[Music] in addition to thoughts or emotions we are unsure of how many aspects of the brain work we can't tell you how how neurons in the brain or cells in the brain known as neurons fire we don't know how many neurons in the brain talk to each other or how neurons in the brain communicate with the rest of our bodies to tell us to move our limbs or to hold our breath think about that next time you're doing an important task such as driving a car or picking up a baby but science has begun to
unravel part of this mystery it turns out that we may have had that all the answers all along we had these answers but they were just not in our brain they're a little bit further south they were in our gut the connection between the gut and the brain is real it's powerful and may revolutionize medicine as we know it as I told you the there are many aspects of the brain function that we simply don't understand but the brain has to process information and create new thoughts and I add in actions now you may be
wondering how does the gut possibly talk to the brain after all the brain has a lot of built-in protections our skulls for example and on the inside of our brain is a coating called the blood-brain barrier the blood-brain barrier is like a gate that selectively allows good molecules to pass with useful information but prevents the entry of bad or irrelevant molecules good molecules include neurotransmitters hormones and nutrients that pass freely between the blood and the brain bad molecules include waste products from our own cells or toxins from the environment that would be harmful if they
entered the brain yet despite all of these protections the gut in the brain are in constant communication either through incoming or outgoing nerves or through small molecules that pass through the blood-brain barrier these signals tell us about our mood our cognition feelings of hunger and other responses remarkably it turns out that many of the molecules that cross the blood-brain barrier aren't even made by our own bodies they're made by the hundred trillion bacteria that live inside of us known as the human microbiome all people are born without any bacteria but by the time we are
three years old we are teeming with bacteria and other microorganisms on all environmentally exposed surfaces there are more back here in your body than there are human cells and these bacteria can weigh as much as the brain itself bacteria help us digest our food they help us fight off infections and help help augment our immune system and we're the most of these bacteria live they live in our gut the gut is the largest portal to the molecular world around us it absorbs nutrients from our food but also absorbs thousands of molecules from our gut microbiome
thus molecules not made by our bodies but made by microbes reach all corners of our bodies including our brain think about that that foreign creatures are sending signals to the deepest reaches of our brains and may affect thoughts or emotions and may even tell neurons whether to live or die all this means is that the gut may be a window into into our brains and may help scientists understand how the brain works both in our normal everyday lives and during disease and in fact most the research to date about molecules that cross through the blood-brain
barrier does come from that from the study of diseases autism spectrum disorder which is often shortened to autism is a neuropsychiatric condition children with autism suffer from core behavioral deficits such as decreased vocalization and social interaction as well as repetitive behavior about a million children and adolescents in the United States have been diagnosed with autism and there are many reports these numbers are on the rise suggesting that autism may be one the most pressing social met goal and economic issues today surprisingly many children with autism a classic neurological condition also experienced digestive issues such as
abdominal cramps pain bloating and constipation it's these gastrointestinal issues that made us wonder a few years ago if gut bacteria were involved in the disease process furthermore cesarean section birth childhood use of antibiotics and formula feeding all change our microbiomes and are surprisingly all risk factors for autism so when we looked in two groups of mice those were symptoms of autism and those without we got our answer the gut bacteria were different between those two groups of mice in addition we discovered that the mice that had features of autism had a syndrome called leaky gut
that the lining of their digestive tract was damaged and allowed many molecules to pass even toxic compounds that would never get across the healthy gut even more astonishing we learned that many of these molecules that are altered in the gut microbiomes of children with autism and in the mice cross the blood-brain barrier and actually changed the way neurons and other cells function this rewiring of the brain by gut microbial molecules led to the hallmark symptoms of autism it's remarkable to think that these molecules coming from microbes coming from creatures that live inside of us can
affect complex behaviors and animals now we don't know what causes autism and we're still a long way from from understanding whether these similar process occurs in people but we do know that the gut microbiome of children with autism we're different than that of the general population and they produce some the same molecules that we found to be altered in the mice this leads us to a very provocative hypothesis that perhaps some forms of autism aren't diseases of the brain they may be diseases of the gut yes it's only a hypothesis today but we do know
that chemical signals from the gut can reach the brain and those signals can affect behavior and it works in the opposite direction as well as the brain can influence the intestine when my brain needs a little bit of help I may rely on a gut feeling a gut instinct or turn to a gut reaction when I'm a little bit anxious or nervous my first symptom isn't the headache it's a stomachache it's remarkable to think that the complex interactions between the gut and the brain may affect many aspects of our day-to-day lives it may change our
emotions and may affect the way our gut functions it is surprising that we have assigned complex behaviors thoughts and feelings to an organ that's not even our brain phrases like gut wrenching or no guts no glory seem to imply that the intestines may be part of our decision-making process of course we still have a long way to go before we understand how we form thoughts or emotions but it appears that some forms of negative thought do impact our intestines they'd be remarkable if gut feelings actually changed the way we think and this can happen very
rapidly for example we can get those butterflies in our stomach within seconds of a negative thought this suggests that in addition to microbial molecules that neurons carry signals from the gut to the brain rapidly and this makes sense because our bodies send signals to our brain via neurons our eyes ears noses and other parts of our bodies take cues from the environment and send information to the brain via our nervous system but what about the gut a single neuron called the vagus nerve flows out from the brain to many organs but also allows the rest
of our body including our gut to talk to our brain in some cases the message from the gut to the brain is not pleasant one we believe this is the case in Parkinson's disease Parkinson's is a neurodegenerative disorder where neurons in the brain die leading to classical motor symptoms such as tremors difficulty in walking hunched posture and rigidity neurologists have been studying Parkinson's for many years and have focused on the brain but recently some new evidence has emerged it turns out that people who've had the vagus nerve cut during surgery or their impending removed are
less likely to develop Parkinson's disease of the three million people in the United States that suffer from Parkinson's disease the vast majority of them up to 80 percent also have constipation and their constipation can precede their motor symptoms by years if not decades and this were more recent emergence of the study of the microbiome has led many people to think is there potentially a gut origin to Parkinson's then in 2016 using mice that show symptoms of Parkinson's we were able to prove that gut bacteria are involved in a disease process the experiment that we performed
was quite simple we took mice engineered to have symptoms of Parkinson's and we removed all of their gut bacteria and all their symptoms were gone when we took these animals and put them into sterile bubbles to remove their gut microbiomes and shield them from contamination they no longer exhibited any of the symptoms of Parkinson's then we added back certain microbial molecules to these disease free mice and their symptoms came back so it appears that gut microbial molecules may initiate a cascade of events starting in the gut that reaches the brain and then results in the
death of neurons that make us move place-to-place this is very similar to what happens in human Parkinson's disease the research is only in mice today but at least this type of information has given us some insight into the gut brain connection both during disease and in our normal everyday lives therefore the gut may hold the key to unlocking one of the great mysteries of science how some aspects of how the brain works and this communication has likely been going on for centuries though we are only now beginning to understand that gut brain connection indeed if
the origin of some cases of autism and Parkinson's disease does originate or does not originate in the brain then the gut may hold the keys to some novel drug therapies it turns out that in addition to autism Parkinson's disease a variety of other neurological conditions also shows some of these same features anxiety depression schizophrenia patients all show changes in their guts their microbiomes and their bearing brain chemistry's on average only a small portion of the drugs that we take actually reach our brain for example the antidepressant Prozac is given to people orally but only about
1% of it gets into the brain to increase levels of serotonin a neurotransmitter that improves mood and even then we have no ways of directing those drugs to the regions of the brain where they're needed the most if your car was low on oil drugs of today are akin to pouring oil all over the engine in the hopes that some of it gets into the oil cap while medicines of today's struggle with the challenge of getting across the blood-brain barrier drugs of the future may target therapies to the gut and change the microbiome and if
the microbiome is a trigger for disease then delivering these drugs for the gut arm is much more efficient and may be much more effective than delivering these drugs to the brain and since bacteria have the roadmap between the gut and the brain fixing those problems in the gut may naturally fix those those issues in the brain that are associated with many different diseases the future of medicine may include the concept of drugs from Bug's meaning that someday you and I may go to the doctor and be prescribed a pill with a live bacteria inside of
it as the remedy and because bacteria have have figured out the this road map those signals that we sent to the gut may naturally correct the problems that we have in the brain this is a remarkable departure from how we viewed back here just a few years ago as these insidious little creatures that only want to make us sick we now know that's far from the truth that there are many beneficial bacteria that live inside of us and perhaps the absence of bacteria is a risk factor for disease remember those autistic mice that I told
you about when we treated them with certain beneficial bacteria that we wear that we recover from humans we were able to correct their vocalization deficits and their repetitive behaviors as we learn more about the connections between the gut and the brain we can harness this link and by doing so we may be able to fix problems in the first place before they go wrong and when we do this may transform aspects of our own normal day-to-day lives such as our mood in the morning or help us to remember where we put our keys but it
may also revolutionize medicine and help us treat a variety of different neurological disorders only time will tell if these exciting discoveries will lead to safe natural and effective ways to maintain health and that time may not be too far away at all thank you [Applause]
