Opinion: Microbial Mind Control—Truth or Scare?

Normal brain function may have evolved to depend on gut microbes and their metabolites.

By Katerina Johnson | May 1, 2018

ISTOCK, PERCEPTION7The community of microorganisms living in the human gut, estimated to total 100 trillion, may have a profound effect on many aspects of our physiology, including immunity, metabolism, and even our brain and behavior. The majority of studies on the latter have so far been conducted in animals, demonstrating that gut bacteria (especially species belonging to Lactobacillus and Bifidobacterium) can influence social behavior, anxiety, stress, and symptoms of depression.  For instance, supplementation with a Lactobacillus species has been found to increase sociability in stressed mice, while germ-free mice exhibit impaired social behavior.

There are several possible mechanisms by which gut bacteria may affect the brain, including communication via the vagus nerve (the major neural link between the gut and brain), the immune system, and hormonal changes. It is also particularly intriguing that some gut bacterial species can produce chemicals of identical structure to our brain’s own neurotransmitters. This emerging evidence of the intricate links between the gut microbiome and the brain begs the question of whether bacteria have evolved to alter our neurochemistry and behavior in ways that benefit themselves.

Can microbes manipulate us for their own benefit?

It is an appealing proposition that gut microbes may manipulate our behavior for their own advantage, such as improving their transmission to new hosts or enabling them to acquire food. For example, several prominent researchers in the field suggest that gut bacteria may make us more sociable in order to help them spread between people and may alter our cravings for particular foods to satisfy the nutrients that they need to survive.

If bacteria do have an effect on their hosts, it must be by means other than advantageous manipulation.

This is a compelling idea, fueled by examples of parasites seemingly controlling the behavior of their hosts, such as the Ophiocordyceps fungus that infects ants. This parasite is known as the “zombie-ant” fungus because it induces ants to climb to the canopy and bite on vegetation, securing themselves in a position in the forest that is favorable for fungal growth and sporulation.

Applying evolutionary theory

So what conditions would need to be satisfied to allow gut bacteria to manipulate the behavior of their hosts? Two important criteria include having a high abundance within the gut microbiome and a lack of competition from other species. However, neither of these conditions is met in the complex microbial ecosystem of the gut, where there is a vast diversity of competing species and strains, with even the most abundant ones making up only a few percent of the total number of microbial cells.

The consequence of such microbial diversity means that a bacterial species producing a neuroactive chemical to try and control its host would likely be outcompeted by other non-manipulating bacteria. This is because any additional energetic investment made by the manipulating bacteria to produce the chemical would slow down its growth rate and so it would struggle to persist in the genetically diverse and competitive environment of the mammalian gut microbiome. If bacteria do have an effect on their hosts, therefore, it must be by means other than advantageous manipulation.

Evolution of “that gut feeling”

If the application of evolutionary theory suggests that our gut microbes are not pulling the strings on our behavior, then how did “that gut feeling” evolve? In our Perspective article, published last week (April 24) in Nature Reviews Microbiology, my coauthor Professor Kevin Foster also at the University of Oxford, and I propose that the effect of the gut microbiome on behavior is likely a result of natural selection on microbes to grow and compete in the gut, and natural selection on hosts to depend on their microbes. 

Microbial growth results in the production of a diverse range of metabolites. For example, short-chain fatty acids produced by bacterial fermentation in the gut may directly affect brain function, while other metabolites may indirectly influence human behavior through their interactions with our immune system. In turn, we may also expect our physiology to have adapted to make use of such microbial products.

Akin to the “hygiene hypothesis,” which suggests that an absence of microbes impairs immune system development and may increase people’s susceptibility to allergies, we propose that humans may have evolved to depend on our symbiotic microbes for normal brain function, such that a change in our gut microbiome could then influence our behavior. Although this idea of evolved dependence has not previously been considered in relation to the microbiome-gut-brain axis, it may prove critical to explaining how the gut microbiome affects the brain.

Ultimately, by probing the evolutionary and ecological dynamics of the gut microbiome, this may help us to engineer it in ways that may benefit mental health and well-being. For example, commonly used probiotic strains are not particularly effective at colonizing the crowded and competitive environment of the gut.  However, by focusing on naturally occurring strains in the human gut whose microbial products affect the host in beneficial ways, this may help the development of probiotic treatments that can establish in the gut microbiome and so potentially influence gut-brain communication.

Katerina Johnson is a doctoral student at the University of Oxford researching the connections between the microbiome, brain, and behavior.

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Avatar of: David vun Kannon

David vun Kannon

Posts: 2

May 2, 2018

It is not enough to say that no species or strain is more than a few percent of the total gut population to dispense with evolutionary arguments. It is well known that the gut microbiome has a biogeography that is diverse along the length of the gut and in specialized tissues such as the lumen, mucosa, and crypts. In these areas, bacterial species and strains may rise to dominate the mix, allowing the stated evolutionary forces to come into play.

Avatar of: James V. Kohl

James V. Kohl

Posts: 526

May 2, 2018

For God's sake, pay attention to the extant literature that links the creation of the sun's anti-entropic virucidal energy to biophysically constrained viral latency in species from bacteria to humans and stop touting neo-Darwinian nonsense.

Virus-mediated archaeal hecatomb in the deep seafloor

We show here for the first time the crucial role of viruses in controlling archaeal dynamics and therefore the functioning of deep-sea ecosystems, and suggest that virus-archaea interactions play a central role in global biogeochemical cycles.

See also: Nutrient-dependent pheromone-controlled ecological adaptations: from atoms to ecosystems

Avatar of: James V. Kohl

James V. Kohl

Posts: 526

Replied to a comment from David vun Kannon made on May 2, 2018

May 2, 2018

What "evolutionary forces" have you linked to the virus-archaea interactions, which play a central role in global biogeochemical cycles and sympatric speciation?

Avatar of: Alexandru


Posts: 101

May 3, 2018

Microbial mind control is a reality, but only if Eve mtDNA (maternal mitochondria) manipulate Adam mtDNA (paternal mitochondria).

"Biological systems are open since they exchange mass, energy, and information with their environments… Biological systems display a central control and steering which is provided by brain activity in mammals. The brain receives information from individual parts of the hierarchical system, processes it, and reacts to it by sending controlling signals. Body communication systems with information channels are an indispensable part of the brain's control-and-command function…"  (Jiry Pokorny)


Dear Katerrina, excuse my English because I learned this language alone.

I am enrolled too as doctoral student at Technical University of Cluj-Napoca with a theme that begins to take shape in the scientific world, Extrasensory bio-communications, where I proposed the convergence of the science with world religions

You found my books on:


but only first book is integral translated in English and the last (doctoral reports) contains only scientific references in English.

Because I proposed to genetically certify GENESIS not to many scientists communicate with me.

I am electronically engineer specialized in wireless and satellite communications and, because the mitochondrion structures looks like antennas for communication, I speculated that the paternal mitochondria is the biological antenna for GOD and CREATION communication (30-33 THz - no material obstacles) and maternal mitochondria is the biological antennas for communication only with CREATION (5-30 GHz) but in a limited area.

Because geneticists consider that paternal mitochondria it is not inherited and do not have any purpose in the body they eliminates Adam mtDNA during IN VITRO FERTILISATION.

The simply logic to dispute this error is the presence of Adam mtDNA in the naturally borne man's sperm and the failure of this in the sperm of IVF man.

Now, during IVF the geneticists can introduce a CIP in the brain to control the body reactivity. Please see my comment on:




Where can we look the truth?  

Allan Sandage : "The nature of God is not to be found within any part of the findings of science. For that, one must turn to the Scriptures." (http://leaderu.com/offices/schaefer/docs/scientists.html)

Because in Romania I didn't found the endowed genetically laboratories, I ask you if you have the possibility to make genetic test in the place recommended by Paul (Hebrews 4.12 - the connection of the xiphoid process with the sternum) to find the main biological antennas for human wireless communications, Adam mtDNA and Eve mtDNA, "male and female" (Mathew 19.4) that contains all genome data.

If we joint this information with Genesis 2.21-24 and 3.15 we can prove genetically the GENESIS.

You can contact me on clepsydra92@gmail.com



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