Gut Microbes Influence Human Brain Intelligence

The Secret of Human Intelligence?

Microbes in our gut may hold the key to the development of the human brain and its ongoing functioning. A recent study from Northwestern University reveals that gut bacteria can directly influence how the brain develops and operates. Researchers found that when they transferred microbes from different species of primates to mice, the brains of these mice began to resemble those of the original host species. Microbes from primates with larger brains enhanced brain energy and learning pathways, while others triggered very different patterns. The results suggest that gut microbes may have played a hidden role in shaping the human brain and influencing mental health.

The Impact of Microbes on the Brain

The study highlighted how gut microbes can reconfigure the brain in significant ways. Northwestern University researchers presented direct experimental evidence showing that the gut microbiome contributes to functional brain differences among primate species. "Our study demonstrates that microbes influence traits relevant for understanding evolution, particularly the evolution of human brains," stated Katie Amato, Associate Professor of Biological Anthropology and principal investigator of the study.

Examining Brain Functionality

Researchers conducted a strictly controlled experiment by introducing gut microbes from two species of primates with large brains (humans and squirrel monkeys) and one species with a smaller brain (macaques) into germ-free mice. After eight weeks, distinct differences in brain activity were observed. Mice that received microbes from primates with small brains showed distinct operational brain patterns similar to those of primates with larger brains.

Associations with Neurodevelopmental Conditions

An unexpected finding was that mice receiving microbes from primates with smaller brains exhibited gene expression patterns associated with ADHD, schizophrenia, bipolar disorder, and autism. Previous studies have found correlations between conditions like autism and gut microbiome composition. "This study provides further evidence that microbes may causally contribute to these disorders—showing the gut microbiome's role in shaping brain function during development," Amato added.