Guido Meijer
@guidomeijer.com
👨🔬 Neuroscientist at the Donders Institute in the Battaglia lab.
🧠 Previously: International Brain Laboratory
Using Neuropixels and virtual-reality to understand how the brain creates internal models of the world.
www.guidomeijer.com
🧠 Previously: International Brain Laboratory
Using Neuropixels and virtual-reality to understand how the brain creates internal models of the world.
www.guidomeijer.com
Pinned
Guido Meijer
@guidomeijer.com
· Aug 5
Serotonin drives choice-independent reconfiguration of distributed neural activity
Serotonin (5-HT) is a central neuromodulator which is implicated in, amongst other functions, cognitive flexibility. 5-HT is released from the dorsal raphe nucleus (DRN) throughout nearly the entire f...
doi.org
🚨Pre-print alert🚨
We stimulated serotonin with optogenetics while doing large-scale Neuropixel recordings across the mouse brain. We found strong widespread modulation of neural activity, but no effect on the choices of the mouse 🐭
How is this possible? Strap in! (1/9) 👇🧵
doi.org/10.1101/2025...
We stimulated serotonin with optogenetics while doing large-scale Neuropixel recordings across the mouse brain. We found strong widespread modulation of neural activity, but no effect on the choices of the mouse 🐭
How is this possible? Strap in! (1/9) 👇🧵
doi.org/10.1101/2025...
Reposted by Guido Meijer
Main postdoc study out! We can redefine prefrontal cortex regions with single-unit activity! Grateful to @carlenlab.bsky.social and @weltgeischt.bsky.social who made this crazy project real. Thanks to all co-authors, collaborators, and reviewers.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
A prefrontal cortex map based on single-neuron activity - Nature Neuroscience
The authors mapped spontaneous and choice activity across mouse prefrontal cortex. The activity maps aligned with intrinsic connectivity rather than anatomical subregions, suggesting that connectivity...
www.nature.com
January 20, 2026 at 10:53 AM
Main postdoc study out! We can redefine prefrontal cortex regions with single-unit activity! Grateful to @carlenlab.bsky.social and @weltgeischt.bsky.social who made this crazy project real. Thanks to all co-authors, collaborators, and reviewers.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Reposted by Guido Meijer
fMRI signals “up,” but neural metabolism might be going “down.”
In our @natneuro.nature.com paper, we demonstrate that about 40% of voxels with robust BOLD responses exhibit opposite oxygen metabolism, revealing two distinct hemodynamic modes.
rdcu.be/eUPO8
funds @erc.europa.eu
#neuroskyence 🧵:
In our @natneuro.nature.com paper, we demonstrate that about 40% of voxels with robust BOLD responses exhibit opposite oxygen metabolism, revealing two distinct hemodynamic modes.
rdcu.be/eUPO8
funds @erc.europa.eu
#neuroskyence 🧵:
December 16, 2025 at 3:43 PM
fMRI signals “up,” but neural metabolism might be going “down.”
In our @natneuro.nature.com paper, we demonstrate that about 40% of voxels with robust BOLD responses exhibit opposite oxygen metabolism, revealing two distinct hemodynamic modes.
rdcu.be/eUPO8
funds @erc.europa.eu
#neuroskyence 🧵:
In our @natneuro.nature.com paper, we demonstrate that about 40% of voxels with robust BOLD responses exhibit opposite oxygen metabolism, revealing two distinct hemodynamic modes.
rdcu.be/eUPO8
funds @erc.europa.eu
#neuroskyence 🧵:
The Power Pixels pipeline just keeps getting better! The latest update comes with:
- OpenEphys support
- AP_Histology support
- automatic high-frequency noise reduction
- NWB format export option
- zarr compression of raw data
And, most importantly: a cool new logo!
github.com/NeuroNetMem/...
- OpenEphys support
- AP_Histology support
- automatic high-frequency noise reduction
- NWB format export option
- zarr compression of raw data
And, most importantly: a cool new logo!
github.com/NeuroNetMem/...
November 11, 2025 at 11:25 AM
The Power Pixels pipeline just keeps getting better! The latest update comes with:
- OpenEphys support
- AP_Histology support
- automatic high-frequency noise reduction
- NWB format export option
- zarr compression of raw data
And, most importantly: a cool new logo!
github.com/NeuroNetMem/...
- OpenEphys support
- AP_Histology support
- automatic high-frequency noise reduction
- NWB format export option
- zarr compression of raw data
And, most importantly: a cool new logo!
github.com/NeuroNetMem/...
Halloween isn’t my thing. My idea of a scary night is reading the plots of horror movies on Wikipedia.
October 31, 2025 at 9:16 AM
Halloween isn’t my thing. My idea of a scary night is reading the plots of horror movies on Wikipedia.
I never understood why everyone always complains about the clocks changing.
Then I had a kid.
Then I had a kid.
October 25, 2025 at 10:13 AM
I never understood why everyone always complains about the clocks changing.
Then I had a kid.
Then I had a kid.
Thanks! I always save the illustrator file as an editable pdf, that way it is self contained even when the panels are technically links.
October 21, 2025 at 3:16 PM
Thanks! I always save the illustrator file as an editable pdf, that way it is self contained even when the panels are technically links.
Thanks! Yes, that's a good way of doing it if you don't like Illustrator, I just find it way too time consuming to position everything programmatically (and I have free Adobe through my uni 😁)
October 21, 2025 at 3:12 PM
Thanks! Yes, that's a good way of doing it if you don't like Illustrator, I just find it way too time consuming to position everything programmatically (and I have free Adobe through my uni 😁)
I didn't know that, that's cool!
October 16, 2025 at 9:02 AM
I didn't know that, that's cool!
I hope you found this useful! Here is a Google Colab with example code of what was discussed in this thread:
colab.research.google.com/drive/1UlCET...
colab.research.google.com/drive/1UlCET...
Google Colab
colab.research.google.com
October 16, 2025 at 8:26 AM
I hope you found this useful! Here is a Google Colab with example code of what was discussed in this thread:
colab.research.google.com/drive/1UlCET...
colab.research.google.com/drive/1UlCET...
The workflow: Python plots single panels, saved as pdfs. Create an empty figure of 7 inch (180 mm) wide in Illustrator and place the panels as links. Add the panel letters (a,b,c). Now, if a new version of a panel is generated you just have to click update links in Illustrator and it's there. 🤩
October 16, 2025 at 8:26 AM
The workflow: Python plots single panels, saved as pdfs. Create an empty figure of 7 inch (180 mm) wide in Illustrator and place the panels as links. Add the panel letters (a,b,c). Now, if a new version of a panel is generated you just have to click update links in Illustrator and it's there. 🤩
A note about colors 🌈 Imagine you made eight figures and your PI asks you to change the color of an element you've consistently plotted green into orange. If you define your colors in the plotting function you only have to change it there and rerun the plotting scripts, this save a lot of time!
October 16, 2025 at 8:26 AM
A note about colors 🌈 Imagine you made eight figures and your PI asks you to change the color of an element you've consistently plotted green into orange. If you define your colors in the plotting function you only have to change it there and rerun the plotting scripts, this save a lot of time!
Full width figures typically have four panels next to each other, a good rule of thumb is that a single panel is 1.75 by 1.75 inch. Create two figure panels like this:
f, axs = plt.subplots(1, 2, figsize=(1.75 * 2, 1.75), dpi=300)
⚠️ If it's too small increase the dpi, not the figsize!
f, axs = plt.subplots(1, 2, figsize=(1.75 * 2, 1.75), dpi=300)
⚠️ If it's too small increase the dpi, not the figsize!
October 16, 2025 at 8:26 AM
Full width figures typically have four panels next to each other, a good rule of thumb is that a single panel is 1.75 by 1.75 inch. Create two figure panels like this:
f, axs = plt.subplots(1, 2, figsize=(1.75 * 2, 1.75), dpi=300)
⚠️ If it's too small increase the dpi, not the figsize!
f, axs = plt.subplots(1, 2, figsize=(1.75 * 2, 1.75), dpi=300)
⚠️ If it's too small increase the dpi, not the figsize!
The font size of each plot element can be easily set with seaborn. Write a function like this that sets the font size and any other style element you like to have in all your plots and the function each time before plotting (link to the code in the last post).
October 16, 2025 at 8:26 AM
The font size of each plot element can be easily set with seaborn. Write a function like this that sets the font size and any other style element you like to have in all your plots and the function each time before plotting (link to the code in the last post).
Journals have criteria figures have to adhere to. Generally, a full-width figure should be 7 inch wide and font sizes cannot be smaller than 7 pts. If you get into the habit of always creating figures that fit these criteria this will save you a lot of time when submitting.
October 16, 2025 at 8:26 AM
Journals have criteria figures have to adhere to. Generally, a full-width figure should be 7 inch wide and font sizes cannot be smaller than 7 pts. If you get into the habit of always creating figures that fit these criteria this will save you a lot of time when submitting.
Want to make publication-ready figures come straight from Python without having to do any manual editing? Are you fed up with axes labels being unreadable during your presentations? Follow this short tutorial including code examples! 👇🧵
October 16, 2025 at 8:26 AM
Want to make publication-ready figures come straight from Python without having to do any manual editing? Are you fed up with axes labels being unreadable during your presentations? Follow this short tutorial including code examples! 👇🧵
I was doing the second-to-last recording of my project and was happily thinking to myself that I haven't broken a single Neuropixel in the entire two year project.
You can guess what happened next...
Now I have to install a new probe just for one final recording 🙃
You can guess what happened next...
Now I have to install a new probe just for one final recording 🙃
October 8, 2025 at 10:37 AM
I was doing the second-to-last recording of my project and was happily thinking to myself that I haven't broken a single Neuropixel in the entire two year project.
You can guess what happened next...
Now I have to install a new probe just for one final recording 🙃
You can guess what happened next...
Now I have to install a new probe just for one final recording 🙃
I love how they came up with all this random stuff but for this one area they were like "I really don't know, just put a question mark"
October 5, 2025 at 10:40 AM
I love how they came up with all this random stuff but for this one area they were like "I really don't know, just put a question mark"
Getting a hundred bucks would have been nice! We had to pay them twelve thousand bucks instead.
September 21, 2025 at 9:33 AM
Getting a hundred bucks would have been nice! We had to pay them twelve thousand bucks instead.
When I told my dad I published in Nature he was like "wow, you must have made a lot of money with that"
September 20, 2025 at 9:31 AM
When I told my dad I published in Nature he was like "wow, you must have made a lot of money with that"
Of course, that makes complete sense 🙃
September 12, 2025 at 1:13 PM
Of course, that makes complete sense 🙃
I don't know why people say X is going down the drain, my last post got lovely replies like this one:
September 12, 2025 at 12:52 PM
I don't know why people say X is going down the drain, my last post got lovely replies like this one:
Reposted by Guido Meijer
Want to collaborate with the International Brain Laboratory on your own project? We have funding to work with groups anywhere in the world to do new large-scale projects and we are looking for new partners! Learn more and apply: www.internationalbrainlab.com/ibl-core-apply
September 11, 2025 at 12:27 PM
Want to collaborate with the International Brain Laboratory on your own project? We have funding to work with groups anywhere in the world to do new large-scale projects and we are looking for new partners! Learn more and apply: www.internationalbrainlab.com/ibl-core-apply
Reposted by Guido Meijer
Thrilled to share that our work is now published in Science! ✨
We found a preference for visual objects in the mouse spatial navigation system where they dynamically refine head-direction coding. In short, objects boost our inner compass! 🧭
www.science.org/doi/10.1126/...
🧵1/
We found a preference for visual objects in the mouse spatial navigation system where they dynamically refine head-direction coding. In short, objects boost our inner compass! 🧭
www.science.org/doi/10.1126/...
🧵1/
September 11, 2025 at 8:14 PM
Thrilled to share that our work is now published in Science! ✨
We found a preference for visual objects in the mouse spatial navigation system where they dynamically refine head-direction coding. In short, objects boost our inner compass! 🧭
www.science.org/doi/10.1126/...
🧵1/
We found a preference for visual objects in the mouse spatial navigation system where they dynamically refine head-direction coding. In short, objects boost our inner compass! 🧭
www.science.org/doi/10.1126/...
🧵1/
Reposted by Guido Meijer
If you're into podcasts, here's a good one on the @intlbrainlab.bsky.social brainwide map, by @newscientist.com
www.newscientist.com/podcasts/fir...
www.newscientist.com/podcasts/fir...
September 9, 2025 at 1:22 PM
If you're into podcasts, here's a good one on the @intlbrainlab.bsky.social brainwide map, by @newscientist.com
www.newscientist.com/podcasts/fir...
www.newscientist.com/podcasts/fir...
Reposted by Guido Meijer
Sad day for peope who still believe brain areas are the primary organizational units of function in the brain.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
A brain-wide map of neural activity during complex behaviour - Nature
The International Brain Laboratory presents a brain-wide electrophysiological map obtained from pooling data from 12 laboratories that performed the same standardized perceptual decision-making task i...
www.nature.com
September 4, 2025 at 11:17 AM
Sad day for peope who still believe brain areas are the primary organizational units of function in the brain.
www.nature.com/articles/s41...
www.nature.com/articles/s41...