The “Second Brain”
There was an intriguing article in Scientific American last week called “Think Twice: How the Gut’s ‘Second Brain’ Influences Mood and Well-Being.” Although I work at a neuroscience company, I was unfamiliar with the “second brain.” It turns out it’s a mass of tissue in our intestines that shares many qualities with our brains–millions of neurons, many of the same key chemicals (like dopamine and serotonin). This “second brain” is officially called the “enteric nervous system,” and it’s a fascinating part of the body.
Here’s a little context: As you probably know, the brain and spinal cord are known as the “central nervous system.” The central nervous system receives and makes sense of information from other parts of the body (such as “ouch! that hurt!”). It also sends messages out (such as “right hand: wave good bye”). The “peripheral nervous system” connects the central nervous system to the rest of the body, moving the messages along until they reach their destination. The enteric nervous system (the “second brain”) is part of the peripheral nervous system.
What makes the “second brain” unique from other parts of the peripheral nervous system, though, is that it can function even without input from the central nervous system, and sends many more messages to the central nervous system than it receives. And while it’s not a center of conscious thought, it has widespread influence on our physical bodies and our emotional well-being. This may have implications for how we treat emotional problems like depression.
I encourage you to read the article to find out more about this fascinating “second brain.” I certainly learned something new about how my brain(s) work!
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Posted: Odds and Ends, Research studies
Posit Science's corporate blog is the place where our employees share their thoughts about Posit Science and its products, brain fitness, breakthroughs in neuroscience, and any other topic they find interesting and relevant. 
February 23rd, 2010 at 5:36 am
Very interesting article. Our bodies are so wonderfully made, doing so many things at all times.
February 23rd, 2010 at 7:07 am
Thanks for the fantastic info. I don’t know that it will solve any of my daily problems, but I might be able to use it in my continual war between drive and dread.
February 23rd, 2010 at 12:54 pm
There is also a third brain, in your heart. It is always amazing how few people know about this.
Some people have been talking about the Enteric brain for a while already.
http://www.heartmath.org/research/research-our-heart-brain.html
February 23rd, 2010 at 1:02 pm
The paradox is that Serotonin is a +/ positive “ingredient that makes a person feel good, & if there is too much in the 2nd brain, it works the other way?
February 23rd, 2010 at 2:08 pm
How is it that we all come equipped with a second brain, yet so many of us seem to lack even one soul?
February 23rd, 2010 at 2:46 pm
This is very interesting to me. After my husband died-suddenly and unexpectedly-22 years ago, I was aware of this second brain. There was knowledge that could not have come from my conscious brain, helping me in amazing ways. I remember telling others that I had another brain somewhere. Mary
February 23rd, 2010 at 3:04 pm
I see how this relates to my desire to eat when I am anxious, bored, frightened, depressed. As one person said, “I can fix my stuff or stuff my face.” Though the desire to eat is still there, I have been abstinent from my eating disorder for over 20 years. For me, it took a spiritual solution through the 12 Steps of Overeaters Anonymous along with, finally, inpatient treatment to address family of origin issues.
February 23rd, 2010 at 5:33 pm
I read the Scientific American article with interest as this was my area of study for 20 plus but I retired 8 years ago. The most striking info in that article is that there are many more times sensory nerves to the central nervous system from the gut than there are motor nerves to the gut from the CNS (and these go mainly to the independent enteric nervous system). Thus the big brain sees what is going on in the gut but has less control over the function of the gut, which with its own nervous system controls the local function Of interest the gut has its own unique immune system.
February 23rd, 2010 at 6:05 pm
This is amazing!In 1970 I joined a Taoist martial art school heavily based in the “mysticaly”work of Taoist monks.The Grand Master spoke often of this Second brain,stating it was the source of the building and storing “internal” energy. The Process could only happen if you deconditioned your habitual belief systems,and not take anything
as an absolute,undeniable,unchangeable,fact.Of course,this is an over simplification,but I am amazed just how much esoteric knowledge is begining to be proven true.Just take accupuncture
or the fact we are energy fields swimming in a sea of Ouantum partrticles,called the Akashic by the ancients,or take Chi now recognised as being real,not just an old superstition or new age jargon. Al
February 23rd, 2010 at 9:31 pm
Thanks for this article and also thanks to Robert’s comment that this is actually the third brain, after the head and heart brains, to be recognised at a physical level.
February 24th, 2010 at 6:39 am
Strangely enough, the chinese – in meditation and chi kong – call our belly the monkey brain – and if we rub gently – we leave our higher brain (where we are always thinking) and hopefully concentrate on our monkey brain – helping us relax – think the chinese already knew about the Second Brain?
February 24th, 2010 at 9:02 am
Thank you all for your comments. I’m glad you found it as interesting as I did!
February 24th, 2010 at 10:10 am
In the early 20th century already, the American physiologist Robinson described the “Abdominal and Pelvic Brain” (Robinson, 1907). He worked on the premise that our ‘gut’ included a complex nervous system, responsible for regulating vegetative processes of the abdominal viscera.
Robinson was not alone in his fascination with the nervous system of the abdomen. At about the same time that Robinson was discovering the “abdominal brain,” British physiologist Johannis Langley of Cambridge University recognized that “the nervous system of the gut had integrative functions independent of the central nervous system” Langley first labeled the brain in the gut the enteric nervous system.
February 24th, 2010 at 12:35 pm
THANK YOU I ALWAYS NEW THERE WAS SOMETHING TRUE
ABOUT HAVING A GUT FEELING ABOUT CERTAIN THINGS
MAYBE WE SHOULD ALL FOLLOW OUR GUT FEELINGS
SHIRLEY
February 25th, 2010 at 5:44 pm
The Hawaiians have always known about this too and call it our na‘au, which includes the bowels, the mind, and the heart. The mind can be easily influenced and/or confused by all that it senses. However, when we are also in touch with what we feel in our heart and our gut or the inner core, this keeps us grounded and connected to doing what is pono (right, moral, proper). It is our own bodyʻs system of check and balance, which is unfortunately often ignored. Iʻm glad science is able to shed light on the knowledge that has been passed on and labeled as beliefs and practices. Iʻm hoping future research will fully validate and support it.
March 15th, 2010 at 1:16 pm
When I read ‘evolved’ concerning the second brain, I was ‘through.’
March 17th, 2010 at 1:35 am
this article is very interesting..
it sounds like we should know more about our body.
I was surprised to hear that we do have a second brain and I’m also impressed of this article because now I knew that there is a second brain of us..
May 8th, 2010 at 8:58 am
[...] Merzenich provides more details on this “Second Brain”. The second brain is a mass of tissue in our intestines that shares many qualities with our [...]