Brain may ‘see’ more than the eyes, study indicates

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(Medical Xpress)—Vision may be less important to “seeing” than is the brain’s ability to process points of light into complex images, according to a new study of the fruit fly visual system currently published in the online journal Nature Communications.


University of Virginia researchers have found that the very simple eyes of fruit fly larvae, with only 24 total photoreceptors (the contains more than 125 million), provide just enough light or to allow the animal’s relatively large brain to assemble that input into images.

“It blows open how we think about vision,” said Barry Condron, a in U.Va.’s College of Arts & Sciences, who oversaw the study. “This tells us that visual input may not be as important to sight as the brain working behind it. In this case, the brain apparently is able to compensate for the minimal visual input.”

Condron’s graduate students, Elizabeth Daubert, Nick Macedonia and Catherine Hamilton, conducted a series of experiments to test the vision of fruit fly larvae after they noticed an interesting behavior of the animals during a different study of the nervous system. They found that when a larva was tethered to the bottom of a petri dish, other larvae were attracted to it as it wiggled attempting to free itself.

The animals apparently saw the writhing motion and were attracted to it, willingly traveling toward it. After several further experiments to understand how they sensed the motion, the researchers learned that the nearly blind animals were seeing the action, by wagging their heads side-to-side in a scanning motion to detect it, rather than by only hearing it or feeling vibration or by smelling the trapped larva. This was a surprise because of the very simple and limited vision of fruit fly larvae.

Written By: Fariss Samarrai – Medical Xpress
continue to source article at medicalxpress.com

11 COMMENTS

  1. Interesting as the article is, you’ve got it here.  Perception researchers have long known that the brain can fill in details and focus on specific incoming data according to inbuilt assumptions and biases.  It’s got to solve the literally unsolvable problem of reverse optics.  Prosopagnostics, for instance, see virtually the same as everyone else, but because of brain configurations they lack the ability to recognize faces.

    So if humans, why not maggots?

  2. I immediately thought of a case in which a young person could not *report* seeing anything, but some clever testing showed that s/he had nevertheless taken in visual information and acted upon it.  It may have involved navigating a path with obstacles – I don’t recall exactly.

  3. I was getting a feeling of” nothing to see here” (sorry) as I read the article. It wasn’t until I got near the end that I spotted what was novel.
     For me at least, I haven’t come across the idea of visual images being built up over several passes of incoming light, rather than light comes in brain makes image. It’s a subtle difference, but like all good science pretty obvious in hindsight.

    Greg

  4. An interesting experiment to do about that : Take 2 persons (or things) a few feet apart.  When you look at one, you can hardly distinguish the other one in the corner of your eye. If you look at the second one, then again you can’t really see the first one (you kind of guess it’s there, but you can’t know if they’re smilling or looking away, etc.). Now, move quickly your eyes from one to the other, back and forth, a few times. You now think you are seeing them both at the same time together, even though you just have proven you technically can’t.

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