Gut-Brain Connection
Most of us can relate to the experience of having butterflies in our stomach, or to a visceral gut-wrenching feeling, and how often are we told not to ignore our “gut-instinct” or “gut-feeling” when making a decision - Jennifer Wolkin

image by: Kenneth Brown, MD
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Think Twice: How the Gut's "Second Brain" Influences Mood and Well-Being
The little brain in our innards, in connection with the big one in our skulls, partly determines our mental state and plays key roles in certain diseases throughout the body.
Although its influence is far-reaching, the second brain is not the seat of any conscious thoughts or decision-making.
Technically known as the enteric nervous system, the second brain consists of sheaths of neurons embedded in the walls of the long tube of our gut, or alimentary canal, which measures about nine meters end to end from the esophagus to the anus. The second brain contains some 100 million neurons, more than in either the spinal cord or the peripheral nervous system, Gershon says.
Resources
A Gut Check for Many Ailments
The gut—considered as a single digestive organ that includes the esophagus, stomach and intestines—has its own nervous system that allows it to operate independently from the brain. This enteric nervous system is known among researchers as the "gut brain." It controls organs including the pancreas and gall bladder via nerve connections. Hormones and neurotransmitters generated in the gut interact with organs such as the lungs and heart.
Hey, There's a Second Brain in Your Gut
Now, in new research, 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.
Science says your “gut feeling” isn’t a metaphor
The brain’s powers are a little overrated. To keep your body going, you don’t need a functioning brain, but you do need something to provide energy. Enter the gut.
The bowel and beyond: the enteric nervous system in neurological disorders
The enteric nervous system (ENS) is large, complex and uniquely able to orchestrate gastrointestinal behaviour independently of the central nervous system (CNS). An intact ENS is essential for life and ENS dysfunction is often linked to digestive disorders. The part the ENS plays in neurological disorders, as a portal or participant, has also become increasingly evident.
The Brain-Gut Connection
If you’ve ever “gone with your gut” to make a decision or felt “butterflies in your stomach” when nervous, you’re likely getting signals from an unexpected source: your second brain. Hidden in the walls of the digestive system, this “brain in your gut” is revolutionizing medicine’s understanding of the links between digestion, mood, health and even the way you think.
Are My Stomach Problems Really All in My Head?
Scientists often debate whether irritable bowel syndrome is a mental or physical issue. That’s not much help for those who suffer from it.
Clues to brain health may lie in the gut
Deep in the gut hides the enteric nervous system, part of the autonomic nervous system that functions independently of the body's central nervous system, guiding human desires and behaviors. It has more nerve cells than the spinal cord. Researchers call it "the second brain."
Does Your Gut Always Steer You Right?
Weighing a big decision? Here’s what experts say about when to go with your gut or your rational brain—or some combination of both.
Explainer: why do we get butterflies in our stomachs?
The human body is capable of looking after itself without too much voluntary thought. It quite happily regulates heart rate, blood flow and the distribution of nutrients around the body without you having to consciously intervene in any way – a process run by the autonomic nervous system (ANS).
Feeling Depressed? Bacteria in Your Gut May Be to Blame
New studies point to the trillions of organisms in the human microbiome as playing an unexpectedly huge role in our well-being.
Germs in Your Gut Are Talking to Your Brain. Scientists Want to Know What They’re Saying
The body’s microbial community may influence the brain and behavior, perhaps even playing a role in dementia, autism and other disorders.
Gut Bacteria Might Guide The Workings Of Our Minds
Mayer found that the connections between brain regions differed depending on which species of bacteria dominated a person's gut. That suggests that the specific mix of microbes in our guts might help determine what kinds of brains we have — how our brain circuits develop and how they're wired.
Gut feelings
The theory that bacteria are involved in some cases of autism gets a boost.
How Your Gut Controls Your Brain
More and more, researchers are finding that the health of bodily microbe populations could be deeply connected to conditions like depression, anxiety, and even autism.
Hungry? Your Stomach Really Does Have a Mind of Its Own
The "gut brain," formally known as the enteric nervous system, is made up of some 500 million nerve cells, as many as there are in a cat's brain. They help to control muscular contractions in the gut as well as the secretions of glands and cells. And they help balance hunger and satiety, or the sense of being full, communicating those states to the big brain.
Let the Mind Help Tame an Irritable Bowel
If you’ve ever had butterflies in your stomach or an attack of nerves that sent you racing for the bathroom, you already know that the intestinal tract has a mind of its own. The millions who suffer from irritable bowel syndrome, or I.B.S., perhaps know it best.
Meet Your Second Brain: The Gut
Most of us can relate to the experience of having butterflies in our stomach, or to a visceral gut-wrenching feeling, and how often are we told not to ignore our “gut-instinct” or “gut-feeling” when making a decision. Even from our simple slang, it’s clear just how symbolically connected the gut is to our emotions. Now, there’s tangible proof to support these popular metaphors.
Our gut-brain connection
“Organs-on-a-chip” system sheds light on how bacteria in the human digestive tract may influence neurological diseases.
Serotonin is a Sword and a Shield of the Bowel: Serotonin Plays Offense and Defense
The gut contains far more serotonin (5-hydroxytryptamine; 5-HT) than does any other organ of the body
The brain and the gut talk to each other: how fixing one could help the other
It’s widely recognised that emotions can directly affect stomach function. As early as 1915, influential physiologist Walter Cannon noted that stomach functions are changed in animals when frightened. The same is true for humans. Those who stress a lot often report diarrhoea or stomach pain. We now know this is because the brain communicates with the gastrointestinal system. A whole ecosystem comprising 100 trillion bacteria living in our bowels is an active participant in this brain-gut chat.
The Gut Brain Connection: How Gut Health Affects Mental Health
Researchers say controlling the bacterial population of the gastrointestinal tract may help improve symptoms of mental disorders.
The second brain: a groundbreaking new understanding of nervous disorders of the stomach and intestine
Dr. Gershon's groundbreaking book fills the gap between what you need to know-and what your doctor has time to tell you. Dr. Michael Gershon has devoted his career to understanding the human bowel (the stomach, esophagus, small intestine, and colon). His thirty years of research have led to an extraordinary rediscovery: nerve cells in the gut that act as a brain. This "second brain" can control our gut all by itself. Our two brains-the one in our head and the one in our bowel-must cooperate. If they do not, then there is chaos in the gut and misery in the head-everything from "butterflies" to cramps, from diarrhea to constipation.
When Gut Bacteria Change Brain Function
Some researchers believe that the microbiome may play a role in regulating how people think and feel.
Think Twice: How the Gut's "Second Brain" Influences Mood and Well-Being
The emerging and surprising view of how the enteric nervous system in our bellies goes far beyond just processing the food we eat.
Dr. Michael Gershon
It seems that Dr. Gershon has made it his life's mission to discover and document the workings of the "gut-brain", or the nougaty center of truthiness that lies at the center of us all. It seems that the gut is uniquely privileged in being able to assert that the brain is not the bos
ScienceDirect
The enteric nervous system (ENS) controls effector systems of the digestive tract, consisting of the musculature, secretory glands, and blood vessels. As in the central nervous system, circuits at the effector sites have evolved as an organized array of different kinds of neurons interconnected by chemical synapses.

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