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Biotech Science

Cells In the Retina Tile Like Puzzle Pieces 29

Posted by timothy
from the rather-than-scrabble-tiles dept.
tim writes "Recent work at the Salk Institute in La Jolla, Calif. shows that cells in the retina sample visual space like a multi-layered jigsaw puzzle. High resolution measurements of light response reveal that individual cells have irregular shapes, but together their shapes coordinate to tightly cover visual space. This type of large scale, exquisite coordination could be a general organizing principle of the brain, but no one has seen it previously because technical obstacles typically prevent recording from large cell populations." Here's a link to full paper.
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Cells In the Retina Tile Like Puzzle Pieces

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  • Puzzle Pieces (Score:4, Informative)

    by Jack9 (11421) on Wednesday April 08, 2009 @12:48PM (#27506329)

    Fits together like puzzle pieces? I think the dames call it "Tessalation"

    http://en.wikipedia.org/wiki/Tessellation [wikipedia.org]

  • I cannot see the big breakthrough here. For example, the corneal endothelium [wikipedia.org] also fits like a puzzle. The cells are responsible for pumping water out of the cornea. That only works properly when all cells coordinate to cover the entire back-surface. When a cell dies, then other cells will migrate and change shape to fill the gap. Cells do die as cell concentration decreases with age.
    • by interkin3tic (1469267) on Wednesday April 08, 2009 @01:07PM (#27506589)

      I think the breakthrough here is not that the cells themselves fit together but that the individual fields they each sense are coordinated. Like one cell type senses a field that is circle shaped, the one right next to it, if it sensed a circle, would have overlap and would cause imaging problems, instead the cell right next to it senses a crescent shape, fitting with the one next to it to avoid overlap.

      FTA

      These regions fit together like pieces of a puzzle, preventing "blind spot" and excessive overlap that could blur our perception of the world.

      How the cells come together is regulated but it still isn't like pixels, the junctions between the cells are not a perfect grid, there are irregularities. The cells compensate for that. I haven't read in depth but that seems to be the gist.

      • by Chris Burke (6130)

        How the cells come together is regulated but it still isn't like pixels, the junctions between the cells are not a perfect grid, there are irregularities. The cells compensate for that. I haven't read in depth but that seems to be the gist.

        I know you're correct without reading the article, since I've seen the grid of my own optic cells myself in all its organic beauty -- the term 'grid' is still useful if you don't assume straight Cartesian lines separating rows and columns but rather swooping arcs and spir

        • by fractoid (1076465)
          I got grids of octarine elephants on a sphere rotating around a giant octarine elephant which was rotating the other way, myself.

          I'd always wondered about the tiny specks you can see when you look at a solid, bright background for a while, turns out they're white blood cells moving through the vessels that supply your retina. Cool, huh? :)
      • by fractoid (1076465)

        Like one cell type senses a field that is circle shaped, the one right next to it, if it sensed a circle, would have overlap and would cause imaging problems, instead the cell right next to it senses a crescent shape, fitting with the one next to it to avoid overlap.

        It looks to me more like a case of "random shaped squishy things squish together with no gaps". I'd say you have cause and effect mixed a little here - the crescent-sensing cells aren't crescent-sensing because they go "there's a circle next to me so I ought to check for crescents to improve the accuracy of the retina as a whole". They go "I'm squished into a crescent shape, so I'll naturally give a stand-out signal when a light pattern the same shape as me shines on me". The interesting question is how the

  • by Anonymous Coward

    They talk about an exquisite coordination that is finely tuned to prevent blind spots while avoiding overlap.

    Perhaps it is more like cells with random variation simply growing outward until reaching a neighboring cell at which point some chemical signaling occurs to establish a mutual border.

    Or maybe a time lapse of cell cultures would show an ever changing chemical war fighting over the borders like neighboring corals do.

    A system like this should provide maximal coverage with minimal overlap with no exquis

    • by Ichoran (106539) on Wednesday April 08, 2009 @02:39PM (#27508109)

      The output cells of the retina use inputs from lots of primary detector cells (rods and cones) through several layers. They also do not fill space, but send slender processes around contacting neighbors.

      Whether it's cooperative coordination or some sort of competition, it is exquisite in that this is not something that is obviously easy to coordinate (unlike cells growing in a sheet which tile space because they get in each others' way).

  • by Anonymous Coward

    That sounds so complex, it's almost as if it could only have been created by god. ...

    (I'm kidding. Please be gentle!)

    • by Timberwolf0122 (872207) on Wednesday April 08, 2009 @01:29PM (#27506949) Journal
      God lives in my pocket, it's the only way I can explain how a simple piece of straight string can tie it's self into such a complex ball of knots, Kent Hovind told me that extra information (such as knots) can't form naturally and adding energy (by say walking) is destructive ergo god is in my pocket tangling all my strings. Bastard.
      • by Mozk (844858)

        Honestly, how do earbuds get tangled up into knots so badly after only five minutes in a bag?

    • by fractoid (1076465)
      For some reason this made me think of a scene from The Flight of Mavin Manyshaped [librarything.com], where a member of a village built in a huge chasm is told by an outsider that the wind in the chasm is caused by a glacier at one end and a desert at the other (hot and cold source generating a convection current). The villager had always believed that his god caused the wind to blow to clear smoke out of the village.

      The outsider politely smiles and nods, then shrugs to herself and thinks that if god wanted to clear the smo
  • by phantomcircuit (938963) on Wednesday April 08, 2009 @01:07PM (#27506581) Homepage

    What is this?

    Not only is there a link directly to the article, but there is a link to the actual paper!?

  • In spanish that eye disease is called cataratas, and that word can be translated too to waterfalls. When read about a puzzle in the eye, tetris was my 1st idea with that in mind.
  • Will this type of thing be of any use in fixing that problem people have with color?
  • I hate to say it but the fact that our vision system has complete coverage over the visual field is so f**ing obvious and has been shown so often before that there should be little need to do yet more research on that subject.

    What is really valuable and novel about this research?

  • you're eye is just organically attracted, narcissistically, to patterns that resemble itself

    beauty is in the eye of the beholder

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