# Left\_right\_ccf\_coordinate of the Visual Coding Neuropixels data **URL:** \ **Category:** Science\ **Tags:** brain-observatory-visual-coding\ **Created:** [August 14, 2025, 10:11am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649 "2025-08-14T10:11:44Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![NaixinRen](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/naixinren/32/2332_2.png) [@NaixinRen](https://community.brain-map.org/u/NaixinRen)\ **Post date:** [August 14, 2025, 10:11am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/1 "2025-08-14T10:11:44Z")
Hi, I was trying to understand whether the recording sites of the visual coding neuropixels are in the left or the right hemisphere. I have noticed that in the [technical whitepaper](https://brainmapportal-live-4cc80a57cd6e400d854-f7fdcae.divio-media.net/filer_public/80/75/8075a100-ca64-429a-b39a-569121b612b2/neuropixels_visual_coding_-_white_paper_v10.pdf) the monitor was placed at the mouse’s right eye so I would assume the recording sites are in the left hemisphere. However, the left\_right\_ccf\_coordinates from the Visual Coding Neuropixels data usually range from 6,000 to 10,000, which suggests the right hemisphere. Could someone please let me know if I’ve misunderstood anything? Best, Naixin ---
**Author:** ![joshs](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/joshs/32/8_2.png) [@joshs](https://community.brain-map.org/u/joshs)\ **Post date:** [August 14, 2025, 11:53pm UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/2 "2025-08-14T23:53:47Z")
The recordings were definitely done in the left hemisphere. This means that the L/R CCF coordinates somehow got reversed from what was done in the actual experiments, causing the unit locations to be mirrored to the right side of the brain. ---
**Author:** ![NaixinRen](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/naixinren/32/2332_2.png) [@NaixinRen](https://community.brain-map.org/u/NaixinRen)\ **Post date:** [August 15, 2025, 1:54am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/3 "2025-08-15T01:54:23Z")
Thank you for the reply! I loaded the CCF coordinates directly from AllenSDK, I think they need to be fixed in the next update. ---
**Author:** ![NaixinRen](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/naixinren/32/2332_2.png) [@NaixinRen](https://community.brain-map.org/u/NaixinRen)\ **Post date:** [August 18, 2025, 2:00am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/4 "2025-08-18T02:00:19Z")
Hi Josh, to fix the LR CCF, if I see a LR CCF = 7000 in this dataset, does it mean that the true CCF = 11400 - 7000 = 4400, where 11400 is the total LR length in CCF? ---
**Author:** ![joshs](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/joshs/32/8_2.png) [@joshs](https://community.brain-map.org/u/joshs)\ **Post date:** [August 19, 2025, 10:54pm UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/5 "2025-08-19T22:54:39Z")
Yep, that’s correct! ---
**Author:** ![NaixinRen](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/naixinren/32/2332_2.png) [@NaixinRen](https://community.brain-map.org/u/NaixinRen)\ **Post date:** [August 22, 2025, 6:59am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/6 "2025-08-22T06:59:48Z")
Hi Josh, I’ve noticed the same thing in the visual _behavior_ neuropixels data: the recording sites were in the left hemisphere, but the LR CCF values for the neurons range from 6,000 to 10,000. Am I misunderstanding how the LR CCF is defined? Is it reversed too in this dataset, or is the zero point for LR CCF actually on the right? ---
**Author:** ![joshs](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/joshs/32/8_2.png) [@joshs](https://community.brain-map.org/u/joshs)\ **Post date:** [August 22, 2025, 7:00pm UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/7 "2025-08-22T19:00:22Z")
The CCF conventions are definitely for coordinates to increase from left to right (left = 0). Because the brain volumes for Visual Behavior and Visual Coding were processed in the same way, it likely explains why this reversal is present in both datasets. ---
**Author:** ![NaixinRen](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.brain-map.org/naixinren/32/2332_2.png) [@NaixinRen](https://community.brain-map.org/u/NaixinRen)\ **Post date:** [August 25, 2025, 1:53am UTC](https://community.brain-map.org/t/left-right-ccf-coordinate-of-the-visual-coding-neuropixels-data/4649/8 "2025-08-25T01:53:45Z")
Okay. Thanks for the explaination!