“The inflammatory process causes the gut vascular barrier to become more permeable, resulting in the spread of inflammation beyond the intestine, while the vascular barrier in the choroid plexus shuts down, helping protect the brain from inflammation but also potentially impairing communication between organs and impairing some brain functions.”
Paper: DOI: 10.1126/science.abc6108
Article: https://www.genengnews.com/news/gut-brain-axis-may-drive-ibd-linked-psychiatric-symptoms/