Mark D Humphries
@markdhumphries.bsky.social
Theoretical systems neuroscientist. Author of “The Spike: An Epic Journey Through the Brain in 2.1 Seconds”: https://tinyurl.com/ymwy9jrh
Lab: https://humphries-lab.org
Essays on the brain: https://drmdhumphries.medium.com/
Lab: https://humphries-lab.org
Essays on the brain: https://drmdhumphries.medium.com/
Reposted by Mark D Humphries
I missed some exciting stuff last year!
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
January 9, 2026 at 3:34 PM
I missed some exciting stuff last year!
Reposted by Mark D Humphries
I can't believe it took me this long to find @markdhumphries.bsky.social on Bluesky, but his annual review makes up for the lost time. On excellent form as always.
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
January 7, 2026 at 8:57 PM
I can't believe it took me this long to find @markdhumphries.bsky.social on Bluesky, but his annual review makes up for the lost time. On excellent form as always.
Thanks Anastasia. I’ve been a lot quieter of late!
January 9, 2026 at 9:10 AM
Thanks Anastasia. I’ve been a lot quieter of late!
Reposted by Mark D Humphries
Great read as always. There is clearly accelerating tension between ever more complex computational approaches applied to brain data and actually figuring stuff out about the brain.
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
January 1, 2026 at 7:03 PM
Great read as always. There is clearly accelerating tension between ever more complex computational approaches applied to brain data and actually figuring stuff out about the brain.
Reposted by Mark D Humphries
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
December 30, 2025 at 3:52 PM
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
Fair point! Yes, I think a lot of the problem is in the hype of what they promise, not the interesting and often innovative technical work underneath
December 31, 2025 at 9:43 AM
Fair point! Yes, I think a lot of the problem is in the hype of what they promise, not the interesting and often innovative technical work underneath
Thanks Nicole. Not sure I’ll manage another 10!
December 31, 2025 at 9:38 AM
Thanks Nicole. Not sure I’ll manage another 10!
Reposted by Mark D Humphries
Always full of insightful laughs! Thank you for keeping it up for 10 years, @markdhumphries.bsky.social.
" ... It can though predict with fair accuracy the activity of held-out neurons during videos of natural scenes. Scenes like driving through a desert. As mice do ... "
" ... It can though predict with fair accuracy the activity of held-out neurons during videos of natural scenes. Scenes like driving through a desert. As mice do ... "
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
December 30, 2025 at 4:31 PM
Always full of insightful laughs! Thank you for keeping it up for 10 years, @markdhumphries.bsky.social.
" ... It can though predict with fair accuracy the activity of held-out neurons during videos of natural scenes. Scenes like driving through a desert. As mice do ... "
" ... It can though predict with fair accuracy the activity of held-out neurons during videos of natural scenes. Scenes like driving through a desert. As mice do ... "
That’s a great quote!
December 31, 2025 at 9:37 AM
That’s a great quote!
Reposted by Mark D Humphries
Great summary, thanks for writing this!
One nit, we started the 'core' merely as a shared feature space for (translation invariant) visual neurons*. Simple idea, not to be conflated with all the 'foundation model' and 'digital twin' marketing later 😜
* proceedings.neurips.cc/paper/2017/f...
One nit, we started the 'core' merely as a shared feature space for (translation invariant) visual neurons*. Simple idea, not to be conflated with all the 'foundation model' and 'digital twin' marketing later 😜
* proceedings.neurips.cc/paper/2017/f...
proceedings.neurips.cc
December 30, 2025 at 5:49 PM
Great summary, thanks for writing this!
One nit, we started the 'core' merely as a shared feature space for (translation invariant) visual neurons*. Simple idea, not to be conflated with all the 'foundation model' and 'digital twin' marketing later 😜
* proceedings.neurips.cc/paper/2017/f...
One nit, we started the 'core' merely as a shared feature space for (translation invariant) visual neurons*. Simple idea, not to be conflated with all the 'foundation model' and 'digital twin' marketing later 😜
* proceedings.neurips.cc/paper/2017/f...
Thanks David, and thanks for sharing your NeuriPs paper - good to see the smart ideas underneath the behemoth.
Especially fun to see you proposed the barcode idea at the end!
Especially fun to see you proposed the barcode idea at the end!
December 31, 2025 at 9:35 AM
Thanks David, and thanks for sharing your NeuriPs paper - good to see the smart ideas underneath the behemoth.
Especially fun to see you proposed the barcode idea at the end!
Especially fun to see you proposed the barcode idea at the end!
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
2025: A Review of the Year in Neuroscience
Enlightening the brain
medium.com
December 30, 2025 at 3:52 PM
Just published my review of neuroscience in 2025, on The Spike.
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
The 10th of these, would you believe?
This year we have foundation models, breakthroughs in using light to understand the brain, a gene therapy, and more
Enjoy!
medium.com/the-spike/20...
🚨Funded PhD studentship project🚨
"Leveraging population activity trajectories to optimise Brain-computer interfaces for arm movement" with myself & @katjakornysheva.bsky.social
By: Jan 9th 2026
Info on project, funding & how to apply: more.bham.ac.uk/mrc-aim/phd-... (submit to Nottingham)
"Leveraging population activity trajectories to optimise Brain-computer interfaces for arm movement" with myself & @katjakornysheva.bsky.social
By: Jan 9th 2026
Info on project, funding & how to apply: more.bham.ac.uk/mrc-aim/phd-... (submit to Nottingham)
PhD Opportunities – MRC AIM
more.bham.ac.uk
December 9, 2025 at 10:34 AM
🚨Funded PhD studentship project🚨
"Leveraging population activity trajectories to optimise Brain-computer interfaces for arm movement" with myself & @katjakornysheva.bsky.social
By: Jan 9th 2026
Info on project, funding & how to apply: more.bham.ac.uk/mrc-aim/phd-... (submit to Nottingham)
"Leveraging population activity trajectories to optimise Brain-computer interfaces for arm movement" with myself & @katjakornysheva.bsky.social
By: Jan 9th 2026
Info on project, funding & how to apply: more.bham.ac.uk/mrc-aim/phd-... (submit to Nottingham)
Reposted by Mark D Humphries
Read yet another review today that ascribes GECIs' larger SNR vs GEVIs to their being evolved earlier (suggesting the GECIs are better optimized). This assumption is understandable but incorrect. GEVIs' photonic response per molecule per AP have been as good as GECIs since ASAP3.
December 6, 2025 at 12:36 AM
Read yet another review today that ascribes GECIs' larger SNR vs GEVIs to their being evolved earlier (suggesting the GECIs are better optimized). This assumption is understandable but incorrect. GEVIs' photonic response per molecule per AP have been as good as GECIs since ASAP3.
Terrific work led by @emmaroscow.bsky.social showing that hippocampal replay reflects events with large prediction errors, all the better to bootstrap learning as we slumber
Congratulations to Matt Jones & Nathan Lepora for seeing this through to the end!
www.nature.com/articles/s41...
Congratulations to Matt Jones & Nathan Lepora for seeing this through to the end!
www.nature.com/articles/s41...
Post-learning replay of hippocampal-striatal activity is biased by reward-prediction signals - Nature Communications
It is unclear which aspects of experience shape sleep’s contributions to learning. Here, by combining neural recordings in rats with reinforcement learning, the authors show that reward-prediction sig...
www.nature.com
November 27, 2025 at 10:24 AM
Terrific work led by @emmaroscow.bsky.social showing that hippocampal replay reflects events with large prediction errors, all the better to bootstrap learning as we slumber
Congratulations to Matt Jones & Nathan Lepora for seeing this through to the end!
www.nature.com/articles/s41...
Congratulations to Matt Jones & Nathan Lepora for seeing this through to the end!
www.nature.com/articles/s41...
Reposted by Mark D Humphries
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
November 12, 2025 at 4:32 PM
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
Reposted by Mark D Humphries
Excited to share our preprint on variability in patch leaving decisions! Check out the 🧵 below
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
November 13, 2025 at 9:19 AM
Excited to share our preprint on variability in patch leaving decisions! Check out the 🧵 below
Reposted by Mark D Humphries
Super pleased with this one, led by the amazing PhD student and foraging expert @emmavscholey.bsky.social!
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
November 12, 2025 at 8:07 PM
Super pleased with this one, led by the amazing PhD student and foraging expert @emmavscholey.bsky.social!
A nice example of how sequential and simultaneous choice can fundamentally differ: in the latter, the longer a subject waits to decide, the more variable their decision time.
We show foraging decisions can have independence of decision time and variability, or even an inverted relationship!
End 🧵
We show foraging decisions can have independence of decision time and variability, or even an inverted relationship!
End 🧵
November 12, 2025 at 4:32 PM
A nice example of how sequential and simultaneous choice can fundamentally differ: in the latter, the longer a subject waits to decide, the more variable their decision time.
We show foraging decisions can have independence of decision time and variability, or even an inverted relationship!
End 🧵
We show foraging decisions can have independence of decision time and variability, or even an inverted relationship!
End 🧵
In another weird prediction, we show that if the reward in a patch decays linearly when harvested, then the forager should be *more* variable the *earlier* they leave
Also exactly what we see in data: foragers leave earlier in rich environments but are more variable (data, solid; model, dashed)
Also exactly what we see in data: foragers leave earlier in rich environments but are more variable (data, solid; model, dashed)
November 12, 2025 at 4:32 PM
In another weird prediction, we show that if the reward in a patch decays linearly when harvested, then the forager should be *more* variable the *earlier* they leave
Also exactly what we see in data: foragers leave earlier in rich environments but are more variable (data, solid; model, dashed)
Also exactly what we see in data: foragers leave earlier in rich environments but are more variable (data, solid; model, dashed)
Perhaps the weirdest prediction is that, under a wide range of conditions, foragers’ stochasticity is independent of when they leave. In other words, their variability is decoupled from their reward information
And that’s exactly what we see in the data (solid lines; model predictions: dashed)
And that’s exactly what we see in the data (solid lines; model predictions: dashed)
November 12, 2025 at 4:32 PM
Perhaps the weirdest prediction is that, under a wide range of conditions, foragers’ stochasticity is independent of when they leave. In other words, their variability is decoupled from their reward information
And that’s exactly what we see in the data (solid lines; model predictions: dashed)
And that’s exactly what we see in the data (solid lines; model predictions: dashed)
We ask if foragers’ variability can be explained by them making deliberately stochastic leaving choices: basically, whether they flip a biased coin
We show deliberately stochastic choice makes weird predictions for how foragers’ respond to their environment, and test them across tasks and species
We show deliberately stochastic choice makes weird predictions for how foragers’ respond to their environment, and test them across tasks and species
November 12, 2025 at 4:32 PM
We ask if foragers’ variability can be explained by them making deliberately stochastic leaving choices: basically, whether they flip a biased coin
We show deliberately stochastic choice makes weird predictions for how foragers’ respond to their environment, and test them across tasks and species
We show deliberately stochastic choice makes weird predictions for how foragers’ respond to their environment, and test them across tasks and species
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
November 12, 2025 at 4:32 PM
🧪Preprint!
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
How foragers depart from optimal models can tell us a lot about how they compute their decisions.
A strong but underexplored departure is that foragers widely vary when they leave identical patches.
A 🧵
doi.org/10.1101/2025...
With
@emmavscholey.bsky.social @brainapps.bsky.social
Reposted by Mark D Humphries
Delighted to share our latest preprint. It's been a long time coming. Thanks to all the authors for their unique contribution and for for their patience. We show how the visual thalamus deals with active and passive head motion in freely moving animals: www.biorxiv.org/content/10.1...
Efficient mixed representation of active and passive motion in the mouse visual thalamus during natural behaviour
During natural behaviour, changes in the visual scene are largely driven by the subject’s own movements, which can be actively generated (e.g., walking) or passively imposed by external forces (e.g., ...
www.biorxiv.org
November 9, 2025 at 3:43 PM
Delighted to share our latest preprint. It's been a long time coming. Thanks to all the authors for their unique contribution and for for their patience. We show how the visual thalamus deals with active and passive head motion in freely moving animals: www.biorxiv.org/content/10.1...
Reposted by Mark D Humphries
Okay, here are some first reflections on Watson.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
November 8, 2025 at 11:22 PM
Okay, here are some first reflections on Watson.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.
Watson's life is a tragedy, really of Shakespearean proportions. He did not, as most bios will tell you, do one great thing when he was young and then collect laurels for it for the next 60 years. His career arc was unlike any in science.