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>> HELLO.
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WELCOME TO TODAY'S WEDNESDAY AFTERNOON
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LECTURE AT NATIONAL INSTITUTES
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OF HEALTH.
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THANK YOU FOR COMING.
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MY NAME IS JUSTIN TERASKA.
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I'M AN INVESTIGATOR IN THE
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LABORATORY OF MOLECULAR
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BIOPHYSICS IN THE NATIONAL HEART
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LUNG AND BLOOD INSTITUTE.
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IT'S MY PLEASURE TO INTRODUCE
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DR. JAMES ROTHMAN AS TODAY'S
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WALS SPEAKER.
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DR. ROTHMAN IS WALS PROFESSOR OF
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BIOMEDICAL SCIENCES AND CHAIR OF
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DEPARTMENT OF BIOMEDICAL AT
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YALE.
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HE'S ONE OF THE MOST INNOVATIVE
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AND INFLUENTIAL CELL BIOLOGISTS
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AND BUY CHEMISTS WORKING OFFER
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THE LAST FEW DECADES.
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DURING TENURES AT STANFORD,
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PRINCETON, INVENTORY DEBT R,
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COLUMBIA AN YALE, -- CLONE
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KETTERING AND YALE, THIS IS
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INCLUDED SEMINOLE DISCOVERIES
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RELATED TO HOW PROTEINS INSERT
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INTO MEMBRANES.
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HOW VESICALES TRAFFIC THROUGH
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THE CELL, AND HOW VESICALES FUSE
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WITH THE MEMBRANE, A PROCESS
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CALLED EXOCYTOSIS.
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ASIDE FROM THE BIOLOGICAL
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DISCOVERIES HIS LAB HAS INVENTED
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IMPORTANT METHODS INCLUDING IN
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VITRO RECONSTITUTION OF VESICAL
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TRAFFICKING PATHWAYS WHICH HAS
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REALLY ALLOWED THE COMPLEX STEPS
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OF VESICAL TRAFFICKING TO BE
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TEASED APART AT THEIR MOST
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FUNDAMENTAL LEVEL H.
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ADDITIONALLY DEVELOPED NOVEL PH
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FLUORESCENCE PROTEINS THAT ALLOW
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INDIVIDUAL SYNAPSES AND SINGLE
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VESICALES TO BE WATCHED IN
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LIVING CELLS IN REAL TIME.
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IN PARTICULAR, DR. ROTHMAN HAS
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HELPED TO ESTABLISH THE SNARE
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HYPOTHESIS OF MEMBRANE FUSION
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WHICH PROPOSES THAT THE CORRECT
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PAIRING OF ALPHA HELICAL
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PROTEINS ON TWO OPPOSED
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MEMBRANES DIRECTS AND CATALYZES
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THEIR FUSION.
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ALONG WITH THESE IMPORTANT
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DISCOVERIES DR. ROTHMAN MENTORED
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AND TRAINED MANY PROMINENT
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SUCCESSFUL BIOCHEMISTS AND CELL
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BIOLOGISTS.
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HE'S A MEMBER OF THE NAB
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NATIONAL ACADEMY, INSTITUTE OF
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MEDICINE AND RECIPIENT OF
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NUMEROUS AWARDS INCLUDING LASTER
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AWARD FOR BASIC SCIENCE AND
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CAVALI PRIZE FOR NEUROSCIENCE.
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HE WILL DISCUSS HIS RECENT WORK
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ON SNARES AND THE ACCESSORY
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PROTEINS THAT DIRECT THEIR
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FUSION.
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IN A TALK TITLED MOLECULAR
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MECHANISMS OF SYNCHRONOUS
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NEUROTRANSMITTER RELEASE. AFTER
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THE SEMINAR THERE WILL BE A
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RECEPTION IN THE LIBRARY SO
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PLEASE COME AND THEY'LL GIVE YOU
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AN OPPORTUNITY TO SPEAK MORE
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INFORMALLY WITH DR. ROTHMAN.
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JOIN ME GIVING A WARM WELCOME TO
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JIM ROTHMAN.
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[APPLAUSE]
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>> THANK YOU.
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THANKS FOR ARRANGING THE DAY,
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BEING A GREAT HOST AND ALSO
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SHARING WITH ME YOUR RECENT AND
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EXCITING WORK especially on
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novel methods used Ford
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measuring confirmational changes
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in proximity with fret.
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IT'SER EXCITING, I HOPE WE CAN
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COLLABORATE AS A RESULT OF THAT.
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PLEASURE TO BE HERE WITH YOU
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TODAY.
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I'M GOING TO AS THE TITLE
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SUGGESTS, TALK ABOUT THE PROCESS
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OF SYNCHRONOUS NEUROTRANSMITTER
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RELEASE.
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THERE'S BEEN A LOT OF PROGRESS
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OVER THE LAST FIVE YEARS I WOULD
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SAY ESPECIALLY IN BEGINNING TO
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UNDERSTAND THE MECHANISM BY
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WHICH THIS VERY IMPORTANT
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PHYSIOLOGICAL PROCESS OCCURS IN
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STRUCTURAL AND BIOCHEMICAL
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TERMS.
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SO WHAT I WOULD LIKE TO DO TODAY
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IS OFFER SOME HISTORICAL
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BACKGROUNDS TO THE THE PROBLEMS
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AND THEN AFTER THAT SHARE WITH
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YOU OUR CURRENT VIEW IN THE FORM
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OF A MODEL OF HOW A SYNCHRONOUS
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TRANSMISSION NEUROTRANSMITTER
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RELEASE MAY WORK.
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A STRUCTURAL BUOY CHEMICAL MODEL
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AND AFTER THAT SHOW YOU SOME OF
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THE EVIDENCE ACCUMULATED FOR THE
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MODEL OVER THE LAST TWO OR THREE
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YEARS ESPECIALLY.
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WHAT DO I MEAN BY SYNCHRONOUS
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NEUROTRANSMITTER RELEASE?
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IT'S ACTUALLY THE PHYSIOLOGISTS
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HAVE VARIOUS COMPLEX SCHEMES TO
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MEASURE IT AND WAYS OF DEFINING
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IT.
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TO ME IT'S VERY SIMPLE BUT
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FUNDAMENTAL CONCEPT IN
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NEUROSCIENCE WHICH IS WHEN THE
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ACTION POTENTIAL COMES DOWN THE
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END OF THE NERVE AND YOU RELEASE
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A NEUROTRANSMITTER ACROSS A
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SYNAPSE TO THE NEXT NERVE OR
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PERHAPS MUSCLE CELL, THE
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NEUROTRANSMITTER NEEDS TO BE
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RELEASED AT THE RIGHT TIME.
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WE DIDN'T WANT THE
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NEUROTRANSMITTER TO BE RELEASED
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ASYNCHRONOUSLY ON ITS OWN ACCORD
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BECAUSE IN THAT CASE IT'S A
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FALSE ALARM.
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YOU ALSO DON'T WANT THE
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NEUROTRANSMITTER TO GO NOT BEING
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RELEASED BECAUSE YOU MISSED AN
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IMPORTANT SIGNAL.
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IN FACT WHAT YOU WANT, YOU WANT
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THE NEUROTRANSMITTER TO BE
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RELEASED PRECISELY SYNCHRONOUSLY
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WITH THE ARRIVAL OF ACTION
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POTENTIAL AT SYNAPTIC TERMINAL.
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THE WAY THAT'S ACHIEVEED IS
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THROUGH MEMBRANE GATED CALCIUM
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CHANNELS, PROBABLY EVERYONE
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KNOWS THAT ARE LOCALIZED IN THE
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SYNAPTIC PRE-SYNAPTIC REGION
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THAT OPENED UP THE GATE FOR
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CALCIUM ENTRY AND IT ACTS AS A
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SECOND MESSENGER TO TRIGGER
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RELEASE OF NEUROTRANSMITTER
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STORED IN VESICALES.
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THE PROBLEM THAT WE HAVE TAKEN
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ON THAT I WOULD LIKE TO ADDRESS
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HERE IS NUMBER ONE HOW ARE THESE
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VESICLES RELEASED?
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HOW DO THEY FUSE WITH THE
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SURROUNDING MEMBRANE HAVING
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STORED THE NEUROTRANSMITTER
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WITHIN THEMSELVES.
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HOW DO THEY DO IT SO RAPIDLY?
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SO MUCH MORE RAPIDLY, ORDERS OF
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THE MAGNITUDE MORE RAPIDLY.
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THAN OTHER MEMBRANE FUSION
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PROCESSES THAT TAKE PLACE IN THE
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CELL.
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SO THOSE ARE THE ASPECTS BUILT
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INTO SIN CROW IN THISTY.
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IT'S OBVIOUSLY IMPORTANT AT A
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GROSS LEVEL.
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IN YOUR BRAIN IF YOUR
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NEUROTRANSMITTERS WERE RELEASED
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HEALTHER SETTLER, THERE WOULD BE
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NO POSSIBILITY OF C9
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INFORMATION PROCESSING OR
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ANYTHING OF ANY REMOTE INTEREST.
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YOU WOULD HAVE A -- THINK ABOUT
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WHAT EXPERIENCE WOULD BE IF YOUR
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VESICALES ALL FUSED AS THEY
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SHOULD BECAUSE THE FUSION
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PROTEINS ARE CONSTITUTIVELY
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ACTIVE.
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THEY SHOULD FUSE AND RELEASE
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NEUROTRANSMITTER ALL AT ONCE SO
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THEN YOU HAVE EVERY
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NEUROTRANSMISSION TAKING PLACE
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AT ONCE WITHIN A SHORT PERIOD OF
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TIME, NO THOUGHTS WHATSOEVER OR
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PERHAPS EVERY THOUGHT YOU WOULD
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HAVE AND NOT BE ABLE TO
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COMMUNICATE TO EVERYONE ELSE, IT
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MIGHT BE AN INTENSELY
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TRANSFORMATIONAL EXPERIENCE BUT
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IT WOULD BE ONE THAT LASTS 10
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MILLISECONDS.
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SO THAT CLEARLY DOESN'T HAPPEN.
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IN A MUCH MORE SUBTLE LEVEL THE
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SPEED OF SYNAPTIC TRANSMISSION
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IS VERY IMPORTANT FOR THE
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COMPLEX CIRCUITS THAT WE HAVE.
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IT TYPICALLY TAKES A FEW
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MILLISECONDS FOR A SIGNAL TO BE
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TRANSPORTED ACROSS A SYNAPSE OF
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WHICH THE RELEASE PROCESS,
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INITIATION OF IT TAKES TYPICALLY
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LESS THAN A MILLISECOND IN
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CENTRAL SYNAPSES.
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THAT'S ACTUALLY VERY IMPORTANT
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BECAUSE FROM THE TIME THAT A
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PRIMARY PIECE OF POTENTIAL
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COGNITIVE INFORMATION LIKE
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VISUAL FIELD AND AUDITORY
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PATTERN WHAT HAVE YOU, IS
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SENTENCED BY OUR INPUT OUTPUT
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DEVICES, IT HAS MAYBE 20 OR 30
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MILLISECONDS FOR ALL THOSE
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PATTERNS COALESCE AT YOUR
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HIGHEST CENTERS HAVING BEEN
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TRANSMITTED THROUGH PERHAPS TEN
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OR 15 DIFFERENT SYNAPSES.
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I THINK WE'RE ALL FAMILIAR WITH
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SOME ANYWAY ARE OLD ENOUGH TO
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REMEMBER WHAT MOVIES USED TO BE
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LIKE WHERE THE FILM GOES BY AND
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YOU HAVE 35, THE MAGIC NUMBER
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FRAMES PER SECOND.
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WHY 35?
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BECAUSE IF IT'S FASTER THAN 35
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IT LOOKS LIKE A CONTINUUM TO
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YOU.
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IF IT'S SLOWER THAN 35, YOU SEE
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SEPARATE PICTURES.
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HOLLYWOOD FOLKS WEREN'T SPEND
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THRIFTS THEY WERE LOOKING FOR
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PROFITS, SO THEY FIGURED OUT
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THAT THE GRANULARITY OF HUMAN
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EXPERIENCE IS ABOUT 25 OR 30
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MILLISECONDS.
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SO YOU CAN GET BY WITH THE LEAST
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NUMBER OF PHOTOGRAPHIC FILM AT
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THAT SPEED.
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SO THAT 25, 30 MILISEDGES IS
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WHAT YOU HAVE THAT REPRESENTS
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SIN CROW IN THISTY AND THE JOB
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IS TO GET THROUGH 10, 15
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SYNAPSES AND PLOW THROUGH THEM
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FROM HERE AND HERE UP TO HERE.
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FAST ENOUGH.
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HOW DOES THAT WORK IN MOLECULAR
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TERMS?
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THAT'S THE PROBLEM I WOULD LIKE
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TO THE ADDRESS TODAY.
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THE SOLUTION TO THIS PROBLEM HAS
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COME I WOULD SAY OVER SEVERAL
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DECADES, ACTUALLY MORE LIKE HALF
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A CENTURY, MANY WHICH CELL
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BIOLOGY AND NEUROSCIENCE OR
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NEUROPHYSIOLOGY AS IT WAS THEN
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CALLED DOVE TAILED TOGETHER,
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GONE APART COME BACK TOGETHER
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AND THERE'S MANY CRITICAL COMING
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TOGETHERS OF THESE TWO FIELDS.
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THE BEGINNING OF THIS FIELD IN
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FACT REFLECTED THAT.
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GOING BACK TO THE CLASSIC WORK