Symbiotic Relationship: Microbes and the Brain

Our body has a million cells......

But our body also has a trillion microbes!!

A symbiotic relationship is one that involves two organisms which rely on each other for survival. 

Today I observed that as hosts to colonizing microbial colonies, we can directly experience the changes that occur in our bodies due to the changes that occur in the microscopic organisms living within our body; microbes! In the past 5 years, microbes have been found to be directly connected to evolutionary changes in brain development, function and behavior.  Here are some examples of how changes in microbes that live inside our body, correlate with changes in our brain:

1. During evolution, there seemed to be a correlation with decreased gut metabolism and increased brain metabolism due to increase brain complexity and function.
2. Microbes also seemed to have played a role in our evolution of sociality.  Scientists believe that through social interaction with our closed groups, we were able to share microbes that would defend us against disease. In fact, we still do this with individuals in our social groups; such as when we have skin contact with our family, friends, mates, etc. (so.. could microbes be one of the reasons why our species has survived?)
3. Our behaviors around social interactions could have evolved due to our desire to exchange microbes that would make us more resilient.
4. Jet lag can in fact disrupt the microbe cycle which has been synchronized with our own circadian rhythms, resulting in weight changes.
5. Microbial disturbances in the gut can lead to stress and isolation.
6. Microbial disturbances also seem to result in neurological disorders like: Psychosis, Schizophrenia, Alzheimer's disease, and Parkinson's disease.

As this Microbiome field continues to grow and more research is conducted, then we will have a better understanding of how microbes directly affect the Brain.


Citations:
Stilling, R., & Bordenstein, S. (2014). Friends with social benefits: Host-microbe interactions as a driver to brain evolution and development?Frontiers in Cellular and Infection Microbiology, 4, 17-17. Retrieved January 22, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4212686/pdf/fcimb-04-00147.pdf