Did you know that human beings have a second brain, and it might control you far more thank you could think: Your gut and some of the bacteria that live in it, also known as the Enteric nervous system. Check it out!
The enteric nervous system has been described as a “second brain” for several reasons. The enteric nervous system can operate autonomously. It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems. However, vertebrate studies show that when the vagus nerve is severed, the enteric nervous system continues to function. [Source]