Gloss Or Not? How Monkeys Tell The Difference

How glossy a surface is can be defined by three parameters that are recognized in specific parts of the temporal context, scientists say.

AsianScientist (Sep. 29, 2014) – Scientists have pinpointed the neural pathways involved in recognizing gloss in monkeys. This research has been published in the Journal of Neuroscience.

The gloss of an object surface provides information about the condition of that object. For instance, whether it is wet or dry, whether food is fresh or old. Several gloss-related physical parameters such as specular reflectance and diffuse reflectance have been described and used in computer graphics so far. However, the parameters used when neurons respond to gloss have not yet been found.

A research group led by Hidehiko Komatsu, professor of the National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences (NINS), in collaboration with the Advanced Telecommunications Research Institute International (ATR) prepared 16 images representing various glosses and showed them to monkeys.

They then measured the monkeys’ responses to the different glosses in 39 neurons, using microelectrodes. They found that a specific population of neurons changed the intensities of the responses linearly according to either the contrast-of-highlight, sharpness-of-highlight, or brightness of the object. This shows that these three perceptual parameters are used by the brain to distinguish between a variety of glosses. The researchers were also able to identify which parameters were represented by each population of neurons.

In a circumscribed area in the inferior temporal cortex of the brain, neurons strengthened their responses proportionately as the contrast-of-highlight and/or sharpness-of-highlight got higher. Neural responses also vary greatly depending on the brightness, for instance, whether the object is black, gray, or white. Furthermore, the perceptual gloss parameters of the presented image could be fairly precisely predicted from the strengths of the population neural responses.

By applying these findings in an artificial image recognition system, the researchers expect that it would be able to develop robots that recognize gloss like humans do.

The article can be found at: Nishio et al. (2014) Perceptual Gloss Parameters Are Encoded by Population Responses in the Monkey Inferior Temporal Cortex.


Source: National Institutes of Natural Sciences.
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