Scientists have known for years that there’s a “second brain” of autonomous neurons in your long, winding human digestive tract—but that’s about where their knowledge of the so-called abdominal brain ends. Now, research published in 2020 shows that scientists have catalogued 12 different kinds of neurons in the enteric nervous system (ENS) of mice. This “fundamental knowledge” unlocks a huge number of paths to new experiments and findings. The gut brain greatly affects on how you body works. Your digestive system has a daily job to do as part of your metabolism, but it’s also subject to fluctuations in functionality, and otherwise related to your emotions.