Researchers Explore the Microbiome Brain Connection
Northwestern University researchers have identified a striking link between gut microbial composition and brain function, suggesting that shifts in the microbiome may influence how the mind operates. Dr. Katie Amato, who led the study, emphasized that the findings point to microbial contributions that could illuminate traits shaped through human evolution. Prior work from her team indicated that microbes collected from primates with larger brains boosted metabolic energy production when transferred into mice. Increased energy availability is widely considered essential for supporting larger brains with high metabolic demands.
Experiment Tests Microbes from Primates with Different Brain Sizes
The latest study, published in PNAS, examined the brain directly by assessing whether transferring microbes from primates with different brain sizes could alter neural function in germ free mice. The researchers introduced microbial communities from humans and squirrel monkeys, both larger brained primates, as well as from macaques, which have smaller brains. After 8 weeks, the mice displayed distinct changes in brain activity that corresponded to the species origin of the microbes they received.
Microbes from Larger Brains Boosted Key Gene Activity
Mice colonized with microbes from larger brained primates showed elevated expression of genes linked to energy production and synaptic plasticity, processes essential for learning and neural circuit adaptability. Those that received microbes from smaller brained primates exhibited reduced expression of these genes. Dr. Amato noted that comparisons between mouse brain gene expression patterns and data from humans and macaques revealed shared patterns, demonstrating that the mice developed molecular profiles resembling the primates that donated their microbes.
Findings Tie Some Microbial Profiles to Psychiatric Disorders
The team also identified gene expression signatures associated with conditions such as ADHD, schizophrenia, bipolar disorder and autism in mice colonized with microbes from smaller brained primates. Evidence has previously hinted at links between these disorders and microbiome differences, yet data directly supporting a causal role in shaping brain function has been limited. Dr. Amato stated that the results raise the possibility that the microbiome may play a contributing role in certain disorders by influencing brain development. She added that exposure to microbial communities that are not well matched to developmental needs could alter neural processes and potentially relate to symptom emergence.
Implications for Clinical Research and Evolutionary Science
The findings may hold clinical relevance for understanding the biological mechanisms involved in psychological and psychiatric conditions while also offering fresh insight into brain development from an evolutionary perspective. Researchers believe this work may guide future studies examining how the microbiome and brain co evolved and how microbial factors might inform approaches to human health.
