Jan 9, 2026 02:13 AM
https://www.zmescience.com/science/news-...-activity/
EXCERPTS: The human brain is a greedy organ. It gulps energy, demands constant upkeep, and somehow grew far larger (relative to body size) than the brains of any other primate. Scientists have always wondered how evolution paid that bill.
A new study from Northwestern University suggests part of the answer may be alive inside us. Our gut microbes, it turns out, don’t just help digest food. They may actively shape how brains develop and function across primate species.
By transplanting gut microbes from different primates into mice, researchers found that microbes alone could push mouse brains toward activity patterns seen in humans, squirrel monkeys, or macaques.
In other words, bacteria can make a mouse brain behave — at the genetic level — like the brain of a primate.
[...] When researchers looked closely at brain tissue, they found that microbes from large-brain primates boosted activity in genes tied to energy production and synaptic plasticity.
Synaptic plasticity allows brains to learn, adapt, and rewire. It’s foundational to memory, problem-solving, and complex behavior. Those same pathways stayed quieter in mice colonized with microbes from smaller-brained primates. Then came the surprise.
“What was super interesting is we were able to compare data we had from the brains of the host mice with data from actual macaque and human brains, and to our surprise, many of the patterns we saw in brain gene expression of the mice were the same patterns seen in the actual primates themselves,” Amato said.
“In other words, we were able to make the brains of mice look like the brains of the actual primates the microbes came from.” (MORE - details)
EXCERPTS: The human brain is a greedy organ. It gulps energy, demands constant upkeep, and somehow grew far larger (relative to body size) than the brains of any other primate. Scientists have always wondered how evolution paid that bill.
A new study from Northwestern University suggests part of the answer may be alive inside us. Our gut microbes, it turns out, don’t just help digest food. They may actively shape how brains develop and function across primate species.
By transplanting gut microbes from different primates into mice, researchers found that microbes alone could push mouse brains toward activity patterns seen in humans, squirrel monkeys, or macaques.
In other words, bacteria can make a mouse brain behave — at the genetic level — like the brain of a primate.
[...] When researchers looked closely at brain tissue, they found that microbes from large-brain primates boosted activity in genes tied to energy production and synaptic plasticity.
Synaptic plasticity allows brains to learn, adapt, and rewire. It’s foundational to memory, problem-solving, and complex behavior. Those same pathways stayed quieter in mice colonized with microbes from smaller-brained primates. Then came the surprise.
“What was super interesting is we were able to compare data we had from the brains of the host mice with data from actual macaque and human brains, and to our surprise, many of the patterns we saw in brain gene expression of the mice were the same patterns seen in the actual primates themselves,” Amato said.
“In other words, we were able to make the brains of mice look like the brains of the actual primates the microbes came from.” (MORE - details)