Garden of Eyewire: Fractal Hunt

Why do neurons have dendrites, anyway? How do dendrites get that name? Well, dendrite comes from a Greek root for “tree.” You might notice how we talk about cell branches on Eyewire, too. And it all seems very fitting, because lots of neurons grow in shapes and patterns that can remind us of bare tree limbs, branches, and twigs.

The similarity is so close that a seasoned Eyewirer can have trouble looking at real trees without seeing neurons! But why have these two completely separate parts of life on Earth evolved to share this resemblance? After all, neurons aren’t plant cells, and as far as anyone can tell, plants don’t have nerves.

We can find the answer to this mystery in mathematics, specifically the mathematical field of fractal geometry. A fractal pattern is a recursively self-similar shape where the same pattern can often be viewed again and again, at smaller and smaller scales. These patterns can be mathematically described and quantified, which is great because fractal geometry is found all over the natural world. There are all kinds of fractals to find and analyze!

And it just so happens that fractal geometry describes both the growth of neurons and the growth of trees or other plants. The mathematical models for their growth patterns are not identical, and of course there’s a lot of variation across neuron type and plant species; but it is a beautiful coincidence of biology that both animal and plant DNA allow for these similar shapes. Maybe not such a coincidence, either, because a lot of the genes between animal and plant DNA are the same, just used for different things. In any case, computational neuroscience has recently demonstrated that connecting synapses with as little wiring as possible will wind up producing tree-like fractals, which confirms Santiago Ramón y Cajal’s theories from more than a century past.

Here are some classic fractals generated by nature or by computers! Which ones remind you the most of neurons and trees? Which ones seem governed by very different formulas?

Image by Schnobby (CC BY-SA 3.0)

Image by Rafael Ruggiero (CC BY-SA 4.0)

But on top of these examples, why not look at the cell overview for a while? You might even spot mergers better now, since many break a cell’s natural morphology. We’ve got a Hunt all ready for you! There are 12 mergers in the Hunt cell; you have 5.5 days and 24 guesses to locate them all, between midnight EDT on 5/23 and noon EDT on 5/28.

How to identify and report mergers

    1. Select Hunt cell from Change Cell menu. Stay in the overview.
    2. Type /debug into chat. This will reveal a special box with information about the cell (located above the “Start Playing” box).
    3. Use ALT+click to select the origin point of the merger you have identified. It is a good idea to zoom in close on the merger before you select it to get the most accurate coordinates.
    4. Find the coordinates of the merger’s origin in the cell information box. These are next to the word “center.”
    5. In the chat pm thehunt bot your coordinates. For example: /pm thehunt 5123 4321 5678.
    6. thehunt bot will let you know if you got it right or wrong and tell you how many guesses you have left.
    7. To check how many mergers you have found and to check what guesses you have submitted, type “/pm thehunt !list”; the bot will give you a list of all the coordinates you have guessed, and whether or not there was a merger at each set of coordinates. A + means there was a merger there, a — means there was not a merger there.
    8. If you accidentally submit the same coordinate a second time, it does not count as two guesses.

Do not reveal your coordinates to other players. Do not do anything against the spirit of the Hunt. Anyone caught cheating will be automatically disqualified from the event and will not receive any points.

Proximity to merger start point is determined by number of voxels (1 voxel = approx. 1/250th of a cube’s width). Mergers are only counted as found if guessed within a distance of 250 voxels. Pieces of dust floating in space don’t count as mergers, so please don’t report them! We also do not count fused mergers that could not be removed during the Hunt prep process.

Swag (generously sponsored by @susi): The top scoring player will win their choice of a mug or notebook, plus their choice of a sticker or magnet! Second and third place may each also choose between sticker or magnet.

Bonus info is available in your in-game notifications. Good luck, and happy hunting!