Better Together

Organoids are tiny, three-dimensional, lab-grown clumps of tissue that share certain cell-types, structures and functions of the organ they represent. Compared with cells grown in a dish, organoids offer scientists superior models for studying various developmental and disease processes. Now, these superior models have themselves been further improved, and the image shows one such advance. Two types of organoid – thalamus (pink) and cortex (green) – are being grown together as a brain assembloid, which enables researchers to study how different parts of the organ interact. These particular assembloids were shown to form synapses between the two regions, with the thalamus actively promoting maturation of the cortical circuitry – such maturation was not seen when cortical organoids were grown alone. So, whether studying the brain or any other organ, creating assembloid cultures can provide valuable physiological context that organoids grown alone might lack.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image from work by Masatoshi Nishimura and colleagues
• Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
• Image originally published with a Creative Commons Attribution – NonCommercial – NoDerivs (CC BY-NC-ND 4.0)
• Published in Proceedings of the National Academy of Science (PNAS), November 2025