Orientation detectors in insects
Article Abstract:
Studies of the mechanism for visual orientation in bees and dragonflies is discussed. One study showed that bees readily distinguish between a pattern of stationary horizontal stripes from a similar pattern of vertical stripes, indicating the presence of neurons for spatial pattern detection. Another study reports the discovery in the optic lobe of dragonflies of a new class of neurons which is similar to the simple cells of the mammalian visual cortex in that they respond optimally to elongated bars of a specific orientation. These results suggest that insects are acpable of very complex visual tasks inspite of their tiny brains.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Three-dimensional illusory contours and surfaces
Article Abstract:
Visual information about the shape, position and orientation of an object can be conveyed by stereoscopic viewing or by cues from motion parallax. This holds for illusory objects as well as real ones. Both kinds of object are perceived to retain their shape when viewed from different positions and orientations. In the case of illusory objects, the representation of three-dimensional geometry is constructed from partial cues. This suggests that some neurons in the visual system may select three-dimensional geometric information.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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Speed of processing in the human visual system
Article Abstract:
The visual processing necessary to recognize whether a previously unseen photograph flashed for just 20 ms shows an animal takes less than 150 ms. Event-related potential analysis of the go/no-go categorization task indicates a frontal negativity for no-go trials that forms 150 ms after the stimulus begins. No-go specific activity indicates that processing in the visual system is complete. The capacity for complex image analysis in such a short time indicates that the visual system is based on feed-forward mechanisms.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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