---
title: "Human brain cells transplanted into mice to study disease"
publication: "MediaBias News"
url: "https://mediabias.news/tech/human-brain-cells-transplanted-into-mice-to-study-disease"
api: "https://mediabias.news/api/v1/stories/human-brain-cells-transplanted-into-mice-to-study-disease"
markdown: "https://mediabias.news/tech/human-brain-cells-transplanted-into-mice-to-study-disease.md"
audio: "https://mediabias.news/api/audio/human-brain-cells-transplanted-into-mice-to-study-disease"
category: "Science & Tech"
published: "2026-09-16T19:46:37.263Z"
source_reported: "2026-09-16T19:09:02.000Z"
updated: "2026-09-16T19:46:37.263Z"
trust_score: 42
critic_score: 61
hype_score: 41
assessment_type: "coverage-and-source-reporting-analysis"
fact_check_status: "not-performed"
coverage_measured: "2026-09-16T21:00:10.066053+00:00"
---

# Human brain cells transplanted into mice to study disease

*Researchers replaced parts of mouse cerebral cortex with lab-grown human neurons, showing improved function and human-like responses.*

**Scores for the source reporting** (0-100, assessing the original journalism this article was written from, not this write-up): 

- Trust 42 of 100, higher is better. Central claim attributed to named body, with two independent outlets and specific date and location.
- Craft 61 of 100, higher is better. Reporting includes quotes from affected parties, names specific figures, and states what happens next.
- Hype 41 of 100, lower is better. Headlines promise a breakthrough and new avenues for cures, with some loaded adjectives.

Scored by MediaBias News; method at https://mediabias.news/methodology.

**The short version**

- Researchers have developed a method to implant millions of human brain cells into mice by replacing parts of their cerebral cortex.
- This technique allows for the study of neurodegenerative diseases and human brain function in a more natural environment than a petri dish.
- The altered mice demonstrated improved memory tasks, better interaction with other mice, and exhibited human-like responses to low-oxygen conditions.
- The research raises ethical questions regarding the implications of this technique in larger animals and the treatment of these mice.

Scientists have developed a new method to transplant lab-grown human brain cells into mice, aiming to create better models for studying neurodegenerative diseases and human brain function. The technique involves genetically engineering mice to lack significant portions of their cerebral cortex and then replacing these areas with human neurons.

The human brain cells, grown in a lab, were implanted into the genetically engineered mice. These altered mice showed improvements in memory tasks and social interaction compared to their unmodified counterparts. Furthermore, they displayed human-like reactions to low-oxygen conditions, a response not seen in regular mice. Researchers suggest this offers a more integrated biological system for studying brain conditions than traditional laboratory models.

## Disagreement on integration and function

While some reports indicate the human brain cells integrated and occupied over 90% of the available space, others suggest they did not organize on a larger scale. Ars Technica noted that the results were only a slight improvement over mice missing the entire brain structure. However, multiple outlets reported that the human cells formed functional neural networks and integrated into the animal's nervous system.

## What the coverage left out

None of the digests mention the specific number of mouse neurons removed or the exact volume of the human cortical neurons added. The full report from NPR states that researchers removed approximately 14 million mouse neurons and added around 4 million human cortical neurons, a detail not present in the digests.

## Who covered it

Shares of the 35 covering outlets with a published leaning rating:

- Left: 31% (11)
- Centre: 49% (17)
- Right: 20% (7)

16 of 51 covering outlets carried no usable leaning rating and were excluded from those percentages. Coverage measured 2026-09-16T21:00:10.066053+00:00.

**Coverage watch:** developing. Checked 8 times; 0 checks found a material change. Most recently checked 2026-09-16T21:45:13.748Z.

## How the sides framed it

### Left

- Left-rated reports highlighted the potential of the research to study neurodegenerative diseases and human brain function, with many mentioning Sergiu Pașca, the Romanian-led Stanford team. Outlets like Gizmodo and Le Monde focused on the scale of the achievement, with Gizmodo stating scientists grew more human brain tissue in a mouse than ever before. The ethical questions raised by the research were also a common theme, as seen in headlines from Le Monde and IndexHR. Several reports, including those from HotNews.ro and El Pais, emphasised the potential for new treatments for serious diseases like schizophrenia and epilepsy.

### Centre

- Centre-rated reports focused on the technical achievement and its implications for disease research. BBC News described it as a "science breakthrough" and highlighted the genetic alteration of mice to receive human brain cells. Medical Xpress and ElNacional.cat noted that the engineered mice provided space for human brain organoids to form working circuits and occupy more than 90% of the cortex. Reuters and 20minutos reported on the transplantation of lab-grown human brain tissue into mice, suggesting it could speed research into devastating disorders and accelerate study into neurological disorders.

### Right

- Right-rated reports, such as those from Korrespondent.net and Globo, focused on the creation of mice with a significant portion of their brains being human. Regional Media News and Independent Journal Review highlighted the transplantation of lab-grown human brain tissue and organoids into mice engineered to lack most of their cortex. ABC.es reported that scientists grafted human neurons into "half-brained" mice, regaining their capabilities. The potential for studying neurological disorders was a common thread across these reports.

## Factuality profile of the covering outlets

These are published factuality ratings of the outlets, not a verdict on whether this story or its claims are true.

- mixed: 2
- high: 11
- unknown: 16
- veryHigh: 22

## Verification scope

This page compares coverage and scores the source reporting. It is not a ClaimReview verdict on whether the underlying event or claim is true.

## Original reporting this was written from

- [robertocavada.com](https://robertocavada.com/cultivan-tejido-cerebral-humano-en-modelos-de-raton-para-el-futuro-estudio-de-enfermedades) — Cultivate Human Brain Tissue in Mouse Models for Future Disease Study
- [Gândul](https://gandul.ro/educatie/experimentul-revolutionar-al-unui-cercetator-roman-la-stanford-ar-putea-vindeca-boli-grave-a-reusit-sa-transplanteze-tesut-cerebral-uman-la-soareci-21009956) — The Revolutionary Experiment of a Romanian Researcher at Stanford Could Cure Serious Diseases. He Managed to Transplant Human Brain Tissue Into Mice.
- [Adevarul](https://adevarul.ro/stil-de-viata/stiinta/cercetatorii-au-creat-soareci-cu-tesut-cerebral-2558064.html) — Researchers Have Created Mice with Human Brain Tissue. The Experiment, Coordinated by a Romanian From Stanford University
- [Hot News](https://hotnews.ro/realizare-de-exceptie-a-unei-echipe-de-la-stanford-condusa-de-un-roman-un-succes-ce-deschide-calea-catre-vindecarea-unor-boli-grave-2350928) — A Team of Researchers at Stanford, Led by a Romanian, Transplanted Human Brain Tissue to Mice: "Opens the Way for the Cure of Serious Diseases - HotNews.ro
- [Ars Technica](https://arstechnica.com/science/2026/09/researchers-swap-in-human-brain-cells-for-a-mouses-cortex) — Researchers swap in human brain cells for a mouse's cortex
- [jurnalul.ro](https://jurnalul.ro/stiri/observator/premiera-in-medicina-un-cercetator-roman-a-transplantat-celule-cerebrale-umane-la-soareci-1044418.html) — Primera in Medicine: A Romanian Researcher Transplanted Human Brain Cells to Mice
- [Korrespondent.net](https://korrespondent.net/tech/science/4912348-uchyonye-sozdaly-myshei-s-napolovynu-chelovecheskym-mozghom) — Scientists Created Mice with Half a Human Brain.
- [Unknown](https://neakriti.gr/kosmos/2200280_anthropinos-egkefalikos-istos-rizose-ston-egkefalo-pontikion-protofanes-peirama-poy) — Human Brain Tissue "Rooted" in the Brains of Mice - The Unprecedented Experiment that Opens New Paths in Medicine (Pics)
- [Mediafax](https://mediafax.ro/life-inedit/un-cercetator-roman-de-la-stanford-in-spatele-unui-experiment-fara-precedent-tesut-cerebral-uman-transplantat-in-soareci-23808560) — A Romanian Researcher From Stanford, Behind an Unprecedented Experiment: Human Brain Tissue, Transplanted Into Mice
- [Pančevo 013 info](https://013info.rs/zanimljivosti/naucnici-uzgojili-ljudsko-mozdano-tkivo-u-misevima) — Scientists Have Grown Human Brain Tissue in Mice
- [regionalmedianews.com](https://regionalmedianews.com/news/national/health/scientists-transplant-lab-grown-human-brain-tissue-into-mice) — Scientists transplant lab-grown human brain tissue into mice - Regional Media News
- [antena3.ro](https://antena3.ro/life/experiment-fara-precedent-un-profesor-roman-si-echipa-lui-de-la-stanford-au-creat-soareci-cu-creiere-pe-jumatate-umane-803504.html) — Unprecedented Experiment: a Romanian Teacher and His Stanford Team Created Half-Human Mice with Brains
- [Globo](https://g1.globo.com/ciencia/noticia/2026/09/16/cientistas-fazem-ratos-com-metade-do-cerebro-humano.ghtml) — Scientists Make Rats with Half the Human Brain
- [delo.si](https://delo.si/novice/svet/bolezni-mozganov-misi-raziskave-bolezni) — New Model for Studying Complex Brain Diseases
- [Unknown](https://eleftherostypos.gr/tech/den-einai-epistimoniki-fantasia-erevnites-dimiourgisan-pontikia-me-anthropino-egkefalo) — It's Not Science Fiction: Researchers Have Created Mice with Human Brains
- [IndexHR](https://index.hr/vijesti/clanak/ljudsko-mozdano-tkivo-uspjesno-uzgojeno-unutar-miseva/2835351.aspx) — Human Brain Tissue Successfully Grown Inside Mice
- [ElNacional.cat](https://elnacional.cat/ca/societat/ratolins-milions-neurones-humanes-obren-nova-via-estudiar-trastorns-neurologics_1696366_102.html) — Mice with Millions of Human Neurons Open a New Avenue for Studying Neurological Disorders
- [20minutos](https://20minutos.es/salud/cientificos-logran-injertar-tejido-humano-ratones-sin-corteza-cerebral-que-ayudara-estudio-trastornos-neurologicos_7037643_0.html) — They Manage to Graft Human Tissue Into Mice without Cerebral Cortex, Which Will Help the Study of Neurological Disorders
- [El Mundo](https://elmundo.es/salud/2026/09/16/6aaaa6aee4d4d8c0078b45b2.html) — A New Mouse Model Facilitates the Integration of Human Mini Brains
- [BBC News](https://bbc.co.uk/news/articles/c60m3k28j81mo) — Part-human part-mouse brain developed in science breakthrough
- [Independent Journal Review](https://ijr.com/discover/science-2026-09-16-human-brain-organoids-build-circuits-cortexless-mice-1f200b47) — Human Brain Organoids Build Circuits in Cortex-Less Mice
- [Le Monde](https://lemonde.fr/sciences/article/2026/09/16/des-cellules-cerebrales-humaines-implantees-dans-le-cerveau-de-souris_6775425_1650684.html) — Human Brain Cells Implanted in the Mouse Brain
- [elDiarioAR](https://eldiarioar.com/ciencia/primer-raton-corteza-cerebral-humana-permitira-investigar-mejor-enfermedades-psiquiatricas_1_13515506.html) — The First Mouse with a "Human" Cerebral Cortex Will Better Investigate some Psychiatric Illnesses
- [Gizmodo](https://gizmodo.com/scientists-grew-more-human-brain-tissue-in-a-mouse-than-ever-before-and-people-have-questions-2000812503) — Scientists Grew More Human Brain Tissue in a Mouse Than Ever Before—and People Have Questions
- [Medical Xpress](https://medicalxpress.com/news/2026-09-mice-human-brain-organoids-space.html) — Engineered mice give human brain organoids space to form working circuits
- [nplus1.ru](https://nplus1.ru/news/2026/09/16/brain-organoids-in-cortex) — Human Brain Organoids Built Neural Nets in Mice
- [Hola News](https://holanews.com/cultivan-tejido-cerebral-humano-en-modelos-de-raton-para-el-futuro-estudio-de-enfermedades) — Cultivate Human Brain Tissue in Mouse Models for Future Disease Study
- [diariomedico.com](https://diariomedico.com/medicina/neurologia/organoides-cerebrales-ganan-realismo-gracias-nueva-plataforma-experimental-raton.html) — Brain Organoids Gain Realism Thanks to a New Experimental Mouse Platform
- [El Pais](https://elpais.com/ciencia/2026-09-16/ratones-con-millones-de-neuronas-humanas-en-su-cerebro-acercan-la-respuesta-a-enfermedades-mentales.html) — Mice with Millions of Human Neurons in Their Brain Bring the Response to Mental Illness
- [Reuters](https://reuters.com/business/healthcare-pharmaceuticals/scientists-transplant-lab-grown-human-brain-tissue-into-mice-2026-09-16) — Scientists transplant lab-grown human brain tissue into mice
- [The Scientist](https://the-scientist.com/human-derived-brain-organoids-create-functional-networks-in-mice-74996) — Human-Derived Brain Organoids Create Functional Networks in Mice
- [BizToc](https://biztoc.com/x/a40b742461290a5b) — Scientists transplant lab-grown human brain tissue into mice
- [WTVB](https://wtvbam.com/2026/09/16/scientists-transplant-lab-grown-human-brain-tissue-into-mice) — Scientists transplant lab-grown human brain tissue into mice
- [NewScientist](https://newscientist.com/article/2589612-human-organoids-restore-cognition-in-mice-with-half-a-brain) — Human organoids restore cognition in mice with half a brain
- [endpoints.news](https://endpoints.news/researchers-implant-human-neurons-in-mice-brains-to-study-disease) — Mice with human brain cells open a new testing ground for drugmakers to study disease
- [abc](https://abc.es/ciencia/cientificos-injertan-neuronas-humanas-ratones-medio-cerebro-20260915170011-nt.html) — Scientists Graft Human Neurons Into Half-Brained Mice and Regain Their Capabilities
- [IFLScience](https://iflscience.com/human-mini-brains-have-been-transplanted-into-the-heads-of-mice-forming-new-neural-networks-84660) — Human Mini-Brains Have Been Transplanted Into The Heads Of Mice, Forming New Neural Networks
- [Eldiario.es](https://eldiario.es/sociedad/primer-raton-corteza-cerebral-humana-permitira-investigar-mejor-paralisis-cerebral-demencia_1_13512097.html) — The First Mouse with a ‘Human’ Cerebral Cortex Will Better Investigate Cerebral Palsy and Dementia
- [La Vanguardia](https://lavanguardia.com/ciencia/20260916/11636139/organoides-cerebros-humanos-crecen-ratones-estudiar-trastornos-neurologicos.html) — Human Neurons Implanted in Mice Accelerate the Study of Mental Disorders
- [Live Science](https://livescience.com/health/neuroscience/scientists-shrank-mices-brains-and-replaced-the-missing-tissue-with-human-organoids) — Scientists shrank mice's brains and replaced the missing tissue with human 'organoids'
- [Science Alert](https://sciencealert.com/scientists-grew-human-brain-tissue-inside-mice-heres-what-happened) — Scientists Grew Human Brain Tissue Inside Mice. Here's What Happened.
- [STAT](https://statnews.com/2026/09/16/human-brain-organoids-neuro-chimeric-mice-study-published-nature) — Scientists made mice with half a brain. Then they filled them with human organoids
- [thetransmitter.org](https://thetransmitter.org/spectrum/human-brain-organoids-flourish-in-emptied-mouse-cortex) — Human brain organoids flourish in emptied mouse cortex
- [Georgia Public Broadcasting](https://gpb.org/news/2026/09/16/mice-human-brain-cells-offer-tool-study-disease-ethicists-ask-whats-next) — Mice with human brain cells offer a tool to study disease. Ethicists ask: What's next?
- [npr](https://npr.org/2026/09/16/nx-s1-5968873/lab-mouse-human-brain-cells-organoid-disease-ethics) — Mice with human brain cells offer a tool to study disease. Ethicists ask: What's next?
- [KPBS](https://kpbs.org/news/science-technology/2026/09/16/mice-with-human-brain-cells-offer-a-tool-to-study-disease-ethicists-ask-whats-next) — Mice with human brain cells offer a tool to study disease. Ethicists ask: What's next?
- [ksfr.org](https://ksfr.org/npr-news/2026-09-16/mice-with-human-brain-cells-offer-a-tool-to-study-disease-ethicists-ask-whats-next) — Mice with human brain cells offer a tool to study disease. Ethicists ask: What's next?
- [Science News](https://sciencenews.org/article/mice-brain-human-organoid-cells) — These mice have human (nerve cells) on the brain
- [MIT Technology Review](https://technologyreview.com/2026/09/16/1144210/meet-a-mouse-whose-brain-cortex-is-made-up-of-human-cells) — Meet a mouse whose brain cortex is made up of human cells
- [Unknown](https://chosun.com/economy/science/2026/09/17/QR2GQYH7OJF7HLPX4GRWQWWBA4) — Human ‘Mini-Brain’ Grown in Mouse Brain… Most of the Outer Surface of the Cerebrum Filled with Human Neural Tissue
- [Nature](https://nature.com/articles/d41586-026-02912-8) — Human brain cells transplanted into mice in ‘most extensive’ integration ever

## Questions

**What did scientists do in this experiment?**

Researchers transplanted lab-grown human brain cells into genetically engineered mice. They replaced parts of the mice's cerebral cortex with these human neurons, creating a hybrid brain model for scientific study.

**What are the potential benefits of this research?**

This technique allows for a more integrated study of neurodegenerative diseases and human brain function. The altered mice showed improved memory and behaviour, potentially speeding up research into conditions like schizophrenia, epilepsy, and cerebral palsy.

**Did the human brain cells fully integrate into the mouse brain?**

Reports indicate varying degrees of integration. Some suggest the human cells occupied a large portion of the space and formed functional networks, while others noted they did not organize on a larger scale and the functional improvement was slight.

**What ethical concerns have been raised?**

The research raises ethical questions about the implications of using this technique in larger animals and the potential for consciousness to emerge in the human brain cells. Researchers have taken steps to address these concerns, such as limiting the age of the human cells in the study.

---

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