New study reveals preconfigured neural activity in human brain organoids and early mouse cortex
Source: https://bsse.ethz.ch/news-and-events/d-bsse-news/2025/12/new-study-reveals-preconfigured-brain-activity-patterns-in-human-brain-organoids.html Parent: https://bsse.ethz.ch/news-and-events/d-bsse-news.html?AUTHOR=Q2Fyb2xpbiBBcm5kdCBGb3BwYQ&path=L2NvbnRlbnQvc3BlY2lhbGludGVyZXN0L2Jzc2UvZGVwYXJ0bWVudC9lbi9uZXdzLWFuZC1ldmVudHMvamNyOmNvbnRlbnQvcGFyL25ld3NmZWVkXzQzMTg
A new paper published in Nature Neuroscience shows that the human brain may develop fundamental patterns of activity long before it receives any external input. Research – led by scientists from the University of Santa Cruz in California in a collaboration with the Hierlemann lab – demonstrates that developing brain organoids, i.e. tiny, lab-grown models of the human brain, naturally generate structured sequences of neuronal firing that closely resemble patterns seen in brains of newborn mice.
Neuronal firing sequences are thought to be essential for how the brain processes and transmits information. But scientists have long debated when these sequences first appear: do they emerge as a result of experience, or are they built into the developing brain from the start?\
“Using advanced recording devices with cortical slices allowed us to study these patterns in detail. Observing spike sequences emerge in early circuits is a striking indication of them being part of the brain’s developmental programme.”
Julian Bartram, contributing author and senior researcher in the Bio Engineering lab of Andreas Hierlemann
The new study provides strong evidence for this hypothesis. Researchers monitored spontaneous neural activity in both human and mouse brain organoids, as well as in slices of newborn mouse cortices, the latter of which were studied in the Bio Engineering Lab of Andreas Hierlemann using microelectronic devices of extremely high electrode density (3500 electrodes per square millimetre). Across all of these three systems, they observed repetitive defined firing sequences – some highly defined and others more flexible. These sequences could not be found in cultures of dissociated neurons, suggesting that the architecture of an organised brain-like tissue is necessary for such patterns to emerge.
Together, the described findings indicate that early brain circuits are shaped by an inherent developmental programme rather than by external input or experience. By showing that organoids naturally recapitulate these early firing dynamics, the study highlights their value as models for understanding how the human brain develops and establishes its fundamental wiring. The research opens new avenues for studying brain development, neurodevelopmental disorders, and the basic principles that govern how neural circuits form and function.
Find original publication in Nature Neuroscience:
van der Molen, T., A. Spaeth, M. Chini and colleagues (2025) external page Preconfigured neuronal firing sequences in human brain organoids. Nature Neuroscience, https://doi.org/10.1038/s41593-025-02111-0
Learn about research in the Bio Engineering Lab (BEL) led by Andreas Hierlemann; news post on this study.