Malcolm Campbell
@malcolmgcampbell.bsky.social
Postdoc in Uchida Lab, Harvard (dopamine, learning, circuit computation) | PhD in Giocomo lab, Stanford (grid cells, path integration, navigation) | NIH NIDA K99/R00 | Bridging theory and biology of animal learning and decision making
Pinned
🚨Our preprint is online!🚨
www.biorxiv.org/content/10.1...
How do #dopamine neurons perform the key calculations in reinforcement #learning?
Read on to find out more! 🧵
www.biorxiv.org/content/10.1...
How do #dopamine neurons perform the key calculations in reinforcement #learning?
Read on to find out more! 🧵
Isn’t calcium likely to be more compartmentalized than voltage?
January 5, 2026 at 7:22 PM
Isn’t calcium likely to be more compartmentalized than voltage?
Reposted by Malcolm Campbell
I am incredibly excited and proud to share my first preprint from my postdoc! Thank you to all of the co-authors for all your hard work!
Check out the paper for big insights into plasticity mechanisms in navigation circuits! And surprising motifs for inhibitory synaptic plasticity!
Check out the paper for big insights into plasticity mechanisms in navigation circuits! And surprising motifs for inhibitory synaptic plasticity!
*First preprint from our lab* !!!!!
How does the brain learn to anchor its internal sense of direction to the outside world? 🧭
led by Mark Plitt @markplitt.bsky.social & Dan Turner-Evans, w/ Vivek Jayaraman:
“Octopamine instructs head direction plasticity” www.biorxiv.org/content/10.6...
Thread ⬇️
How does the brain learn to anchor its internal sense of direction to the outside world? 🧭
led by Mark Plitt @markplitt.bsky.social & Dan Turner-Evans, w/ Vivek Jayaraman:
“Octopamine instructs head direction plasticity” www.biorxiv.org/content/10.6...
Thread ⬇️
December 15, 2025 at 6:43 PM
I am incredibly excited and proud to share my first preprint from my postdoc! Thank you to all of the co-authors for all your hard work!
Check out the paper for big insights into plasticity mechanisms in navigation circuits! And surprising motifs for inhibitory synaptic plasticity!
Check out the paper for big insights into plasticity mechanisms in navigation circuits! And surprising motifs for inhibitory synaptic plasticity!
Reposted by Malcolm Campbell
New paper alert!!...🤩 Led by @blogeman.bsky.social, we identify how cell type-specific hormonal responses in the hypothalamus tunes parenting behavior in males and females 🐭🧠🍼. Highlights in thread 👇 1/6
www.biorxiv.org/content/10.6...
www.biorxiv.org/content/10.6...
Cell Type-Specific Hormonal Signaling Configures Hypothalamic Circuits for Parenting
Parenting behavior emerges from hormonally sensitive circuits, but how distinct circuit components are affected by, and contribute to, sex and state dependent changes in infant caregiving remains uncl...
www.biorxiv.org
December 13, 2025 at 2:03 PM
New paper alert!!...🤩 Led by @blogeman.bsky.social, we identify how cell type-specific hormonal responses in the hypothalamus tunes parenting behavior in males and females 🐭🧠🍼. Highlights in thread 👇 1/6
www.biorxiv.org/content/10.6...
www.biorxiv.org/content/10.6...
Reposted by Malcolm Campbell
I am thrilled to share our latest work led by @zurisullivan.bsky.social in collaboration with @moffittlab.bsky.social ! We find that the brain encodes distinct, pathogen-specific sickness states across behavior, physiology, neural activity, and gene expression 1/6
www.biorxiv.org/content/10.6...
www.biorxiv.org/content/10.6...
www.biorxiv.org
December 9, 2025 at 12:05 PM
I am thrilled to share our latest work led by @zurisullivan.bsky.social in collaboration with @moffittlab.bsky.social ! We find that the brain encodes distinct, pathogen-specific sickness states across behavior, physiology, neural activity, and gene expression 1/6
www.biorxiv.org/content/10.6...
www.biorxiv.org/content/10.6...
This is insane
For one investment manager's compensation, you could hire 50-60 (!!) lecturers. Yet the endowment performance often lags the S&P 500. They could just put the money in index funds and double all the lecturer salaries.
cepr.net/publications...
cepr.net/publications...
University Endowment Returns Don’t Measure Up
cepr.net
December 10, 2025 at 2:39 PM
This is insane
Reposted by Malcolm Campbell
Congratulations to my wonderful colleague Nao Uchida @naoshigeuchida.bsky.social now Jeff C. Tarr Professor! 👏🤩🧠🎉
Naoshige Uchida Named Jeff C.Tarr Professor; Launches New Simons-Funded Autism Research Collaboration 🧠 🧪🧬 #AcademicSky #higherEd
www.mcb.harvard.edu/department/n... @rachellegaudet.bsky.social @naoshigeuchida.bsky.social @neurovenki.bsky.social @dulaclab.bsky.social @harvardbrainsci.bsky.social
www.mcb.harvard.edu/department/n... @rachellegaudet.bsky.social @naoshigeuchida.bsky.social @neurovenki.bsky.social @dulaclab.bsky.social @harvardbrainsci.bsky.social
Naoshige Uchida Named Jeff C.Tarr Professor; Launches New Simons-Funded Autism Research Collaboration - Harvard University - Department of Molecular & Cellular Biology
MCB is pleased to announce that Naoshige (Nao) Uchida, a leading neuroscientist whose work has reshaped our understanding of learning, decision-making, and sensory processing, has been appointed the [...
www.mcb.harvard.edu
November 25, 2025 at 11:45 PM
Congratulations to my wonderful colleague Nao Uchida @naoshigeuchida.bsky.social now Jeff C. Tarr Professor! 👏🤩🧠🎉
Gorgeous. The trumpet player is Nils Petter Molvær, a well known jazz musician. Love the combination.
November 21, 2025 at 3:24 AM
Gorgeous. The trumpet player is Nils Petter Molvær, a well known jazz musician. Love the combination.
Reposted by Malcolm Campbell
"Postdoc in the job market"
November 16, 2025 at 7:52 PM
"Postdoc in the job market"
Reposted by Malcolm Campbell
Heading to San Diego for #sfn25 today! I’ll be presenting a poster on this work Monday afternoon!
looking forward to meeting neuroscientists! please stop by my poster or reach out if you’re going and want to talk motor neuro/behavior, evolution, neuroethology…or whatever else! 🧠🥳 #neuroskyence
looking forward to meeting neuroscientists! please stop by my poster or reach out if you’re going and want to talk motor neuro/behavior, evolution, neuroethology…or whatever else! 🧠🥳 #neuroskyence
🧠🌟🐭 Excited to share some of my postdoc work on the evolution of dexterity!
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
November 13, 2025 at 1:41 PM
Heading to San Diego for #sfn25 today! I’ll be presenting a poster on this work Monday afternoon!
looking forward to meeting neuroscientists! please stop by my poster or reach out if you’re going and want to talk motor neuro/behavior, evolution, neuroethology…or whatever else! 🧠🥳 #neuroskyence
looking forward to meeting neuroscientists! please stop by my poster or reach out if you’re going and want to talk motor neuro/behavior, evolution, neuroethology…or whatever else! 🧠🥳 #neuroskyence
For anyone attending the pre-SFN Molecular and Cellular Cognition Society meeting, I'll be giving a short talk there on Friday (Nov 14) at 4:20 pm
event.fourwaves.com/MCCS25/pages
event.fourwaves.com/MCCS25/pages
Molecular and Cellular Cognition Society 2025 Annual Meeting
Fourwaves - Molecular and Cellular Cognition Society 2025 Annual Meeting
event.fourwaves.com
November 13, 2025 at 6:55 PM
For anyone attending the pre-SFN Molecular and Cellular Cognition Society meeting, I'll be giving a short talk there on Friday (Nov 14) at 4:20 pm
event.fourwaves.com/MCCS25/pages
event.fourwaves.com/MCCS25/pages
I'll be presenting a poster on this at SFN on Monday morning, poster QQ5. Come say hi!
Looking forward to hearing about all the great science everyone's been doing!
Looking forward to hearing about all the great science everyone's been doing!
🚨Our preprint is online!🚨
www.biorxiv.org/content/10.1...
How do #dopamine neurons perform the key calculations in reinforcement #learning?
Read on to find out more! 🧵
www.biorxiv.org/content/10.1...
How do #dopamine neurons perform the key calculations in reinforcement #learning?
Read on to find out more! 🧵
November 13, 2025 at 6:48 PM
I'll be presenting a poster on this at SFN on Monday morning, poster QQ5. Come say hi!
Looking forward to hearing about all the great science everyone's been doing!
Looking forward to hearing about all the great science everyone's been doing!
Reposted by Malcolm Campbell
How do VTA DA neurons sculpt downstream representations to reinforce actions? VERY excited about our new preprint (by Alex Pan Vazquez & @czimmerman.bsky.social )
VTA dopamine neuron activity produces spatially organized value representations https://www.biorxiv.org/content/10.1101/2025.11.04.685995v1
November 7, 2025 at 8:46 PM
How do VTA DA neurons sculpt downstream representations to reinforce actions? VERY excited about our new preprint (by Alex Pan Vazquez & @czimmerman.bsky.social )
Reposted by Malcolm Campbell
How does the brain balance learning new things without overwriting what it already knows? Our new paper tackles this long-standing stability–plasticity dilemma during active navigation. With Tony Drinnenberg from the Deisseroth Lab (@deisseroth.bsky.social)
doi.org/10.1101/2025...
doi.org/10.1101/2025...
Environmental Novelty Modulates Rapid Cortical Plasticity During Navigation
In novel environments, animals quickly learn to navigate, and position-correlated spatial representations rapidly emerge in both the retrosplenial cortex (RSC) and primary visual cortex (V1). However,...
doi.org
October 24, 2025 at 3:40 AM
How does the brain balance learning new things without overwriting what it already knows? Our new paper tackles this long-standing stability–plasticity dilemma during active navigation. With Tony Drinnenberg from the Deisseroth Lab (@deisseroth.bsky.social)
doi.org/10.1101/2025...
doi.org/10.1101/2025...
Reposted by Malcolm Campbell
🧠🌟🐭 Excited to share some of my postdoc work on the evolution of dexterity!
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
October 22, 2025 at 8:41 PM
🧠🌟🐭 Excited to share some of my postdoc work on the evolution of dexterity!
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
We compared deer mice evolved in forest vs prairie habitats. We found that forest mice have:
(1) more corticospinal neurons (CSNs)
(2) better hand dexterity
(3) more dexterous climbing, which is linked to CSN number🧵
Ezra Klein show?
October 11, 2025 at 10:52 PM
Ezra Klein show?
Reposted by Malcolm Campbell
Finally out: our recent work with Nick Betley is a view into how the brain reshapes its behavior in the face of competing survival needs- and also a potential angle on treatment targets for enduring pain.
A brief rundown...
www.nature.com/articles/s41...
A brief rundown...
www.nature.com/articles/s41...
A parabrachial hub for need-state control of enduring pain - Nature
Activity in a set of parabranchial neurons in the mouse brain is increased during chronic pain, predicts coping behaviour, and can be modulated by circuits activated by survival threats.
www.nature.com
October 9, 2025 at 1:15 PM
Finally out: our recent work with Nick Betley is a view into how the brain reshapes its behavior in the face of competing survival needs- and also a potential angle on treatment targets for enduring pain.
A brief rundown...
www.nature.com/articles/s41...
A brief rundown...
www.nature.com/articles/s41...
Reposted by Malcolm Campbell
Had a blast writing about this new @currentbiology.bsky.social study from @leo-perrier.bsky.social, Lény Lego et al. on African striped mice
The paper: doi.org/10.1016/j.cu...
Dispatch with some context about why it's so cool: authors.elsevier.com/a/1luVG3QW8S...
#bioacoustics
#neuroskyence
The paper: doi.org/10.1016/j.cu...
Dispatch with some context about why it's so cool: authors.elsevier.com/a/1luVG3QW8S...
#bioacoustics
#neuroskyence
Ultrasonic signals support a large-scale communication landscape in wild mice. 👇 New paper by the ENES Bioacoustics Research Team in @currentbiology.bsky.social
authors.elsevier.com/a/1llMH3QW8S...
authors.elsevier.com/a/1llMH3QW8S...
authors.elsevier.com
October 6, 2025 at 6:37 PM
Had a blast writing about this new @currentbiology.bsky.social study from @leo-perrier.bsky.social, Lény Lego et al. on African striped mice
The paper: doi.org/10.1016/j.cu...
Dispatch with some context about why it's so cool: authors.elsevier.com/a/1luVG3QW8S...
#bioacoustics
#neuroskyence
The paper: doi.org/10.1016/j.cu...
Dispatch with some context about why it's so cool: authors.elsevier.com/a/1luVG3QW8S...
#bioacoustics
#neuroskyence
Reposted by Malcolm Campbell
Did you know that facial expressions reveal more than meets the eye? 🤯
Our new study shows that even a mouse's face 🐭 can reflect hidden neural computations🧠. Turns out, facial expressions are more than just emotions!
We're so excited to see this paper out @natneuro.nature.com 🎉
🔗: rdcu.be/eIQzO
Our new study shows that even a mouse's face 🐭 can reflect hidden neural computations🧠. Turns out, facial expressions are more than just emotions!
We're so excited to see this paper out @natneuro.nature.com 🎉
🔗: rdcu.be/eIQzO
Facial expressions in mice reveal latent cognitive variables and their neural correlates
Nature Neuroscience - The face reveals more than just emotion. Cazettes, Reato and colleagues show that subtle facial movements reveal hidden cognitive states, reflecting the brain’s ongoing...
rdcu.be
September 30, 2025 at 11:30 AM
Did you know that facial expressions reveal more than meets the eye? 🤯
Our new study shows that even a mouse's face 🐭 can reflect hidden neural computations🧠. Turns out, facial expressions are more than just emotions!
We're so excited to see this paper out @natneuro.nature.com 🎉
🔗: rdcu.be/eIQzO
Our new study shows that even a mouse's face 🐭 can reflect hidden neural computations🧠. Turns out, facial expressions are more than just emotions!
We're so excited to see this paper out @natneuro.nature.com 🎉
🔗: rdcu.be/eIQzO
Thanks Kameron!
September 29, 2025 at 11:25 AM
Thanks Kameron!
Also thank you, I’m really glad you enjoyed it!
September 29, 2025 at 1:13 AM
Also thank you, I’m really glad you enjoyed it!
It didn’t make it into the preprint but dopamine neurons respond to D2 stim as a sign-flipped TD error, which fits nicely in that framework
September 29, 2025 at 12:49 AM
It didn’t make it into the preprint but dopamine neurons respond to D2 stim as a sign-flipped TD error, which fits nicely in that framework
Great question… my current thinking based on plasticity rules is that they learn pessimistically biased sign-flipped value from dopamine dips, as in @sromeropinto.bsky.social’s and Adam Lowet’s papers
September 29, 2025 at 12:49 AM
Great question… my current thinking based on plasticity rules is that they learn pessimistically biased sign-flipped value from dopamine dips, as in @sromeropinto.bsky.social’s and Adam Lowet’s papers
Thanks Alex!
September 21, 2025 at 4:18 PM
Thanks Alex!