AUTHOR=Al Noman Abdullah , Alhudhaibi Abdulrahman Mohammed , Afroza Moushumi , Tonni Susmita Deb , Shehab Habibul Mohsin , Jahan Iba Nusrat , Taha Tarek H. , Abdallah Emad M. TITLE=Neuroplasticity and the microbiome: how microorganisms influence brain change JOURNAL=Frontiers in Microbiology VOLUME=Volume 16 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1629349 DOI=10.3389/fmicb.2025.1629349 ISSN=1664-302X ABSTRACT=Neuroplasticity, the brain's ability to reorganize and adapt, has traditionally been attributed to external stimuli, learning, and experience. However, emerging research highlights the gut microbiota as a key modulator of neuroplasticity through the gut-brain axis. This review examines the mechanisms by which intestinal microorganisms influence brain function, including microbial metabolite production, immune system modulation, neurotransmitter synthesis, and hormonal regulation. Dysbiosis, or microbial imbalance, has been linked to neurodevelopmental disorders, major depressive disorder (MDD), and cognitive impairments, emphasizing the microbiome's role in psychiatric and neurological health. Animal and human studies suggest that microbiota-targeted interventions, such as probiotics, prebiotics, and dietary modifications, may enhance neuroplasticity and mitigate mental health disorders. Future research should focus on understanding direct microbial-neuronal interactions and developing personalized microbiome-based therapies. This study underscores the gut microbiota's potential as a novel target for improving brain plasticity and mental health outcomes.