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Channel / Source:
TEDx Talks
Title: Mind-altering microbes: how the microbiome affects brain and behavior: Elaine Hsiao at TEDxCaltech
Published: 2013-02-08
Source: https://www.youtube.com/watch?v=FWT_BLVOASI
all so it never ceases to amaze me that each of us carries around a three pound mass of cells in our heads that controls literally everything we do importantly though the brain doesn't act in isolation from the body but rather it responds to the needs and experiences of each of our organ systems now here's a staggering statistic that some of you may have heard before our
bodies are comprised of ten times more microbial cells than our own human you carry out exiles these microbes switcher primarily bacteria but also viruses and protozoa they're part of our normal flora and they make up what's called the commensal microbiome in the intestines there a hundred trillion of these bugs reflecting over ten thousand unique species and contributing a hundred and fifty times more genes than our
own human genomes it's even estimated that collective lead these microbes that way to the six pounds which is up to twice the weight of an average adult human brain more and more we're learning that these commensal microbes that make up us have co evolved to play fundamental roles in normal brain development and function so we can study the role of commensal microbes by raising my says
completely germ free and re colonizing them with whichever microbes are of interest and by these types of studies were learning that commensal microbes regulate several complex behaviors like anxiety learning and memory appetite and satiety among lots of other behaviors so you can see now that by studying this micro brained inner action we can learn really important lessons about how microbes can contribute or fact our brain
health and disease so you might be wondering how in the world is a microbe that losing your guide affect your brain and there are many different what mechanisms one way is by activating the vagus nerve so the vagus nerve contacts the gut lining and extends all the way up to the brain stem itself and this is a mechanism by which the bacterium called Lactobacillus ram gnosis
affects depressive like behavior in my so in the task that measures depression related to spare mice that have been treated with this bug exhibit less depression like symptoms and this is not seen if the Vegas nervous favored another way by which microbes can affect the brain is by activation of the immune system so about eighty percent of the body's immune solids reside in the guts an
immune abnormalities contribute to several neurological disorders this is one mechanism by which the bacterium Bacteroides fragilis prevents a mouse version of multiple sclerosis so my city been treated with this bag are more resistant to the disease as shown with by the of the red line in this graph and this depends on the activity of a special sub side of immune cells called regulatory T. cells that
expresses the markers CD twenty five so he blocked the activity of the simian cell then the beneficial effects of the bugs are prevented another way by which bugs can affect the brain is by activating the god endocrine system so gut endocrine cells are primary producers of neuropeptides and your transmitters gut microbes themselves can also produce metabolite that could affect brain function and this is one pathway
that we think is involved in the micro based treatment that we in the %HESITATION Patterson and mas money and lives here at cal tech have used to treat autism like symptoms in mice so by treating myself with %HESITATION this bacterium Bacteroides for jealous were able to correct core abnormalities %HESITATION such as the communication deficit that's depicted here but the hallmark symptom or diagnostic %HESITATION symptom of
autism so here mice died are autistic like display less communication as depicted by the blue bar and treating them with the bag a corrects this the fact as shown by the red bar so I think that the implications of these discoveries is huge because what if we could without a single invasive procedure treat disorders like autism depression and multiple sclerosis micro based therapeutics might offers a
way to build a stable community structure that can impart long lasting effects without the need for continuous treatment also since microbes are relatively easy to manipulate and even eliminate they can be readily modified for better functioning regulatory control targeting and even delivery so the take home message I want you to remember that not only are we made up of mainly microbial cells but that some of
these files can be truly mind altering affecting our brain development function and even our behavior and also in light of several studies showing important roles of commensal microbes in a variety of biological processes from nutrition an immunity to now brain and behavior consider all the things that we do on a day to day basis to change or disrupt our microbiome and how this might affect their
