Depth perception from moving cast shadow in macaque monkey

Mizutani, Saneyuki; Usui, Nobuo; Yokota, Takanori; Taira, Masato; Katsuyama, Narumi

doi:10.1016/j.bbr.2015.04.005

Cited by 2 publications

(3 citation statements)

References 27 publications

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“…The moving cast shadow was presented in catch trials in which binocular disparity was not available as a depth cue because it was either too small or static. The monkey produced the same responses in the catch trials as in the trials with the binocular disparity cue, indicating that it was able to discriminate the motion direction in depth based on the 2D motion of the cast shadow [48]. This finding will enable us to conduct future investigations of the detailed neuronal mechanisms underlying motion perception in three-dimensional space.…”

Section: Discussionmentioning

confidence: 96%

Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

2016

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A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity.

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Section: Discussionmentioning

confidence: 96%

Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

2016

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“…Cast shadows can be visually perceived as shadows by other animals (Mizutani et al, 2015;Yonas and Granrud, 2006). When presented with a long cast shadow produced by a side light on the tall 3D cylinders, the cuttlefish chose a camouflage pattern that was the same as the one they produced over a completely flat 2D image of white circles and printed black virtual replicates of the shadows (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…They speculate that chimpanzees see shadows as separate from the objects that cast them, and not as a depth cue. However, macaques do appear to recognise real cast shadowsand depth information from the shadowswhen the shadows are moving (Mizutani et al, 2015). It is therefore interesting to ask whether cuttlefish use real stationary cast shadows of 3D objects, as well as virtual cast shadows, as a depth cue or whether they visualise them as something else.…”

Section: Introductionmentioning

confidence: 99%

Visual perception and camouflage response to 3D backgrounds and cast shadows in the European cuttlefish, Sepia officinalis

Nagar

Osorio

Zylinski

et al. 2021

Journal of Experimental Biology

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To conceal themselves on the seafloor European cuttlefish Sepia officinalis express a large repertoire of body patterns. Scenes with 3-D relief are especially challenging because neither is it possible to directly recover visual depth from the 2-D retinal image, nor for the cuttlefish to alter its body shape to resemble nearby objects. Here we characterise cuttlefish's camouflage responses to 3-D relief, and to cast shadows, which are complementary depth cues. Animals were recorded in the presence of cylindrical objects of fixed (15mm) diameter, but varying in height, greyscale and strength of cast shadows, and to corresponding 2-D pictorial images. With the cylinders the cuttlefish expressed a ‘3-D’ body pattern, which is distinct from previously described Uniform, Mottle, and Disruptive camouflage patterns. This pattern was insensitive to variation in object height, contrast, and cast shadow, except when shadows were most pronounced, in which case the body patterns resembled those used on the 2-D backgrounds. This suggests that stationary cast shadows are not used as visual depth cues by cuttlefish, and that rather than directly matching the 2-D retinal image, the camouflage response is a two-stage process whereby the animal first classifies the physical environment and then selects an appropriate pattern. Each type of pattern is triggered by specific cues that may compete allowing the animal to select the most suitable camouflage, so the camouflage response is categorical rather than continuously variable. These findings give unique insight into how an invertebrate senses its visual environment to generate the body pattern response.

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Depth perception from moving cast shadow in macaque monkey

Cited by 2 publications

References 27 publications

Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

Visual perception and camouflage response to 3D backgrounds and cast shadows in the European cuttlefish, Sepia officinalis

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