Now, a new Northwestern University study has discovered that the brain's structural features reside in the vicinity of a similar critical point—either at or close to a structural phase transition. Surprisingly, these results are consistent across brains of humans, mice and fruit flies, which suggests the finding might be universal.

Although the researchers don't know between which phases the brain's structure is transitioning, they say this new information could enable new designs for computational models of the brain's complexity and emergent phenomena.

The research was published today in Communications Physics.

"The human brain is one of the most complex systems known, and many properties of the details governing its structure are not yet understood," said Northwestern's István Kovács, the study's senior author.

"Several other researchers have studied brain criticality in terms of neuron dynamics. But we are looking at criticality at the structural level in order to ultimately understand how this underpins the complexity of brain dynamics. That has been a missing piece for how we think about the brain's complexity. Unlike in a computer where any software can run on the same hardware, in the brain the dynamics and the hardware are strongly related."