Mechanistic · Editorial synthesis
Biological routes of microbiota–gut–brain communication
The microbiota–gut–brain axis is a bidirectional network of neural, immune, endocrine and metabolite-associated signalling, not a single pathway.
Research
Gut–Brain Axis
Bidirectional communication linking intestinal, neural, endocrine and immune systems.
Research library
Research articles
Experimental animal model · Editorial synthesis
Experimental models in microbiota–gut–brain research
Animal models enable controlled tests of barrier, microbiome, molecular and behavioural hypotheses while imposing strict limits on human translation.
Human observational · Longitudinal human protocol · Systematic review · Meta-analysis
Human evidence in microbiota–gut–brain research
Human observational and longitudinal designs reveal clinically relevant patterns and time course, but association remains distinct from mechanism and causation.
Experimental animal model · Human observational · Longitudinal human protocol · Systematic review · Meta-analysis · Editorial synthesis
From association to mechanism in gut–brain research
Observation, replication, temporal evidence, mechanism, causation, prediction and treatment effect are connected but distinct scientific claims.
Related ideas
Perspective · Regulation · Aug 25, 2026
Permeability is not the problem. Dysregulation is.
Health lies less in maintaining a fixed state than in a system’s capacity to regulate, adapt and recover. Intestinal permeability provides a biological starting point for asking when a response is appropriate—and when regulation becomes dysregulation.
Evidence interpretation · Zonulin · Aug 25, 2026
Zonulin: pathway, marker and measurement are not the same.
Zonulin provides a concrete example of a wider scientific problem: turning a dynamic regulatory mechanism into a simple linear disease model. Each step from pathway to measurement, permeability and pathology requires its own evidence.
Perspective · Living Boundaries · Aug 24, 2026
The intestinal barrier is not a wall.
Living Boundaries concerns the health of communication: how a boundary receives, sets limits and adapts according to context. The intestinal barrier is the biological starting point for that larger question.