Researchers identify spatial organization of color perception

[fafalone]

Perceiving color is a feat generally taken for granted, but now scientists have begun to identify what part of our brain is responsible for this amazing feat.

Publishing in the January 30th, 2003 issue of the British journal Nature, University of Texas-Houston Medical School researcher Youping Xiao and colleagues report on the organization of cells in the brain that respond to color. The experiment was carried out using macaque monkeys, whose blood flow to various areas of the brain was monitors while they were shown colors by using tracers injected into their system. The neurons were part of what are called cytochrome oxidase stripes. Multiple trials were conducted spaced several hours apart, in order to show the reliability of the results.

Previous experiments have been done that identified the neurons involved, but this experiment was the first to elucidate the spatial organization. The activity in response to color takes place in cortical area V2. There are a variety of types of neurons, each of which responds to a very specific hue. These neurons form bands for each color, and these are next to the bands for other colors each between 0.07mm and .32mm- violet, blue, cyan, green, yellow, orange, red, etc. This provides a color map, which, by the activity in each area, the peak is responsible for the color that you perceive. They discovered this as each area was activated in succession as the monkeys were shown the different colors. The order of the colors corresponds to their order in the DIN color system.

While the study was carried out in macaques, the researchers believe that the model for color perception in humans would be very similar.

The results of this experiment are quite significant. If prosthetic devices were made to stimulate the same areas of the brain, color vision could be restored to the blind. Currently, prosthetic visual systems that stimulate the brain directly are only capable of displaying monochrome outlines, so this experiment provides a glimpse of what the future of curing blindness will be.

[PogoC7]

Poor macaque monkeys. Hours of sitting in chairs. We don't thank the monkeys enough.

It's great that science is unlocking secrets about the brain (no need for lobonomy). Now, as a whole, let invision science without restraints such as War$$$$$$$$.

[fafalone]

Actually they did kill the monkeys to map where the tracers went.

[Giles]

Presumably this was done via blood flow measurement and some variant of resonant imaging, which is not neccesarily a good way of mapping brain activity.

 

The obvious next stage is to try stimulating these nerves, to see if they are the whole story even of the direct perceptual mechanisms.

 

I suspect in this case the research will be vindicated however

[fafalone]

It was done by post mortem locating of tracers in the blood. This method is superior to all other forms of measuring brain activity. fMRI certainly can't compete.