EVANSTON, IL, November 21, 2023 – The microscopic world within our guts isn’t just about digestion; it’s actively shaping how our brains function, according to a groundbreaking new study.Researchers have discovered a direct link between the gut microbiome and brain activity, suggesting that the composition of gut bacteria can influence cognitive processes and even contribute to neurodevelopmental conditions.
Gut Microbes: A Surprising Influence on Brainpower
Table of Contents
New research reveals how the gut microbiome directly impacts brain function, offering insights into evolution and potential treatments for neurological disorders.
- The gut microbiome influences brain function across primate species.
- Mice receiving gut microbes from primates with larger brains exhibited increased activity in genes linked to learning and energy production.
- Microbial imbalances might potentially be linked to neurodevelopmental conditions like ADHD,schizophrenia,and autism.
- This research provides the first direct experimental evidence of the microbiome’s role in shaping brain differences.
Humans possess the largest brain size relative to body size of any primate,yet the evolutionary mechanisms driving this development-and the immense energy demands it requires-remain largely mysterious. Now, researchers at Northwestern University have uncovered a surprising connection: the gut microbiome.
The Experiment
In a laboratory experiment, they introduced gut microbes from two large-brain primate species-humans and squirrel monkeys-and one small-brain primate species-macaques-into mice that had been raised without any gut microbes of their own.
After eight weeks, the researchers observed notable differences in brain activity. Mice that received microbes from small-brain primates exhibited distinct patterns of brain function compared to those that received microbes from large-brain primates.
Changes in Brain Genes and Learning Pathways
Mice given microbes from large-brain primates showed heightened activity in genes associated with energy production and synaptic plasticity-the brain’s ability to learn and adapt. conversely, these same pathways where significantly less active in mice that received microbes from smaller-brained primates.
“What was super fascinating 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. “Simply put, we were able to make the brains of mice look like the brains of the actual primates the microbes came from.”
Unexpected Links to Neurodevelopmental Conditions
The researchers also uncovered an unexpected and perhaps significant finding.Mice that received microbes from smaller-brained primates displayed gene expression patterns associated with ADHD, schizophrenia, bipolar disorder, and autism.
While previous studies have identified correlations between conditions like autism and differences in gut microbiome composition, direct evidence demonstrating a causal link has been limited.
“This study provides more evidence that microbes may causally contribute to these disorders — specifically, the gut microbiome is shaping brain function during development,” Amato said. “Based on our findings, we can speculate that if the human brain is exposed to the actions of the ‘wrong’ microbes, it’s development will change, and we will see symptoms of these disorders, i.e., if you don’t get exposed to the ‘right’ human microbes in early life, your brain will work differently, and this may lead to symptoms of these conditions.”
Implications for Understanding Brain Development
Amato believes these findings have crucial clinical implications, notably for understanding the origins of certain psychological disorders and for approaching brain development from an evolutionary perspective.
“It’s interesting to think about brain development in species and individuals and investigating whether we can look at cross-sectional, cross-species differences in patterns and discover rules for the way microbes are interacting with the brain, and whether the rules can be translated into development as well.”
The study, titled “Primate gut microbiota induce evolutionarily salient changes in mouse neurodevelopment,” was published by the Proceedings of the National academy of Sciences of the United States of America.
