Brain Evolution News

Witmer with a 3D print of the brain endocast of Tyrannosaurus rex on exhibit at the Fukui Prefecture Dinosaur Museum in Fukui, Japan, based on CT scanning of AMNH 5117.

3D print of the brain endocast of Tyrannosaurus rex on exhibit at the Fukui Prefecture Dinosaur Museum in Fukui, Japan, based on CT scanning of AMNH 5117.

We published on the braincase and endocast of tyrannosaurs way back in 2009: https://bit.ly/47fChUf

More on National Fossil Day here: https://www.nps.gov/subjects/fossilday/index.htm

It's #NationalFossilDay here in the USA, so here's a photo of our T. rex brain endocast based on a US national fossil—AMNH 5117. The surprise was to see it on exhibit in Japan at the Fukui Prefectural Dinosaur Museum. Feel free to print one of your own: skfb.ly/Mqsq ! 🦖

Image credits: Federica Marinaro

Thrilled to share that I’ve successfully defended my PhD thesis on human brain evolution at @humantechnopole.bsky.social 🎓 A heartfelt thank you to everyone who has been part of this journey. Excited for what comes next!

One motivation behind this review was that recently, I learned that neurobiologists knew of Ludwig Edinger while paleontologists knew of Tilly Edinger, his daugther. It made me realized how much, we had been disconnected from one another. I hope that this review brings these fields closer again ☺️

The functional adaptations of mammalian brain structures through a behavioural ecology lens - Nature Reviews Biodiversity Palaeontologists and comparative neurobiologists share a common interest in the evolution of the mammalian brain, but often fail to realize the benefits of this shared interest. This Review draws thes...

New paper out! It was an honor to collaborate with the legend Leah Krubitzer on this review to show that paleontologists and neurobiologists working together can only improve our understanding of brain evolution 🧠
www.nature.com/articles/s44...

Full access to the paper: rdcu.be/eK167

From nociception in aneural animals to human suffering: toward a comparative biology of pain Summary: The biology of widely shared and unusual features of human pain is informed by functional and mechanistic comparisons of nociception and pain-like aversive states across vertebrate and invert...

2025. From nociception in aneural animals to human suffering: toward a comparative biology of pain url: journals.biologists.com/jeb/article-...

Can Only Meat Machines be Conscious? New paper in Trends in Cognitive Sciences, free download until November 26 with this URL: authors.elsevier.com/a/1luwh4sIRv...

Impact of intermittent lead exposure on hominid brain evolution Lead exposure, as influenced by NOVA1 expression, affected brain function in multiple hominid species.

Homo no-lead-i. ... in seriousness, this is an interesting new paper! www.science.org/doi/10.1126/...

The functional adaptations of mammalian brain structures through a behavioural ecology lens Nature Reviews Biodiversity, Published online: 15 October 2025; doi:10.1038/s44358-025-00095-0Palaeontologists and comparative neurobiologists share a common interest in the evolution of the mammalian brain, but often fail to realize the benefits of this shared interest. This Review draws these fields together, demonstrating the utility of a cross-disciplinary, synergistic approach.

New online! The functional adaptations of mammalian brain structures through a behavioural ecology lens

Excited to share our new #biorxivpreprint:
“Sexual dimorphism in the complete connectome of the Drosophila male central nervous system” www.biorxiv.org/content/10.1...

We describe the #connectomics reconstruction and analysis of an entire adult #maleCNS #drosophila central nervous system. 1/10

Evolution of intelligence in our ancestors may have come at a cost By tracing when variations in the human genome first appeared, researchers have found that advances in cognitive abilities may have led to our vulnerability to mental illness

Evolution of intelligence in our ancestors may have come at a cost
www.newscientist.com/article/2499...

Ancient Lead Exposure Influenced the Evolution of the Human Brain A groundbreaking new study has profoundly reshaped our understanding of lead exposure and its impact on human evolution, revealing that the toxic metal’s influence extends back nearly two million y

Ancient Lead Exposure Influenced the Evolution of the Human Brain
bioengineer.org/ancient-lead...

Evolution may have capped human brain size to balance energy costs and survival Human brain growth slowed about 300,000 years ago, research in Brain & Cognition suggests. Energy demands and shifting climates may have capped brain size, pushing survival toward cultural innovations...

Evolution may have capped human brain size to balance energy costs and survival
www.psypost.org/evolution-ma...

Moreover, AGI might also require social interactions to become a reality, where cultural evolution (and extended mind) play a major role. It is not by chance that brain and culture evolved together, allowing complex minds to emerge @anilseth.bsky.social @mitibennett.bsky.social

An evolutionary perspective is much required to truly understand consciousness, how it originates and what clases we might find. We proposed a space of possible cognitions and did a comparative analysis

Can general artificial intelligence emerge by not following the evolution of complex brains? In this 2022 paper with @brigan.bsky.social we argued that embodiment, mind reading (mirror systems), mental time traveling... are necessary conditions
www.mdpi.com/1099-4300/24... @anilseth.bsky.social

a man in a suit and tie is giving a thank you sign . ALT: a man in a suit and tie is giving a thank you sign .

Thanks to Arendt group: Detlev, Leslie, Tobi, Nico @galicae.bsky.social and Phil. My amazing students @gulceserka.bsky.social, @anaverbanac.bsky.social,Maite and Dori. Huge thanks to the Kaessmann lab for all their support and fruitful discussions @kaessmannlab.bsky.social @evo-and-devo.bsky.social

We now have a unique opportunity to keep developing cartilaginous fish models. Throug their study we will be able to explore how these and other features evolved across vertebrates and uncover the molecular mechanisms driving brain evolution. Stay tuned for more discoveries and tool developments!

a stuffed shark is standing in front of a fire ALT: a stuffed shark is standing in front of a fire

Our study moved the postulated origin of several developmental pallial features back to the jawed common ancestor. We hypothesize these features likely contributed to the increased complexity of their brains coincident with the emergence of predation.

Using the plasmid, we showed that the dorsal pallial area gives rise to a layered structure aligned with the positions of Reelin and CRs. Moreover, this structure corresponds with a complex anatomical region that brings together glutamatergic and GABAergic neurons, likely forming a complex circuitry

We developed a protocol to label shark neural tissue with a reporter plasmid- First time this is achieved in a Cartilaginous Fish! Impossible without (bluesky-less) Maite Boersig, Isabel Rollán, Dori Torres-Sabino and Rami Reshef. The coolest shark team ever!🦈💙

schema showing that sharks and all other tetrapods develop their telencephalons by evagination, while only the bony fish lineage develop everted telencephalons

Till recently, bony fish have been the main fish reference group for comparative purpose, but contrary to cartilaginous fish, they are evolutionary speedsters, with brains that have taken unique paths.

In our lab we study the evolutionary origin of neurons and nervous systems. For this we use #choanoflagellates & #ctenophores as model organisms. Enjoy this beautiful ctenophore Mnemiopsis leidyi filmed in our facility in Bergen: www.uib.no/en/michaelsa... #evolution #origin #neuron

Another key finding of our work is that nervous systems may have became centralized EARLIER than previously assumed 🤩.

We found that the ctenophore aboral organ is tightly associated with a condensed SYNCYTIAL nerve net. See below: comparison of regular vs. condensed nerve net.

The aboral organ of a 1-day-old ctenophore is composed of ca. 900 cells, encompassing 17 distinct cell types 🤩. Below are examples for each cell type.

#cilia #sensory #vesicles #diversity #neuron

13. Gabi et al. 2010, Brain Behav Evol, doi:10.1159/000319872

9. Cunha et al. 2022, Front Neuroanat, doi:10.3389/fnana.2022.1048261
10. Teles et al. 2012, J Comp Physiol A, doi:10.1007/s00359-012-0721-6
11. Zupanc 1999, J Exp Biol, doi:10.1242/jeb.202.10.1435
12. Zupanc 2021, J Exp Biol, doi:10.1242/jeb.226357

5. Olkowicz et al. 2016, PNAS, doi:10.1073/pnas.1517131113
6. Kverková et al. 2022, PNAS, doi:10.1073/pnas.2121624119
7. Herculano-Houzel et al. 2011, Brain Behav Evol, doi:10.1159/000330825
8. Herculano-Houzel et al. 2015, Front Neuroanat, doi:10.3389/fnana.2015.00064

Bibliography:

1. Jerison 1973, Evolution of the Brain and Intelligence, Academic Press
2. Marhounová et al. 2019, Evolution, doi:10.1111/evo.13805
3. Herculano-Houzel et al. 2007, PNAS, doi:10.1073/pnas.0611396104
4. Herculano-Houzel et al. 2014, Front Neuroanat, doi:10.3389/fnana.2014.00077

Over generations, step changes → cohorts diverge in brain, body & neuron number.
Some clades (primates, parrots, songbirds) evolve bigger brains with more neurons; others (rodents, sauropsids, mammals) grow brains faster than neurons → lower density 3-6,13.
👉 Plasticity drives brain diversity.

Across cohorts (different densities):
🐟 Larger fish → larger brains with up to 20× more neurons.
Neuron density = constant or decreasing.
📐 This mirrors well-known interspecies scaling patterns, even though all fish came from the same stock.