Gut-Brain Psychology: Rethinking Psychology From the Microbiota–Gut–Brain Axis

Abstract

Mental disorders and neurological diseases are becoming a rapidly increasing medical burden. Although extensive studies have been conducted, the progress in developing effective therapies for these diseases has still been slow. The current dilemma reminds us that the human being is a superorganism. Only when we take the human self and its partner microbiota into consideration at the same time, can we better understand these diseases. Over the last few centuries, the partner microbiota has experienced tremendous change, much more than human genes, because of the modern transformations in diet, lifestyle, medical care, and so on, parallel to the modern epidemiological transition. Existing research indicates that gut microbiota plays an important role in this transition. According to gut-brain psychology, the gut microbiota is a crucial part of the gut-brain network, and it communicates with the brain via the microbiota–gut–brain axis. The gut microbiota almost develops synchronously with the gut-brain, brain, and mind. The gut microbiota influences various normal mental processes and mental phenomena, and is involved in the pathophysiology of numerous mental and neurological diseases. Targeting the microbiota in therapy for these diseases is a promising approach that is supported by three theories: the gut microbiota hypothesis, the “old friend” hypothesis, and the leaky gut theory. The effects of gut microbiota on the brain and behavior are fulfilled by the microbiota–gut–brain axis, which is mainly composed of the nervous pathway, endocrine pathway, and immune pathway. Undoubtedly, gut-brain psychology will bring great enhancement to psychology, neuroscience, and psychiatry. Various microbiota-improving methods including fecal microbiota transplantation, probiotics, prebiotics, a healthy diet, and healthy lifestyle have shown the capability to promote the function of the gut-brain, microbiota–gut–brain axis, and brain. It will be possible to harness the gut microbiota to improve brain and mental health and prevent and treat related diseases in the future.

Probiotics Alleviate the Progressive Deterioration of Motor Functions in a Mouse Model of Parkinson’s Disease

“…Earlier studies have reported the relationship between the brain and the GI system, the so-called gut-brain axis or brain-gut axis. It has been hypothesized that GI dysfunctions could reflect the disruptions of the microbiome-gut-brain axis, leading to serious GI inflammatory diseases (e.g., acute pancreatitis or inflammatory bowel disease), endothelial dysfunction, altered immune functioning and regulation of appetite control, neural inflammation, subsequent neurodegeneration, cognitive or psychoneurological disorders (e.g., depression, anxiety, autism, dementia), and disease progression of PD [8][9][10][11][12][13][14][15][16][17][18][19]. In addition to the use of peptides for the improvement of gastrointestinal or digestive dysfunctions [13,[20][21][22], and in order to improve GI function and the balance of microbiota, probiotics could be one of the powerful tools to be used for altering the PD-associated microbiota composition and mitigating the related inflammatory process [12,23].…”

Role of Gut Microbiota in Neuroendocrine Regulation of Carbohydrate and Lipid Metabolism via the Microbiota-Gut-Brain-Liver Axis

“…Reconstitution of Bifidobacterium infantis reversed the exaggerated HPA stress response in GF mice [115]. Since then, a series of observations, based on microbiota perturbation models (GF or antibiotic-treated animals), probiotic, or bioactive treatment models and fecal transplantation in animal models or human trials, indicated that gut microbiota are not only essential for maintaining normal neurophysiology and behaviors [116], but also influence the pathogenesis of various diseases, including neurologic disorders, gastrointestinal diseases, and metabolic disorders [117,118].…”

The Microbiota-gut-immune-glia (MGIG) Axis in Major Depression<strong> </strong>

“…There are various mechanisms of how intestinal microbiota can interact with the central nervous system and there is a broad outstanding literature covering microbiota-gut-brain axis interactions (32,211). In this article, we will approach this topic from the microbiota-gutimmune-glia (MGIG) axis perspective, and we will explore the role of microbiota in intestinal and BBB permeability in the regulation of microglial, oligodendrocyte and BBB maturation and functions (Figure 1).…”