Scientists just discovered a big limitation in lab-grown minibrains — they have a skewed 'sense of time'

The brain develops in stages, and it's important that certain cells form before others so that precise neural connections can emerge later. But miniature models of the brain, called organoids, may not share this same sense of time, a new study finds.

These brain organoids are clusters of lab-grown neurons that mimic structural and functional aspects of full-size brains. Some scientists use these "minibrains" to study brain disorders that can arise during fetal development.

If the precisely timed processes involved in brain development go wrong, it can lead to conditions like macrocephaly and microcephaly in which the brain grows abnormally large or small, said study co-author Simon Hippenmeyer, a neuroscientist at the Institute of Science and Technology Austria.

Because it's not possible to directly study thes...