Inference by sampling in a model of ambiguous visual perception

Certain visual inputs can be consistently interpreted in more than one way. One classic example of this is the young-woman/old-woman puzzle: An important finding related to these types of illusions is that we don’t perceive both possibilities at once, but rather switch spontaneously between them. Buesing et al.’s recent study formalized a network model of spiking [...]

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A top-down feedback system in vision

That is the focus of an interesting article called “Top-Down Predictions in the Cognitive Brain” from the journal Brain and Cognition. The authors summarize various models pertaining to how inputs from the retinas are transferred to high level areas in the brain. They first draw attention to how complex and fast-moving our visual processes must [...]

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Carbon nanotubes as an interface for retinal implants

Shoval et al recently tested the efficacy of TiN electrodes, fabricated on oxidized silicon substrates and coated with multi-wall carbon nanotubes, as a multielectrode array for the treatment of retinal degeneration. Vision loss due to retinal degradation is common, but since the output retinal ganglion cells remain intact, it has been suggested that a retinal [...]

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Mechanism for neural attenuation in attentional blink

If humans see two objects in quick succession (less than 700 ms), they are only able to focus on one of them. This phenomenon is a specific type of the more general “information processing bottleneck” found in many cognitive systems. Prior research has suggested that this deficiency in human processing is due to “later” mechanisms [...]

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An ideal observer model for grating illusions

Weiss, Simoncelli, and Aldeson’s 2002 paper Motion Illusion as Optimal Percepts sets out a useful model to explain a few of the inconsistencies in human vision. First, some background on a couple of these inconsistencies. The aperture problem results when parallel lines move along a two dimensional slit. You can view an animation of it [...]

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Percieved speed varies based on visual contrast

At lower speeds, an object moving through a background with less contrast will appear slower. At around 8 Hz, percieved speed is not affected by contrast. And at higher speeds, reducing contrast will result in overestimation of speed. That is, the perceieved speed of the object will increase. That’s the thrust of the research by [...]

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