence for fusion in V3B/KO and that this activity was linked to psychophysical judgments (Figure 10d ).…”

White matter dissection and structural connectivity of the human vertical occipital fasciculus to link vision-associated brain cortex

“…For instance, saccade planning evokes cortical activity in both the dorsal (V3A/B, IPS0) and ventral visual areas (hV4, VO-1) in functional MRI (fMRI) study 17 . The dorsal visual cortex is strongly engaged by three-dimensional (3D) perception cooperating with the ventral visual cortex [18][19][20] . These functional findings suggest the significance of the interaction between the two visual streams, which is to be revealed by not only neuroimaging methods but also white matter dissection.…”