The secret to human intelligence? It might be in our gut
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Gut microbes can rewire the brain in powerful ways, according to a new study that swapped primate bacteria into mice. The mice’s brains began to function like those of the primates the microbes came from, hinting that microbes may have helped fuel the evolution of large, energy-hungry brains.
Researchers at Northwestern University have now provided the first direct experimental evidence that the gut microbiome helps shape differences in brain function across primate species.
Transplanting Primate Microbes Into Mice
To test this, the team conducted a tightly controlled laboratory experiment. They introduced gut microbes from two large-brain primate species (human and squirrel monkey) and one small-brain primate species (macaque) into mice that had no microbes of their own.
After eight weeks, the researchers observed clear differences in brain activity. Mice that received microbes from small-brain primates showed distinct patterns of brain function compared with mice that received microbes from large-brain primates.
"Our study shows that microbes are acting on traits that are relevant to our understanding of evolution, and particularly the evolution of human brains," said Katie Amato, associate professor of biological anthropology and principal investigator of the study.