WHAT IF YOU HAD A SECOND BRAIN?

 The brain... Everytime you think, feel or perform a multitude of unconscious processes, the 100 billion neurons in your skull conduct electrical signals to communicate and carry messages between them, ultimately creating, well - you, and everything you do. It's the most complex, essential and identifiable organ in the body, acting as the centre of the nervous system in all vertebrates. But what if how you think and feel isn't just controlled by the brain, basically the central nervous system, but in fact, a second brain that you didn't know about?

The brain uses the vagus nerve to connect and communicate with many parts of the body, including the vocal cords, heart, lungs and most of the digestive tract. It also uses this nerve to convey 'fight or flight' messages to the body, which explains why you might experience a cracking voice, racing heart, shortness of breath and a knot in your stomach when you're really stressed or nervous. 

But while this extensive network is constantly sending signals from the brain to your body, scientists have noted that 80-90% of the nerve fibers in the enteric nervous system are actually going from the gut to the brain. In fact, the enteric nervous system which is an extensive mesh - like network of neurons, that controls your entire digestive tract from the oesophagus to the anus, doesn't even require the brain at all. When the vagus nerve is severed, the enteric nervous system is capable of organising and initiating it's own reflexes for digestion because it has such a complex collection of neurons. It is your second brain, and it controls you far more than you realise.

From an evolutionary perspective - before modern food safety protocols - our biggest choices were about eating. Is it safe? Will it make me sick? Will it give me energy? This is why we would need a direct line of communication between the gut and the brain. For eg: Fat and sugar are good sources of fuel for the body, so we have evolved mechanisms to notify the brain to release the 'feel - good' neurotransmitter, dopamine when we eat foods high in fats and sugars, that make us continually seek them out. The microbes in your gut actually produce over 50% of the dopamine found in your body, and 90% of the serotonin; two neurotransmitters that drastically affect your mood, happiness and pleasure.

And these microbes can manipulate your cravings and eating behaviors for their own survival. Your diet affects which bacteria will thrive, but as a result, the flourishing bacteria in your gut, can then send signals to the brain, via the vagus nerve, to tell you to keep eating the foods they love. This is why treatment with probiotics or fecal transplants are suggested as an effective therapy for overeating; by getting rid of certain bacteria that generate intense cravings for high - fat and high - sugar foods. A gut with healthy microbes is a strong predictor of emotional and mental health. 

Stimulating the vagus nerve at different frequencies, by implanting a small pacemaker, can help patients with treatment - resistant depression, by mimicking vagus nerve activity, like a person with a healthy gut. And the essential role of the gut doesn't end there. Given that large social groups increase the potential of one's genes being passed on - for us and our bacteria - now a new belief says that the function of the microbiome is partly to promote pro - social behaviours. 

Healthy gut bacteria can lead to a higher resilience of negative emotions from others, which makes you more forgiving and better at fostering strong social connections.

All thanks to your second brain !!