Excerpt: This micro-ecosystem serves the host by protecting it against pathogens, metabolizing complex lipids and polysaccharides that otherwise would be inaccessible nutrients, neutralizing drugs and carcinogens, modulating intestinal motility, and making visceral perception possible. It is now evident that the bidirectional signaling between the gastrointestinal tract and the brain, mainly through the vagus nerve, the so called “microbiota–gut–vagus–brain axis,” is vital for maintaining homeostasis and it may be also involved in the etiology of several metabolic and mental dysfunctions/disorders.
My comment: When I saw the citation to Kohl (2012), I thought of my work and how it could have been placed into the context of this article. See for example:
Kohl, J.V. (2012) Human pheromones and food odors: epigenetic influences on the socioaffective nature of evolved behaviors. Socioaffective Neuroscience & Psychology, 2: 17338.
However, from a broader perspective, the link from microbial metabolism of nutrients to species-specific pheromones that control the physiology of reproduction, and thus control adaptive evolution in species from microbes to man, may be more important to consider in the context of neuroscientific facts. See for example:
Kohl, J.V. (2013) Nutrient-dependent/pheromone-controlled adaptive evolution: a model. Socioaffective Neuroscience & Psychology, 3: 20553.
See also: “From Fertilization to Adult Sexual Behavior” In our 1996 Hormones and Behavior Review article, our section on the molecular epigenetics of what are obviously nutrient-dependent alternative splicings predicted that the alternative splicings, which link the epigenetic “landscape” to the physical landscape of DNA, would be controlled by species-specific pheromones.
These authors bring that concept forward to human chemical communication, albeit without integrating the evolutionary continuum of ecological, social, neurogenic, and socio-cognitive niche construction that is nutrient-dependent and pheromone-controlled in the context of adaptive evolution. Are theories about birds the problem?
Others have also failed to incorporate what is now known about pheromones in birds, which is probably because they continue to be misrepresented as primarily visual and auditory creatures. However, we know now that “Bird odour predicts reproductive success.”
1) Kohl, K. D. (2012). Diversity and function of the avian gut microbiota.
will be considered in the future in the context of Frontiers in Integrative Neuroscience, which would extend integrative neuroscience to Socioaffective Neuroscience & Psychology.