The 4E approach to the human microbiome: Nested interactions between the gut-brain/body system within natural and built environments.

Summary

Human cognition depends not only on brain processes but also on bodily and environmental factors, a view known as the 4E perspective (embodied, embedded, enacted, extended). The human microbiome—the community of microorganisms living in and on the body—is a key mediator of this interaction, influencing brain function and mental health across a person's lifetime. This theoretical review presents a 4E approach to the microbiome, arguing that microbial networks from the gut, skin, and built environments shape mental processes. The authors review evidence for this framework and outline future research and clinical interventions that integrate biological, psychological, social, and environmental factors, particularly targeting the brain-gut-microbiome axis for low-cost, personalized mental health treatments.

Study at a glance

Abstract

The complexity of the human mind and its interaction with the environment is one of the main epistemological debates throughout history. Recent ideas, framed as the 4E perspective to cognition, highlight that human experience depends causally on both cerebral and extracranial processes, but also is embedded in a particular sociomaterial context and is a product of historical accumulation of trajectory changes throughout life. Accordingly, the human microbiome is one of the most intriguing actors modulating brain function and physiology. Here, we present the 4E approach to the Human Microbiome for understanding mental processes from a broader perspective, encompassing one's body physiology and environment throughout their lifespan, interconnected by microbiome community structure and dynamics. We review evidence supporting the approach theoretically and motivates the study of the global set of microbial ecosystem networks encountered by a person across their lifetime (from skin to gut to natural and built environments). We furthermore trace future empirical implementation of the approach. We finally discuss novel research opportunities and clinical interventions aimed toward developing low-cost/high-benefit integrative and personalized bio-psycho-socio-environmental treatments for mental health and including the brain-gut-microbiome axis.