Gut Microbes and the Brain: Paradigm Shift in Neuroscience

Abstract

The discovery of the size and complexity of the human microbiome has resulted in an ongoing reevaluation of many concepts of health and disease, including diseases affecting the CNS. A growing body of preclinical literature has demonstrated bidirectional signaling between the brain and the gut microbiome, involving multiple neurocrine and endocrine signaling mechanisms. While psychological and physical stressors can affect the composition and metabolic activity of the gut microbiota, experimental changes to the gut microbiome can affect emotional behavior and related brain systems. These findings have resulted in speculation that alterations in the gut microbiome may play a pathophysiological role in human brain diseases, including autism spectrum disorder, anxiety, depression, and chronic pain. Ongoing large-scale population-based studies of the gut microbiome and brain imaging studies looking at the effect of gut microbiome modulation on brain responses to emotion-related stimuli are seeking to validate these speculations. This article is a summary of emerging topics covered in a symposium and is not meant to be a comprehensive review of the subject.

Modulatory Effects of Gut Microbiota on the Central Nervous System: How Gut Could Play a Role in Neuropsychiatric Health and Diseases

“…2,3 In recent years, however, emerging knowledge about gut microbiota has compelled us to re-examine the directionality of this process. [4][5][6][7][8][9][10][11] The presence of a healthy and diverse gut microbiota appears to be imperative not only for normal gastrointestinal function, but may also influence a variety of systemic and mental processes. Our understanding of the interaction between gut microbiota and the CNS is incomplete and only at its starting point.…”

Neural Mechanisms of Exercise: Effects on Gut Miccrobiota and Depression

“…Microbiota is a set of microorganisms resident in gut ecosystem that reacts to psychological stressful stimuli, and is involved in depressed or anxious status in both animals and human being [1][2][3][4][5]. For instance, maternal separation stress or chronic restraint stress leads to decreased faecal lactobacilli and the altered microbiota composition [6].…”

More-than-humanizing the Anthropocene

“…The form and behaviour of an organism is falsely reified when considered in isolation from the contributory influences circulating throughout by these collaborating organisms. From the mitochondria powering eukaryotic cells (Margulis 1981) to the gut microbes turning on and off intestinal genes affecting their hosts' moods and dispositions (Mayer et al 2014;Dinan and Cryan 2013), from emotion altering Toxoplasmosis (Pearce et al 2012) to carbohydrate cravings induced by Prevotella (Alcock et al 2014), we see the pervasive contribution of otherness in our humanness. The physiological point of view, just like the phenomenological one, reveals that human agency is entwined in perplexing symbiotic assemblages with causality distributed throughout and circulating in ongoing transactions between the wholes and their varied parts.…”