hey, folks! in an attempt to be more transparent about what stuff gets added to mozak and when, we’re going to start posting changelogs every time a change hits the server. to start off, here’s what we’ve been up to over the past couple weeks (it’s a little light because of the holiday season):


  • Added leaderboard to main menu.
  • Fixed a bug that would result in neurons failing to load in some situations ("clip volume off of edge").
  • Changed the game to draw less reconstruction outside of the part of the neuron you're looking at, in an attempt to reduce visual noise.

  • Started fixing resource leaks that lead to our consensus server being unstable.
  • Fixed a consensus performance issue we introduced with an earlier emergency fix to a consensus performance issue.
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  • More fixes to stability and performance of consensus.
  • In-game chat: now you can talk to your fellow reconstructors about what you see and what you're up to!


  • Minor tweaks to chat formatting.
  • Fixed a bug in the sad brain dialog that would lead to its text oozing off the side of the page.
  • Fixed an issue where the chat scrollbar would blink annoyingly.


  • New feature: hotspots! When you click the flame icon in-game, regions of the neuron we call hotspots are specially highlighted, to direct you to regions that we think contain important reconstruction work. Currently, these hotspots are regions that other reconstructors have done work in but that we aren’t sure enough about to make part of the consensus reconstruction.


  • Bug fix: chat is now hidden when you’re in full-screen, pending more changes to provide a more user-friendly full-screen chat experience.


  • Bug fix: fixed an issue where typing in chat would trigger keyboard shortcuts in the game.
  • Bug fix: fixed an issue where your mouse could act like you were holding down a button when you weren't.
  • Bug fix: fixed display of notification settings on your user profile page.
  • Bug fix: fixed reliability issues with neuron images failing to load.

We’ve been working on a big new feature for the past month that won’t be shipped until we finish it, so apologies again for the paucity of the changelog, but a couple small changes came out today:


  • Bug fix: the game should now no longer silently stop working correctly if your computer suspends and resumes while it's up.
  • Memory usage and performance fixes.


  • We've redesigned the way the consensus process works (this is the big feature I talked about above.) Before, every time we'd compute the consensus between your reconstruction and others', we'd save it aside and not show any of it to you, except to figure out which parts of the image to gray out because we didn't think the neuron was present in them. Now, once a day, we run a special version of the consensus algorithm which merges your reconstructions together, then changes each of your individual reconstructions to reflect this consensus, so you can build off of other players' work. (This is particularly nice for new players entering a challenge in the middle, because they won't have to draw all the way out from the center of the neuron to the "frontier" to contribute.)

    The downside is, once a day, each challenge will become read-only while consensus runs once, then go back to normal a few minutes later when it finishes; the upside is that you'll get to build off the work of the community instead of all reconstructing in isolation. We'll be fine-tuning this behavior as we go, so please let us know if there's any suggestions or ideas for improvement you've got.
  • When scientists leave comments on parts of the neuron, or where there's a hotspot present, you'll always be able to see the underlying neuron inside the comment box, even if it would otherwise be grayed out.
  • On the back end, we've added a framework to provide you with more information about each of the neurons you're reconstructing — information like the species of animal and brain region they came from. We haven't populated this information yet, but we'll populate it for all the old challenges over the next couple of days.
  • We had to perform an emergency fix a while ago that broke a subtle assumption in the consensus algorithm. The upshot is that for a while, scores have been proportional to one another, but several times lower than we originally intended. We fixed that, and in the near future we'll go back and re-score all of the past challenges the same way.
  • The Web site is now fully SSL-enabled. We'll keep the HTTP access around for a while longer, but eventually we'll remove it completely.
  • Bug fix: the consensus process was incorrectly generating overly pessimistic results (i.e., it wouldn't recognize consensus between nodes it should have), and we've fixed that.
  • There was an occasional bug in the hotspots visualization where the visual effect wouldn't render properly; until we can find a fix for that bug, we've worked around it by changing the visual effect to one that works more reliably.

3/13/2017 5:18 PM: we’ve disabled the new consensus feature temporarily because we saw a bug in it on the production site that we weren’t seeing in testing. we’ve identified a workaround for the bug and we’ll fix it ASAP tomorrow morning (Pacific Daylight Time). I’ll edit this post once it’s fixed.

update 3/15/2017 10:16 AM: we wrote a fix for the issue and deployed it, but the fix itself caused some responsiveness problems on the server. the feature’s still disabled and we’re working to remedy those responsiveness problems now.

update 3/15/2017 2:44 PM: we’ve deployed the fix and the feature is turned back on now. sorry for the rocky launch!

4/18/2017 5:40 PM PST:

  • We upgraded several computers used in our backend in anticipation of increased traffic in the future weeks.

  • We gave users the ability to report inappropriate chat messages to our admins, and made it easier for admins to respond to these reports.

  • We added leaderboards to the gameplay page to reflect score on current tutorials.

  • Admins now have the ability to change offensive usernames.

  • We unified the format of timestamps around various parts of the page.

4/22/2017 1:40 PM PST:

  • We paralleled the processes that handles communicating to users and communicating to our consensus servers.

  • The VF extend highlight now reflect the underlying colors of the consensus.

  • General improvement to our tutorials.

  • Visiting Mozak with unsupported browsers will now show warning messages.

  • Improved workflow on changing various parts of the user profile, including a bugfix.

5/24/2017 10:30am PDT

  • Added first version of auto z-depth. When using the Connect-the-dots tool to trace, you can toggle a mode where the app will try to find the brightest z-layer at the point you clicked for you. Hopefully this will help save you some time scrolling through layers when placing dots. You can use the ‘A’ key to toggle this mode off if you prefer having total control on picking the z-layer.

  • Added results section to the individual challenge web pages. When we receive results back from our partners at the AIBS for completed neuron traces, you can view the feedback they gave as well as view a comparison image between the community consensus trace and the expert trace by the scientists.

  • Server software upgrade and refactoring. We upgraded various packages on our server that were fairly out of date and cleaned up code in our own system. In the future this will hopefully make development and deployment of new features and bug fixes a little bit quicker.
  • 5/31/2017 9:10am PDT

  • Added first version of undo/redo. During a session, after using one of the four tools (Virtual finger, Connect-the-Dot, Delete Node, or Delete branch) an undo button should pop up near the bottom left hand side of the screen allow you to undo your previous actions using those tools. Note that when undoing a Connect-the-Dots trace, it will undo the entire last committed branch, i.e. the last one where you did a right click to finalize.
  • 6/26/2017 3:25am PDT

  • Added settings menu to the top right corner of the client. More settings to come in the future.
  • Added a number of keyboard shortcuts. Right now they are not customizable, in the future this will change.

  • 7/10/2017 7:00am PDT
  • Change ui to allow zooming in and out multiple resolution levels at once.
    Click on the magnifying glass icons multiple times to set the next zoom level, then click on the image to jump to that resolution level.
  • Minor wording tweaks to the tutorials.

  • 7/12/2017 5:00pm PDT
  • You can use the connect the dots tool to start and end a trace at existing nodes provided they do not form a cycle. This will allow you to connect disjointed connections.
  • Settings in the dropdown menu (hide consensus, enable/disable audio) now saved across session and different browsers/machines.
  • Fix issues with camera controls not working correctly after switching through specific order of view modes

  • 7/20/2017 7:00am PDT
  • New scientist comment that will disable adding traces in a particular region. This is to improve the quality of traces sent to our partners at AIBS
  • 7/25/2017 12:40pm PDT

  • Re-enabled ability to end Connect-the-Dots traces on an existing node
  • Add warning if a trace you are about to add creates a cycle. Cycles cause problems with aggregating all player traces into consensus so they are disallowed.
  • Bug fix for auto-z tool to address traces jumping to incorrect locations along the xy plane.
  • Updates to the registration page
  • Updates to the About page

  • 7/27/2017 1:10pm PDT
  • Fixed bug where “slow” clicks did not register as a click
  • Loading scientist comment view will take you to the correct z-slice
  • If you pause in the middle of the scan animation, the next time you use Connect-the-Dots you will be at the same z-slice you paused at
  • The z-slice you are on properly adjusts itself when changing resolution levels. For example, if you are on the z-slice half way in the image at resolution level 1 and then zoom in to level 5 you will still be on the z-slice that is half way in the image.
  • Bug fixes to cycles sometimes not being detected when using Connect-the-Dots.
  • 8/18/2017 7:00am PDT

  • Disable Disconnected View Mode due to bugs in the system to be fixed first related to connecting traces.
  • Add ability to delete individual edges/lines between two nodes
  • Added setting to view thicker drawn lines
  • Bug fix for some preferences not being saved
  • Added button on your profile page to resend confirmation email
  • Updates to the help page

  • 8/28/2017 2:00pm PDT

  • Disconnected View Mode re-enabled.
  • Menu item for auto-z
  • Collapse long chat messages
  • Animation for newly added scientist comments
  • Indicator when hotspot areas have changed.
  • Other minor bug fixes.
  • 8/30/2017 14:57 PDT:

    • consensus: we fixed a bug in our handling of ‘fast-forward’ consensus passes where certain edges would be deleted unpredictably. (thanks to all the players who helped report this issue to us!)
    • fixed bad advice in tutorials about how to rotate the game view on Mac trackpads.
    • fixed an issue where some nodes and lines that should not have been drawn were drawn.

    9/11/2017 8:30 PDT:

    • Add help page with details about how the application works and tips on how to play.

    • Allow user to choose view mode in Connect-the-Dots that will hide traces that are not near the current z-slice you are at.

    • Add user interface at the beginning of regular challenges that shows tips and tricks for playing. Can be toggled off.

    • Start off in disconnected view mode if too many disconnected fragments are in a neuron reconstruction on load.

    9/20/2017 7:30 PDT:

    • Allow changing of the viewable volume in Virtual Finger mode. Using mouse wheel with shift or alt will change the size and position of the image volume.

    • Allow scientists to create comments that are extruded polygons instead of only axis aligned bounding boxes.

    • Disable starting at Disconnected View Mode until consensus issues resolved.

    • Add menu setting to allow users with more powerful machines to always have high quality image even while rotating the image.

    • Fix a bug with the predicted score calculation.

    • Fix bug where hover over color of disconnected nodes was not consistent with actual node color

    • Fix bug where z-clip node could still be moused over

    10/4/2017 13:48 PDT:

    • We fixed another issue in consensus regarding edges being dropped from fast-forward consensus reconstructions. We think that this should drastically reduce the number of instances in which you see connections getting deleted from your reconstruction, though it may still occur in cases where your reconstruction and the consensus reconstruction form a cycle. Thanks again for your patience while we try to deal with this issue.

    10/6/2017 7:00 PDT:

    • Added toggle switch ui that changes the type of new traces being created between axon and dendrite.

    • Added new settings view mode for axon and dendrite that is enabled by default. Disconnected View also shows the difference between the two types as different colors if the axon/dendrite view is enabled.

    • Fixed bug where keyboard arrows do not work sometimes.

    • Edit tutorials to reference new component.

    • Made it easier to alter the consensus vote threshold per neuron, this can allow more people to trace common areas before consensus is produced.

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