I'M MICHA MICHAEL CHIANG, DIR
OF THE NATIONAL EYE INSTITUTE.
I WANT TO WELCOME YOU TO THIS
2024 SAYER VISION RESEARCH
LECTURE.
SO THANKS TO EVERYBODY WHO'S
JOINING US HERE AT THE NIH
CLINICAL CENTER AND ALSO ON THE
VIDEOCAST ONLINE.
AND WE'RE REALLY GLAD THAT YOU
COULD BE PART OF THIS VERY
SPECIAL EVENT.
SO FIRST OF ALL, I WANT TO GIVE
A HUGE THANKS TO OUR SPEAKER
WHO'S DR. MARLA FELLER, WHO'S
FROM UNIVERSITY OF CALIFORNIA AT
BERKELEY, AND THERE'S GOING TO
BE A LOT MORE THAT YOU'RE GOING
TO HEAR ABOUT DR. FELLER AND
OBVIOUSLY FROM DR. FELLER.
AND SHE'S REALLY GOING TO SHARE
SOME REALLY RYE MARKABL REMARKAS
INTO THE VISUAL SYSTEM HERE.
IN ADDITION TO THAT, I WANT TO
THANK OUR COLLEAGUES AT THE
FOUNDATION FOR THE NATIONAL
INSTITUTES OF HEALTH, THE FNIH,
AND DR. JOE MINETSKI WHO WILL
SAY A LITTLE BIT MORE COMING UP
HERE.
JOE, IT'S BEEN AWESOME TO HAVE
YOUR SUPPORT AND COLLABORATION
THROUGH THIS AND ALL THE OTHER
PROJECTS WE'VE WORKED ON
TOGETHER.
AND SO A BIG THANKS TO OUR
ORGANIZING TEAM FROM THE NEI,
AND ALSO FROM THE FNIH.
THE FOLKS IN THE BACK WHO ARE
WORKING THE A.V. AND THE OTHER
EVENT SUPPORT, A LOT OF PEOPLE
WORKED REALLY HARD TO MAKE
TODAY'S EVENT POSSIBLE.
SO AT THIS POINT, WHAT I WANT TO
DO IS JUST TAKE A MOMENT TO
REFLECT ON THE LEGACY OF
DR. JANE SAYER.
IT WAS DR. SAYER'S VISION AND
DEDICATION THAT BROUGHT THIS
SERIES TO LIFE.
IN 2006, DR. SAYER WAS A
PIONEERING SCIENTIST AT NIDDK,
THE NATIONAL INSTITUTES OF
DIABETES AND DIGESTIVE AND
KIDNEY DISEASES AND SHE WAS THE
ONE THAT REALLY ESTABLISHED THIS
LECTURE.
AND IN PARTNERSHIP WITH US AT
THE NEI AND WITH THE FNIH.
AND SHE DID THIS REALLY TO HONOR
HER PARENTS, WHO WERE WINTHROP
AND LAURA SAYER AND TO CREATE A
PLATFORM FOR CELEBRATING
GROUNDBREAKING RESEARCH IN
VISION SCIENCE.
THIS LECTURE SERIES REALLY
REFLECTS DR. SAYER'S DEEP
COMMITMENT TO INTERDISCIPLINARY
COLLABORATION, AND BY FOSTERING
CONNECTIONS BETWEEN VISION
SCIENCE AND OTHER FIELDS, IT'S
REALLY BECOME A CORNERSTONE TO
ADVANCING RESEARCH THAT CAN
EVENTUALLY HAVE OBVIOUSLY FAR
REACHING MEDICAL APPLICATIONS.
SO THANKS TO DR. SAYER'S
EFFORTS, WE'RE ABLE TO BE HERE
TODAY TO CELEBRATE AND LEARN
FROM THE WORK OF ESTEEMED
SCIENTISTS LIKE DR. FELLER THAT
REALLY EMBODY THE SPIRIT OF
INNOVATION.
SO TODAY WE'RE REALLY HONORED TO
HAVE DR. MARLA FELLER WITH US.
I KNOW MANY OF YOU KNOW HER FROM
BEFORE, AND WE SEE SOME OF YOU
COMING UP HERE AND INTRODUCING
YOURSELVES AND LOVE SEEING THAT.
AND MANY OF YOU KNOW AND YOU'LL
HEAR THAT HER RESEARCH ON REALLY
PROVIDES INSIGHTS ON THE SORTS
OF MECHANISM THAT SHAPE HOW WE
SEE THE WORLD.
SO I THINK THAT DR. FELLER'S
WORK REALLY EXEMPLIFIES THE SORT
OF TRANSFORMATIONAL SCIENCE THAT
THE SAYER LECTURE IS REALLY
MEANT TO HIGHLIGHT.
SO AT THIS POINT, WHAT I WANT TO
COULD IS WELCOME DR. JOE
MINITSKI, SENIOR VICE PRESIDENT
AND CHIEF TRANSLATIONAL SCIENCE
OFFICER, AND HE'S GOING TO GIVE
SOME REMARKS ON THE SIGNIFICANCE
OF THIS COLLABORATION.
SO WITH THAT, COULD YOU PLEASE
JOIN ME IN WELCOMING JOE TO THE
STAGE.
[APPLAUSE]
>> THANKS, DR. CLANG.
CHIANG.
I AM DELIGHTED TO WELCOME YOU
HERE TO THE 2024 SAYER VISION
LECTURE AND TODAY WE ARE PLEASED
TO HONOR DR. MARLA FELLER WHO
WILL PRESENT TODAY'S LECTURE AND
I AM LOOKING FORWARD TO THAT
PRESENTATION BECAUSE I WAS
LOOKING OVER YOUR WORK AND IT'S
VERY COMPLICATED.
[LAUGHTER]
I'M A SIMPLE BIOCHEMIST.
IT'S VERY INTERESTING.
AS YOU MAY KNOW, ALL OF YOU MAY
KNOW, THE FOUNDATION FOR NIH WAS
ESTABLISHED ABOUT 25 YEARS AGO
BY CONGRESS TO SUPPORT THE
MISSION OF NIH IN THREE MAIN
WAYS.
THE FIRST IS TO ACCELERATE THE
GENERATION OF NEW THERAPIES AND
NEW DIAGNOSTICS.
THE SECOND IS TO HELP DEVELOP
AND ADVANCE GLOBAL HEALTH.
AND THE THIRD IS WE CELEBRATE
GREAT SCIENCE AND GREAT
SCIENTISTS, AND THAT'S WHY WE'RE
HERE TODAY.
SO AS DR. CHIANG SAID IN 2006,
DR. SAYER ESTABLISHED THE SAYER
VISION RESEARCH FUND, AND TO
HONOR HER FAMILY AND
PARTICULARLY HER PARENTS.
THE SAYER VISION LECTURE THAT
WE'RE HAVING TODAY IS ORGANIZED
BY NEI AND SO WITH THE HELP OF
FNIH, AND THE ANNUAL
PRESENTATION FEATURES AN
INVESTIGATOR WHO IS CONDUCTING
OUTSTANDING RESEARCH IN THE AREA
OF VISION AND RELATE AREAS.
AND DR. FELLER'S WORK IS EXACTLY
THE TYPE OF RESEARCH THAT THIS
LECTURE AND DR. SAYER WAS MEANT
TO RECOGNIZE AND CELEBRATE.
WE WERE DEEPLY SADDENED TO LEARN
OF DR. SAYER'S PASSING LAST
DECEMBER, HOWEVER, WE ARE
PROFOUNDLY GRATEFUL FOR HER
SUPPORT, WHICH WILL ALLOW US TO
CARRY ON HER VISION WITH THIS
LECTURE TODAY.
TRYING TO KEEP THIS SHORT, I
WILL NOW TURN THINGS BACK OVER
TO DR. HENDRICK NEBORG TO
INTRODUCE DR. FELLER.
THANK YOU FOR JOINING US FOR
THIS EVENT AND PLEASE ENJOY THIS
LECTURE.
[APPLAUSE]
>> SO WELCOME FOR THE THIRD TIME
FOR THIS YEAR'S DR. JANE SAYER'S
VISION RESEARCH LECTURE.
I'M A SENIOR INVESTIGATOR AT THE
NEI, AND IT'S A TRUE HONOR FOR
ME TO INTRODUCE TODAY'S SPEAKER
AND SAYER AWARD RECIPIENT,
PROFESSOR MARLA FELLER.
DR. FELLER IS DISTINGUISHED
PROFESSOR, FORMER HEAD OF THE
DIVISION OF FLUORO BIOLOGY AND
DEPARTMENT OF MOLECULAR AND CELL
BIOLOGY AND A MEMBER OF THE
HELEN WILLS NEUROSCIENCE
INSTITUTE AT THE UNIVERSITY OF
CALIFORNIA, BERKELEY.
WITH A BACHELOR'S AND A PH.D. IN
PHYSICS ALSO FROM BERKELEY
STUDYING THE PROPERTIES OF
LIQUID CRYSTAL INTERFACES AND
RESEARCH STATES AS BELL LABS,
SHE IS A PHYSICIST TURNED GIANT
IN NEUROSCIENCE.
THE WAY IN WHICH DR. FELLER HAS
LEVERAGED HER INTERDISCIPLINARY
BACKGROUND TO ADDRESS DEEP
QUESTIONS ABOUT THE DEVELOPMENT
OF NEURAL CIRCUITS IS TRULY
INSPIRING.
WHEN SWITCHING TO NEUROSCIENCE
AS A POSTDOC, SHE USED HER
BACKGROUND IN PHYSICS TO PIONEER
MICROSCOPY TECHNIQUES FOR
IMAGING IN LARGE POPULATIONS OF
CELLS.
SHE THEN CAPITALIZED ON THESE
TECHNIQUES TO REVEAL THE
DYNAMICS OF SPONTANEOUS ACTIVITY
IN THE RETINA THAT OCCURRED
DURING EYE DEVELOPMENT EVEN
BEFORE BIRTH, CALLED RETINAL
WAVES.
THIS FOUNDATIONAL DISCOVERY HAS
BEEN CENTRAL TO HER LAB'S
RESEARCH SINCE.
SHE INITIALLY STARTED HER OWN
LAB HERE AT NIH AT THE NINDS,
BUT AFTER A VERY SHORT PERIOD
ACTUALLY, SHE WAS RECRUITED AWAY
FROM THE UNIVERSITY OF
CALIFORNIA SAN DIEGO, WHERE SHE
RAPIDLY MOVED THROUGH THE RANKS
BEFORE RETURNING TO HER ALMA
MATER, UC BERKELEY, WHERE SHE
HAS BEEN SINCE.
SHE EXAMINES THIS AT THE LEVEL
OF THE RETINA BY COMBINING
QUANTITATIVE IMAGING, PHYSICIAN
PHYSIOLOGY, GENETIC AND MORE
RECENTLY BEHAVIORAL APPROACHES
IN MICE.
HER LAB IS PRIMARILY FOCUSED ON
INVESTIGATING THE MECHANISMS
THAT UNDERLIE RETINAL WAVES IN
THE DEVELOPMENT OF THE NERVOUS
SYSTEM AND THE SIGNIFICANCE OF
THIS IN THE FORMATION OF RETINAL
NEURONAL CIRCUITS.
HER FINDINGS REALLY CHANGED THE
WAY WE THINK ABOUT HOW SENSORY
SYSTEMS DEVELOP, SHOWING THAT
THIS EARLY NEURAL ACTIVITY CAN
REALLY SHAPE BRAIN ARCHITECTURE
BEFORE AN INDIVIDUAL EVEN
EXPERIENCES ANY TYPE OF VISUAL
INPUT.
AN INTRIGUING RECENT EXAMPLE OF
THIS IS HER GROUP'S WORK ON MAPS
OF THE -- THESE MAPS SHOW SKEWS
FOR THE REPRESENTATION OF OPTIC
FLOW THAT IS BIASES FOR THE
MOTION GENERATED BY AN ANIMAL'S
MOVEMENT THROUGH SPACE.
YET HER GROUP'S WORK FOUND THAT
THESE BIASES ARE PRESENT EVEN
BEFORE AN ANIMAL EVER HAD ANY
EXPERIENCE OF OPTIC FLOW.
AND HER LAB DISCOVERED THAT THE
DEVELOPMENT OF A PARTICULAR TYPE
OF RETINAL GANGLION CELLS DEPEND
ON THESE RETINAL WAVES.
SHE LEADS A LAB WELL-FUNDED BY
SEVERAL GRANTS.
SHE IS A MEMBER OF THE AMERICAN
ACADEMY OF ARTS AND SCIENCES, AS
WELL AS THE NATIONAL ACADEMY OF
SCIENCES.
SHE HAS BEEN AND IS SERVING ON
MANY EDITORIAL AND ADVISORY
BOARDS AND HAS RECEIVED NUMEROUS
AWARDS INCLUDING THE BRIAN
BOYCOT PRIZE IN RETINAL
NEUROBIOLOGY AND VISUAL
PROCESSING BUT PERHAPS JUST AS
IMPORTANTLY, PROFESSOR FELLER IS
A COMMITTED MENTOR AND TEACHER
AS EVIDENCED BY THE MANY
TEACHING AWARDS SHE HAS
RECEIVED, AND THE GENUINELY
IMPRESSIVE COHORT OF TRAINEES
WHO HAVE GONE ON TO TOP
INSTITUTIONS WORLDWIDE TO MAKE
THEIR OWN SIGNIFICANT
CONTRIBUTIONS TO THE FIELD.
TODAY WE ARE REALLY FORTUNATE TO
HEAR ABOUT HER WORK BY RIDING
THE RETINAL WAVE THROUGH VISUAL
SYSTEM DEVELOPMENT.
PLEASE JOIN ME IN WELCOMING
PROFESSOR FELLER.
[APPLAUSE]
>> OKAY.
WOW, THANK YOU FOR THAT AMAZING
INTRODUCTION.
THANK YOU TO THE FOUNDATION, TO
NATIONAL EYE INSTITUTE FOR
SELECTING ME FOR THIS INCREDIBLE
HONOR AND THIS OPPORTUNITY TO
GIVE THIS PRESENTATION TODAY.
MY LAB IS ENTIRELY FUNDED BY THE
NATIONAL EYE INSTITUTE, SO I
THANK YOU FOR THAT AS WELL.
OKAY, SO TODAY, I AM GOING TO
TALK TO YOU ABOUT THE RESEARCH
THAT'S GOING ON IN THE LAB.
MY GOALS FOR TODAY ARE OUTLINED
HERE.
LET'S SEE, I'M NOT SURE YOU GUYS
CAN SEE THE LITTLE POINTER
THERE?
OKAY.
SO I'M GOING TO START WITH
ACTUALLY A VERY LONG
INTRODUCTION THAT SORT OF
INTRODUCES THE CONCEPT OF
RETINAL WAVES.
I KNOW NOT A LOT OF PEOPLE HERE
WORK ON DEVELOPMENT, AND SO I
JUST AM HOPING THAT THROUGH THIS
INTRODUCTION, YOU CAN SEE HOW
IMPORTANT SORT OF THIS EARLY
DEVELOPMENTAL PHENOMENON IS FOR
SETTING UP LOTS OF CIRCUITS
WITHIN THE VISUAL SYSTEM, AND
THEN I'M GOING TO FOCUS ON A
COUPLE QUESTIONS THAT WE'RE
CURRENTLY WORKING ON IN THE LAB.
AND HOPEFULLY IF THERE'S TIME AT
THE END, ENDING WITH SOME REALLY
VERY NEW WORK WE HAVE
UNDERSTANDING HOW RETINAL WAVES
MIGHT ACTUALLY BE IMPORTANT FOR
SETTING UP THE VASCULATURE
NETWORK WITHIN THE RETINA.
SO WE'LL SEE HOW WE GO ON TIME.
OKAY.
SO WE'RE GOING TO START, AS
YOU'VE HEARD, MY LAB WORKS ON
DEVELOPMENT AND I WANTED TO
START BY SHOWING YOU THIS
SCHEMATIC OF HUMAN BRAIN
DEVELOPMENT BEFORE BIRTH.
AND SO THE EYE AND RETINA
DEVELOP INDEPENDENTLY OF THE
BRAIN.
AND AT THIS INCREDIBLY EARLY
GESTATIONAL AGE IS WHEN THE
OPTIC NERVE EMERGES AND STARTS
TO MAKE CONNECTIONS AND THE
VISUAL SYSTEM STARTS TO WIRE UP.
CLEARLY BEFORE THERE'S ANY SORT
OF VISUAL EXPERIENCE THAT'S
GOING ON FOR THE ANIMAL.
HUMANS ACTUALLY OPEN THEIR EYES
AT AROUND FIVE MONTHS IN
GESTATION, AND THIS IS ABOUT THE
AGE WHEN MICE ARE BORN, AND THIS
IS SORT OF THE STATE -- AND WE
USE MICE AS OUR MODEL ORGANISM
TO STUDY THESE VERY EARLY
DEVELOPMENTAL PHENOMENON.
AND SO AT THIS INCREDIBLY EARLY
STAGE OF DEVELOPMENT, ALTHOUGH
VISION IS NOT PLAYING A ROLE IN
SORT OF SETTING UP ANY
CONNECTIONS, IT TURNS OUT THAT
NEURAL ACTIVITY ACTUALLY IS
PLAYING A ROLE, AND THIS NEURAL
ACTIVITY THAT IS THERE AT THIS
AGE IS SPONTANEOUSLY GENERATED,
AND THE PHENOMENON THAT WE CALL
THE SPONTANEOUS ACTIVITY IS
RETINAL WAVES.
AND SO RETINAL WAVES HAVE BEEN
MEASURED THROUGH A VARIETY OF
DIFFERENT MODALITIES, AND I
WANTED TO GO THROUGH ALL OF THEM
TO SORT OF ALSO GIVE YOU THE
HISTORY OF THE FIELD.
SO RETINA SPONTANEOUS ACTIVITY
WAS FIRST RECORDED IN THE RETINA
BY GALLI AND MAFFEI IN A LAB IN
ITALY WHERE THEY TOOK A FETAL
RAT PUP WHILE IT WAS STILL
ATTACHED BY THE UMBILICAL CORD
TO THE MOTHER, AND THEY DID
RECORDINGS FROM THE RETINA, AND
THEY WERE ABLE TO SEE THAT THERE
WERE THESE SPONTANEOUS BURSTS OF
ACTION POTENTIALS OF ACTIVITY
THAT ARE BEING GENERATED AT THE
RETINA AT THIS EARLY AGE.
SOON AFTER THAT, THERE WAS A
TECHNOLOGY THAT WAS DEVELOPED BY
MARCUS MEISTER WHO COLLABORATED
WITH WONG, WHERE THAT ALLOWED
THEM TO DISSECT THE RETINA,
PLACE IT ON THIS BED OF
ELECTRODES AND MEASURE THE
ACTION POTENTIALS BEING
GENERATED BY THE RETINA, AND YOU
CAN SEE THESE SPONTANEOUS BURSTS
OF ACTION POTENTIALS THAT ARE
PROPAGATING ACROSS THE TISSUE.
MY LAB AND OTHERS, INCLUDING
RACHEL WONG WONG'S LAB, TURNED O
USING IMAGING TO LOOK AT THIS
ACTIVITY.
THIS IS AN EXAMPLE OF AN ARARE,
AGAIN OF A RETINA THAT'S BEEN
DISSECTED AND IT IS SOAKED WITH
A FLUORESCENT DITHAT ALLOWS YOU
TO LOOK AT NEURAL ACTIVITY.
THIS DYE IS PARTICULARLY
SENSITIVE TO CALCIUM.
ONE OF THE NICE THINGS ABOUT
USING THESE FLUORESCENT DYES IS
YOU CAN IMAGE OVER THESE VERY
LARGE AREAS THEE ARE RECENT
MOVIES TAKEN BY THE LAB WHERE
WE'VE DISSECTED THE ENTIRE
RETINA OUT OF A MOUSE PUP AND
BEEN ABLE TO LOOK AT WHAT THE
SPONTANEOUS ACTIVITY LOOKS LIKE
ACROSS THE ENTIRE DISSECTED
RETINA.
SO THIS ROBUST ACTIVITY IS
THERE, WE KIND OF THINK OF IT AS
A TEST PATTERN THAT'S BEING
GENERATED IN THE RETINA THAT'S
PROPAGATING UP THROUGH THE
VISUAL SYSTEM THAT'S IMPORTANT
FOR THINGS TO GET WIRED UP
DURING DEVELOPMENT.
SO IT'S BEEN THIS QUESTION THAT
HAS REALLY FASCINATE AND DRIVEN
OUR RESEARCH FOR A LONG TIME.
SO LET'S JUST TAKE A STEP
BACK -- OH, I WANTED TO SAY THAT
ALTHOUGH WE STUDY THIS IN THE
RETINA, IT TURNS OUT THIS
PHENOMENON OF SPONTANEOUSLY
GENERATING THESE KIND OF BURSTS
OF ACTIVITY ARE FOUND THROUGHOUT
THE DEVELOPING NERVOUS SYSTEM.
SO IN ALL OF THESE CIRCUITS,
RETINA, SPINAL CORD,
HIPPOCAMPUS, CEREBELLUM,
COCHLEA, THEY ALL GENERATE VERY
SIMILAR, REMARKABLY SIMILAR
ACTIVITY, BURSTS OF ACTION
POTENTIALS, CORRELATED ACROSS
LARGE NUMBERS OF CELLS THAT
OCCUR ABOUT ONCE A MINUTE.
SO VERY INFREQUENT, BUT THESE
LARGE POPULATION EVENTS.
AND DESPITE THE FACT THAT THESE
CIRCUITS ARE INCREDIBLY
DIFFERENT IN THEIR MECHANISMS BY
WHICH THEY GENERATE THIS
ACTIVITY, WHETHER OR NOT THERE'S
EXCITATION OR INHIBITION OR
SOMETIMES EVEN TRANSIENT ORGANS
THAT ARE THERE TO HELP MEDIATE
THIS ACTIVITY, THEY ALL HAVE
THIS KIND OF SIMILAR FUNCTION SO
WE THINK OF THIS AS NOT BEING
UNIQUE THROUGH THE VISUAL
SYSTEM, IT'S FOUND THROUGHOUT
THE NERVOUS SYSTEM, WE KIND OF
THINK OF IT AS THE BRAIN IS
GETTING WIRED UP, THIS IS A
PERIOD OF ITS DEVELOPMENT THAT
IS IMPORTANT TO TAKE INTO
CONSIDERATION.
BUT WE WILL BE FOCUSING ON HOW
THIS ACTIVITY IS GENERATED IN
THE RETINA, AND WHAT ROLE IT
PLAYS IN VISUAL SYSTEM
DEVELOPMENT.
SO I CERTAINLY DON'T NEED TO
TELL A NATIONAL EYE INSTITUTE
AUDIENCE WHAT THE RETINA IS, BUT
JUST IN CASE THERE'S SOMEONE OUT
THERE IN THE WORLD WHERE THIS IS
NEW TO THEM, THE WAY THAT VISION
BEGINS IS THERE'S LIGHT PHOTONS
REFLECTED OFF OF OBJECTS OUT IN
THE VISUAL WORLD.
THERE'S A BIG LENS IN YOUR EYE
THAT FOCUSES THAT LIGHT ON TO
THE RETINA, WHICH IS THIS LITTLE
NEURAL TISSUE THAT LINES THE
BACK OF THE EYE.
THE RETINA IS NOT JUST A PIXEL
ATED CAMERA BUT IT IS A LITTLE
NEURAL CIRCUIT WHOSE JOB IS TO
EXTRACT SALIENT FEATURES OF THE
VISUAL WORLD SO THAT IT CAN SEND
IT UP TO THE BRAIN.
SO LIGHT PASSES THROUGH THIS
CHUNK OF NEURAL TISSUE,
ACTIVATES THE PHOTORECEPTORS OF
THE BACK OF THE EYE.
THERE ARE A SERIES OF
INTERNEURONS THAT PROCESS THAT
INFORMATION FROM THE
PHOTORECEPTORS, AND THAT
INFORMATION CONVERGES ON THE
RETINAL GANGLION CELLS AND THERE
ARE AXONS THAT FORM THE OPTIC
NEVNERVE THAT GO UP TO THE BRAI.
SO DURING THIS PERIOD OF
DEVELOPMENT WHEN THERE ARE
RETINAL WAVES, THE RETINA IS
QUITE IMMATURE, AND SO HERE WE
HAVE THE ADULT ON THE LEFT, BUT
THIS IS SORT OF WHAT WE'RE
LOOKING AT ON THE RIGHT IS WHAT
HAPPENS BEFORE VISION IS
POSSIBLE.
SO THE OUTER RETINA DEVELOPS,
THE PHOTORECEPTORS ARE
DEVELOPING, THEY HAVE VERY SMALL
OUOUTER SEGMENTS, THEY'RE STARTG
TO FORM SYNAPSES WITH SOME POST
SYNAPTIC PARTNERS CALLED
HORIZONTAL CELLS.
THE GANGLION CELLS ARE THE FIRST
TO MATURE, THEY MY GATE TO THE
RIGHT PART OF THE RETINA, THEY
SEND THEIR AXONS UP TO THE
BRAIN, ALL THE WAY UP THERE
WHILE THE REST OF THE RETINA IS
UNDERGOING THIS DEVELOPMENT.
AND THEY'RE STARTING TO FORM
SNAP TIB CIRCUITSYNAPTIC CIRCUIT
IMPORTANTLY AT THESE EARLY
STAGES OF DEVELOPMENT, THESE
NEURONS THAT CONNECT THE OUTER
RETINA TO THE INNER RETINA, THAT
CONNECT THOSE PHOTORECEPTORS TO
THE GANGLION CELLS HAVE NOT
FORMED THEIR SYNAPSES, SO EVEN
IF YOU CAN GET A WEAK, LIGHT
RESPONSE EARLY IN DEVELOPMENT,
THE RETINAL GANGLION CELLS ARE
BLIND TO THAT LIGHT, BUT INSTEAD
THEY'RE GENERATING THIS ACTIVITY
SPONTANEOUSLY.
SO ONE OF THE WAYS THAT WE LOOK
AT THIS TO SORT OF EXPLAIN HOW
WE DO THESE EXPERIMENTS IS I
JUST WANTED TO -- IS VIA
IMAGING, SO WHAT WE DO IS WE
DISSECT OUT RETINAS, WE PLACE
THEM IN A CHAMBER THAT'S SHOWN
HERE IN THE LOWER LEFT, WE
PERFUSE THE RETINA WITH THE
SOLUTIONS THAT IT WOULD NORMALLY
BE EXPOSED TO WHEN IT'S IN THE
EYE.
WE PUT IT UNDER A MICROSCOPE
OBJECTIVE AND WE HAVE A
SPECIALIZED MICROSCOPE IN THIS
CASE CALLED A 2 PHOTON
MICROSCOPE THAT ALLOWS US TO
RECORD FLUORESCENT SIGNALS
GENERATED BY THE RETINA, AND IN
THIS CASE THOSE FLUORESCENT
SIGNALS ARE GENERATED BECAUSE
WE'VE SOAKED THE RETINA IN A
FLUORESCENT DYE THAT GOES INTO
THE CELLS AND ARE SENSITIVE TO
CALCIUM.
SO WE'RE GOING TO NOW LOOK AT
MOVIES THAT ARE GENERATED BY
IMAGING AT THE GANGLION CELL
LAYER, AND JUST TO GIVE YOU A
SENSE, THIS IS -- IF YOU LOOK AT
THE WHOLE RETINA, THIS IS
ROUGHLY THE FIELD OF VIEW OVER
WHICH WE IMAGE, AND THIS IS THE
SAME MOVIE THAT YOU SAW BEFORE.
EXCEPT THIS MOVIE ISN'T PLAYING.
IT WAS THE SAME MOVIE YOU SAW
BEFORE, WI WHERE YOU COULD SEE E
SPONTANEOUS INCREASES IN
FLUORESCENCE FOR PROPAGATING
ACTIVITY ACROSS THE TISSUE.
SORRY ABOUT THAT MOVIE NOT
WORKING.
SO MY LAB IS SUPER INTERESTED IN
HOW THIS IS BEING GENERATED.
THIS IS CLEARLY SOMETHING THE
ADULT RETINA DOES NOT DO, IF WE
HAD SPONTANEOUS DEPOLARIZATIONS
PROPAGATING AGAINST OUR RETINAS,
VISION WOULD BE VERY CONFUSING
SO THERE'S SOMETHING ABOUT THE
DEVELOPING RETINA AT THIS STAGE
OF DEVELOPMENT THAT GENERATES
THIS ACTIVITY.
YOU NEED SOMETHING TO
SPONTANEOUSLY DEPOLARIZATION,
YOU NEED SOMETHING TO CARRY --
TO PROPAGATE THAT ACTIVITY LAD
LATERALLY ACROSS THE RETINA.
SO TO SORT OF GET AT THIS
PHENOMENA, WE STARTED USING
PHYSIOLOGICAL TECHNIQUES.
A BIG ONE THAT WE USE IS CALLED
WHOLE CELL VOLTAGE CLAMP
RECORDINGS.
THIS IS WHERE WE CAN STICK AN
ELECTRODE ON AN INDIVIDUAL
GANGLION CELL AND THESE
DEFLECTIONS THAT YOU'RE LOOKING
AT ON THE BOTTOM TRACE REPRESENT
EVIDENT THAT THERE ARE SYNAPTIC
CIRCUITS THAT EXIST AT THIS
TIME.
SO THESE ARE CURRENTS THAT ARE
DUE TO EXCITATORY
NEUROTRANSMITTER, BINDING TO THE
RECEPTORS ON THE CELL, SO
CIRCUIT ARE STARTING TO EMERGE.
WE CAN TAKE A SECOND ELECTRODE.
THESE ARE EXPERIMENTS THAT WERE
DONE BY BLANK INSHIP WHILE A
STUDENT IN THE LAP WHERE WE CAN
LOOK AT THE MEMBRANE POTENTIAL
CHANGES IN CELLS AND YOU CAN SEE
THAT THEY FIRE BURST OF ACTION
POTENTIALS AND IF WE
SIMULTANEOUSLY DO IMAGING AT
THAT TIME, YOU SEE THAT THERE'S
INCREASES IN FLUORESCENCE THAT
YOU SAW IN THE MOVIES DUE TO
ACTION POTENTIALS WHICH ARE DUE
TO A BARRAGE OF EXCITATORY
SYNAPTIC CURRENTS ON TO THE
CELLS.
SO WE KNOW THAT THIS ACTIVITY IS
GENERATED BY THIS KIND OF EARLY
SYNAPTIC CIRCUITS.
MY LAB HAS SPENT A LOT OF TIME
SORT OF IDENTIFYING WHAT THESE
CIRCUITS ARE.
AND ONE OF THE THINGS THAT I
FIND REALLY -- HAVE BEEN REALLY
FASCINATING ABOUT THIS QUESTION
IS THAT RETINAL WAVES PERSIST
FOR AN INCREDIBLY LONG PERIOD OF
DEVELOPMENT.
AND IN FACT I'LL JUST REVEAL ALL
OF THESE.
AND DURING THIS PERIOD OF
DEVELOPMENT, THE RETINA ITSELF
IS UNDERGOING A TREMENDOUS
AMOUNT OF DEVELOPMENT.
SO THE EARLIEST AGE AT WHICH WE
SEE THESE RETINAL WAVES IN MICE
IS EMBRYONIC DAY 16, WHICH IS
WHEN THE RETINA -- WHERE THE
GANGLION CELLS ARE REALLY THE
ONLY CELLS THAT HAVE
DIFFERENTIATED, THEY SENT THEIR
AXONS TO THE BRAIN, AND THE REST
OF THE RETINA IS KIND OF A
DIVIDING NEUROEPITHELIAL LAYER
WITH JUST A FEW CELLS THAT ARE
STARTING TO MATURE, THAT ARE
SHOWN THERE IN THE BLUE.
THEN WAVES PERSIST UNTIL
POSTNATAL DAY 12, OR 13 IN MICE,
AND THAT'S WHEN MICE OPEN THEIR
EYES.
WHEN A MOUSE OPENS THEIR EYES,
THEY CAN SEE.
SO THE REST OF THE CIRCUIT IS
MATURE, AND SO AT THIS STAGE, AT
THE LATER STAGE OF RETINAL
WAVES, ALL OF THE CELLS ARE
WIRED IN, SO THERE'S A BRIEF
PERIOD OF TIME WHERE THERE'S
KIND OF VISION THAT'S COMING
THROUGH THE CLOSED EYELIDS, AND
RETINAL WAVES ARE BEING
GENERATED.
AND THEN THERE'S THIS MEDIUM
TIME WHERE WE SPENT MOST OF OUR
EFFORTS WHERE WE'VE IDENTIFIED A
CIRCUIT THAT'S MEDIATED BY
ACETYLCHOLINE THAT'S THERE
TRANSIENTLY DURING DEVELOPMENT.
SO WE KNOW THAT THERE'S A
PARTICULAR CLASS OF CELLS,
THEY'RE CALLED STARBURST AM KRON
CELLS, YOU'RE GOING TO HEAR
ABOUT THEM QUITE A FEW TIMES
TODAY IN THE TALK.
IT'S A BEAUTIFUL INTERNEURON
THAT RELEASES ACETYLCHOLINE.
THEY SPONTANEOUSLY DEPOLARIZE
VERY INFREQUENTLY, THEY RELEASE
ACETYLCHOLINE AND THAT
ACETYLCHOLINE ACTIVATES
NICOTINIC RECEPTORS AND THAT IS
WHAT DRIVES RETINAL WAVE
PROPAGATION.
SO THESE STAGES OF DEVELOPMENT,
OR THIS SPANS ALMOST THREE WEEKS
OF DEVELOPMENT, AND THE CIRCUITS
THAT ARE MEDIATING WAVES ARE
CHANGING AND SO DURING THAT TIME
AS THE CIRCUITS CHANGE, ACTUALLY
THE PROPAGATION PROPERTIES OF
THE WAVES CHANGE.
SO WHAT YOU'RE LOOKING AT HERE
ARE WAVES ON THE LEFT THAT ARE
SHOWN ON EMBRYONIC DAY 17 SO
RIGHT BEFORE THE MOUSE IS BORN,
IN THE MIDDLE OF THE FIRST
POSTNATAL WEEK AND IN THE SECOND
POSE NATAL WEEK AND IN THE TOP
ARE WHAT WAVES LOOK LIKE IN
REALTIME.
AND THE BOTTOM IS THE
SEGMENTATION ALGORITHM THAT WAS
WRITTEN TO IDENTIFY THE WAVES
AND YOU CAN SEE THAT AS THE
CIRCUITS THAT MEDIATE WAVES
CHANGE, ACTUALLY THE PROPERTIES
OF THE WAVES CHANGE A LOT.
SO IN THE STAGE TWO, WHICH WE
SPENT -- THIS IS THIS
CHOLINERGIC CIRCUIT, WE THINK OF
THEM AS WAVES ON THE BEACH, YOU
MAY NOTICE THERE'S BEEN ONE WAVE
THAT'S PROPAGATING ACROSS THAT
ENTIRE WAVE WHILE I'VE BEEN
TALKING, THEY STILL PROPAGATE
RATHER STOWLY, WHILE AT STAGE
III, THEY'RE RAPID, SMALL AND
MORE CIRCUITOUS.
SO ALL OF THESE PROPERTIES OF
THE WAVES ARE REALLY CHANGING AS
THE CIRCUITS THAT MEDIATE
CHANGE, AND I WILL ARGUE THAT
THESE CHANGING PROPERTIES OF THE
WAVES ARE SERVING -- SENDING
DIFFERENT SIGNALS UP TO THE
BRAIN THAT ARE CRITICAL FOR
WHATEVER IS DEVELOPING IN THE
VISUAL SYSTEM AT THAT TIME.
SO TO CONVINCE YOU THAT THIS
ACTIVITY ACTUALLY IS PROPAGATING
UP THROUGH THE BRAIN, THESE ARE
ACTUALLY EXPERIMENTS THAT WERE
DONE BY MIKE CRER'S LAB WHO WAS
ABLE TO DO RECORDINGS IN THE
SUPERIOR COLLICULUS, WHILE THE
MOUSE IS EXPERIENCING RETINAL
WAVES.
SO WHAT YOU'RE LOOKING AT HERE,
WHAT HE'S DONE IS TWO DIFFERENT
KINDS OF EXPERIMENTS.
ONE IN WHICH HE'S PUT A CALCIUM
DYE IN THE RETINA LIKE WE HAVE,
BUT NOW THAT GOES DOWN THE AXON,
THE AXONS PROJECT TO THE SURFACE
OF THE COLLICULUS, AND YOU CAN
SEE THAT THEY HAVE VERY SIMILAR
PROPAGATION PROPERTIES TO WHAT'S
HAPPENING IN THE RETINA, BUT
THEN HE CAN ALSO PUT A CALCIUM
DYE IN THE POST SYNAPTIC CELLS
IN THE COLLICULUS AND THAT'S
SHOWN IN THE BOTTOM, SEE IF WE
CAN PLAY THAT AGAIN.
WHERE YOU CAN SEE THIS ACTIVITY
GENERATED BY THE RETINA IS VERY
RELIABLY RADIATING DOWN TO THE
COLLICULUS AND DEPOSING THE
COLLICULUS.
THEY PROPAGATE TO THE LGN, TO
THE PRIMARY VISUAL CORTEX, AND
IN FACT THERE'S BEEN SIGNATURES
OF RETINAL WAVES ACTIVATING
LARGE AREAS OF VISUAL CORTEX,
BOTH DURING THESE VERY EARLY
STAGE TWO WAVES AND STAGE III
WAVES FROM THE CORTEX ITSELF IS
JUST DEVELOPING SO THIS IS
REALLY PROPAGATING UP THROUGH
THE VISUAL SYSTEM BEFORE THE
ANIMAL CAN SEE.
SO ONE OF THE FEATURES AND
SOMETHING I'D LIKE TO EMPHASIZE
THAT MAKES ALL OF THIS POSSIBLE
EARLY IN DEVELOPMENT IS THE FACT
THAT WE DON'T THINK OF -- SO AS
I SAID, THESE SEEM TO BE
MEDIATED BY SYNAPSES, AND FOR
THOSE OF US WHO STUDY THE
NERVOUS SYSTEM, WE LIKE TO THINK
OF SYNAPSES AS BEING KIND OF
POINT-TO-POINT CONNECTORS,
NEURON A ACTIVATES NEURON B BUT
NOT NEURON C OR D SO WE REALLY
WANT TO HAVE THIS VERY PRECISE
WIRING.
TURNS OUT ONE OF THE FEATURES
THAT'S CRITICAL FOR PROPAGATING
RETINAL WAVES IS THAT EARLY IN
DEVELOPMENT, NEUROTRANSMITTERS
SEEM TO BE RELEASE IN THIS VERY
DIFFUSE WAY.
SO YOU HAVE THIS KIND OF BEFORE
SYNAPSES HAVE MATURED, YOU HAVE
CELLS THAT ARE RELEASING
NEUROTRANSMITTER BUT THEY'RE
RELEASING THEM IN CLOUDS.
SO THIS IS TRUE FOR BOTH STAGE
TWO AND STAGE III WAVES WHERE
THERE'S THIS DIFFUSE RELEASE,
AND I JUST WANT TO SHOW YOU THE
KINDS OF EXPERIMENTS WE'VE DONE
TO DEMONSTRATE THIS VOLUMETRIC
RELEASE OF NEUROTRANSMITTER.
SO ONE OF THEM WERE EXPERIMENTS
CARRIED OUT BY KEVIN FORD WHO
USED A REALLY AMAZING -- WHAT'S
CALLED CELL-BASED SENSOR.
THIS IS A HEX CELL EXPRESSING A
MUSCARINIC ACETYLCHOLINE
RECEPTOR, COUPLED TO RELEASING
CALCIUM FROM STORES.
THIS HEX CELL IS ALSO EXPRESSING
A CALCIUM SENSOR AND THE IDEA IS
WHEN ACETYLCHOLINE BINDS TO THIS
G PROTEIN COUPLED RECEPTOR YOU
GET A RELEASE FROM STORES AND
YOU'LL SEE A SIGNATURE IN THE
CALCIUM.
SO THIS IS A HEX CELL, SO HOW
ARE WE GOING TO USE THIS TO
RECORD ANYTHING IN RELATION TO
THE RETINA?
WHAT KEVIN DID IS HE LITERALLY
THREW IT ON THE SURFACE OF THE
RETINA WHILE HE'S DOING
RECORDING FROM A GANGLION CELL.
SO HERE ARE EXAMPLES OF HEX
CELLS EXPRESSING THESE
INDICATORS.
WHAT KEVIN FOUND IS THAT EVERY
TIME YOU COULD USE THIS VOLTAGE
CLAMP RECORDING TO SAY I KNOW
ACETYLCHOLINE IS BEING RELEASED
AT THIS STAGE BECAUSE WE CAN SEE
THE SYNAPTIC CURRENTS, HE SAW
THIS VERY RELIABLE CLOUD OF
ACETYLCHOLINE NOT ONLY DIFFUSING
THROUGH THE SURFACE OF THE
RETINA, TO THE HEX CELL SITTING
MICRONS AWAY.
SO THIS IS REALLY EVIDENCE THAT
ACETYLCHOLINE IS BEING RELEASED
IN A CLOUD.
WE'VE ALSO USED SOME GENETICALLY
ENCODED INDICATORS.
THIS IS AN EXAMPLE OF SOMETHING
CALLED GLUE SNIFFER, GREAT NAME,
IT'S A WAY OF DETECTING DIFFUSE
RELEASE OF GLUTAMATE.
WE COULD EXPRESS THAT IN THE
RETINA AND YOU CAN SEE DURING
STAGE 3 WAVES, THIS IS GOING TO
BE GLUTAMATE THAT'S NOT CONFINED
TO SYNAPSES, BUT IT'S JUST
GETTING RELEASED IN CLOUDS
DURING THIS TIME.
THIS IS GOING TO BE VERY
IMPORTANT WHEN I TALK LATER
ABOUT SOME CURRENT WORK IN THE
LAB, IF I GET TO IT, ABOUT
MATURATION OF SAY THE
VASCULATURE BECAUSE NOW YOU HAVE
THIS CLOUD OF NEUROTRANSMITTER
THAT'S BEING RELEASED AND
THERE'S A LOT OF DEVELOPMENT OF
OTHER CELL TYPES IN THE RETINA
THAT MIGHT BE INFLUENCED BY
RELEASE OF NEUROTRANSMITTERS.
SO THIS DIFFUSE RELEASE GOES
AWAY AS THE ANIMALS MATURE, SO
IT'S DEFINITELY A FEATURE OF
SOMETHING THAT JUST HAPPENS
DURING RETINAL WAVES.
SO THAT GIVES YOU A KIND OF A
FEEL OF EXPERIMENTS WE DO IN THE
LAB.
WE WANT TO UNDERSTAND THE
CIRCUIT BASIS OF HOW THESE WAVES
ARE GENERATED BUT FOR ANYONE TO
CARE ABOUT THIS, WE HAVE TO SHOW
THERE'S A ROLE THEY PLAY, A ROLE
FOR THESE WAVES IN DEVELOPMENT.
SO TO GET -- SO WHAT'S GOING ON
DURING DEVELOPMENT?
WELL, IF DURING THE FIRST
POSTNATAL WEEK IS WHEN THE
RETINA IS MAKING ITS CONNECTIONS
TO THE BRAIN, AND WHEN THE
RETINA MAKES ITS CONNECTIONS TO
THE BRAIN, RETINAL GANGLION CELL
AXONS ASH RISE AN ARBORIZE AND A
VARIETY OF REFINEMENTS.
THE WAY THAT WE WANTED TO SEE IF
RETINAL WAVES WERE INVOLVED IN
THIS DEVELOPMENTAL PROCESS IS WE
TOOK ADVANTAGE OF KNOWING THAT
THIS WAS A CIRCUIT MEDIATED BY
ACETYLCHOLINE SO WE MADE MICE
THAT WERE LACKING THE BETA
2 SUBUNIT OF THE AN ANY COTINGE
ACETYLCHOLINE RECEPTORS AND WERE
ABLE TO SHOW THIS MOUSE HAD
REDUCED RETINAL WAVES AND WOULD
BE A GOOD MODEL CY SYSTEM.
THIS IS A MULTIELECTRODE ARRAY
RECORDING FROM A WILD TYPE
MOUSE.
I JUST LOVE TO SHOW THIS TO SHOW
YOU WHAT THE PATTERN IS.
WHAT'S ALONG THE Y AXIS IS A
DIFFERENT GANGLION CELL, ALONG
THE X AXIS IS TIME AND YOU CAN
SEE WHEN A WAVE COMES THROUGH,
YOU GET A BURST OF ACTION
POTENTIALS AND THEN NOTHING.
THEN A BURST OF ACTION
POTENTIALS THAT PROPAGATE ACROSS
AND THEN NOTHING.
IN THE BETA 2 KNOCKOUT, WAVES
ARE MUCH LESS FREQUENT.
YOU CAN'T SEE IT IN THIS TIME
SCALE BUT INSTEAD OF IT BEING A
PROPAGATING WAVE, THEY HAD
FLASHES.
SO THEY PROPAGATED SUPER FAST
AND MOSTLY THE RETINA WAS
SILENT.
SO WHAT HAPPENS TO THE RETINAL
PROJECTIONS IN THE BRAIN IN THIS
MODEL OF MICE?
THE FIRST SET OF EXPERIMENTS WE
DID IS WE LOOKED AT THE
RETINOTOPIC PROJECTION FROM THE
RETINA TO THE SUPERIOR
COLLICULUS.
SO THE WAY WE WOULD LOOK AT THIS
IS THESE WERE IN LAB RANGE OF
MOTION WITH TODD MCLAUGHLIN
WHILE A POSTDOC IN DENNIS
O'LEARY'S LAB AT THE SALK
INSTITUTE.
SO WE PUT A LITTLE CRYSTAL OF A
FLUORESCENT DYE IN THE RETINA SO
A FEW GANGLION CELLS WOULD TAKE
UP THIS CRYSTAL AND IT WOULD
DIFFUSE DOWN THEIR AXONS, AND
YOU COULD SEE WHERE THOSE AXONS
PROJECT IN THE SUPERIOR
COLLICULUS.
AND SO WHEN YOU DO THAT, SO WHAT
YOU'RE LOOKING AT HERE IS AN
IMAGE OF THE SUPERIOR COLLICULUS
AFTER WE'VE PUT THIS CRYSTAL IN,
WE WAIT 24 HOURS, WE CAN DISSECT
OUT THE COLLICULUS AND SEE THESE
FEW GANGLION CELLS PROJECT TO A
VERY SMALL REGION IN THE
COLLICULUS AND THIS IS THE BASIS
OF THE RETINOTOPIC MAP.
SO AS YOU MOVE ACROSS THE RETINA
AT DIFFERENT LOCATIONS, YOU MOVE
ACROSS THE COLLICULUS IN A VERY
SMOOTH MAPPING.
YOU DO THAT SAME EXPERIMENT,
THIS IS POSTNATAL DAY 8, JUST
ONE WEEK EARLIER, AND YOU SEE
THAT THOSE RETINAL GANGLION
CELLS, THAT SMALL CLUSTER OF
RETINAL GANGLION CELLS PROJECT
ALL OVER THE COLLICULUS, AND
THEN THIS FIRST POSTNATAL WEEK
REPRESENTS THIS PERIOD OF
REFINEMENT, SO THIS NOW BEFORE
VISION, THIS IS WHEN THERE ARE
RETINAL WAVES, SO WE LOOK TO SEE
WHAT HAPPENS TO THIS REFINEMENT
PROCESS IN THE BETA 2 KNOCKOUT.
THESE ARE TWO EXAMPLES OF WHAT
WE SAW ON THE RIGHT.
SO NORMALLY AT POSTNATAL DAY 8,
WE HAVE THIS NICE -- WE CALL
THEM TERMINATION ZONES, WE HAVE
THIS NICE NARROW PROJECTION
PATTERN BUT IN THE MOUSE THAT
DEPARTMENT HAVE WAVES OR HAD
REDUCED WAVES AT THAT TIME, YOU
GET SOME REFINEMENT BUT NOT
NEARLY AS MUCH REFINEMENT AS YOU
WOULD GET IN A WILD TYPE.
THIS SORT OF RETINAL GANGLION
CELLS PROJECTING BROADLY MEANT
THEY HAD BLURRY VISION AND THAT
WAS ONE OF THE THINGS THEY FOUND
FOR THESE MICE.
SO WE THINK RETINAL WAVES ARE
IMPORTANT FOR DRIVING THIS
RETINOTOPIC REFINEMENT AND EVEN
WHEN THIS MOUSE OPENS ITS EYES
AND HAS VISION, THEY GET A
LITTLE BIT OF REFINEMENT BUT IT
DOESN'T MAKE UP FOR WHAT THEY
LACKED WHEN THEY DIDN'T HAVE
RETINAL WAVES.
SO WAVES ARE IMPORTANT FOR
SETTING UP THIS SMOOTH
RETINOTOPIC MAP, THAT'S
IMPORTANT FOR SHARP VISION.
OH, AND ANOTHER THING THAT
PEOPLE MAY HAVE HEARD ABOUT IS
THAT THERE'S A FEATURE IN VISUAL
SYSTEMS CALLED OCULAR DOM NABS E
COLUMNS, SO OCULAR DOMINANCE
COLUMNS EMERGE FROM -- FIRST IN
EYE-SPECIFIC SEGREGATION THAT
HAPPENS IN THE THALAMUS.
SO THE WAY WE LOOK AT THIS IS
THE FOLLOWING, AS WE PUT ONE
COLOR DYE IN ONE EYE AND IT GETS
SEPTEMBER SENT DOWN THE AXONS O,
THEN YOU HAVE A DIFFERENT COLOR
IN THE OTHER EYE, AND YOU'LL
FIND THAT WHEN YOU LOOK IN THE
THALAMUS, THAT THERE IS THIS
SEGREGATION FROM THE LEFT EYE TO
THE RIGHT EYE, AND IT'S THOSE
NEURONS WITHIN THOSE TWO PARTS
OF THE LGN THAT WILL GO UP AND
FORM THE OCULAR DOMINANCE
COLUMNS.
THESE WERE DONE BY ALEX TIRIAC.
ALEX JUST STARTED HIS OWN LAB AT
VANDERBILT UNIVERSITY.
WHAT ALEX DID FOR THESE
EXPERIMENTS WAS HE WOULD DO
THESE INJECTIONS, HE'D WAIT 24
HOURS FOR THIS TRANSPORT TO
HAPPEN, AND THEN HE WOULD USE
THIS METHOD CALLED CUBIC THAT
ALLOWED YOU TO CLEAR THE WHOLE
BRAIN, AND THEN HE COULD LOOK AT
THE RETINAL PROJECTIONS
EVERYWHERE IN THE BRAIN, BOTH IN
A WILD TYPE AND IN KNOCKOUT.
SO WHEN YOU DO THAT, WHILE
LOOKING THROUGH THE LATERAL
NUCLEUS YOU SEE A STRON
CONTRALATERAL PROJECTION, NOW
WE'RE SORT OF TRAVELING THROUGH
THE THALAMUS, THE VISUAL
THALAMUS, AND YOU CAN SEE
THERE'S AN IPSILATERAL
PROJECTION THAT'S SEGREGATED SO
IN WILD TYPE DOMINATED BY
CONTRALATERAL PRO JEX, AND THATY
START INITIALLY BY OVERLAPPING
AND THE SEGREGATION OCCURS
DURING THE FIRST POSTNATAL WEEK
AND IN THE MICE THAT ARE LACKING
RETINAL WAVES, WE SEE VERY
LITTLE SEGREGATION.
IT STAYS FROZEN IN THE IMMATURE
PATTERN WHERE THE CONTRAIS NOT
DRIVEN OUT WHERE THE I PSI
PROJECTION IS AND THE IPSI
PROJECTION IS A LITTLE BIT
BROADER.
SO FROM THIS WE KNOW RETINAL
WAVES ARE IMPORTANT FOR DRIVING
THIS EYE-SPECIFIC SEGREGATION
AND INDEED THESE MICE WHEN THEY
GROW UP HAVE DEFICITS IN
BINOCULAR VISION, KIND OF WEAK
IN MICE TO BEGIN WITH BUT THEY
DO HAVE DEPTH PERCEPTION AND
IT'S IMPAIRED IN THESE MICE,
SOMETHING IMPORTANT FOR SETTING
UP THEREBY KNOCK LAR CIRCUITS.
OKAY.
SO ANOTHER THING HAPPENING
DURING THIS SECOND POSTNATAL
WEEK ARE THE CIRCUITS IN THE
RETINA THEMSELVES ARE GETTING
WIRED UP SO WE HAVE MORE
RECENTLY BEEN LOOKING TO SEE
WHETHER OR NOT RETINAL WAVES ARE
IMPORTANT FOR SETTING UP THE
CIRCUITS WITHIN THE RETINA.
THIS IS WHAT WAS REFERRED TO IN
THE INTRODUCTION.
SO THESE ARE RECENT EXPERIMENTS
LED BY ALEX TIRIAC AND TWO
GRADUATE STUDENTS, AND I'LL TALK
ABOUT THEIR WORK ABOUT HOW
RETINAL WAVES ARE IMPORTANT FOR
SENDING UP A PARTICULAR CIRCUIT
IN THE RETINA AND THIS WAS
PUBLISHED LAST YEAR.
SO WITHOUT GOING INTO TOO MANY
DETAILS BECAUSE IT WAS SO NICELY
INTRODUCED, THERE ARE CELLS IN
YOUR RETINA THAT ARE VERY
SENSITIVE TO THE DIRECTION THAT
SOMETHING MOVES IN THE VISUAL
WORLD AND I WANT TO SAY THESE
ARE VERY IMPORTANT BECAUSE THESE
ARE THE CELLS THAT ARE CALLED
DIRECTION-SELECTIVE GANGLION
CELLS, AND THESE CELLS ARE VERY
IMPORTANT FOR MICE WHEN MICE
MOVE THROUGH THE WORLD, THEY
HAVE OPTIC FLOW THAT GOES ACROSS
THE RETINAS, THEY HAVE
COMPENSATORY EYE MOVEMENTS THAT
ARE MEDIATED -- IT'S A REFLEXIVE
EYE MOVEMENT WHICH IS THEIR WAY
OF STABILIZING IMAGES, SO THEY
DON'T HAVE THE SAME SORT OF
MICRO -- THEY DON'T HAVE THE
SAME SORT OF MICRO SACCADIC
STRATEGIES THAT PRIMATES HAVE
BUT THEY HAVE THIS REFLEXIVE EYE
MOVEMENT THAT'S VERY IMPORTANT
FOR THAT.
SO THERE ARE FOUR TYPES OF THESE
DIRECTION SELECTIVE GANGLION
CELLS.
THERE ARE THE ONES THAT PREFER
LEFT, RIGHT, UP AND DOWN, AND
ONE OF THE THINGS THAT WE FOUND
VERY SURPRISING WAS THAT IN A
MOUSE THAT DOESN'T HAVE RETINAL
WAVES, THEY STILL HAVE AN UP
PREFERENCE, A DOWN PREFERENCE
BUT THEY NOW HAVE NO CELLS THAT
PREFER LEFT OR RIGHT.
AND THAT MEANS THAT THESE MICE
ACTUALLY DON'T HAVE A HORIZONTAL
OPTOKINETIC REFLEX BUT A
PERFECTLY NORMAL VERTICAL
OPTOKINETIC REFLEX.
TOTAL TOTALLY BIZARRE AND A BIG
QUESTION THE LAB IS TRYING TO
UNDERSTAND BUT WE KNOW WAVES ARE
IMPORTANT FOR SETTING UP THIS
REFLEX.
WE HAVE A HYPOTHESIS OF HOW THIS
MIGHT BE HAPPENING THAT YOU'LL
HEAR ABOUT SOON.
SO WE KNOW WAVES ARE IMPORTANT
FOR THAT.
SO WE ALSO WANT TO LOOK AND SEE
IF WAVES ARE IMPORTANT FOR
THINGS THAT ARE HAPPENING VERY
EARLY IN DEVELOPMENT.
SO WAVES ARE THERE AROUND
EMBRYONIC DAY 16, AND DURING
THAT TIME IS WHEN THERE'S A LOT
OF NEUROGENESIS.
THE CELLS ARE POSITIONING
THEMSELVES IN THE GANGLION CELL
LAYER, AND ACTUALLY THERE'S A
ROBUST PERIOD OF CELL DEATH THAT
OCCURS AROUND POSTNATAL DAY TWO,
AND CHRIS CLANE VOUFO, HER
THESIS WAS TO LOOK AND SEE IN
MICE THAT LACKED THESE STAGE I
WAVES, THESE EARLY WAVES,
WHETHER OR NOT THESE WERE
AFFECTED BY A LOSS OF RETINAL
WAVES AND IT TURNS OUT THEY WERE
NOT SO RETINAL WAVES DON'T SEEM
TO BE IMPORTANT FOR DRIVING CELL
DEATH AS HAS BEEN FOUND IN OTHER
PARTS OF THE NERVOUS SYSTEM.
MORE RECENTLY, IN A STUDY WE
JUST SUBMITTED LAST WEEK, WE
WANTED TO LOOK AND SEE WHETHER
RETINAL WAVES WERE IMPORTANT FOR
THE DIFFERENTIATION OF THE
DIFFERENT CELL TYPES WITHIN THE
RETINA.
I'M GOING TO SAY BECAUSE OF
TIME, I THINK I'M GOING TO SKIP
THE DETAILS HERE, BUT I JUST
WANT TO SORT OF HIGHLIGHT, THESE
WERE EXPERIMENTS LED BY A
POSTDOC IN MY LAB, AND MATTHEW
POE IS A GRADUATE STUDENT AND
OUR STRATEGY HERE WAS TO USE
SINGLE CELL RNA SEQUENCING AS A
WAY OF IDENTIFYING ALL THE
DIFFERENT GANGLION CELL TYPES
AND THESE ARE ALL THE DIFFERENT
GANGLION CELL TYPES THAT HAVE
BEEN IDENTIFIED IN THE MOUSE
RETINA, AND WHAT WE COMPARED IS
WILD TYPE RETINAS WHICH ARE
SHOWN IN THE BLUE HERE, THE
GREEN ARE MATURE, THE EXPRESSION
PROFILES OF MATURE RETINAL
GANGLION CELLS AND WHAT'S SHOWN
IN THE RED ARE THE MICE THAT
LACK BETA 2 -- THAT LACK WAVES
IN THE FIRST PO POSTNATAL WEEK.
AS YOU'LL SEE THEE THERE'S LINES
ALL LOOK PRETTY SIMILAR AS YOU
LOOK ALONG DIFFERENT CELL TYPES,
AND WE FOUND NO DRAMATIC IMPACT
ON THE DIFFERENTIATION OF CELL
TYPES AT THIS STAGE, IN FACT WE
LOOKED FOR ANY THINGS REGULATED
ON THE TRANSCRIPTIONAL LEVEL AND
WE FOUND VERY, VERY LITTLE.
SO THERE WERE SOME CELL TYPES OF
GANGLION CELL TYPES THAT
ACTUALLY WERE STRONGLY AFFECTED
BY ACTIVITY, BUT MOST OF THE
CELL TYPES WERE NOT, AND
NOTABLY, THOSE DIRECTION
SELECTIVE GANGLION CELLS WERE
ONE OF THE CELLS NOT AFFECTED BY
TRANSCRIPTION.
SO FROM THIS STUDY -- OR NOT
AFFECTED AT THIS TRA TRANSCRIPTN
LEVEL.
WE THINK WHATEVER WAVES ARE
DOING TO SET UP THE HORIZONTAL
DIRECTIONAL SELECTIVITY, IT'S
EITHER POST TRANSCRIPTIONAL OR
POTENTIALLY POST TRANSLATIONAL,
AND HAPPY TO TALK TO PEOPLE
ABOUT THAT LATER.
SO I'M GOING TO SKIP THIS.
SO THIS INTERIM STUDY BEFORE I
TALK ABOUT THE ONGOING WORK IN
THE LAB.
SO RETINAL WAVES ARE A ROBUST
SOURCE OF ACTIVITY.
BEFORE VISION AND IS REQUIRED
FOR THE PRECISE CONNECTIVITY TO
EMERGE THROUGHOUT THE VISUAL
SYSTEM.
DIFFERENT STAGES OF WAVES HAVE
DIFFERENT SPATIOTEMPORAL
PROPERTIES AND THERE'S TRANSIENT
ELEMENTS SUCH AS VOLUME RELEASE
OF NEUROTRANSMITTER IMPORTANT
FOR DRIVING THIS.
THAT RETINAL ACTIVITY HAS BEEN
IMPLICATED IN THE WIRE FG DS
CIRCUITS SETTING EXCITABILITY OF
CELLS BUT NOT DIFFERENTIATION OF
CELL TYPES.
SO WHY ARE WAVES DOING ANY OF
THESE THINGS?
WHAT ABOUT WAVES IS IMPORTANT
FOR SETTING UP ANY OF THESE
CIRCUITS?
THE IDEA THAT THE FIELD HAS SORT
OF COME TO SETTLE ON IS THE IDEA
IS, WELL, DIFFERENT FEATURES OF
WAVES MIGHT BE IMPORTANT FOR
SETTING UP DIFFERENT ASPECTS OF
DIFFERENT MAPS.
SO FOR EXAMPLE, THIS IS THE
RETINOTOPIC REFINEMENT.
THE IDEA HERE IS THAT WELL, IF
YOU HAVE PROPAGATING ACTIVITY,
YOU'RE GOING TO HAVE NEIGHBORING
CELLS THAT ARE MORE CORRELATED
IN THEIR FIRING THAN DISTANT
CELLS SO THERE'S INFORMATION
ABOUT RETINOTOWY THPY THAT LEADO
THIS SORT OF REFINEMENT.
IF WE HAVE FOUR RETINAL GANGLION
CELLS THAT ARE TRANSIENTLY
CONNECTED TO TWO TACTILE NEURAL
TARGET CELLS, IF INITIALLY
THEY'RE MAKING A LOT OF
CONNECTIONS USING -- BROADLY U
USING CELLS THAT ARE FIRED
TOGETHER, WIRED TOGETHER, YOU'RE
GOING TO GET THIS KIND OF MATURE
PATTERN WHERE YOU GET
RETINOTOPIC REFINEMENT.
SO THIS IDEA THAT A PROPAGATING
WAVE IS IMPORTANT FOR
RETINOTOPY.
FOR EYE SPECIFIC SEGREGATIONS,
YOU HAVE STRONG CORRELATIONS
WITHIN A RETINA BUT VERY WEAK
CORRELATIONS ACROSS A RETINA.
ONE RETINA WILL FIRE A WAVE AND
IT'S SILENT FOR A MINUTE,
CHANCES ARE THE OTHER RETINA
WILL FIRE DURING THAT
INTERVENING TIME.
SO THE LACK OF -- THE LOW
FREQUENCY OF WAVES MIGHT BE
IMPORTANT FOR EYE-SPECIFIC
SEGREGATION.
SO THERE'S A NEW FEATURE OF
WAVES THAT WE'VE BEEN TALKING A
LOT ABOUT THE FIELD AND THAT HAS
TO DO WITH SOMETHING THAT IS THE
PROPAGATION BIAS OF RETINAL
WAVES.
IT TURNS OUT THAT RETINAL WAVES,
THEY LOOKED RANDOM AND SOME OF
THE VIDEOS I WAS SHOWING YOU,
BUT IT TURNS OUT MOST WAVES
PROPAGATE NASALLY ON THE RETINA
AND THAT'S ACTUALLY REPRESENTS
OPTIC FLOW.
SO THE IDEA IS THAT MAYBE
RETINAL WAVES HAVE
EVOLUTIONARILY COME ABOUT
BECAUSE MAMMALS DON'T MOVE
DURING THIS PERIOD OF
DEVELOPMENT AS OPPOSED TO SAY
FROGS.
FROGS DON'T HAVE RETINAL WAVES,
THEY HAVE VISION, AT THE SAME
TIME WHEN THE RETINA IS WIRING
UP, THEY HAVE OPTIC FLOW BECAUSE
THEY'RE CONSTANTLY SWIMMING.
SO THIS IDEA THAT THERE MIGHT BE
A PROPAGATION BIAS THAT RETINAL
WAVES GIVE US A SIGNATURE OF
OPTIC FLOW BEFORE YOU HAVE ANY
EXPERIENCE IN THIS.
OPTIC FLOW IS SOMETHING WE'VE
DESCRIBED, WHAT'S CALLED THE
ROSE PLOT WHERE YOU HAVE MORE
WAVES PROPAGATING NASAL ON THE
RETINA VERSUS THE OTHER
DIRECTIONS, AND THIS IS
SOMETHING MIKE CRAIR'S LAB IS
INVESTIGATING, THAT HE'S ALSO
SEEN PROPAGATING UP TO THE
TECTUM.
SO THERE IS THIS PROPAGATION
BIAS OF RETINAL WAVES AND THAT
MIGHT BE IMPORTANT.
IN FACT MIKE CRIAR'S WAVE AS
SHOWN IF YOU GET RID OF OPTIC
FLOW USING A VARIETY OF
MANIPULATIONS, THE PROPAGATION
BIAS WHICH MIMICS OPTIC FLOW,
THAT YOU GET RID OF DIRECTION
SELECTIVITY AS RECORDED IN THE
COLLICULUS, SO HE THINKS IT'S
VERY IMPORTANT FOR THAT.
OKAY.
SO TO BE COMPLETELY HONEST, I'M
NOT SO MUCH OF A ARE WAVES
IMPORTANT, I JUST CARE ABOUT HOW
THEY'RE GENERATED BECAUSE THAT'S
JUST THE KIND OF SCIENTIST I AM,
SO WE'VE BECOME VERY FASCINATED
WITH THIS QUESTION ABOUT WHAT
CAUSES PROPAGATION BIAS.
WHAT IN THE RETINA IS GOING TO
MAKE WAVES GO MORE NASALLY?
SO AS I TOLD YOU BEFORE, THERE'S
DIFFUSE RELEASE OF
NEUROTRANSMITTER.
NEUROTRANSMITTER IS BEING
RELEASED IN CLOUDS SO WHAT IS
THE BASIS OF THIS PROPAGATION
BIAS?
THIS HAS BEEN A PROPERTY THAT
MIAH PITCHER IN COLLABORATION
WITH DARIO TOMMASINI HAVE BEEN
CHARACTERIZING PROPAGATION BIAS
AND TESTING SOME BIASES.
ONE WAY YOU MIGHT GET
PROPAGATION BIAS IS YOU HAVE
MORE WAVES INITIATE -- IF THEY
ALL START ON ONE SIDE, THEN
YOU'RE GOING TO GET MORE GOING
THIS WAY.
SO THAT'S ONE POSSIBILITY.
THE OTHER POSSIBILITY IS THAT NO
MATTER WHERE THEY START, THEY
ALWAYS SEEM TO GO NASALLY, AND
THAT'S SOMETHING THAT WE CAN
DETERMINE EXPERIMENTALLY.
SO WE WANT TO ASK THIS QUESTION
ABOUT WHAT ARE THE -- IF THERE
IS AN ASYMMETRIC -- NO MATTER
WHERE IT STARTS, IT ALWAYS GOES
NASALLY, THERE HAS TO BE
SOMETHING IN THAT CIRCUIT THAT
IS CAUSING THAT BIAS FOR THEM TO
GO THAT DIRECTION.
SO WHAT'S CAUSING THOSE THINGS?
SO THE WAY THEY'VE BEEN GETTING
AT THIS IS USING -- SO YOU WERE
SEEING AN EXAMPLE OF A WAVE
THAT'S PROPAGATING AND HAS -- IF
YOU LOOK AT ITS CENTER OF MASS,
IT'S GOT THIS PROPAGATION
CONVOLUTED PATHWAY.
WE JUST GO FROM START TO FINISH
AND THAT'S HOW WE FIGURE OUT
WHAT DIRECTION IT'S MOVING.
AND SO WHEN WE DO THAT, THIS IS
WHAT WE FIND.
SO FIRST WE FIND INDEED THERE IS
AN INITIATION SITE BIAS.
WHAT YOU'RE LOOKING AT HERE IS
THE DENSITY OF INITIATION SITES,
AND MANY MORE WAVES START IN THE
TEMPLE EDGE OF THE RETINA.
SO THAT ABSOLUTELY SEEMS TO BE
TRUE.
SOME BUT NOT ALL OF THEM SEEM TO
START THERE.
AND IN FACT, WHAT YOU'RE LOOKING
AT HERE ARE THE MANY -- THERE
ARE A WHOLE BUNCH OF WAVES HERE
THAT STARTED IN THE LEFT HALF OF
THE RETINA, AND THEY ALSO SEEM
TO HAVE THIS PROPAGATION BIAS.
SO IT DOESN'T SEEM TO BE
AFFECTED BY -- SO THERE IS AN
INITIATION BIAS BUT THERE ALSO
SEEMS TO BE A LOCAL PROPAGATION
BIAS.
SO WHAT'S CAUSING THIS?
WHAT IS CAUSING THIS -- IS IT A
GRADIENT OF EXCITATION?
IS IT A GRADIENT OF INHIBITION?
WHAT MIKE CRIAR'S LAB AND
ACTUALLY A COUPLE OTHER LABS
VERY RECENTLY A AT CONFERENCES,
WE'VE TALKED ABOUT THE START
BURST AMACRINE CELLS RELEASING
ACETYLCHOLINE -- IT RELEASES
ACETYLCHOLINE AND GABA, THAT'S
NOT WHY THEY THINK THAT BUT IT'S
BOTH EXCITATORY AND INHIBITORY
SO IT COULD DO EITHER OF OUR
HYPOTHESES.
IT'S KNOWN TO BE ASYMMETRICALLY
WIRED INTO THE RETINA, THAT'S
IMPORTANT FOR DIRECTION
SELECTIVITY, AND KILLING THESE
CELLS OR THERE'S A MU TAKE IN
THESE CELLS THAT IT DOESN'T
MATTER WHAT THE MUTATION IS BUT
JUST A MUTATION IN THE CELL
ACTUALLY MIKE CRIAR'S LAB HAS
SHOWN BOTH THOSE CASES YOU GET
LESS PROPAGATION BIAS.
SO IF YOU KILL THE CELL OR DO A
MUTATION IN THE CELL THAT GETS
RID OF DIRECTION SELECTIVITY,
THAT GETS -- WE WANT TO KNOW --
AND THEY SAID THAT ALSO SEEMS TO
GET RID OF PROPAGATION BIAS.
SO WE THINK THE CELL IS INVOLVED
AND WE'RE TRYING TO TEST IS IT
EXCITATION OR INHIBITION FROM
THE CELL.
SO THE FIRST THING WE DID IS WE
HAVE OUR MOUSE, SO IT RELEASES
ACETYLCHOLINE SO WE HAVE A MOUSE
THAT IS LACKING THE BETA
2 SUBUNIT OF NICOTINIC
ACETYLCHOLINE RECEPTORS AND WE
FIND UNFORTUNATELY THAT THE
PROPAGATION BIAS WE SEE IN WILD
TYPE IS STILL PRESERVED IN THE
BETA 2 KNOCKOUT.
SO IT DOESN'T SEEM TO BE AT
LEAST MEDIATED BY THIS NICOTINIC
RECEPTOR.
SO THEN WE THOUGHT WELL, MAYBE
IT'S GABA, AND INDEED, WHEN WE
PUT ON GABA-A RECEPTOR BLOCKERS,
THE WAVES GO NUTS, BUT IN THERE
GOING NUTS, THEY ALSO SEEM TO
LOSE THEIR PROPAGATION BIAS.
THEY MIGHT HAVE A LITTLE BIT OF
IT LEFT BUT THEY SEEM TO LOSE
THEIR PROPAGATION BIAS.
SO THAT'S CONSISTENT WITH THE
IDEA THAT IT'S MEDIATED BY THE
RELEASE OF GABA RECEPTORS.
YOU CAN SEE PROPAGATION BIAS IS
NOT AS STRONG IN THE PRESENCE OF
GABA-A ANTAGONISTS.
BUT THEN WE TOOK ADVANTAGE OF A
MOUSE LINE THAT WAS GENERATED B-
WHERE YOU CAN RELEASE GABA JUST
FROM THE STARBURST CELLS.
WE LOOK JUST AT THAT MOUSE, NO
GABA RELEASE FROM STARBURST
CELLS, IT STILL HAS PROPAGATION
BIAS, AND SO WE DON'T KNOW THE
ANSWER.
SORRY.
SO WE'RE STILL WORKING ON IT.
BUT I WANTED TO THROW THAT OUT
THERE AS A PUZZLE FOR YOU
CIRCUIT PEOPLE OUT THERE, IF YOU
HAVE ANY IDEAS IN WHAT WE CAN
PURSUE.
OKAY.
SO -- AND ONE OF THE
POSSIBILITIES IS THAT, AGAIN, IT
COULD BE ACETYLCHOLINE RECEPTORS
THAT ARE NOT THE BAY A
2 CONTAINING ONES AND THOSE ARE
EXPERIMENTS THAT MAIAH IS DOING
THIS WEEK SO I CAN GET BACK TO
SOME OF YOU THAT CARE ABOUT
THIS.
SO THE LAST THING I WANT TO TALK
ABOUT IS A REALLY NEW DIRECTION
FOR THE LAB.
THIS WAS PROJECTS THAT WERE
INITIATED BY A GRADUATE STUDENT
IN THE LAB, WHO'S A CELL
BIOLOGIST, AND IT WAS ALL --
STARTED BY TWO THINGS.
ONE WAS THIS IMAGING EXPERIMENT
THAT WAS DONE, SO THIS IS A
CALCIUM IMAGING EXPERIMENT
LOOKING AT WAVES BUT YOU CAN SEE
ON THE SURFACE OF THE RETINA,
THERE IS SOME VASCULATURE, AND
THAT YOU CAN SEE THAT WHEN A
WAVE SORT OF GOES THROUGH THAT
REGION, THAT THERE'S A LOT OF
CALCIUM ACTIVITY THAT'S GOING ON
AROUND THE VASCULATURE.
I DON'T KNOW IF YOU CAN SEE IT
HERE.
IT'S REALLY BEAUTIFUL ON MY
SCREEN.
THIS LED TO THIS IDEA THAT
MAYBE -- IS THERE ANY SIGNALING
FROM NEURONS OR GLIA TO THE
VASCULATURE DURING THE PERIOD OF
TIME WHEN THE VASCULATURE IS
GROWING.
AND IT'S BECAUSE THE VASCULATURE
IS GROWING AT THE SAME TIME THAT
THERE ARE RETINAL WAVES.
SO LET ME JUST INTRODUCE YOU TO
THE VASCULATURE OF THE RETINA SO
ANOTHER REASON WHY -- WELL, I
LOVE THIS PROJECT IS BECAUSE THE
VASCULATURE IN THE MOUSE RETINA
IS GORGEOUS, AND SO -- AND
YOU'LL SEE IT APPEARS IN THREE
LAYERS.
THERE IS A SUPERFICIAL LAYER
THAT'S ALONG THE GANGLION CELL
LAYER.
THERE IS A DEEP VASCULATURE, AND
THEN THERE'S AN INTERMEDIATE
VASCULATURE.
AND THEY'RE ALL CONNECTED BY
THESE DIVING VESSELS THAT ARE
EXTREMELY PERPENDICULAR GOING
THROUGH THE RETINA.
SO WHAT I'M GOING TO SHOW YOU IS
A CONFOCAL IMAGE, HOPEFULLY THIS
WILL WORK, OF THE VASCULATURE
THAT'S BEEN LABELED WITH AN
ANTIBODY.
THIS IS THE SUPERFICIAL
VASCULATURE AND IT'S GOING BACK,
AND THEN YOU CAN SEE THOSE ARE
THE DIVING VESSELS, THAT'S THE
INTERMEDIATE VASCULATURE, DIVING
VESSELS AND THEN YOU CAN SEE THE
DEEP VA CLA TOUR.
IT'S INCREDIBLY WELL ORGANIZED.
IF YOU LOOK AT IT, HERE'S THE
SUPERFICIAL VASCULATURE, DEEP
AND IMMEDIATE.
THEY EMERGE IN A VERY
STEREOTYPICAL TIME COURSE DURING
DEVELOPMENT.
THE SUPERFICIAL VASCULATURE
GROWS OUT FIRST BETWEEN
POSTNATAL DAY ZERO, DONE BY
POSTNATAL DAY 9.
THEN THE DEEP VASCULATURE
EMERGES DURING THE SECOND WEEK.
YOU CAN SEE THIS IS ALL
HAPPENING AT THE SAME TIME AS
THERE ARE RETINAL WAVES.
SO WE REALLY WANTED TO KNOW IF
NEURAL SIGNALING WAS SOMEHOW
INFLUENCING THIS PROCESS.
I DO WANT TO MAKE NOTE IN THIS
DIAGRAM, THERE'S ALSO A GLIAL
CELL AND I'M GOING TO TALK ABOUT
THAT GLIAL CELL IN JUST A
MOMENT.
SO WE CHARACTERIZES THE
MATURATION OF THE VASCULATURE,
SO HERE'S THE SUPERVISOR VISUAL
VASCULATURE AS A FUDGES FUNCTIOF
AGE, AGE IS GOING DOWN.
WE MEASURED THE DENSITY OF THE
VASCULAR, BOTH PROXIMAL AND
DISTAL, AND THEN FOR EACH AGE,
EACH LINE HERE IS A RETINA, THIS
IS A WAY TO REPRESENT WHAT THE
DENSITY IS ACROSS THE
VASCULATURE.
WE THEN DO IT FOR THE DEEP AND
THEN THE INTERMEDIATE
VASCULATURE.
ONE OF THE THINGS I LIKE THAT
REPRESENTATION.
ONE OF THE THINGS I ACTUALLY
FOUND REMARKABLE, THIS IS KIND
OF AN ASIDE BUT FOR -- I STILL
THOUGHT IT WAS REMARKABLE, IS
THAT IF YOU LOOK AT THE DENSITY
OF THE VASCULATURE ACROSS THE
WHOLE RETINA EVEN DURING
DEVELOPMENT, IT IS INCREDIBLY
UNIFORM.
NO MATTER WHERE YOU ARE IN THE
RETINA, EVEN AS IT'S GROWING, IT
HAS THIS INCREDIBLE UNIFORM
DENSITY ACROSS THE RETINA, WHICH
I JUST FIND REMARKABLE.
THIS IS WHEN LIKE THE PHYSICIST
IN ONE COMES OUT, LIKE WHAT IS
REGULATING SORT OF THE
INCREDIBLE REGULARITY OF THAT.
THIS IS JUST AN ASIDE, MAYBE
WE'LL UNDERSTAND HOW THAT
EMERGES BUT YOU CAN SEE POSE
NATAL DAY 7 THE SUPERVISOR
VISUAL VASCULATURE IS VERY
UNIFORM, NOT FULLY GROWN OUT YET
AND THEN WHEN YOU LOOK AT A WEEK
LATER, THE DEEP VASCULATURE HAS
GOT A HIGHER DENSITY, THE
SUPERVISOR VISUAL VASCULATURE IS
REFINED BUT THAT REFINEMENT IS
REALLY QUITE REMARKABLY UNIFORM.
OKAY.
THAT'S MY LITTLE ASIDE.
SO IF WE LOOK NOW, THIS IS
DEVELOPMENT, WE LOOK IN THE WILD
TYPE, THIS IS NOW IN THE CENTRAL
RETINA VERSUS THE PERIPHERAL
RETINA, THE SUPERFICIAL
VASCULATURE IS THERE, IT
UNDERGOES A PERIOD OF
REFINEMENT, THE KEEP VASCULATURE
EMERGES AROUND POSTNATAL DAY 8,
THIS IS KIND OF THE PERIPHERY,
IT GROWS OUT A LITTLE LATER AND
WE LOOKED IN THE BETA TWO --
THIS HAS BEEN DESCRIBED BY
OTHERS BEFORE, WE LOOK IN THE
BETA TWO KNOCKOUT AND IT LOOKS
PERFECTLY NORMAL.
SO ANOTHER -- SO I WON'T SAY
IT'S PERFECTLY NORMAL.
IT'S A LITTLE BIT DELAYED, AND
ACTUALLY THERE WAS EXPERIMENTS
DONE BY BISWAS PUBLISHED THIS
YEAR THAT FOUND THE DELAY.
SO IT SEEMS LIKE ACTIVITY IS
REGULATING THE PACE AT WITH IT
HAPPENING BUT EVERYTHING SEEMS
TO GET THERE IN THE END.
SO IT DOESN'T SEEM IMPORTANT FOR
THAT.
SO WHAT WE'RE REALLY FOCUSING ON
NOW IS THIS OTHER CELL TYPE, AND
THAT IS THIS MUELLER GLIAL CELL
AND WHAT ROLE IT PLAYS IN
DEVELOPING THE VASCULATURE.
THIS IS IMPORTANT BECAUSE
MUELLER GLIAL CELLS ARE THE LAST
CELLS IN THE RETINA TO MATURE.
THEY TRAVERSE THE ENTIRE
THICKNESS OF THE -- AND THEY ARE
GROWING OUT THESE LATERAL
PROCESSES DURING THE SAME
STAPLING OF DEVELOPMENT.
THIS PROJECT WAS ACTUALLY
COMPLETELY MOTIVATED BY A STUDY
THAT CAME OUT FROM -- LED BY
WILL GRIMES WHO IS IN DIAMOND'S
LAB, APPARENTLY PAPER IS BEING
PUBLISHED NEXT WEEK AND IT'S
THIS INKREDZIBLE -- WHAT WILL
HAS BEEN ABLE TO SHOW IS THAT
THIS VASCULATURE IS COMPLETELY
ENCHIEFED BY THE MULLER GLIAL
CELLS.
EVERYWHERE YOU LOOK AT THAT
VASCULATURE, WHETHER IT'S A
DIVING VESSEL, LATERALIZED
CAPILLARY BED, THERE ARE GLIAL
CELLS EVERYWHERE THERE.
THERE ARE A FEW PATCHES WHERE
THERE AREN'T GLIAL CELLS BUT
95%, WELL, 96% IS COMPLETELY
COVERED BY GLIAL CELLS.
HE KNOWS THE ANSWER TO THAT.
THIS IS AN EXAMPLE THAT YOU CAN
SEE.
SO EACH MULLER GLIAL CELL HAS A
BUNCH OF LATERAL PROCESSES
COMING OUT AND IT SENDS ONE
PROCESS TO THE VASCULATURE SO
THE VASCULATURE IS COVERED BY A
SINGLE LATERAL PROCESSES FROM A
WHOLE BUNCH OF MULLER GLIAL
CELLS.
IT'S BEAUTIFUL.
THIS IS ALL EMERGING AT THE SAME
TIME IN DEVELOPMENT.
AND WE WERE INTERESTED IN THIS
BECAUSE A GRADUATE STUDENT IN MY
LAB, JOSH, WHO LIKES HUGGING
THINGS, WAS STUDYING THE
EMERGENCE OF THE LATERAL
PROCESSES FROM THESE GLIAL
CELLS, SO HERE'S A STALK, HERE'S
A STALK AND THESE LATERAL
PROCESSES ARE COMING IN.
IF YOU LOOK AT THIS ONE RIGHT
HERE, I'M CONVINCED THIS IS
GROWING OUT AND GROWING AROUND A
BLOOD VEST W VESSEL EMERGING.
THESE GUYS ARE INCREDIBLY
MOTILE, AND SO WE WANT TO SEE
WHETHER OR NOT THERE'S SOME SORT
OF SIGNALING BETWEEN THESE GLIAL
CELLS AND THE VASCULATURE.
IF YOU LOOK AT -- SO THESE ARE
EXPERIMENTS BEING DONE BY SAMIRA
WHERE IF YOU LOOK AT THE
VASCULATURE -- AT THE EARLIEST
AGES WHERE WE CAN SEE THE DIVING
VESSELS, THEY'RE COMPLETELY
ENSHEATHED BY GLIAL CELLS.
THE SUPERFICIAL LAYER, THEY'RE
COVERED AND THE DEEP
VASCULATURE, THEY ALSO APPEAR TO
BE COVERED AND I THINK THIS IS A
MOVIE THAT'S NOT WORKING THAT
WOULD SHOW YOU THAT WHEN YOU
LOOK AT A VESSEL, IT'S JUST
LITERALLY CRAWLING UP THROUGH
WHERE THE MULLER GLIA ARE.
WE'RE REALLY INTERESTED IN THIS
QUESTION WHETHER SIGNALING
BETWEEN THESE CELL TYPES MATTER
AND WE'RE INTERESTED IN THIS
BECAUSE RETINAL WAVES, IT TURNS
OUT, CAUSE CALCIUM TRANSIENCE IN
GLIAL CELLS, SO THESE ARE A
WHOLE BUNCH OF GLIAL STALKS.
THESE ARE THERE -- I THINK YOU
MIGHT BE ABLE TO SEE, WHEN A
WAVE GOES THROUGH THE TISSUE,
HOPEFULLY YOU'LL BE ABLE TO SEE
WHEN A WAVE GOES THROUGH, YOU
SEE ALL THE LATERAL PROCESSES
GET LIT UP, AND SOME -- IN SOME
EXPERIMENTS THAT ARE GOING ON BY
ANGEL GARCIA, YOU'RE LOOKING AT
A DIVING VESSEL HERE.
WE HAVE A CALCIUM DIVE EXPRESSED
ONLY IN THE GLIAL CELLS AND YOU
CAN SEE THAT THERE ARE SOME --
AND THEN THIS IS NOW IN THE DEEP
PLEXUS AND YOU CAN SEE THAT
THERE IS SOME CALCIUM TRANSIENCE
THAT ARE HAPPENING IN THE GLIAL
CELLS.
WILL HAS SHOWN THIS BEAUTIFULLY
IN THE ADULT VASCULATURE, AND
WE'RE LOOKING TO DO THIS EARLY
IN DEVELOPMENT, AND OUR QUESTION
IS, WHO'S LEADING WHOM?
DO THE BLOOD VESSELS GROW UP
ALONG THE GLIAL CELLS, DO THE
GLIAL CELLS COME UP TO THE BLOOD
VESSELS AND WHAT IS THE
SIGNALING BETWEEN THE CELLS THAT
MEDIATE THIS PHENOMENON.
OKAY.
SO THAT'S TO SUMMARIZE TODAY.
RETINAL WAVES ARE BOTH SOURCE OF
ACTIVITY BEFORE VISION, THEY'RE
IMPORTANT FOR SETTING UP
CONNECTIONS THROUGHOUT THE
VISUAL SYSTEM, THEY'RE IMPORTANT
FOR SETTING UP SOME CIRCUITS
WITHIN THE RETINA, BUT NOT FOR
DIFFERENTIATION OF CELL TYPES.
THERE IS A PROPAGATION BIAS
WHICH IS A FEATURE OF RETINAL
WAVES.
IT'S DEPENDENT ON GABA SIGNALING
BUT THE ORIGINS OF IT REMAIN
UNKNOWN.
RETINAL WAVES PLAY A LIMITED
ROLE IN ANGIOGENESIS AND THE
TIME COURSE OF IT, OR A LITTLE
BIT IN THE TIME COURSE BUT NOT
IN THE OVERALL STRUCTURE BUT WE
THINK GLIAL SIGNALING MAY BE
CRUCIAL FOR GUIDING THE
VASCULATURE DEVELOPMENT.
THIS IS THE FELLER LAB.
AND IN A RECENT VISIT TO --
THERE'S A MUSEUM OF THE EYE NEAR
FISHERMAN'SFISHERMAN'S WHARF.
I THINK I'VE DESCRIBED
EVERYONE'S PROJECT TODAY, AND I
WANT TO END BY SAYING THAT,
AGAIN, WE'RE FUNDED BY THE
NATIONAL EYE INSTITUTE, AND FOR
THAT, I AM TREMENDOUSLY
GRATEFUL.
SO THANK YOU VERY MUCH.
[APPLAUSE]
>> THANK YOU VERY MUCH FOR A
WONDERFUL TALK.
WE HAVE TIME FOR TWO QUESTIONS.
>> BEAUTIFUL TALK.
I THINK YOU TALKED ABOUT YOUR
20, 30 YEARS OF WORK HERE AND
I'VE BEEN FOLLOWING YOUR WORK
BUT I HAVE JUST TONS OF
QUESTIONS.
I'LL TALK TO YOU MORE TOMORROW.
BUT I'M INTRIGUED THAT IF
NEUROTRANSMITTER LIKE GABA OR
CHOLINE OR GLUTAMATE ARE
INITIATING THIS, THEY'RE
RELEASED BY ALMOST, YOU KNOW,
DIFFERENT KINDS OF CELLS
EVERYWHERE.
WHAT KIND OF CELLS IN THE
TEMPORAL REGION ARE INITIATING
THAT?
DO YOU HAVE ANY IDEA WHAT THOSE
CELLS ARE?
AND IF YOU ABLATE THEM BY, SAY,
LASER OR SOMETHING, OR FOR THAT
MATTER, IF YOU INTERRUPT THESE
WAVES DURING DEVELOPMENT BY SORT
OF POINTING SOME LASERS, WHAT
WILL HAPPEN TO THE DEVELOPMENT
OF OTHER CELL TYPES?
>> YEAH, SO THAT IS -- I WAS
GOING TO SHOW YOU THIS ONE
EXPERIMENT WE DID.
SO ONE OF THE CELLS -- THE SLIDE
I SKIPPED IS THIS ONE.
THIS IS AN EXPERIMENT WHERE --
OH, IT'S NOT THIS ONE.
ANYWAY, MAIH CUT THE RETINA IN
HALF AFTER THIS EXPERIMENT.
SHE FOUND WHEN SHE CUT THE
RETINA IN HALF, THAT YOU WOULD
GET WAVES THAT STARTED IN THE
TEMPORAL PART OF THE CUT.
THEY WOULD ALL START HERE.
SO I DON'T THINK THERE'S NIS
SAYERLY A HOT SPOT.
I THINK THAT THERE IS SOMETHING
THAT IS EITHER SAYING DON'T
PROPAGATE THIS DIRECTION IF IT'S
GABA OR DO PROPAGATE IN THIS
OTHER DIRECTION.
SO I DON'T KNOW WHAT IT IS.
I WILL SAY THAT IN THE
ZEBRAFISH, WHERE WAVES REALLY DO
ALSO ALL START FROM A HOT SPOT,
THEY SHOWED IN THE ZEBRAFISH
THAT THERE ARE AN ENRICHMENT OF
RECEPTORS IN BIPOLAR CELLS IN
THAT REGION SO THEY THINK IT'S
JUST A LITTLE BIT MORE EXCITABLE
THERE, AND THAT THERE MIGHT BE A
GRADIENT OF SORT OF EXPRESSION
OF ION CHANNELS THAT MAKE THE
CELLS MORE EXCITABLE.
SO AS YOU KNOW, ACROSS
DEVELOPMENT, THERE'S A LOT OF
DEVELOPMENTAL GRADIENTS, AND IT
COULD JUST BE THERE'S A
GRADIENT -- SO THERE'S NO
PARTICULAR CELL TYPE, BUT THIS
CELL TYPE MATURES EARLIER HERE.
BUT THE FACT THAT -- LIKE IF YOU
SEE DOWN HERE THERE WAS A BUNCH
OF INITIATIONS HERE, BECAUSE
THAT WAS KIND OF THE MOST -- YOU
KNOW, WE CUT THE RETINA, THAT'S
THE MOST TEMPORAL PART OF THAT.
SO IT FEELS LIKE WHATEVER IT IS
IS A GRADIENT ACROSS THE WHOLE
RETINA, AND IF YOU KEPT CUTTING
THE RETINA, THEY WOULD JUST
START AT THE MOST TEMPORAL PART
OF THE RETINA.
BUT I DON'T KNOW WHY.
>> SO SINCE YOU DID NOT SEE ANY
CHANGE WITH THE KNOCKOUT OF YOUR
RECEPTOR AND ALSO THE BLEUT MATE
AND OTHER THINGS, THERE'S A LOT
OF -- IN THE SYSTEM, DID YOU
THINK ABOUT DOING SOME DOUBLE OR
TRIPLE KNOCKOUTS TO SEE -- SO ON
ITS OWN, IT MIGHT INTERRUPT THE
SIGNAL TO WAVES, BUT IT MAY NOT
BE JUST SORT OF SUFFICIENT TO
TAKE CARE OF WHATEVER THOSE
WAVES ARE DOING.
>> I THINK IT'S A GOOD QUESTION.
THE ONLY WORLD WE'VE GONE DOWN
THE DOUBLE AND TRIPLE KNOCKOUT
HAS BEEN FOR GAP JUNCTIONS.
I HAVEN'T TALKED ABOUT
ELECTRICAL SYNAPSES, WE TRIED TO
KNOCK ALL OF THEM OUT AND IT WAS
JUST KIND OF A NIGHTMARE.
AND WE HAVE NOT DONE THAT.
TO GET RID OF ALL OF THE
NEUROTRANSMITTERS WE CAN
BASICALLY AND SEE WHAT HAPPENS
AFTER THAT.
I MEAN, I THINK THE REASON WE
HAVEN'T DONE THAT IS BECAUSE
WE'VE BEEN REALLY FOCUSING
MOSTLY IN OUR LAB ON RETINAL
DEVELOPMENT, AND IF YOU KNOCK
OUT ALL THE NEUROTRANSMITTER
THEN THE ANIMAL CAN'T SEE SO WE
NOW WE CAN'T TEST WHETHER OR NOT
IT'S GOT DIRECTION SELECTIVITY
OR SOMETHING.
SO IT WOULD BE GOOD FOR SORT OF
ANATOMY EXPERIMENTS BUT NOT FOR
ANYTHING FUNCTIONAL AND THAT'S
BEEN THE TRICKY THING.
>> THAT WAS BEAUTIFUL.
I AM INTERESTED IN A BUNCH OF
THINGS, BUT ONE IS YOU'RE
SPEWING ALL THIS
NEUROTRANSMITTER ALL OVER THE
PLACE AND PRESUMABLY MOPPING IT
UP IS AS IMPORTANT AS SPEWING IT
OUT SO PRESUMABLY YOU THOUGHT A
LOT ABOUT THE FUNCTIONAL ROLE
THAT MOPPING UP MECHANISMS MAY
BE PLAYING AND HOW IT'S
ASYMMETRIC.
>> YEAH.
>> THE THING I'M SORT OF NEAR
AND DEAR TO MY HEART IS HOW
THESE SIGNALS MIGHT BE
INSTRUCTIVE FOR THE CORTICAL
CIRCUITS OR THE CENTRAL
CIRCUITS.
DO THEY MATCH NATURAL SEEN
STATISTICS AND ARE THEY SORT OF
FOLLOWING A TRAJECTORY OF
DEVELOPMENT THAT ACTUALLY
PROVIDES SOMETHING INSTRUCTIVE
TO THOSE CIRCUITS SO THAT WHEN
YOU OPENED YOUR EYES, YOU CAN
SEE, AND DON'T TAKE TOO MUCH
LONG BECAUSE I REALLY WANT TO
HEAR WHAT WEY LI'S QUESTION IS.
>> THERE WAS A PERIOD OF TIME
MAYBE 10 OR 15 YEARS AGO WHERE
SOME LABS DID ANALYSIS ON HOW
SPAISH YOE TEMPORAL PROPERTIES
OF RETINAL WAVES MATCHED NATURAL
SCENES.
IN A COURSE ANALYSIS, THEY'RE
RIGHT IN THE MIDDLE KIND OF, OF
WHAT IS THE VISUAL EXPERIENCE OF
A MOUSE.
I THINK THEY DIDN'T DO THE
VISUAL EXPERIENCE OF A MOUSE
WHEN THEY DID THOSE OLD
ANALYSES.
THEY DID THE VISUAL EXPERIENCE
OF A PRIMATE.
AND I THINK THAT THERE IS -- THE
FIELD IS RIPE, THERE ARE MANY --
WE HAVE GIVEN THESE MOVIES TO
MANY DIFFERENT COMPUTATIONAL
LABS AT THIS POINT.
THERE CERTAINLY ARE A LOT OF
LABS THAT HAVE USED THESE AS
RUNNING SIMULATIONS THAT THEY
HAVE ON DEVELOPMENT OF VISUAL
CORTICAL CIRCUITS AND SO THERE
HAS BEEN A LOT OF WORK THAT'S
BEEN DONE IN THAT ARENA.
I'D BE CURIOUS TO THINK IF YOU
THOUGHT ANY OF IT WAS MEANINGFUL
OR NOT.
IN THE CORTICAL CIRCUIT REGIME,
ONE OF I THINK THE REALLY
INTERESTING AREAS WHICH YOU WILL
FIND NOT INTERESTING AT ALL IS
THAT IT TURNS OUT CORTICAL
INHIBITORY INTERNEURONS UNDERGO
A LOT OF CELL DEATH AND IT TURNS
OUT THE FREQUENCY WITH WHICH
THEY PARTICIPATE IN THESE
WAVE-DRIVEN EVENTUALLY
INFLUENCES HOW MANY CORTICAL
INHIBITORY INTERNEURONS SURVIVE.
SO THAT'S IMPORTANT FOR SHAPING
LOCAL CIRCUITS WITHIN CORTEX,
WHAT THAT MEANS ABOUT NATURAL
SCENES, I THINK NOW IS THE TIME
TO DO THAT BECAUSE I THINK WE
HAVE A LOT MORE INFORMATION TO
CHECK THAT OUT.
SO I WOULD LOVE TO TALK MORE
ABOUT THAT.
WEI.
>> MARLA, GREAT TALK.
BEAUTIFUL.
>> THANKS.
>> I PROBABLY SHOULD KNOW THE
ANSWER, BUT IN YOUR BETA
2 KNOCKOUT WHERE YOU LOST
HORIZONTAL PREFERRED DSL, THEY
DIDN'T LOSE THE CELLS BUT THEY
LOST DIRECTION SELECTIVITY.
>> RIGHT.
>> SO DO YOU THINK THE WAVE HAS
SOMETHING TO DO WITH THE SETTING
UP THIS VERY ASYMMETRIC
CONNECTION BETWEEN STARBURST AND
DSL?
>> SO WE HAVE A WHOLE TALK ON
THAT WHICH I DID NOT GIVE, BUT
I'M HAPPY TO GIVE NOW.
JUST KIDDING.
SO YES, SO WE'RE WORKING ON
THAT.
SO IT IS -- SO THEY DO -- SO THE
CELLS DID NOT DIE.
THEY ARE EQUALLY RESPONSIVE TO
LIGHT MOVING IN ANY DIRECTION.
THEY RECEIVE LESS INHIBITION
FROM THE STARBURST CELL WHEN
THEY MOVE IN THE NULL DIRECTION,
WHICH IS SORT OF WHAT GAVE THEM
THEIR DIRECTION SELECTIVITY.
IT SEEMS LIKE THE STARBURST CELL
ITSELF HAS NOT LOST ITS ABILITY
TO RELEASE GABA IN THE BETA
2 KNOCKOUT BUT RATHER WE THINK
IT'S THE WIRING OF THE A STARBUT
CELLS TO THE DIRECT SELECTIVE
GANGLION CELLS, WE DID SINGLE
CELL RNA SEQ, WE KNOW WHICH ARE
THE HORIZONTAL, WHICH ARE THE
VERTICAL.
WHAT GOT LOST IN THE BETA
2 KNOCKOUT, WE LOOKED RIGHT AT
THE AGE WHEN WIRING IS HAPPENING
AND WE FOUND NOTHING.
NOTHING.
SO I DON'T THINK THAT'S
REGULATED AT A TRANSCRIPTIONAL
LEVEL AND WE'RE LOOKING AT
PROTEOMICS NOW.
>> THAT'S INTERESTING BECAUSE
YOU'RE VERTICAL IS STILL THERE,
SO ASYMMETRIC WIRING STILL
HAPPENS IN THOSE VERTICAL ONES.
>> YEAH, BUT I WILL SAY, I WAS
AT A MEETING WHICH I CAN'T
REMEMBER WHERE, WHERE I WAS
TOLD, AND THERE ARE OPTOMETRISTS
AND OPHTHALMOLOGISTS HERE WHO
CAN ANSWER THIS QUESTION.
SO IT TURNS OUT FOR HUMANS,
THERE ARE A LOT OF HUMAN GENETIC
DISORDERS WHERE THEY HAVE
NYSTAGMUS, AND ONE OF THOSE IS
THIS FMR -- FMRD7, THAT ACTUALLY
LEADS TO NYSTAGMUS, AND THIS
OPHTHALMOLOGIST I WAS TALKING TO
AT THIS MEETING TOLD ME THAT
WHEN HUMAN PATIENTS COME IN AND
THEY HAVE HORIZONTAL
OPTONYSTAGMUS, THEY THINK
THERE'S A GENETIC DEFICIT, IT
COULD BE IN THE RET KA, IT COULD
BE ELSEWHERE, BUT IF THEY HAVE
VERTICAL NYSTAGMUS, IT'S AN
INJURY TO THE BRAINSTEM.
THERE'S SOMETHING DIFFERENT
ABOUT THE OPTOKINETIC REFLEX --
NYSTAGMUS IN HORIZONTAL VERSUS
VERTICAL.
THOSE ARE DIFFERENT AXES EVEN
FOR REFLEXIVE EYE MOVEMENTS.
FOR THE MOUSE, THEY TRACK MUCH
MORE RELIABLY HORIZONTALLY THAN
THEY DO VERTICALLY, AND SO THEY
ARE DIFFERENT, RIGHT, AND SO I
DON'T KNOW IF SOMEONE -- SO WHY
ONE MIGHT BE MORE SUSCEPTIBLE TO
EXPERIENCE LIKE WAVES AND THE
OTHER ONE NOT, I DON'T KNOW.
>> SO THE VERTICAL ONE, THE DS
IS ALSO ESTABLISHED BEFORE EYE
OPENING?
>> YEAH.
>> THAT KILLS MY THEORY THAT
MAYBE BLINKING GIVES YOU A
NATURAL SORT OF DIRECTION.
>> OH, MY GOD, I LOVE THAT.
NO, IT'S THERE BEFORE EYE
OPENING.
>> THANK YOU.
>> HI.
>> FANTASTIC TALK.
I'M INTERESTED IN THE
ANGIOGENESIS PART AND I ALSO
THINK FROM THE PERSPECTIVE OF
NEUROMETABOLISM.
SO YOU SHOWED THAT EARLY ON P7,
SOME OF THE PERIPHERAL BLOOD
VESSELS AREN'T THERE YET.
DO YOU SEE WAVES IN AREAS WHERE
THERE'S NO VASCULATURE?
SO YOU SHOWED THAT THE WAVES
AREN'T REALLY IMPORTANT FOR
ANGIOGENESIS, BUT IS
ANGIOGENESIS IMPORTANT FOR THE
WAVES?
SIMILARLY, THE GLIAL CELLS WHICH
WE KNOW ARE INVOLVED IN ENERGY
METABOLISM FOR THE NEURONS, IS
THAT IMPORTANT?
>> YEAH, SO WE HAVEN'T SEEN
THAT, THERE WAS A RETINA
CONFERENCE WHERE EVELYN
CERNIGORE ACTUALLY MADE THE CASE
THAT SHE THOUGHT CONERGIC WAVES
INITIATED FROM THE LEADI LEADINE
OF THE PRIF PERIPHERAL VASCULA.
WE HAVE NOT SEEN THAT BUT
HAVEN'T EXACTLY LOOKED FOR IT
AND SHE MADE THE CASE SHE
THOUGHT THAT WAS KIND OF A
METABOLISM ARGUMENT.
AND THAT IS A SUPER INTERESTING
QUESTION.
HOW DO WE TEST THAT?
I WOULD REALLY -- INSTEAD OF
THIS CORRELATION, HOW WOULD WE
TEST IT?
I LOVE THIS.
>> I DID MY PH.D. IN GARY
ELLEN'S LAB AND THERE'S A WHOLE
SLEW OF BEAUTIFUL
NEUROMETABOLISM BIOSENSORS SO
THAT WOULD BE ONE WAY, IS USE
OTHER BIOSENSORS THAT MIGHT GIVE
YOU A CLUE AS TO WHERE THE
STARTER AREAS ARE.
>> THAT IS A GREAT IDEA.
THANK YOU.
>> SURE.
>> HI.
IT WAS A BEAUTIFUL TALK, AND I
DID MY GRADUATE WORK THE A
BERKELEY, CHA CARLA SCHATZ ALWAS
WOULD TALK ABOUT YOUR RETINAL
WAVE WORK.
I WAS ALWAYS INTRIGUED BY THE
HYPOTHESIS THAT RETINAL WAVES
ARE INVOLVED IN THE DEVELOPMENT
OF PATTERNING AND YOU TALKED
ABOUT HOW DIFFERENT FEATURES OF
THE WAVES COULD BE INVOLVED IN
RETINOTOPY AND OCULAR DOMINANCE.
YOU MENTIONED A LITTLE ABOUT HOW
SOMETIMES THERE'S LIGHT COMING
IN BEFORE THE EYE OPENS, YOU'RE
GETTING SOME VISUAL INFORMATION
EVEN BEFORE EYE OPENING BUT I
GUESS HOW STEREOTYPICAL IS THE
RETINOTOPY FROM ONE ANIMAL TO
ANOTHER?
IS THE PATTERNING ENOUGH TO
AFFECT THE ANATOMY THAT YOU
COULD SAY THIS IS FROM THIS PART
OF THE RETINA VERSUS ANOTHER
PART, AND IF YOU WERE TO REAR
ANIMALS, I GUESS KIND OF A
BINDING QUESTION, AT SOME POINT
YOU HAVE SOME BILATERAL CELLS IN
THE COLLICULUS AND IN THE CORTEX
THAT HAVE INFORMATION IN BOTH
EYES AND THEY HAVE TO BE -- THEY
HAVE TO MATCH FOR THEIR INPUT,
IF YOU WERE TO REAR THE PUPS IN
PURE DARKNESS, DO THEY STILL
HAVE -- IS THERE ANY BINDING
ISSUES BETWEEN THE TWO EYES?
>> THAT'S A GOOD QUESTION.
I DON'T THINK I CAN ANSWER THE
LAST ONE.
IT'S BEEN DONE AND I DON'T KNOW
WHAT THE ANSWER IS.
KNOW J.C. KING HAS DONE THAT IN
THE COLLICULUS AND FOUND -- I
CAN'T REMEMBER -- BINDING
BETWEEN ORIENTATION SELECTIVE
CELLS, THERE WAS LIKE SOMETHING
HE FOUND, THERE WAS SOME FEATURE
THAT WAS INITIALLY ESTABLISHED
SO IN THE BETA 2 KNOCKOUT, IT
WAS LACKING, AND THEN NEVER
COULD GET THE TWO TO ALIGN SORT
OF WHEN THE EYES WERE OPEN, AND
I DON'T REMEMBER WHAT THAT
PARTICULAR FEATURE WAS.
THE RETINOTOPY IS EXTREMELY WELL
STEREOTYPED, I WOULD SAY, SO YOU
CAN SAY, YOU KNOW, IF YOU HAVE A
DEFICIT IN THIS PART OF THE
COLLICULUS, YOU KNOW WHAT PART
OF THE RETINA THAT DEFICIT HAS
EMERGED FROM.
SO THAT ANSWERS THAT QUESTION.
>> THAT COMES PURELY FROM THE
RETINAL WAVES?
>> NO, THERE DEFINITELY ARE
MOLECULAR GRADIENTS THAT HAVE
ESTABLISHED THAT.
IT'S ACTUALLY ANOTHER THING
THAT'S UNIQUE ABOUT THE
HORIZONTAL AXIS VERSUS THE
VERTICAL AXIS, SO THERE'S A VERY
FAMOUS -- IN TEXTBOOKS YOU LEARN
ABOUT FRNA AND FA, SO THERE'S
ONE GRADIENT IN THE RETINA,
THERE'S ANOTHER GRADIENT IN THE
TECTUM.
IT'S A REPULSIVE INTERACTION,
AND EXACTLY WHERE A PARTICULAR
RETINAL GANGLION CELL ENDS UP
SORT OF DEPENDS ON WHERE YOU
HAVE THAT -- WHERE THE REPULSION
IS MINIMAL BETWEEN THOSE TWO,
BUT THAT ONLY WORKS ON THE
HOARDS ONE.
SO THE VERTICAL ONE, WHICH IS
MEDIAL LATERAL ON THE
COLLICULUS, DOES NOT WORK THAT
WAY.
IT'S FBs BUT IT'S NOT A
GRADIENT AND THERE'S SOME SORT
OF SORTING THAT'S THOUGHT TO
HAPPEN IN THE OPTIC TRACK SO
THAT EVERYTHING GROWS IN THE
RIGHT PLACE, AND THEN THERE'S
KIND OF A REFINEMENT ONCE YOU
GET THERE.
SO THAT'S A LITTLE BIT
DIFFERENT.
BUT ALONG THE NASAL TEMPORAL
AXIS RETINA ANTERIOR POSTERIOR
AND THE TECTUM, THAT SEEMS TO BE
WELL-DEFINED BY WHERE YOU ARE IN
THE RETINA.
I DID WANT TO MENTION ONE THING
WHERE THIS IS AN IDEA FROM HOLLY
KLEIN'S LAB THAT PROPAGATION
BIAS MIGHT BE IMPORTANT FOR
RETINOTOPY AND SHE DID THESE
SPARE MENTZ IN XENIPUS, SHE DID
EXPERIMENTS WHERE SHE TOOK A
XENIPUS AND SHE FORCED TO HAVE
REVERSE OPTIC FLOW SO SHE KEPT
IT IN AGAR AND THE RETINOTOPIC
MAPS GOT MESSED UP SO SHE ARGUED
THAT THERE IS AN ACTIVITY,
SOMETHING LIKE -- THE RETINAL
WAVE VISION REPRAYSMENT ACTUALLY
DOES SET UP RETINOTOPY IN THAT
CASE.
SO IT'S NOT TOTALLY MESSED UP,
IT'S JUST -- IT HASN'T REFINED
AS MUCH AS OTHERS.
>> THANK YOU.
[APPLAUSE]
>> THANK YOU FOR MODERATING THIS
Q & A.
MY JOB IS TO CLOSE US OUT AND TO
GET EVERYONE TO THE POST LECTURE
RECEPTION OUTSIDE.
BUT THERE'S MANY PEOPLE WHO I
REALLY WANT TO THANK HERE.
FOR MAKING TODAY HAPPEN.
OUR FOLKS AT THE NEI, WHO HELPED
COORDINATE THIS, JOE AND YOUR
CREW AT THE FNIH, THANKS TO YOUR
TEAM FOR WORKING WITH US.
AND OBVIOUSLY MOST OF ALL,
MARLA, THANK YOU TO YOU FOR
COMING HERE AND SHARING YOUR
SORT OF EXPERTISE WITH US.
THERE ARE SO MANY DIFFERENT
THINGS ABOUT LECTURE THAT I
REALLY LOVED.
WE USE THE PHRASE
INTERDISCIPLINARY COLLABORATION
IN THE BEGINNING, AND I LOVE
THAT YOU WEAVED IN SORT OF
NEUROSCIENCE, ELECTROPHYSIOLOGY,
ANATOMY, ALL INTO THIS.
AND I DIDN'T REALIZE YOU WERE A
PHYSICIST BY BACKGROUND, AND I
THINK THAT CAME THROUGH, THAT
YOU APPROACH THESE PROBLEMS WITH
THE MIND OF A PHYSICIST.
AND I SORT OF LOVED FROM A
PERSONAL PERSPECTIVE -- WELL,
OART THING IS I ACTUALLY LOVED
LISTENING TO THE Q & A.
IF THERE ARE TRAINEES HERE, YOU
MIGHT JUST CONSIDER THINKING
ABOUT THAT, AND MAYBE EVEN
WATCHING THE VIDEOCAST, BECAUSE
I THOUGHT THAT WAS A GREAT
EXAMPLE OF HOW WE CAN ALL LEARN
HOW TO MANAGE A Q & A SECTION
AND HOW IT CAN GENERATE SORT OF
NEW IDEAS.
I THOUGHT THAT WAS FASCINATING
TO LISTEN TO AND JUST -- YOU
MIGHT JUST CONSIDER THAT AND
THINK ABOUT THAT A LITTLE BIT.
AND JUST FROM A PERSONAL
PERSPECTIVE, AS A MEDICAL
STUDENT, I ONCE WORKED IN THE
LAB THAT STUDIED THE STARBURST
AM KRON CELL AND IT WAS GREAT TO
SEE IT LIKE 30 YEARS LATER UP ON
THE SCREEN HERE.
SO JUST THANK YOU FOR SHARING
ALL OF THAT WITH US.
AND SO JOE, ENRIQUE, MARLA, AND
OUR LEADERSHIP TEAM, IF YOU
COULD STAY WITH US JUST TO TAKE
A FEW PHOTOS WITH DUSTIN
AFTERWARDS, BUT TO THE REST OF
YOU, THERE'S A RECEPTION OUTSIDE
AND IF YOU COULD JUST PLEASE
SORT OF TAKE A MINUTE, INTRODUCE
YOURSELF TO DR. FELLER IF YOU
HAVEN'T MET HER AND JUST ENJOY
THE RECEPTION.
THANK YOU.
[APPLAUSE]