Abstract:
The brain reaches down into the bowels. That reality is shocking and not what neuroscientists want to hear. However,
one has to develop a propensity for uncleanliness in order to hold the vulnerability of our existence in our hands. It is
not just about neural connections and bacterial cross-talk. It goes far beyond that to the innate processes which revive
our consciousness and programme our most primitive behaviour. Microbes affect our sleep. They also affect how we
socialise and how we eat. They accomplish this through simple mechanisms, for example by lowering the threshold of the
hypothalamic–pituitary–adrenal axis, and in this way disturbing the body and mind with cortisol and inflammation. Yet, it
goes deeper than this. By gaining access to the homeostatic arsenal, microbes prevent the brain from regenerating during
sleep and from laying down new memories. This throws the psyche and, eventually, the human spirit off course and the
individual becomes isolated and depressed. This is wonderful news for a symbiont turned rogue.
