IT'S MY PLEASURE AND SINCERELY
MY HONOR TO WELCOME YOU TO WHAT
IS THE 20TH ANNUAL ROBERT
WHITNEY NEWCOMB MEMORIAL LECTURE
IN THE NEUROSCIENCES.
THIS IS AN ANNUAL EVENT THAT I
THINK EVERYONE IN THE COMMUNITY
HAS COME TO LOOK FORWARD TO,
IT'S SUPPORTED BY THE ROBERT
WHITNEY NEWCOMB MEMORIAL FUND
WHICH WAS ESTABLISHED BY
DR. NEWCOMB'S FAMILY TO HONOR
HIS MEMORY.
WE ARE PLEASED TO BE JOINED
TODAY BY DR. ROBERT NEWCOMB
SENIOR AND HIS DAUGHTER GAIL
NEWCOMB TODAY.
WE ARE GRATEFUL FOR THE
GENEROSITY O OF THE NEWCOMB FAMY
AND THEIR FRIENDS FOR THE
OPPORTUNITIES THAT THIS FUND
PROVIDES TO THE NEUROSCIENCE
COMMUNITY AT NIH.
IT'S A TRIBUTE TO YOUR SON AND
YOUR BROTHER.
ROBERT BEGAN HIS SCIENTIFIC
CAREER HERE AT THE NIH AS A HIGH
SCHOOL STUDENT, WORKING DURING
THE SUMMER IN A LAB AT NCI, AND
THIS WAS CLEARLY AN EXPERIENCE
THAT HAD AN ENORMOUS IMPACT ON
HIS CAREER.
AFTER THAT, HE WENT TO COLLEGE
AT THE UNIVERSITY OF COLORADO
AND THEN EARNED HIS PH.D. AT THE
UNIVERSITY OF HAWAII, WHERE HE
STUDIED THE STRUCTURE AND
FUNCTION OF INVERTEBRATE
NEUROPEPTIDES, AND THIS WAS AN
INTEREST THAT HE CONTINUED AS A
POSTDOCTORAL FELLOW AT STANFORD
WITH RICHARD SHELLER.
HE SPENT MUCH OF HIS CAREER
WORKING AT NEUREX
PHARMACEUTICALS, AND ALSO
STUDIED MECHANISMS UNDERLYING
TISSUE DAMAGE ARISING FROM
ISCHEMIC STROKE.
IT'S QUITE APPROPRIATE THEN THAT
THIS FUND SUPPORTS AN ANNUAL
LECTURE HERE BY AN EXPERT IN
NEUROSCIENCE.
THE FUND ALSO SUPPORTS STUDENT
SCHOLARS EACH YEAR AS WELL AS
EXCEPTIONAL POSTBACCALAUREATE
STUDENTS, AND OVER THE YEARS,
MORE THAN TWO DOZEN COLLEGE AND
HIGH SCHOOL STUDENTS AND FIVE
POSTBACKS HAVE BENEFITED FROM
THIS SUPPORT.
I SHOULD NOTE THAT THE FUND'S
EMPHASIS ON SCIENCE EDUCATION IS
NO ACCIDENT.
AS BOTH OF ROBERT'S PARENTS, BOB
AND SALLY, ARE THEMSELVES DEEPLY
INVOLVED IN EDUCATION.
WE'RE SORRY THAT SALLY COULDN'T
JOIN US TODAY.
SALLY HAS TWO MASTERS, ONE IN
GEOCHEMISTRY AND EDUCATION AND
THE OTHER IN HISTORY AND
PHILOSOPHY OF SCIENCE.
THAT SOUNDS LIKE FOUR MASTER'S
DEGREES ACTUALLY.
SHE'S TAUGHT IN CALIFORNIA,
MARYLAND AND IN
WASHINGTON, D.C., AND SHE'S BEEN
AN ACTIVE GEOLOGIST AND MEMBER
OF THE GEOLOGICAL SOCIETY OF
AMERICA.
I GUESS PERHAPS TO HOLD HIS OWN
AT THE DINNER TABLE, BOB EARNED
A MASTER'S DEGREE FROM STANFORD
AND A PH.D. AT UC BERKELEY, AND
IS PROFESSOR EMERITUS IN
ELECTRICAL AND COMPUTER
ENGINEERING AT THE UNIVERSITY OF
MARYLAND.
BOB HAS EARNED A NUMBER OF
ACCOLADES FOR HIS LIFETIME OF
WORK.
THERE'S A VOICE RECOGNITION
LABORATORY IN MADRID, SPAIN
NAMED AFTER HIM, AND THERE'S
ALSO AN UNDERGRADUATE FELLOWSHIP
AT POHUNG UNIVERSITY IN SOUTH
KOREA IN HIS HONOR.
SO WE THANK THE NEWCOMB FAMILY
AND THEIR FRIENDS FOR THEIR
CONTRIBUTIONS TO THIS FUND, AND
FOR RECOGNIZING THAT THE NIH
PROVIDES A WONDERFUL ENVIRONMENT
TO INSTILL IN YOUNG PEOPLE A
PASSION FOR BRAIN RESEARCH AND
FOR ELUCIDATING THE
NEUROCHEMICAL BASES OF STROKE
AND AGING, WHICH CLOSELY ALIGNS
WITH DR. NEWCOMB'S CAREER
INTERESTS.
SO WITH THAT, I AM PLEASED TO
ASK ARIEL LEVINE, SENIOR
INVESTIGATOR AT NINDS, TO
INTRODUCE TODAY'S SPEAKER.
THANK YOU, ARIEL.
[APPLAUSE]
>> HELLO, THANK YOU ALL FOR
COMING, AND I HAVE TO SAY, IT'S
REALLY A DELIGHT TO LOOK OUT AND
SEE THIS ROOM PACKED!
AND I KNOW THAT IT BECAUSE WE
HAVE A REALLY EXCITING DRAW.
SO DR. DAN BEGAN HER SCIENTIFIC
LIFE ACTUALLY AS A PHYSICIST.
SHE STUDIED PHYSICS IN HER
UNDERGRADUATE WORK AND IF I MAY,
I THINK THAT ONE OF THE THINGS
THAT YOU'LL SEE WILL
CHARACTERIZE HER WORK IS SHE IS
REALLY BRAVE ABOUT CROSSING
SCALES AND DIFFERENT KINDS OF
PERSPECTIVES ON NEUROSCIENCE,
AND I WONDER IF IT PARTLY CAME
FROM STARTING HER CAREER IN A
DIFFERENT SPACE AND THEN MOVING
INTO NEUROSCIENCE, WHICH SHE DID
FOR HER PH.D., WHICH SHE PERF
PERFORMED STUDYING SYNAPTIC
TRANSMISSION AND PLASTICITY WITH
MOO MING PAO.
SHE OPENED HER OWN LAB IN 19 197
AT THE UNIVERSITY OF CALIFORNIA,
BERKELEY AND SINCE THEN, SHE'S
MADE MAJOR CONTRIBUTIONS TO
MULTIPLE DIFFERENT AREAS OF
NEUROSCIENCE, SCALING FROM
CELLULAR AND SYNAPTIC BIOLOGY
ALL THE WAY UP TO COMPLEX
BEHAVIORAL FUNCTIONS.
IN THE LAST DECADE, HER LAB HAS
HAD AN EXPLOSION OF BEAUTIFUL
PAPERS, PARTICULARLY EXPLORING
THE MOLECULAR, CELLULAR CIRCUIT
AND ORGANISMAL PURPOSE, REALLY,
OF SLEEP.
SHE IS CURRENTLY THE
CHANCELLOR'S CHAIR PROFESSOR IN
THE DEPARTMENT OF MOLECULAR AND
CELL BIOLOGY AT BERKELEY.
SHE HAS BEEN A HOWARD HUGHES
INVESTIGATOR SINCE 2008, A
MEMBER OF THE NATIONAL ACADEMY
OF SCIENCES SINCE 2018.
SHE RECENTLY RECEIVED A REALLY
MAJOR PRIZE, THE EDWARD SKULNIK
PRIZE AND I THINK A FINAL
FEATHER IN HER CAP, SHE'S
MENTORED NEARLY 50 PH.D. AND
POSTDOC TRAINEES AND OVER HALF
OF THEM ALREADY HAVE THEIR OWN
LABS.
SO I THINK THAT REALLY SHOWS NOT
JUST HER CONTRIBUTION AS A
SCIENTIST BUT ALSO THEN AS A
TEACHER, MAKING HER THE PER
FEBRUARY PERSON TO --THE PERFES
LECTURE.
SO WITH THAT, I'D LIKE TO
WELCOME YANG.
[APPLAUSE]
>> SO CAN YOU GUYS HEAR ME IN
THE BACK?
SO FIRST, THANK YOU SO MUCH,
ARIEL, FOR THE VERY KIND
INTRODUCTION.
IT'S REALLY FLATTERING, AND ALSO
IT'S MY GREAT HONOR TO BE GIVING
THIS MEMORIAL LECTURE.
SO I'M GOING TO TALK ABOUT
SLEEP, FOCUSING ON TWO
FUNDAMENTAL QUESTIONS, HOW WE
SLEEP AND WHY WE SLEEP.
SO I'M GOING TO SUMMARIZE OUR
VIEWS ON BOTH TOPICS WITH A
THEORY ON HOW AND HYPOTHESIS ON
THE WHY.
SO SLEEP IS AN ESSENTIAL INMATE
BEHAVIOR.
WE ACTUALLY KNOW HOW TO DO THIS
EVEN BEFORE BIRTH.
WE SPEND A LOT OF TIME SLEEPING
IN OUR MOTHER'S WOMBS.
AS FAR AS WE KNOW, ALL ANIMALS
SLEEP.
AS LONG AS YOU HAVE A NERVOUS
SYSTEM, YOU SLEEP.
SO THAT EVEN INCLUDES JELLYFISH,
SO THESE GUYS DON'T EVEN HAVE A
CENTRAL NERVOUS SYSTEM.
ALL THEY HAVE IS A VERY
PRIMITIVE KIND OF NEURAL NET OR
SOMETHING, AND YET THEY SHOW
SLEEP-LIKE BEHAVIOR.
SO TOTAL SLEEP DEPRIVATION
CAUSES DEATH.
IN FACT, SLEEP DEPRIVATION CAN
PROBABLY KILL AN ANIMAL FASTER
THAN FOOD DEPRIVATION.
SO IT'S REALLY ESSENTIAL.
NOW, FOR NON-MAMMALIAN ANIMALS,
SLEEP IS USUALLY DETECTED BY
LACK OF MOVEMENT.
SO FOR EXAMPLE, FOR DROSOPHILA,
USED AS A VERY POWERFUL MODEL
SYSTEM FOR STUDYING SLEEP, TO
SCORE A SLEEP EPISODE, THE FLY
HAS TO STAY STILL FOR AT LEAST
FIVE MINUTES IN A ROW.
THEN IF YOU APPLY GENTLE SENSORY
STIMULATION, THEY SHOULD SHOW NO
MOTOR RESPONSE, BUT THE READOUT
IS ENTIRELY MOTOR.
DO THEY MOVE OR NOT.
FOR MAMMALIAN ANIMAL MODELS SUCH
AS MICE, WHICH IS OUR ANIMAL
MODEL, WE USUALLY MEASURE EEG
AND EMG, SO THE EMG MEASURES
SKELETAL MUSCLE TONE AND SOMATIC
MOTOR ACTIVITY, AND IS CLEARLY
REDUCED DURING SLEEP.
AND THEN BASED ON EEG, WE CAN
DISTINGUISH BETWEEN RAPID EYE
MOVEMENT, REM SLEEP, DURING
WHICH WE HAVE VIVID DREAMS, AND
NON-REM SLEEP, WHICH IS
BASICALLY A DEEP SLUMBER.
NOW FOR HUMAN, IF YOU'RE BROUGHT
TO A SLEEP CLINIC, IN ADDITION
TO EEG AND EMG, WE ALSO MEASURE
THINGS LIKE HEART BEAT AND
BREATHING.
SO THESE ALSO SLOW DOWN.
THE POINT I WANT TO MAKE HERE IS
THAT FALLING ASLEEP IS NOT JUST
ABOUT CHANGES IN OUR STATE OF
CONSCIOUSNESS OR BRAIN STATE
THAT YOU CAN MEASURE WITH THE
EEG.
IT'S ALSO ABOUT REDUCTION OF
SOMATIC AND AUTONOMIC MOTOR
ACTIVITY.
SO WHEN WE GOT INTO THE SLEEP
FIELD MORE THAN A DECADE AGO,
OUR MAIN OBSESSION AT THE TIME
WAS THE QUESTION OF HOW DO WE
SLEEP.
AND WHAT WE DISCOVERED OVER THE
YEARS IS THAT IN THE MAMMALIAN
BRAIN, THE NEURONS THAT PUT US
TO SLEEP ARE REALLY PART OF THE
MOTOR CIRCUITS CONTROLLING
SOMATIC OR AUTONOMIC MOTOR
ACTIVITY.
SO THIS IS A CIRCUIT DIAGRAM FOR
SOMATIC MOTOR CONTROL.
THE BLUE BOX HERE IS THE BASAL
GANGLIA, SO THERE ARE ACTUALLY
QUITE A FEW EXPERTS AT NIH
STUDYING BASAL GANGLIA, AND YOU
MIGHT RECOGNIZE THE T THE LOOP.
YOU HAVE BRAIN AND BRAINSTEM
CIRCUITS FOR MOTOR AK.
SO NOW WE KNOW THERE ARE NEURONS
THAT PROMOTE SLEEP IN ALL THE
REGIONS CIRCLED IN RED.
YOU CAN SEE THAT IT'S PRETTY
MUCH EVERY LEVEL OF THE NETWORK.
SO HERE'S THE CIRCUIT DIAGRAM
FOR AUTONOMIC CONTROL OF THE
CARDIOVASCULAR SYSTEM.
AND WE HAVE FOUND SLEEP NEURONS
IN ALL THE REGIONS CIRCLED IN
RED.
SO AGAIN, IT'S PRETTY MUCH EVERY
LEVEL OF THE NETWORK.
SO THIS LED US TO PROPOSE A
MOTOR THEORY OF SLEEP CONTROL,
WHICH IS THAT MAMMALIAN SLEEP IS
REALLY CONTROLLED BY DISTRIBUTED
NETWORKS OF NEURONS THAT ARE
INTEGRAL TO SOMATIC AND
AUTONOMIC MOTOR CONTROL.
NOW, IN HINDSIGHT, THIS MIGHT
SEEM EVEN OBVIOUS, RIGHT,
BECAUSE AFTER ALL, MOST OF OUR
MEASUREMENTS FOR DETECTING SLEEP
ARE BASED ON MOTOR ACTIVITY.
AND YET THIS IS NOT HOW THE
FIELD HAS BEEN THINKING ABOUT
IT, AND IT REALLY TOOK US QUITE
A WHILE TO GET HERE.
SO TODAY I WANT TO SHOW YOU SOME
OF THE EXPERIMENTS THAT LED US
TO THIS CONCLUSION.
SO FIRST A LITTLE BIT OF
HISTORICAL BACKGROUND.
PIONEEWE ACTUALLY KNOW QUITE A T
ABOUT THE NEURONS THAT KEEP US
AWAKE.
SO THESE INCLUDE A LOT OF THE
WELL-KNOWN NEUROMODULATORY
SYSTEMS, FOR EXAMPLE, THE
DOPAMINERGIC NEURONS IN THE
MIDBRAIN, CHOLINERGIC NEURONS IN
BOTH THE BRAINSTEM AND BASAL
FOREBRAIN, SEROTONIN NEURONS AND
ALSO SOME PEPTIDE NEURONS,
HYPOCRETIN.
NOW THE SEARCH FOR THE SLEEP
MECHANISM REALLY BEGAN WITH A
LANDMARK DISCOVERY, SO WE JUST
CAME OUT OF THIS BIG PANDEMIC,
BUT RIGHT AFTER PROBABLY THE
BIGGEST PANDEMIC IN HISTORY,
ABOUT 100 YEARS AGO.
SOME PEOPLE CALL IT THE SPANISH
FLU THAT KILLED 50 MILLION
PEOPLE WORLDWIDE.
SO AFTER THAT BIG PANDEMIC, VON
ECONOMO DISCOVERED THAT A SUBSET
OF THE PATIENTS THAT RO RECOVERD
FROM THAT FLU, THEY HAVE SEVERE
INSOMNIA.
AND THESE PATIENTS HAVE LESIONS
IN THIS REGION CIRCLED IN RED.
SO THIS WAS ACTUALLY VON
ECONOMO'S ORIGINAL HAND DRAWING.
THIS IS CALLED THE PRE-OP TICK
AREA, THE POA IN THE
HYPOTHALAMUS, SO THE IDEA IS
THAT PERHAPS THIS REGION IS
REALLY IMPORTANT FOR SLEEP
BECAUSE IF YOU LOSE IT, YOU HAVE
INSOMNIA.
AND THIS WAS LATER CONFIRMED BY
MANY ANIMAL EXPERIMENTS.
YOU CAN DO LESIONS IN ANIMAL
BRAIN AND THAT CONFIRMED THIS
FINDING.
SO THIS HAS LED TO THE TEXTBOOK
MODEL WITH THE POA AS THE SLEEP
CENTER.
SO THE IDEA IS THAT THE POA
PROMOTES SLEEP BY INHIBITING A
LOT OF THESE WAKE-PROMOTING
NEUROMODULATORY SYSTEMS.
AND OF COURSE THE PROPERTIES OF
THE POA SLEEP NEURONS HAVE BEEN
CHARACTERIZED BY MANY LABS,
INCLUDING CLIFFORD SAPER'S GROUP
AND HIS MANY SCIENTIFIC DE16
DESCENDANTS AND MANY OTHER LABS.
EVEN BACK IN THE 1950s AND
60s, SEVERAL STUDIES SHOW THAT
THERE ARE NEURONS IN THE LOWER
BRAINSTEM, REALLY POSTERIOR, SO
THERE ARE SOME NEURONS THAT
PROMOTE NON-REM SLEEP.
THEN ABOUT A DECADE AGO, PATRICK
FULLER'S LAB ALSO DISCOVERED
THIS AREA CALLED THE PARAFACIAL
ZONE IN THE MEDULLA THAT PROMOTE
NON-REM SLEEP.
SO WE ALSO ACCIDENTALLY STUMBLED
UPON A MIDBRAIN REGION THAT
REALLY PROMOTES NON-REM SLEEP
QUITE POWERFULLY.
SO IT SEEMS THAT THE
SLEEP-PROMOTING MECHANISM IS
ACTUALLY MORE DISTRIBUTED THAN
THE STANDARD TEXTBOOK MODEL.
SO TO TRY TO GET AN IDEA OF WHAT
THE ENTIRE SLEEP PROMOTING
MECHANISM MIGHT LOOK LIKE, WE
DECIDED TO DO A WHOLE BRAIN
SCREENING FOR SLEEP NEURONS.
SO WE HAVE TWO BASIC CRITERIA
FOR SLEEP NEURONS.
FIRST THEY SHOULD BE
SLEEP-PROMOTING, MEANING THAT
THEIR ACTIVATION SHOULD INCREASE
SLEEP AND THEIR INACTIVATION
SHOULD DECREASE SLEEP.
SO WE SHOULD ALWAYS DO
BIDIRECTIONAL MANIPULATION.
AND SECONDLY, THEY SHOULD BE
SLEEP-ACTIVE, MEANING THAT WHEN
YOU'RE NOT MANIPULATING THEM, IF
YOU'RE JUST RECORDING THEIR
ACTIVITY, THEY SHOULD BE ACTIVE
EITHER RIGHT BEFORE OR DURING
SLEEP, SO THEY SHOULD BE
SPONTANEOUSLY ACTIVE AT THE
RIGHT TIME TO DO THAT IR JOB.
-- TO DO THEIR
JOB.
WHEN WE WERE DOING WHOLE BRAIN
SCREENING WE ALSO HAVE TWO
CORRESPONDING STRATEGIES.
WE COULD EITHER SCREEN FOR
SLEEP-PROMOTING NEURONS AND SEE
IF THEY'RE ALSO SLEEP-ACTIVE, OR
WE CAN DO SCREENING FOR
SLEEP-ACTIVE NEURONS AND SEE IF
THEY'RE ALSO SLEEP-PROMOTING.
SO IT TURNS OUT THAT BOTH
STRATEGIES WORKED QUITE WELL,
BUT TODAY I'M JUST GOING TO
FOCUS ON THE FIRST STRATEGY TO
SEARCH FOR SLEEP-PROMOTING
NEURONS.
SO THIS EFFORT WAS BASED ON AN
INCREDIBLY SIMPLE LOGIC,
PROBABLY A JUNIOR HIGH SCHOOL
STUDENT CAN COME UP WITH THIS
IDEA.
SO THE IDEA IS THAT WE'RE GOING
TO START WITH THE WAKE-PROMOTING
NEURONS, AS I MENTIONED BEFORE
WE KNOW QUITE A FEW OF THEM.
AND WE'RE GOING TO USE THIS
RETROGRADE TRANS SYNAPTIC
TRACING TO FIND THEIR INHIBITORY
INPUT, BECAUSE WE KNOW THAT
SLEEP AND WAKEFULNESS ARE
MUTUALLY EXCLUSIVE, RIGHT?
SO IF YOU'RE AWAKE, YOU CAN'T BE
ASLEEP AND VICE VERSA.
SO IF YOU CAN FIND NEURONS THAT
INHIBIT THE NEURONS THAT KEEP US
AWAKE, THEN PERHAPS THOSE
NEURONS CAN PROMOTE SLEEP.
IT'S A POSSIBILITY.
AND THEN ONCE WE FIND THE
INHIBITORY SLEEP NEURONS, WE'RE
GOING TO TRACE ONE MORE STEP
BACK, AND LOOK FOR THEIR
EXCITATORY INPUT.
BECAUSE IF YOU'RE A NEURON OONDD
YOU CAN EXCITE A WHOLE BUNCH OF
OTHER NEURONS THAT PROMOTE
SLEEP, THEN PERHAPS YOU YOURSELF
CAN PROMOTE SLEEP.
SO THIS WAS DONE BY A REALLY,
REALLY FANTASTIC FORMER POSTDOC
IN MY LAB WHO'S RUNNING HER OWN
LAB NOW.
SO WE TARGETED A WHOLE BUNCH OF
WAKE PROMOTING NEURONS AND USED
TRACING BASED ON RABIES VIRUS TO
IDENTIFY BRAIN REGIONS WITH
RELATIVELY BROAD GABAERGIC INPUT
TO THOSE WAKE-PROMOTING NEURONS.
SO HERE IS THE LIST OF ALL THE
WAKE-PROMOTING NEURONS THAT CH
CHENYAN TARGETED.
CHOLINERGIC, GABAERGIC NEURONS.
THIS IS A LIST OF THE BRAIN
REGIONS WITH RELATIVELY BROAD
GABAERGIC, MEANING INHIBITORY
PROJECTIONS TO THOSE
WAKE-PROMOTING CELLS.
SO YOU CAN SEE THAT THIS LIST
INCLUDES THE POA, WHICH IS THE
TEXTBOOK SLEEP CENTER.
BUT TO OUR SURPRISE, THE TOP
CANDIDATE THAT CAME OUT OF THIS
SCREENING IS ACTUALLY THE
CENTRAL NUCLEUS OF THE AMYGDALA,
WHICH IS TRADITIONALLY THOUGHT
TO BE A FEAR CENTER.
AND SO CHENYAN WAS ABLE TO
IDENTIFY A SUBSET OF THE
GABAERGIC NEURONS IN THE CEA
THAT EXPRESS -- SHE SHOWED THESE
WERE BOTH SLEEP ACTIVE AND SLEEP
PROMOTING AND ALSO THE
NEUROPEPTIDE NEUROTENSIN ITSELF
IS IMPORTANT FOR THE SLEEP
PROMOTING EFFECT.
FOR THE SAKE OF TIME, I'M GOING
TO SKIP THAT AND FOCUS ON THE
THIRD CANDIDATE REGION THAT CAME
OUT OF THIS SCREENING.
SO THIS WAS CHARACTERIZED BY
ANOTHER BRILLIANT FORMER
POSTDOC, WHO'S ALSO RUNNING HER
OWN LAB NOW.
SO MANY OF YOU PROBABLY KNOW
THAT THE SNR, SUBSTANTIA NIGRA
IS PART OF THE BASAL GANGLIA
CONTROLLING MOTOR ACTIVITY AND
YET WHEN WE WERE DOING THE
SCREENING, WE WERE DOING WHOLE
BRAIN SCREENING WITHOUT
PRECONCEPTION OF WHAT THE BRAIN
AREA MIGHT BE DOING.
YET ONCE YOU KNOW IT'S THE SNR,
YOU CAN'T IGNORE ALL THE
PREVIOUS PUBLICATIONS.
YOU HAVE TO TRY TO LINK TO WHAT
WE KNOW ABOUT SNR.
SO IN ADDITION TO EEG AND EMG,
WHICH WE USUALLY MEASURE FOR
SLEEP, WE ALSO ADDED THE VIDEO
RECORDING TO LOOK AT THE MOTOR
ACTIVITY OF THE MICE.
AND WHEN WE WERE DOING THIS
PROJECT, DEEP LEARNING IS ALL
THE RAGE AND SO WE DIDN'T WANT
TO BE LEFT BEHIND, SO WE LINED
UP SOME COLLABORATORS WHO HELPED
US TO USE DEEP LEARNING TO TRAIN
THIS CONVOLUTION OF THE NEURAL
NETWORK FOR AUTOMATIC IMAGE
SEGMENTATION.
SO THIS IS THE ORIGINAL IMAGE
AND THIS IS THE -- MY CURSOR
DOESN'T WORK VERY WELL.
SO THIS IS THE SEGMENTED MOUSE.
SO ONCE WE WERE ABLE TO AUTOMATE
THIS STEP, IT'S PRETTY
STRAIGHTFORWARD TO EXTRACT SOME
MOVEMENT-RELATED PARAMETERS OF
THE MICE.
SO WE FOCUSED ON TWO PARAMETERS,
ONE IS TRANSLATION AND THE OTHER
IS TOTAL MOVEMENT.
AND WHEN WE PLOTTED THESE TWO
PARAMETERS IN THIS
TWO-DIMENSIONAL SPACE, WE
BASICALLY SAW THREE CLUSTERS.
THE DARK GREEN CLUSTER
CORRESPONDS TO LOCOMOTION.
SO THESE MICE WERE NOT TRAINED
TO DO ANYTHING, THEY WERE JUST
IN THEIR HOME CAGE DOING
WHATEVER THEY WANTED.
SO THE BIGGEST MOST EXCITING
MOVEMENT THAT THEY MAKE IS
BASICALLY RUNNING AROUND IN THE
HOME CAGE.
AND THE LIGHTER GREEN CLUSTER IS
ALL THE SMALLER MOVEMENT
INCLUDING GROOMING, EATING, OR
SOME POSTURAL ADJUSTMENT.
AND THE GREY CLUSTER IS
BASICALLY IMMOBILITY, RIGHT,
THEY'RE NOT REALLY MOVING
VISIBLY.
BUT ONCE WE LOOK AT THE EEG AND
EMG, IT TURNS OUT THERE ARE
ACTUALLY TWO STATES, ONE IS --
AND THE OTHER IS ACTUAL SLEEP.
SO BASICALLY WE CLASSIFIED FOUR
BEHAVIORAL STATES: LOCOMOTION,
THE LARGER MOVEMENT, SMALLER
MOVEMENTS, QUIET WAKEFULNESS,
AND SLEEP.
SO HERE I'M PLOTTING THE EEG
DELTA POWER ACROSS THE FOUR
BEHAVIOR STATES, BASICALLY THE
LOWER FREQUENCY ACTIVITY, BELOW
4 HERTZ.
THE HIGHER THE DELTA POWER, THE
LESS AROUSED THE BRAIN IS.
SO IF YOU SEE A HEIDEL TA POWER,
IT MEANS THAT YOU'RE NOT
THINKING MUCH OR YOU'RE NOT VERY
EXCITED.
SO -- AND THIS IS THE TOTAL EMG
POWER.
THE POINT I WANT TO MAKE IS IF
YOU LOOK AT THE THREE GREENISH
STATES, SO THESE ARE ALL WAKE
STATES, SO WE TEND TO THINK OF
THAT DIFFERENCE IN TERMS OF
MOTOR ACTIVITY, AND OF COURSE
THERE'S EMG CHANGE.
BUT IN FACT, YOU ALSO SEE A VERY
CLEAR DIFFERENCE IN THE EEG.
AND IF YOU COMPARE QUIET
WAKEFULNESS AND SLEEP, SO BOTH
ARE IMMOBILITY STATES, YOU CAN'T
SEE VISIBLE MOVEMENT, SO WE TEND
TO THINK OF THE DIFFERENCE IN
TERMS OF BRAIN SPACE, BUT IN
FACT, THERE'S ALSO CLEAR EMG
DIFFERENCE.
SO IN FACT, THIS IS WHY IF YOU
FOLLOW SLEEP DURING MY TALK --
FALL ASLEEP DURING MY TALK, THE
FIRST THING I WOULD KNOTS IS YOU
NOD OFF BECAUSE YOU LOSE YOUR
NECK MUSCLE EMG, SO THERE'S A
CLEAR EMG DIFFERENCE.
NOW THE POINT HERE IS THAT BRAIN
SPACE MEASURED BY EEG AND MOTOR
STATE MEASURED BY EMG ARE
CORRELATED ACROSS MULTIPLE
BEHAVIOR STATES.
EVEN DURING WAKEFULNESS, THE
MORE ACTIVE YOUR BODY IS, THE
MORE AROUSED YOUR BRAIN IS.
SO THIS IS IMPORTANT.
SO WHEN WE LOOK AT TRANSITIONS
BETWEEN THESE STATES THEY'RE NOT
RANDOM AT ALL.
IF THE MOUSE STARTED OUT
RUNNING, IF WE LOOK AT THE NEXT
MOMENT, LET'S SAY THE NEXT
SECOND, THEY ALWAYS -- IF THEY
TRANSITION AT ALL, THEY ALWAYS
TRANSITION INTO SMALLER
MOVEMENTS.
WE HAVE NEVER SEEN A CASE WHERE
THE MOUSE WAS LIKE RUNNING ONE
MOMENT AND BANG, JUST FALL
ASLEEP THE NEXT MOMENT.
JUST LIKE WE HUMANS DON'T DO
THAT, RIGHT?
IT'S NOT LIKE WE RUN AND THEN WE
JUST, YOU KNOW, CRASH AND FALL
ASLEEP.
AND SO IF THEY STARTED OUT IN
OTHER MOVEMENTS, THEY EITHER GO
BACK TO RUNNING OR INTO QUIET
WAKEFULNESS.
THEY DON'T GO TO SLEEP RIGHT
AWAY.
SO IF WE PUT THESE FOUR STATES
IN A SINGLE CHAIN, ONE
DIMENSIONAL CHAIN, THEN MOST OF
THE TRANSITIONS ARE BETWEEN
NEIGHBORING SPACE, THERE ARE
VERY FEW EXCEPTIONS.
THIS SUGGESTS TO US THAT BOTH
MENTAL AROUSAL AND BEHAVIORAL
MOTOR STATES TEND TO CHANGE
GRADUALLY RATHER THAN ABRUPTLY.
SO ALL OF THIS IS JUST BEHAVIOR,
AND WHAT ABOUT SNR?
SO IT TURNS OUT THAT THERE ARE
ACTUALLY TWO SUBTYPES OF
GABAERGIC NEURONS IN THE SNR.
THE PV POSITIVE CELLS TEND TO BE
LOCATED IN THE LATERAL SNR, AND
THE GATU POSITIVE BUT PV
NEGATIVE TEND TO BE IN THE
MEDIAL SNR.
SO NEXT WE TRACKED EACH CELL
TYPE OPTOGENETICALLY
EXPRESSING -- AND THEN WE
RECORDED THEIR ACTIVITY USING
THIS THING CALLED THE -- IT'S
BASICALLY AN OPTIC FIBER
SURROUNDED BY A BUNCH OF AT T -O
WE BELIEVE THIS IS A GAD2 CELL
BECAUSE WE RECORDED IN THE
GAD2 CRE MOUSE.
WE TURN ON THE LIGHT BRIEFLY,
FOR 10 MILLISECONDS.
EVERYBODY TIME WE TURN ON THE
LASER, THE LITTLE BLUE DOT, IT
EVOKED A SPIKING, SO WE THINK
THIS CELL EXPRESSES CHAN EL DOB
SIN, ONCE WE IDENTIFY THE CELL
TYPE, WE TURN OFF THE LASER AND
JUST RECORD THE SPONTANEOUS
ACTIVITY.
SO HERE YOU CAN SEE THAT THIS
SELL HAS A HIGHER FIRING RATE
DURING NON-REM SLEEP WHICH IS
THE ORANGE PERIOD, AND THEY TEND
TO HAVE LOWER ACTIVITY WHEN THE
MOUSE IS MOVING, EITHER RUNNING
OR OTHER MOVEMENTS.
AND HERE'S THE POPULATION
SUMMARY.
THIS MAGENTA LINE IS THE
POPULATION AVERAGE OF THE
GAD2 CELLS AND YOU CAN SEE THAT
THESE CELLS TEND TO BE MOST
ACTIVE DURING SLEEP AND LESS
ACTIVE DURING HIGH MOTOR
ACTIVITY.
BUT THE PV CELLS TEND TO SHOW
THE OPPOSITE SIGN.
SO IT'S THE GAD2 CELLS THAT ARE
SLEEP-ACTIVE BUT NOT THE PV
CELLS.
SO THIS IS OUR FIRST CRITERION
FOR BEING A SLEEP NEURON.
SO NEXT WE LOOKED AT WHAT
HAPPENS IF WE ACTIVATE THESE
CELLS.
SO IN OUR LAB, OUR STANDARD
PROTOCOL IS TO TURN ON THE LASER
AT 10 HERTZ STIMULATION FOR TWO
MINUTES PER TRIAL AND SO THAT
SHOWS IN THIS BLUE SHADING.
AND YOU CAN SEE THAT EVERY TIME
WE TURN ON LASER AT TIME ZERO,
THERE'S AN IMMEDIATE REDUCTION
OF RUNNING AND ALSO OTHER MOTOR
ACTIVITY.
AND THERE'S AN INCREASE IN
SLEEP.
BUT PV NEURON ACTIVATION HAS
MUCH WEAKER EFFECT.
AND WHEN WE INACTIVATED THESE
CELLS THROUGH THIS INHIBITORY --
WE SEE THE OPPOSITE.
SO GAD2 INACTIVATION CAUSED AN
INCREASE IN MOVEMENT AND
DECREASE IN SLEEP, AND THE PV
ACTIVATION HAS MUCH WEAKER
EFFECT.
SO IT'S THE GAD2 BUT NOT THE PV
CELLS THAT ARE SLEEP ACTIVE AND
ALSO THEIR ACTIVATION PROMOTES
SLEEP, SO THIS IS OUR SECOND
CRITERION FOR BEING A SLEEP
NEURON.
OKAY.
SO EVEN THE GAD2 CELLS SUPPRESS
MOTOR ACTIVITY AND INCREASE
SLEEP, THEY DON'T CAUSE DIRECT
TRANSITION FROM MOVEMENT TO
SLEEP, WHICH IS NOT OBSERVED
NORMALLY.
INSTEAD, THEY ONLY BIAS THE
DIRECTION OF THE NATURAL
TRANSITIONS, SO THESE ARE ALL
THE TRANSITIONS WE SEE DURING
LASER STIMULATION, SO NONE OF
THEM IS ARTIFICIAL, SO WE SEE
ALL THESE TRANSITIONS WITH THE
SPONTANEOUS BEHAVIOR.
BUT YOU CAN SEE THAT ALL THE RED
ARROWS ARE THE ONES PROMOTED BY
LASER STIMULATION AND THE BLUE
ONES ARE SUPPRESSED.
SO ALL THE PR PROMOTED ONES GO
DOWNWARDS, RIGHT?
OKAY.
SO HERE AGAIN, I WANT TO MAKE A
SLIGHT DIGRESSION.
NOW, IF YOU'RE A SYSTEMS
NEUROSCIENTIST LIKE ME AND YOU
OPT GENETICALLY ACTIVATE SOME
NEURONS IN THE BRAIN AND YOU SEE
EVERY TIME YOU TURN ON THE LASER
THE MOUSE STOPS RUNNING AND THEY
START DOING OTHER THINGS, RIGHT,
WHAT WOULD YOU CONCLUDE?
YOU WOULD SAY I FOUND SOME
NEURONS INVOLVED IN MOTOR
CONTROL, RIGHT?
BECAUSE YOU SEE A DIFFERENCE IN
BEHAVIOR.
IF YOU GO FROM MOVEMENTS TO
QUIET WAKEFULNESS, YOU WOULD SAY
THAT'S ALSO MOTOR CONTROL.
BUT IF YOU FIND NEURONS THAT
TRIGGER CHANGES FROM QUIET
WAKEFULNESS TO SLEEP, YOU WOULD
SAY THAT'S BRAIN STATE CONTROL,
BECAUSE THERE'S NO CHANGE IN
MOTOR ACTIVITY, RIGHT?
BUT IN FACT, AS I MENTIONED
BEFORE, FOR EACH OF THESE
TRANSITIONS, THERE ARE CHANGES
IN BOTH EEG, BRAIN STATE, AND
EMG, WHICH IS MOTOR ACTIVITY.
AND IN FACT, THESE SNR NEURONS,
THEY REALLY DON'T CARE WHAT WE
CALL THESE TRANSITIONS, RIGHT?
ALL THEY DO IS TO PUSH THE
ANIMAL DOWN THE CHAIN ONE STEP
AT A TIME.
IN OTHER WORDS, THE BEHAVIORAL
EFFECT DEPENDS ON WHERE THE
MOUSE WAS.
IF THEY'RE RUNNING, YOUR LASER
IS GOING TO PUSH THEM INTO OTHER
MOVEMENTS.
IF THEY'RE DOING GROOMING,
THEY'RE GOING TO STOP DOING THE
GROOMING AND IF THEY'RE IN QUIET
WAKEFULNESS, YOU CAN PUSH THEM
TO SLEEP.
SO IT'S VERY CONTACT-DEPENDENT.
IN OTHER WORDS, SLEEP IN MY MIND
IS REALLY JUST THE LAST STEP IN
A SERIES OF TRANSITIONS THAT
REDUCE BOTH MENTAL AROUSAL AND
MOTOR ACTIVITY.
AND WHEN WE DID THE
INACTIVATION, WE AGAIN DON'T
CREATE ANY ARTIFICIAL
TRANSITIONS, ALL WE DO IS THE
BIAS THE TRANSITIONS IN THE
UPWARD DIRECTION.
OKAY.
SO NEXT WE LOOKED AT THE
DOWNSTREAM TARGETS OF THE SNR
NEURONS.
IF YOU LOOK AT THE PV CELLS,
THEY PROJECT TO THE MOTOR
THALAMUS, THE KNOW LAYERS OF THE
SUPERIOR COLLICULUS AND THIS
REGION THAT PEOPLE CALL THE --
PEOPLE KNOW FOR A LONG TIME IF
YOU DO ELECTRICAL STIMULATION IN
THAT AREA, YOU BASICALLY CAUSE
RUNNING OR INCREASE SPEED.
SO ALL OF THESE ARE VERY
WELL-KNOWN MOTOR REGIONS.
CONTROLLED BY THE BASAL GANGLIA.
BUT IF YOU LOOK AT THE GAD2
NEURONS, IN ADDITION TO THESE
MOTOR AREAS THAT ARE COVERED BY
THE PV CELLS, THEY ALSO PROTECT
THE DORSAL RAFFAE, WHICH
CONTAINS BOTH SEROTONIN AND
DOPAMINERGIC NEURONS THAT
REGULATE BRAIN AROUSAL.
THEY ALSO PROTECT THE LOCUS
JUIUS, AGAIN INVOLVED IN BRAIN
AROUSAL REGULATION.
AND WHEN WE USE THE VIRUS TRICK
TO LABEL THE SUBSET OF THE SNR
NEURONS THAT PROJECT TO THE
MOTOR THALAMUS, WES ARE SAW
THE -- COLLATERALS IN THE DORSAL
RAFFAE AND LOCUS JULIUS AND
CONVERSELY WHEN WE LABELED THE
CELLS THAT PROTECT THE DORSAL
RAFFAE WE ALSO SAW THEIR AXON
COLLATERALS IN THESE MOTOR
REASONS SO WE THINK IT COULD BE
THE SAME NEURONS THAT INNERVATE
BOTH THE REGIONS FOR BRAIN
AROUSAL CONTROL AND ALSO MOTOR
CONTROL.
AND WE THINK THAT THIS KIND OF
COLLATERAL ARRANGEMENT ALLOWS
THESE NEURONS TO COORDINATE THE
CHANGES IN BRAIN STATES AND
MOTOR STATES.
OKAY, SO NOW WE HAVE FOUND THE
POPULATION OF THE GABERGIC
NEURONS THAT PROMOTE SLEEP AND
AS PROMISED, WE'RE GOING TO
TRACE ONE MORE STEP BACK AND
LOOK FOR THEIR EXCITATORY INPUT.
NOW, IF YOU STUDY THE BASAL
GANGLIA, THIS IS ALL OLD NEWS,
YOU KNOW VERY WELL THAT THE
MAJOR INPUT TO THE SNR COMES
FROM THE SUBTHALAMIC NUCLEUS,
THE EXCITATORY INPUT SO THAT'S
CALLED THE STN.
SO THEY ALSO EXPRESS A
NEUROPEPTIDE NEURO10 SIN AND
WHEN WE TARGET THE STN NEURONS
IN NEURO10SIN CRE MICE, WE ALSO
SAW AN INCREASE IN NON-REM SLEEP
AND DECREASE IN WAKEFULNESS SO
THE UPSTREAM EXCITATORY NEURONS
ALSO PROMOTE SLEEP.
OKAY.
SO AS I MENTIONED AT THE
BEGINNING, FALLING ASLEEP IS
ASSOCIATED WITH REDUCTIONS OF
BOTH SOMATIC MOTOR ACTIVITY AND
AUTONOMIC MOTOR ACTIVITY, SO THE
HEARTBEAT ALSO SLOWS DOWN.
SO I JUST TOLD YOU ABOUT THE
STN-SNR PATHWAY FOR SOMATIC
MOTOR CONTROL AND NOW I WANT TO
SPEND JUST THE NEXT FEW MINUTES
TO TALK ABOUT A CIRCUIT FOR
CARDIOVASCULAR CONTROL.
SO THIS CIRCUIT IS INVOLVED IN
CARDIOVASCULAR -- REFLEX AND IS
CHARACTERIZED BY YAO, ANOTHER
FORMER POSTDOC NOW RUNNING HER
OWN LAB.
SO THE BARREL REFLEX IS A RAPID
NEGATIVE FEEDBACK MECHANISM FOR
STABILIZING THE BLOOD PRESSURE.
SO THE BLOOD PRESSURE IS NOT
SOMETHING THAT YOU WANT TO
CHANGE OVER HUGE RANGE, BECAUSE
EITHER YOU FAINT OR YOU MIGHT
HAVE A STROKE.
SO THE MECHANISM IS QUITE WELL
UNDERSTOOD THE RECEPTORS SIT IN
A CERTAIN PART OF THE ARTERY AND
THEY'RE ACTIVATED BY AN INCREASE
IN BLOOD PRESSURE, BP, AND THAT
SIGNAL IS TRANSMITTED TO THE
BRAINSTEM, IT'S CALLED THE
NUCLEUS OF THE SOLITARY TRACT,
SO THESE NEURONS ARE PART OF THE
VAGUS NERVE.
AND THEN THAT SIGNAL TRIGGERS A
SERIES OF CHANGES IN THE HEART
AND THE BLOOD VESSELS TO
STABILIZE THE BLOOD PRESSURE.
SO THE NEUROCIRCUIT IS ALSO
QUITE WELL UNDERSTOOD.
THERE ARE TWO PAIN PATHWAYS, IN
ONE PATHWAY THE NUCLEUS OF THE
SOLITARY TRACT, NST, PROVIDES
EXCITATORY PROTECTION TO THE --
NUCLEUS, WHICH CONTAINS
PREGANGLIONIC CHOLINERGIC
NEURONS, PART OF THE
PARASYMPATHETIC PATHWAY.
THE OTHER BRANCH, THE SOLITARY
TRACT, PROVIDES A GLUTE -- TO
THIS REGION CALLED THE CVLN,
CAUDAL VENTRAL LATERAL MEDULLA,
AND THE VVLN CONTAINS GABERGIC
NEURONS THAT INHIBIT THE RVLM,
ROSTRAL VENTRAL LATERAL ME DID
YOU TA, WHICH CONTAINS
ADRENERGIC NEURONS PART OF THE
PATHWAY.
BASICALLY IN ONE BRANCH YOU
EXCITE THE PARASYMPATHETIC
PATHWAY AND IN THIS OTHER
BRANCH, YOU INHIBIT THE
SYMPATHETIC PATHWAY.
SO THE FIRST THING THAT YUANYUAN
DID IS TO IDENTIFY THE SUBSET
INVOLVED IN CARDIOVASCULAR
CONTROL, BECAUSE THE SOLITARY
TRACT IS THE FIRST STOP OF THE
VAGUS NERVE AND IT'S INVOLVED IN
ALL THE INTERNAL SENSING.
THE GODS, THE STOMACH, WHATEVER,
SO THE LUNGS AND EVERYTHING.
SO ONLY A SUBSET OF THE NEURONS
ARE CARDIOVASCULAR.
SO THE WAY THAT WE DID THAT WAS
TO USE A FALSE TRACK DEVELOPED
AT STANFORD SO I WON'T GO INTO
THE DETAILS BUT BASICALLY WHAT
UANUAN DID WAS TO INJECT THIS
DRUG, YOU CAN SEE AS SOON AS WE
DID INJECTION, YOU SEE IMMEDIATE
INCREASE IN BLOOD PRESSURE AND
ALSO DECREASE IN HEART RATE
SO THIS INDICATES THE BAROREFLEX
HAS KICKED IN.
YOU CAN SEE AFTER PE INJECTION,
YUANYUAN LABELED A LOT MORE --
THIS IS JUST SAYING THAT THE
TRACK METHOD WORKS.
AND THEN NEXT YUANYUAN WANTED TO
MAKE SURE THE TRACK NEURONS ARE
INDEED CARDIOVASCULAR, BECAUSE
THE TRACK TECHNIQUE, THE
SPECIFICITY DEPENDS ON THE CELL
TYPE, THE REGION, SO YOU DO HAVE
TO VALIDATE THAT FUNCTIONALLY.
AGAIN THE WAY SHE DID THAT WAS
TO -- WITH CHAN ELDOXIN AND
IDENTIFIED THEM WITH
OPTORECORDING.
HERE'S AN EXAMPLE, THE MOUSE WAS
AGAIN RUNNING AROUND IN HIS HOME
CAGE DOING WHATEVER HE WANTED.
YOU CAN SEE THE HEART RATE AND
BLOOD PRESSURE SORT OF FLUCTUATE
DEPENDING ON WHAT THE MICE WERE
DOING.
AND HERE'S ONE IDENTIFIED CELL,
YOU CAN SEE THE FIRING RATE
ACTUALLY TRACKS THE UPS AND
DOWNS OF THE BLOOD PRESSURE
QUITE WELL.
AND WHEN WE ZOOM TEMPORALLY, WE
ACTUALLY FOUND A SUBSET OF THE
NEURONS, THEIR SPIKING IS TIME
LOCKED TO INDIVIDUAL HEART
BEATS.
SO THAT SUGGESTS TO US THAT
THESE NEURONS ARE ACTUALLY
SENSITIVE TO THE BLOOD PRESSURE
FLUCTUATIONS IN INDIVIDUAL
CARDIAC CYCLES.
SO ALL OF THESE ARE JUST SAYING
THAT THE TRAP TECHNIQUE KIND OF
WORKED QUITE WELL IN THIS METHOD
AND NEURONS THAT WE HAVE LABELED
ARE INDEED CARDIOVASCULAR.
SO NEXT THE QUESTION IS WHAT
HAPPENS IF WE ACTIVATE THESE
CELLS?
SO THIS IS OUR STANDARD PROTOCOL
IN MY LAB AS I MENTIONED, WE
TURN ON LASER FOR 2 MINUTES PER
TRIAL, AND INTERVAL WAS ABOUT 10
MINUTES OR SO, SO THE BLUE
SHADING INDICATES OPTOGENETIC
STIMULATION.
HERE'S THE POPULATION AVERAGE.
SO AS SOON AS WE TURN ON THE
LASER, WITHIN A COUPLE SECONDS,
YOU SEE A DRAMATIC DEGREECE IN
BLOOD PDE --DECREASE IN BLOOD PD
ALSO HEART RATE, CONSISTENT WITH
THE FACT THAT THESE ARE
CARDIOVASCULAR, BY DESIGN.
IN ADDITION WE SAW A SLOW BUT
CONSISTENT INCREASE IN NON-REM
SLEEP.
SO NEXT WE LOOKED AT THE
DOWNSTREAM TARGETS OF THESE
CELLS.
WHEN WE ACTIVATED THE CVLM
GABERGIC NEURONS, IT ALSO
INCREASED NON-RECOMMEND SLEEP
AND WE THINK THIS EFFECT IS
PARTLY MEDIATED BY THEIR
INHIBITION OF THE RVLM NEURONS
BECAUSE DIRECT OPT GENOMIC
INACTIVATION OF THE RVLM
ADRENERGIC NEURONS ALSO CAUSE AN
INCREASE IN SLEEP.
CONVERSELY WHEN WE INACTIVATED
THE CVLM, WE SAW INCREASE IN
WAKEFULNESS AND THE SAME IS TRUE
IF WE ACTIVATE RVLM.
THIS LAST EXPERIMENT WAS REALLY
JUST A REPETITION OF AN
EXPERIMENT PUBLISHED WAY BEFORE
WE GOT INTO THIS FIELD.
SO THIS WAS PUBLISHED BY PATRICE
GYNES LAB SPECIALIZING IN THE
SYMPATHETIC NERVOUS SYSTEM.
THEY SHOWED THIS ALSO WAKES UP
THE ANIMAL AND THAT EFFECT IS
PARTLY MEDIATED BY THE
EXCITATORY PROTECTION FROM THESE
CELLS TO THE LOCUST JULIUS,
WHICH IS INVOLVED IN WAKING UP
THE BRAIN.
THAT'S ONE PATHWAY.
WE ALSO LOOKED AT THIS OTHER
PATHWAY BY DIRECTLY ACTIVATING
THE CHOLINERGIC NEURONS, KNOWN
TO BE PARASYMPATHETIC.
WHEN WE ACTIVATED THESE CELLS
CHEMO GENETICALLY IN ADDITION TO
DECREASE IN HEART RATE WE ALSO
SAALSO -- THESE NEURONS ALSO
MOONLIGHT IN SLEEP CONTROL.
SO THEY HAVE A SECONDARY JOB IN
CONTROLLING BEHAVIOR AND BRAIN
STATES.
OKAY.
JUST TO SUM UP THIS PART, AS I
MENTIONED AT THE BEGINNING,
FALLING ASLEEP IS ASSOCIATED
WITH REDUCTIONS IN BRAIN AROUSAL
AND ALSO SOMATIC AND AUTONOMIC
MOTOR ACTIVITY.
SO JUST LOGICALLY IT KIND OF
MAKES SENSE FOR THE SLEEP
CONTROL MECHANISM TO INHIBIT ALL
THREE SYSTEMS, RIGHT?
BRAIN AROUSAL, AUTONOMIC AND
SOMATIC MOTOR SYSTEMS.
NOW FOR THE SOMATIC MOTOR
SYSTEM, I SHOWED YOU THE DATA ON
THE SDN -- EVEN THOUGH MY LAB
DID NOT LOOK AT THE STRIATUM,
OTHERS HAVE SHOWN THAT IN BOTH
THE DORSAL STRIATUM AND VENTRAL
STRIATUM ALSO CALLED THE NUCLEUS
ACCUMBENS, THE NEURONS, MEDIUM
SPIKING NEURONS THAT EXPRESS THE
DOPAMINE RECEPTORS, THOUGH
INDUCES NON-REM SLEEP.
AND OF COURSE BASED ON DECADES
OF STUDIES IN THE BASAL GANGLIA,
WE KNOW ACTIVATION OF THE
DRD2 NEURONS IN THE STRIATUM CAN
LEAD TO THE ACTIVATION OF THE
STN AND SNR NEURONS THAT WE HAVE
STUDIED THROUGH THE SO-CALLED
INDIRECT PATHWAY.
SO THE DIRECT PATHWAY/INDIRECT
PATHWAY, THAT'S LIKE THE CLASSIC
BASAL GANGLIA STUFF.
SO EVERYTHING MAKES SENSE.
AND IT ALSO SHOWS THAT EVEN
THOUGH THERE ARE A LOT OF
POPULATIONS OF SLEEP NEURONS,
THEY'RE NOT INDEPENDENT.
THEY'RE REALLY INTERCOULD NCTEDD
WITH EACH OTHER.
IN THE VENTRAL MEDULLA, THERE'S
A POPULATION OF INHIBITORY
NEURONS, IF YOU ACTIVATE THOSE,
THE MICE, IF THEY'RE MOVING, YOU
ACTIVATE THEM, THEY STOP MOVING.
IN FACT, THEIR BODY COLLAPSES
BECAUSE THEY LOSE THEIR MUSCLE
TONE.
SO HER LAB IS A MOTOR LAB, AND
THAT'S WHAT THEY FIND.
IN MY LAB, WE ALSO FOUND THAT
THAT POPULATION INDUCES SLEEP
BECAUSE WE MEASURE THE EEG.
SO ANOTHER EXAMPLE THAT YOU'RE
IN DIFFERENT FIELD AND YOU SORT
OF MAKE THESE DIFFERENT CLAIMS
BUT VERY OFTEN THEY'RE ACTUALLY
REALLY CONNECTED TO EACH OTHER.
SO AGAIN, ANOTHER EXAMPLE OF THE
CLOSE RELATIONSHIP BETWEEN MOTOR
CONTROL AND SLEEP CONTROL.
NOW, FOR THE AUTONOMIC NERVOUS
SYSTEM, I SHOWED YOU THE DATA
SHOWING THERE ARE SLEEP NEURONS
IN THE SOLITARY TRACT, BUT WE
ALSO FOUND SLEEP NEURONS IN THE
PERIAQUEDUCTAL GREY, THE AMIGD
AMYGDALA AND OF COURSE THE
HYPOTHALAMUS.
THERE ARE SUBSETS THAT ALSO
PROMOTE SLEEP.
SO NOW GIVEN ALL THESE SLEEP
NEURONS IN THE FOREBRAIN,
MIDBRAIN AND HINDBRAIN, IN BOTH
THE AUTONOMIC AND SOMATIC MOTOR
CIRCLES, IT SEEMS THAT THIS
TEXTBOOK MODEL WITH A SINGLE
SLEEP CENTER IS REALLY QUITE
INADEQUATE.
INSTEAD IN THE MAMMALIAN BRAIN,
SLEEP IS REALLY CONTROLLED BY
MULTIPLE INTERCONNECTED
POPULATIONS OF NEURONS THAT ARE
BASICALLY INFILTRATING EVERY
LEVEL OF THE SOMATIC AND
AUTONOMIC MOTOR CONTROL
NETWORKS.
IN FACT I WOULD EVEN GO ON AND
SPECULATE A LITTLE BIT, THIS IS
THE PART I MIGHT GET INTO
TROUBLE.
I ACTUALLY THINK THAT FOR
ANIMALS WITH RELATIVELY SIMPLE
NERVOUS SYSTEMS, SLEAP IS
PROBABLY PRIMARILY ABOUT
SUPPRESSING MOTOR ACTIVITY FOR
WHATEVER REASON.
IT'S ONLY FOR ANIMALS WITH MORE
COMPLEX BRAINS LIKE US, THIS
KIND OF REDUCTION OF BRAIN
AROUSAL BECOMES MORE IMPORTANT,
AND FOR THOSE ANIMALS, BRAIN
STATES AND MOTOR STATES CAN BE
COORDINATED BY COLLATERAL
INNOVATION BY THE SAME SLEEP
NEURONS THAT KIND OF CONTROL
BOTH MOTOR ACTIVITY AND BRAIN
STATES TOGETHER, AND AS WE
SHOWED IN THE SNR NEURONS.
OKAY.
SO NOW I FEEL LIKE WE HAVE A
PRETTY GOOD HA HANDLE ON THE HOW
QUESTION.
I'M SURE THERE ARE A LOT MORE
DETAILS TO BE FIGURED OUT,
BECAUSE THESE DIAGRAMS ARE VERY
CRUDE, RIGHT?
THERE'S A LOT MORE CIRCUIT
MAPPING TO BE DONE BUT I SORT OF
FEEL LIKE WE UNDERSTAND THE
GENERAL LOGIC OF THE SLEEP
CONTROL MECHANISM.
SO WE HAVE SWITCHED OUR
ATTENTION TO THE WHY QUESTION.
NOW, WE KNOW THAT SLEEP
DEPRIVATION CAUSES A LOT OF
PROBLEMS.
IN THE BRAIN WE KNOW THAT IT
CAUSES IMPAIRMENTS OF
DECISION-MAKING, LEARNING AND
MEMORY, MEMORY CONSOLIDATION, IT
PROBABLY SLOWS DOWN WASTE
COLLECTION THROUGH THE LYMPHATIC
SYSTEM, IN ADDITION TO COGNITIVE
AND EMOTIONAL IMPAIRMENT, IT
CAUSES CARDIOVASCULAR DISEASE,
HORMONE IMBALANCES, IMMUNE
PROBLEMS, EVERYTHING, RIGHT?
SO THAT REALLY INDICATES THAT
SLEEP BENEFITS ALL OF THESE
DIFFERENT SYSTEMS.
BUT HERE IS THE BIG QUESTION.
DOES SLEEP SUPPORT MULTIPLE
INDEPENDENT PROCESSES?
MAYBE EACH UNDERLIE A DIFFERENT
FUNCTION.
WE KNOW THERE ARE MULTIPLE
FUNCTIONS, SOME INSIDE, EACH
DEPENDS ON THE DIFFERENT PROCESS
SUPPORTED BY SLEEP, OR IS THERE
A SINGLE FUNDAMENTAL PROCESS
THAT UNDERLIES ALL THESE
DIFFERENT EFFECTS?
SO THINK ABOUT FEEDING.
IF YOU'RE FOOD-DEPRIVED FOR
THREE DAYS, I CAN PROMISE YOU
IT'S PROBABLY NOT GOING TO KILL
YOU.
BUT YOU'RE GOING TO HAVE A LOT
OF PROBLEMS.
SOME OF THEM MIGHT EVEN BE
COGNITIVE.
IN FACT, I KNOW FROM MY OWN
EXPERIENCE, I SKIPPED BREAKFAST
FOR MORE SLEEP, BUT IF I DIDN'T
MUNCH THE BARS ARIEL GAVE ME, I
WOULD PROBABLY BE VERY
COGNITIVELY IMPAIRED TO GIVE
THIS TALK.
RIGHT?
AND YET WE WOULDN'T CONCLUDE
THAT FEEDING IS FOR COGNITION.
WE KNOW FEEDING HAS A SINGLE
FUNDAMENTAL PURPOSE, WHICH IS
THE INTAKE OF ENERGY AND
NUTRIENTS, AND YET IF YOU DO
FOOD DEPRIVATION, YOU HAVE MANY
PROBLEMS.
RIGHT?
SO THE QUESTION IS, IS THERE
SOMETHING SIMILARLY BASIC FOR
SLEEP?
AND IF SO, WHAT COULD THAT BE?
SO WE DON'T HAVE THE ANSWER TO
THAT YET, BUT I HAVE A
HYPOTHESIS.
SO THAT'S THAT INACTIVATION OF
CATECHOLAMINE INCLUDING DOPAM
DOPAMINE, NEUROADREN LEAN AND
ADREN LEAN SIGNALING MIGHT BE AN
UNDERLYING PROCESS UNDERLYING
MULTIPLE ASPECTS OF SLEEP.
SO WE FOCUSED ON CATECHOLAMINE
FOR SEVERAL REASONS.
FIRST IN ADDITION TO BRAIN
AROUSAL, WE KNOW THAT THEY
DEFINITELY REGULATE BRAIN
AROUSAL BIG TIME.
THEY ALSO REGULATE SOMATIC AND
AUAUTONOMIC MOTOR ACTIVITY.
WE KNOW HOW IMPORTANT DOPAMINE
IS FOR SOMATIC MOTOR ACTIVITY IN
PD.
WE ALSO KNOW THAT NEURO
ADRENALINE -- IN ADDITION TO
NEURONS IN MUSCLES,
CATECHOLAMINE SIGNALING ALSO
REGULATES METABOLISM AND
REGULATING THE IMMUNE SYSTEM SO
THIS COULD POTENTIALLY EXPLAIN A
WIDE RANGE OF SLEEP DEPRIVATION.
-- BETWEEN THE FUNCTIONS AND
BENEFITS OF SLEEP AND OUR
NATURAL DESIRE AND DRIVE FOR
SLEEP.
SO TODAY, I'M JUST GOING TO GIVE
YOU ONE EXAMPLE OF HOW SLEEP IPT
ACTS INTERACTS WITH THE IMMUNE M
THROUGH -- SO WE FIRST FOCUSED
ON MICROGLIA, THE RESIDENT
IMMUNE CELLS IN THE BRAIN.
WE KNOW WHEN THERE'S DISEASE AND
INJURY, THEY SWITCH TO DEFENSE
MODE, BUT IN A NORMAL HEALTHY
BRAIN, THEIR MAIN JOB REALLY IS
TO MAINTAIN BRAIN HOMEOSTASIS.
AND WE KNOW THAT ONE OF THE MOST
IMPORTANT MARKERS FOR
HOMEOSTATIC MICROGLIA IS P I2Y12
ACTIVATED BY ATP AND ADP
RELEASED BY NEURONS AND AS CROW
SIASTROCYTES, TO DECIDE HOW TO
REACT ACCORDINGLY TO MAINTAIN A
BALANCE IN THE BRAIN.
SO THE FIRST EXPERIMENT WE DID
WAS TO MANIPULATE P2Y12.
SINCE IT IS A GI COUPLED GPCR,
THE FIRST EXPERIMENT THEY DID
WAS TO MANIPULATE MICROGLIA
CHEMO GENETICALLY USING GIDRED
SO THEY CROSS THIS HAD SPECIFIC
DRIVER LINE WITH GIDREADD AND
THAT ALLOWED US TO LABEL
MICROGLIA VERY SPECIFICALLY AND
EFFECTIVELY, ALMOST 100%.
SO HERE ARE JUST SOME EXAMPLE
RECORDING EXPERIMENTS.
WE MEASURED EEG, EMG AND THIS IS
THE COLOR-CODED BRAIN STATE AND
HERE'S A POPULATION SUMMARY.
SO BASICALLY YOU CNO INDUCED
ACTIVATION OF GI SIGNALING IN
MICROGLIA CAUSED AN INCREASE IN
NON-REM SLEEP AND DECREASE IN
WAKEFULNESS COMPARED TO
SIGNALING CONTROL.
WE ALSO DID INACTIVATION OF
P2Y12 BY INFUSING AN ANTAGONIST,
AND THAT CAUSED THE OPPOSITE
EFFECT.
AND SO WE THINK THAT THIS
ANTAGONIST SHOULD ONLY AFFECT
MICROGLIA DIRECTLY IN THE BRAIN,
BECAUSE WE KNOW THAT WITHIN THE
CNS, THE CENTRAL NERVOUS SYSTEM,
P2Y12 IS ONLY EXPRESSED IN
MICROGLIA AND NOT THE ONLY CELL
TYPES.
SO WE ALL KNOW THAT GI, IS TO
DECREASE CYCLIC EMP BUT THERE'S
A NON-CANONICAL PATHWAY THAT
INCREASES CALCIUM, PEOPLE HAVE
SHOWN THIS IN VITRO BEFORE.
SO THE ROLE OF CALCIUM SIGNALING
IN MICROGLIA FUNCTION HAS BEEN
KIND OF UNDERSTUDIED BUT IT'S
GETTING A LOT MO MORE ATTENTIONN
RECENT YEARS.
SO THE NEXT THING WE DID WAS TO
DO CALCIUM IMAGING IN VIVO BY
CROSSING THIS GC ACH M REPORTING
LINE INTO THE MICROGLIA
REPORTING LINE.
SO IF YOU LOOK AT 1 TWH 1 THROU,
THEY'RE ALL IN PROCESSES.
THIS IS CONSISTENT WITH THE
PREVIOUS STUDY DONE, TH SO THEY
SHOW THAT CALCIUM IS A LOT MORE
COMMON IN THE PROCESSES.
AND HERE'S A POPULATION SUMMARY.
SO COMPARED TO CONTROLS, CAUSED
INCREASE IN CALCIUM AND THE SAME
THING IS TRUE IF WE INFUSE THE
P2Y12 AGONIST.
SO IT SEEMS THAT P2Y12/GI
INCREASES CALCIUM IN VIVO, AND
WE ALSO KNOW THAT THIS PATHWAY
INCREASES SLEEP, SO A NATURAL
QUESTION IS WHAT'S THE
RELATIONSHIP BETWEEN MICROGLIA
CALCIUM AND SLEEP?
SO FOR THAT, WE ALREADY HAVE THE
DATA.
WE JUST NEED TO LOOK AT THE
SESSIONS WITHOUT CNO BUT
COMPARING ACROSS DIFFERENT BRAIN
STATES.
SO IN GENERAL, WE SEE THAT A
MICROGLIA CALCIUM -- ARE HIGHER
DURING NON-REM SLEEP COMPARED TO
WAKEFULNESS.
YOU NOTICE THAT I DIDN'T MENTION
REM SLEEP AND THAT'S BECAUSE
HERE'S A DIRTY LITTLE SECRET.
IF YOU DO FLUORESCENCE IMAGING
DURING REM SLEEP, WHATEVER YOU
SEE, DON'T BELIEVE IT RIGHT A
WAY BECAUSE DURING REM SLEEP,
ALL THIS KIND OF CRAZY
CARDIOVASCULAR BLOOD SIGNALS
JUST MAKES THE IMAGING REALLY
TRICKY, YOU SEE ALL KINDS OF
ARTIFACTS, SO WE COULDN'T REALLY
PIECE APART WHAT'S REAL, WHAT'S
ARTIFACT SO WE DECIDED NOT TO
TALK ABOUT REM SLEEP, WHICH
REVIEWERS GAVE US A REALLY HARD
TIME.
AND SAYING I DON'T WANT TO SHOW
ANYTHING UNRELIABLE, THAT'S WHY.
ANYWAY, SO BUT AT LEAST WE KNOW
THAT DURING NON-RECOMMEND SLEEP,
CALCIUM TRANSIENTS ARE HIGHER.
OKAY.
SO MICROGLIA CALCIUM IS
CORRELATED WITH NATURAL SLEEP.
THE QUESTION IS, IS IT CAUSAL.
SO WE HAVE TWO LINES OF EVIDENCE
SUGGESTING IT PLAYS A CAUSAL
ROLE.
FIRST WHEN WE EXPRESS THIS
IP3 SPONG CALLED P130PH, WE
ACTUALLY GOT THIS CONSTRUCT FROM
NIH, SO THIS LARGELY GREATLY
REDUCED CNO INDREESING CALCIUM,
SO THE MAGENTA LINE IS WITHOUT A
SPONG, CAUSING HUGE INCREASE IN
CALCIUM, BUT WITH THIS SPONG,
THE CYAN COLORED LINE, THAT'S
GREATLY REDUCED.
THE INCREASE IN NON-REM SLEEP IS
ALSO LARGELY ABOLISHED.
CONVERSELY WHEN WE INCREASE
CALCIUM USING G -- WE STILL SAW
A STRONG EFFECT OF INCREASE IN
NON-REM SLEEP, SO WE THINK
PROBABLY MICROGLIA CALCIUM CAN
CAUSE AN INCREASE IN SLEEP.
BUT THEN THE QUESTION IS, HOW?
SO AT SOME POINT MICROGLIA WOULD
HAVE TO ACT ON NEURONS TO CHANGE
BRAIN STATES.
SO ONE OF THE MOST POWERFUL
WAKE-PROMOTING NEUROMODULATORS
IS -- ADRENALINE.
IT'S A VERY SMALL NUMBER OF
CELLS BUT THEY REALLY SEND THESE
HUGE AXONS ALL OVER THE BRAIN,
RELEASING NEUROADRENALINE.
NEXT WE LOOKED AT THE
INTERACTION BETWEEN MICROGLIA
AND NORADRENALINE.
SO FIRST WE IMAGED NORADRENALINE
LEVEL USING THE SENSOR DEVELOPED
BY THE LAB, I'M JUST GOING TO
USE THE WORD NE SENSOR.
SO IN GENERAL, THE -- LEVEL IS
HIGHER DURING WAKEFULNESS THAN
NON- -- THIS WAS ALL EXPECTED
BECAUSE WE'VE KNOWN FOR PROBABLY
60 YEARS THAT THE LOCUS JULIUS
NEURONS, THEY'RE MUCH MORE
ACTIVE DURING WAKEFULNESS THAN
SLEEP SO IT KIND OF MAKES SENSE
FOR NORADRENALINE TO BE HIGHER
DURING WAKEFULNESS.
WHAT'S IMPORTANT IS THAT THE --
THEY CHANGE IN OPPOSITE
DIRECTIONS AT BRAIN STATE
TRANSITIONS, SO -- LEVEL GOES
HIGHER WHEN THE ANIMAL WAKES UP
BUT MY MYOGLIA CALCIUM GOES DOW.
WHEN WE ACTIVATED MICRO DPLEE YA
GI USING CNO, IT CAUSED A
DECREASE IN -- LEVEL, SO THEY'RE
NOT JUST ANTICORRELATED, IT CAN
ACTUALLY CAUSE A DECREASE IN NE.
NOW WE KNOW THE MICROGLIA NOT
ONLY SENSE APP AND ADP THROUGH
P2Y12, THEY CAN ALSO HELP TO MA
TABBIZE ATP AND ADP INTO
ADENOSINE, AND IN FACT,
ADENOSINE HAS BEEN KNOWN FOR
DECADES TO BE A SUBSTANCE THAT
PROMOTES SLEEP.
SO PEOPLE TELL YOU TO DRINK A
GLASS OF MILK BEFORE YOU GO TO
SLEEP, IT HELPS YOU BECAUSE OF
ADENOSINE.
I DON'T KNOW IF THAT'S TRUE, BUT
ADENOSINE PART IS TRUE.
SO ADENOSINE DOES PROMOTE SLEEP.
SO NEXT WE USED ANOTHER SENSOR
TO MEASURE -- IN THE BRAIN, AND
INDEED ACTIVATION CAUSED
INCREASE IN ADENOSINE.
AND WHEN WE APPLIED AN ADENOSINE
RECEPTOR AGONIST, IT CAUSED A
DECREASE IN NE.
SO WE THINK THAT THE SUPPRESSION
OF NE LEVEL BY MICROGLIA IS AT
LEAST PARTLY MEDIATED BY
ATENNESSEAN.
NOW WE KNOW THAT NORADRENALINE
PROMOTES WAKEFULNESS AND
INHIBITS SLEEP, SO THIS PATHWAY
THAT WE MAPPED OUT SO FAR IS ONE
MECHANISM FOR MICROGLIA TO
PROMOTE SLEEP.
NOW, WHAT ABOUT INTERACTION IN
THE OPPOSITE DIRECTION?
SO WE KNOW THAT MICROGLIA
EXPRESS A TON OF ADRENERGIC
RECEPTORS.
SO WE WENT BACK TO CALCIUM
IMAGING FOR MICROGLIA AND WHEN
WE APPLIED A NEW REACC RECEPTOR
ANTAGONIST, EITHER A COCKTAIL
THAT BLOCKS MULTIPLE RECEPTORS
OR SPECIFIC BETA 2 ADRENERGIC
RECEPTOR ANTAGONIST, IN BOTH
CASES WE SAW LARGE INCREASE IN
CALCIUM IN MICROGLIA.
SO BASICALLY NE ALSO SUPPRESSES
MICROGLIA CALCIUM AND
INTERACTIONS ARE MUTUALLY
ANTAGONISTIC.
NOW, WE KNOW THE MICROGLIA
CALCIUM IS IMPORTANT FOR THEIR
MOTILITY AND ALSO VAGAL SIGH TO
TICK ACTIVITY, SO THE
SUPPRESSION BY NE MEANS THAT
DURING SLEEP DEPRIVATION, WHEN
THE -- LEVEL IS KEPT HIGH
ARTIFICIALLY FOR A LONG TIME,
THAT CAN INTERFERE WITH THE
FUNCTION, BECAUSE YOU SUPPRESS
THE CALCIUM AND THAT COULD
INTERDEER WITH THESE FUNCTIONS
OF MICROGLIA.
TO ME THE MOST INTERESTING PART
IS MICROGLIA CAN ACTUALLY SIGNAL
BACK.
SO WE THINK PERHAPS WHEN
MICROGLIA SENSE THE NEEDS FOR
THESE HOUSEKEEPING FUNCTIONS,
THEY BASICALLY CAN TELL THE
BRAIN TO GO TO SLEEP BY IB
HIBTI -- BYINHIBITING THIS VERYL
WAKE-PROMOTING NEUROMODULATOR.
IN ADDITION TO THE IMMUNE
SYSTEM, WE ALSO HAVE ANOTHER
PROJECT LOOKING AT THE
NEUROENDOCRINE SYSTEM, WHICH I
WON'T GO INTO THE DATA, I'LL
JUST SORT OF SUMMARIZE.
SO SPECIFICALLY WE LOOKED AT
SLEEP DEPENDENT GROWTH HORMONE
RELEASE.
IT TURNS OUT THAT MOST OF OUR
GROWTH HORMONES ARE RELEASED
DURING SLEEP.
SO IN THIS PATHWAY, IT TURNS OUT
THAT NE IS ALSO PART OF THE
LOOP.
SO WE THINK THAT IN ADDITION TO
REGULATING METABOLISM AND THE
IMMUNE SYSTEM.
THE CATECHOLAMINE PATHWAYS, THEY
CAN ALSO INTEGRATE SIGNALS FROM
THE IMMUNE SYSTEM AND THE
ENDOCRINE SYSTEM, AND THEY CAN
ACTUALLY TELL THE BRAIN WHEN AND
HOW MUCH SLEEP IS NEEDED,
BECAUSE SLEEP IS SERVING ALL
THESE DIFFERENT FUNCTIONS.
METABOLISM AND THE IMMUNE
SYSTEM.
FURTHERMORE, WE THINK THAT
CATECHOLAMINE SIGNALING CAN
ACTUALLY TELL THE BRAIN TO GO TO
SLEEP SIMPLY BY GETTING TIRED
THEMSELVES.
SO WE KNOW THAT THE
CATECHOLAMINE NEURONS ARE
PARTICULARLY VULNERABLE TO
METABOLIC STRESS.
WE KNOW THESE NEURONS DIARILY
EARLY IN BOTH PARKINSON'S
DISEASE AND ALZHEIMER'S DISEASE,
AND WE KNOW THAT SLEEP DEFICITS
CAN ACTUALLY SPEED UP DISEASE
PROGRESSION.
WE ALSO KNOW THAT THESE NEURONS
STRONGLY PROMOTE WAKEFULNESS,
THEY'RE ALSO MUCH MORE ACTIVE
DURING WAKEFULNESS THAN SLEEP.
SO ONE POSSIBILITY IS THAT SLEEP
SIMPLY ALLOWS THESE NEURONS TO
KIND OF TAKE A BREAK AND REST
AND RECOVER FROM THE HIGH
METABOLIC STRESS CAUSED BY HIGH
ACTIVITY DURING WAKEFULNESS.
SO IN OTHER WORDS, MAYBE
SHUTTING DOWN THESE NEURONS
DURING SLEEP ONCE IN A WHILE IS
IMPORTANT NOT ONLY FOR THEIR OWN
HEALTH AND WELL-BEING BUT ALSO
FOR THE OTHER TISSUES AND ORGANS
THROUGH THEIR INTERACTIONS WITH
ALL THESE DIFFERENT OTHER
SYSTEMS.
SO WE THINK THAT IS QUITE
PLAUSIBLE THAT CATECHOLAMINE
INACTIVATION IS A BASIC PROCESS
UNDERLYING MULTIPLE FUNCTIONS OF
SLEEP.
SO THIS IS QUITE SPECULATIVE.
IT'S STILL EARLY IN THE DAYS BUT
THIS IS THE CENTRAL HYPOTHESIS
THAT WE'RE PURSUING RIGHT NOW.
SO FINALLY, THESE ARE THE PEOPLE
IN MY LAB, FORMER CURRENT
TRAINEES, AND SO THE RED ONES
ARE THE ONES THAT ARE
RESPONSIBLE FOR THE DATA I
SHOWED YOU TODAY.
ACTUALLY MOST OF THEM ARE NOW
RUNNING THEIR OWN LABS.
SO WE THANK YOU FOR YOUR
ATTENTION.
[APPLAUSE]
>> HI, HOW ARE YOU?
>> HI.
>> REALLY FANTASTIC TALK.
SO I HAVE A QUICK QUESTION AND
MAYBE A LONG QUESTION.
SO THE QUICK QUESTION IS, THE
RETICULATA NEURONS, THE
GOOD2 KRELTS ARE INCREASED
DURING WAKEFULNESS BUT ALSO THE
LOCUS -- HOW EXACTLY DOES THAT
HAPPEN?
>> THE LOCUS JULIUS NEURONS ARE
MORE ACTIVE DURING WAKEFULNESS.
THE OTHERS ARE MORE ACTIVE
DURING SLEEP.
>> SORRY, I GOT THAT MIXED UP.
>> YEAH, YEAH.
SO THE SNR NEURONS PROJECT TO
THE OSM C, SO WE CAN SAY THE OC
NEWER OPS ARE LESS ACTIVE DURING
SLEEP BECAUSE THEY'RE INHIBITED
BY SNR.
THEY'RE PROBABLY INHIBITED BY
MANY OTHER CELLS, BUT AT LEAST
THAT PATHWAY CONTRIBUTES IN A
POSITIVE WAY.
>> ALL RIGHT, I MIXED THAT UP.
THANKS FOR THAT.
BUT THEN -- SO YOU MENTIONED
THIS, ONE OF THE EARLIEST -- YOU
KNOW THIS, ONE OF THE EARLIEST
SIGNS IN PD IS YOU GET THIS SORT
OF -- THINKING OUT YOUR DREAMS.
I GUESS NOW LOOKING AT YOUR
TALK, OR I GUESS I HAD ALWAYS
THOUGHT THIS, THE LOCUS --
DEGENERATION IS PROBABLY
CONTRIBUTING TO THAT, TO A LARGE
EXTENT, BUT HOW MUCH OF THE
DOPAMINE SYSTEM SORT OF IS
INVOLVED IN THAT?
OF COURSE THEY REGULATE THE
RETICULATA NEURONS.
JUST KIND OF YOUR IDEAS.
I KNOW YOU'RE STUDYING THIS,
BUT --
>> SO WE JUST SAW EACH OTHER IN
ROME A COUPLE MONTHS AGO IN THIS
ASAP MEETING, SO MY LAB GOT INTO
PD WHICH IS THE MOST EXCITING
EVENT IN MY LIFE FOR THE PAST
FEW YEARS.
SO ANYWAY, SO WE KNOW THAT THE
DOPAMINE NEURONS PLAY A BIG ROLE
BECAUSE THE MICE THAT WE'RE
STUDYING, IT'S A DOPAMINE NEURON
SPECIFIC MANIPULATION.
SO IN THAT MOUSE MODEL, WE ONLY
CROSS TO THE -- CRE MICE SO THE
LC NEURONS ARE SPARED.
SO IN THAT EXPERIMENT, WE KNOW
THE DOPAMINE NEURONS DEFINITELY
PLAY A ROLE BECAUSE THOSE MICE,
THEIR SLEEP IS REALLY MESSED UP.
BUT WE HAVEN'T DONE THE CONVERSE
EXPERIMENTS.
IF YOU ONLY SPECIFICALLY
MANIPULATE THE OC NEURONS.
ACTUALLY WE HAVE A LITTLE BIT OF
DATA, IT'S NOT PUBLISHED.
SO IF YOU MESS WITH THE OC
NEURONS, NOT ONLY THE OC NEURONS
BUT THE ADRENERGIC NEURONS
BECAUSE THIS IS -- CRE MICE,
THEN THE SLEEP IS ALSO AFFECTED
AND ACTUALLY NOT AS STRONGLY AS
THE BAD CRE, BUT MORE NEEDS TO
BE DONE.
>> OKAY.
>> HI.
SO I WANT TO GO BACK TO
SOMETHING YOU MENTIONED EARLIER,
SO A LOT OF THESE SLOPE
PROMOTING NEURONS OR REGIONS
THAT YOU'VE MAPPED OUT AS YOU
MENTIONED EARLIER ALSO TAKE PART
IN CONTROLLING FEAR-RELATED
BEHAVIORS, PARENTAL BEHAVIORS,
SO MY QUESTION WAS, IS THE SLEEP
PROMOTING FUNCTION, ARE THESE
LABELS LINES, MAYBE THERE'S
SEPARATE SETS OF NEURONS THAT
ARE DOING THESE THINGS, OR IS
THIS SOME SORT OF INTERACTION
WITH THE STATE AND SORT OF
RELATED TO THAT WHAT I WANTED TO
ASK, WHEN YOU DO THE OPTOGENETIC
EXPERIMENTS AND YOU SEE THE
STATE CHANGES, YOU KNOW, WHEN
YOU DO THE STIMULATION, YOU SEE
THE STATE CHANGE.
WHEN YOU STOP THE STIMULATION,
DOES THE ANIMAL CONTINUE DOWN
THAT PATH FROM SMALL MOVEMENT TO
QUIET WAKEFULNESS, OR DOES IT
STAY THERE AND FRUK T AND FLUCTT
BACK UP?
>> IT VARIES.
IN SOME CASES IT ONLY -- AND IN
MOST CASES, THE EFFECT IS THE
STRONGEST DURING STIMULATION.
SO WHEN YOU STOP STIMULATION,
SOMETIMES YOU SEE THE EFFECT
GRADUALLY KIND OF, YOU KNOW, HAS
SOME LASTING EFFECT, BUT IT'S
WEAKER.
BUT IN OTHER CASES, YOU ACTUALLY
SEE A STRONG REBOUND.
BUT I THINK THAT, YOU KNOW, PART
OF THAT COULD BE YOU KNOW
WHEN -- SOME CELLS YOU STOP
ACTIVATING, THEY GO BACK TO
BASELINE.
SOME CELLS YOU SEE THIS REBOUND.
SO I THINK THE PART OF THAT
DIFFERENT EFFECTS, BEHAVIORAL
EFFECTS COULD BE DEPENDENT ON
THE BIOPHYSICAL PROPERTIES OF
THE NEURONS THAT WE ACTIVATED.
OF COURSE ALSO CIRCUIT.
SO THAT VARIES BUT WE HAVE NEVER
SEEN A CASE WHERE YOU START THE
CASE CADE, YOU LEAVE IT ALONE
AND THE EFFECT GETS STRONGER AND
STRONGER.
THAT RARELY HAPPENS.
YOUR FIRST QUESTION IS BROADER
BUT I THINK IT'S A GREAT
QUESTION, IN FACT, IT'S
SOMETHING THAT I'M SORT OF
TRYING TO SAY, I THINK THAT
WE'RE ALL -- YOU CAN BE STUDYING
PARENTAL BEHAVIOR AND THAT'S THE
ONLY THING YOU STUDY, YOU CAN BE
STUDYING FEAR AND IT'S THE ONLY
THING YOU STUDY.
WE TALK ABOUT SLEEP, IT'S JUST
ONE STAGE.
YEAH, WAKE, WHAT ELSE DO YOU
CARE ABOUT, RIGHT?
BUT OF COURSE WAKEFULNESS IS NOT
A SINGLE STATE.
THEY DO ALL THESE DIFFERENT
THINGS.
SO I THINK THE PART OF THE POINT
THAT I REALIZED, I'M TRYING TO
PREACH, IS THAT WE NEED TO START
TALKING TO EACH OTHER.
BECAUSE THE MOUSE BRAIN IS
PRETTY SMALL.
SOONER OR LATER YOU HIT THE SAME
POPULATION OF NEURONS, YOU CLAIM
THAT'S MOTOR NEURON, I CLAIM
IT'S A SLEEP NEURON.
I'M RIGHT, OF COURSE YOU SAY
YOU'RE RIGHT BUT THEY'RE
RELATED.
SO I THINK YOUR QUESTION -- I
MEAN, AT LEAST I THINK THAT THE
WAKE NEURONS, I'VE BEEN SAYING
THIS LIKE FOREVER, I DON'T THINK
THEIR ONLY PURPOSE IS TO WAKE UP
THE BRAIN.
THEY'RE INVOLVED IN DIFFERENT
WAKE BEHAVIORS, YET WHEN YOU
ACTIVATE THEM, THEY ALSO PROMOTE
AROUSAL, BECAUSE A LOT OF THE
BEHAVIORS, YOU NEED TO BE
AROUSED IN ORDER TO DO THEM.
I THINK THAT THE SLEEP NEURONS
ALSO, THEY KIND OF PUSH THINGS
IN THE OPPOSITE DIRECTION,
RIGHT?
THEY WANT YOU TO REDUCE YOUR
AROUSAL, REDUCE YOUR MOTOR
ACTIVITY, AND IF YOU HAPPEN TO
BE STUDYING SOME PARENTAL
BEHAVIOR, IF THAT BEHAVIOR
REQUIRES A LESS AROUSED STATE
THAN YOU'RE FIGHTING WITH
SOMEBODY, YOU MIGHT PROMOTE
THAT, BUT IT'S ALSO RELATED TO
THIS GENERAL STATE CHANGE, OR
EMOTIONAL STATE CHANGE RATHER
THAN JUST A VERY SPECIFIC
BEHAVIOR.
>> PERHAPS, I MEAN, RELATED TO
WHAT YOU SAID ABOUT NEUROTENSIN,
I DON'T KNOW IF YOU GUYS TRIED
DIFFERENT STIMULATION
PARAMETERS, PERHAPS IT'S ABOUT
THE CANONICAL TRANSMITTER THAT
THESE CELLS ARE USING, GLUTAMATE
OR GABA, PERHAPS THE PEPTIDES
PLAY A DIFFERENT ROLE YOU AND
NEED A DIFFERENT KIND OF
ACTIVITY TO GET THAT --
>> SO THE NEUROTENSIN STUDY, WE
USED CRISPR TO KNOCK OUT EITHER
THE GABA OR NEUROTENSIN -- YOU
KNOCK OUT ONE OF THEM, YOU DON'T
REDUCE BY HALF, YOU REDUCE BY
LIKE 80%.
BUT HOW THEY SYNERGISTICALLY
WORK WITH EACH OA WE DO OTHER, T
KNOW BECAUSE WE HAVEN'T BEEN
DOING A LOT OF SLICE RECORDINGS
TO FIGURE OUT THE DETAIL SORT OF
CIRCUIT STUFF, BUT BEHAVIORALLY,
WE KNOW THAT THEY'RE BOTH
IMPORTANT.
AND WE DON'T EVEN KNOW IF
THEY'RE RELEASED FIRST VERSUS --
SPIKES, DIFFERENTIAL RELEASE,
PEOPLE SAY THAT BUT WE HAVE
NEVER MEASURED IT, AND WHETHER
THEY'RE RELEASED AT THE SAME
SYNAPSIS, THERE ARE CASES WHERE
PEPTIDE IS RELEASED IN ONE
PLACE, TRADITIONAL TRANSMITTER
RELEASED IN OTHER PLACES.
WE DON'T KNOW ANY OF THAT SO I
THINK THERE'S A LOT MORE TO BE
FIGURED OUT.
>> HI.
THANKS FOR A REALLY GREAT TALK.
I MAY HAVE MISSED IT AS YOU WERE
GOING THROUGH, THERE WAS SO MUCH
BEAUTIFUL DATA THERE, BUT I
NOTICED IN THE FIRST PART THAT
MOST OF THE MANIPULATIONS MAY
NOT HAVE CHANGED REM SLEEP, AND
I'M WONDERING, IS THAT BECAUSE
THE MOTOR GAIT IS ALREADY THERE
AND YOU'RE NOT REALLY -- SORT OF
BEHAVIOR?
>> IT'S A GREAT QUESTION.
SO REM SLEEP IS QUITE DIFFERENT.
MY PERSONAL OPINION IS THAT REM
SLEEP, THE CIRCUIT IS SMALLER.
SO MICHELLE JUVE, WHO'S THIS
FANTASTIC SCIENTIST WHO DIED A
FEW YEARS AGO, HE DID A LOT OF
WORK ON REM SLEEP, SO HE
ACTUALLY -- HIS EARLY WORK DID
DIFFERENT TRANSECTIONS IN
DIFFERENT PARTS OF THE BRAIN, HE
PRETTY MUCH SHOWED YOU JUST NEED
A BRAINSTEM FOR REM SLEEP
GENERATION BECAUSE YOU CAN THROW
AWAY THE FOREBRAIN AND REM SLEEP
STILL HAPPENS.
SO WE HAVE FOUND PUBLISHED --
OTHER PEOPLE HAVE FOUND GLUTE
MANNER JIK NEURONS BUT MY
OPINION IS THAT PROBABLY TWO OR
THREE POPULATIONS IN THE
BRAINSTEM, THEY FORM A LOOP AND
THAT'S PROBABLY SUFFICIENT FOR
MOST OF REM.
PEOPLE FOUND SOME THAT REGULATE
REM BUT MY OPINION IS THAT THOSE
ARE MORE LIKE MODULATORY RATHER
THAN DIRECTLY CONTROLLING REM
SLEEP.
SO REM SLEEP IS A VERY DIFFERENT
THING.
SO NORMALLY, GOING FROM
WAKEFULNESS WE FIRST NEED TO GO
INTO NON-REM SLEEP AND THEN YOU
CAN GO INTO REM SLEEP FOR NORMAL
SUBJECTS, UNLESS YOU'RE NARK
HELP TICK.
SO NORMAL TRANSITION IS THAT
FIRST YOU DECIDE DO YOU SLEAP OR
NOT SLEEP.
AND THEN THE FIRST STATE IS
NON-REM.
THEN YOU MAKE A DECISION, DO YOU
GO INTO REM SLEEP OR DO YOU STAY
IN NON-REM SLEEP?
>> THANK YOU FOR YOUR GREAT
TALK.
SO I'M VERY INTERESTED ABOUT
THE -- SO THING IS, I MEAN,
BESIDES THE -- THERE'S ALSO --
[INAUDIBLE] ALSO PRODUCE -- AND
ALSO --
>> SO THIS IS WHAT I READ IN
REVIEW PAPERS, PEOPLE SAY THAT
FOR THE FOREBRAIN, THE MAIN OR
SOLE SOURCE OF NORADRENALINE IS
FROM THE LOCUS JULIUS.
THERE ARE OTHER SOURCES BUT THE
ADRENAL GLAND IS ALSO USED AS A
MORE MOANHORMONE.
MY UNDERSTANDING IS THAT DOES
NOT GO THROUGH THE BLOOD BRAIN
BARRIER.
>> NOREPINEPHRINE, I MEAN THE
ADRENAL GLAND CAN ALSO PRODUCE
NOREPINEPHRINE.
>> I DON'T KNOW FOR SURE BUT MY
UNDERSTANDING IS THAT THAT'S
ONLY IN THE CIRCULATION.
IT DOESN'T GO INTO -- IT DOESN'T
GO THROUGH THE BLOOD BRAIN
BARRIER.
BUT OF COURSE, YOU KNOW, YOU CAN
CHANGE THE BLOOD LEVELS WITH
THAT SYSTEM, I'M SURE IT DOES,
RIGHT?
AND OF COURSE FOR
NEUROSCIENTISTS, WE TEND NOT TO
THICK ABOUT THE BLOOD VESSELS,
THOSE ARE BORING, JUST THE
BLOOD, BUT THEY CHANGE THE BRAIN
IN A HUGE WAY, RIGHT?
YOU CHANGE BLOOD FLOW TO THE
BRAIN, EVERYTHING CHANGES, RIG
RIGHT?
WHICH WE TEND TO IGNORE, WHICH
IS A MISTAKE, I THINK.
>> I GUESS IF I CAN ASK ONE
QUESTION.
REALLY NICE TALK, I REALLY
ENJOYED IT.
I WAS REALLY INTERESTED FROM THE
BOTTOM UPPER SPECULATIVE
THINKING ABOUT THE MUSCULATURE
FEEDING BACK TO THE BRAIN TO
DICTATE BRAIN STATE.
HAVE YOU EVER TRIED ANYTHING
WHERE YOU MANIPULATED MUSCLE
TONE PERIPHERALLY BUT TRIED TO
KEEP THE ANIMAL AT THE SAME
CONSCIOUS STATE, OR THOUGHT
ABOUT KIND OF THE HIGH
DIMENSIONAL DATA THAT YOU GET
FROM ALL THE INDIVIDUAL MUSCLES
AND THEN HOW THAT FEEDS BACK
INTO THE BRAIN STATE, BECAUSE
YOU'RE THINKING ABOUT LIKE
REALLY HIGH ENERGY LOCOMOTION,
THERE'S COORDINATED CONTRACTION
OF HIND LIMBS, FORELIMBS VERSUS
LIKE GROOMING.
>> SO THE WAY THAT WE'RE
THINKING ABOUT IT RIGHT NOW IS
THE RELATIONSHIP BETWEEN THE
MUSCULAR ACTIVITY AND THE BRAIN
STATE IS MORE LIKE THE NEURONS,
THE SAME NEURONS CONTROLLING
BOTH.
BUT OF COURSE -- BUT I THINK
THAT WHAT YOU'RE SAYING IS THAT
COULD THERE BE FEEDBACK.
IF YOU LEAVE THE NEURONS ALONE
BUT YOU PAIR PL -- YOU PARALYZEE
MUSCLES, WHAT'S GOING TO HAPPEN.
I THINK IT'S HARD TO PREDICT
BECAUSE WHEN WE'RE MAKING
MOVEMENTS, CONSTANT FEEDBACK
PLACE A HUGE ROLE IN OUR NEXT
STEP.
IF I TOUCH SOMETHING, I DON'T
SENSE I'M TOUCHING SOMETHING, I
MIGHT BE DOING DIFFERENT THINGS.
SO I THINK -- I'LL BET IF YOU DO
THAT EXPERIMENT, YOU WILL SEE
THAT THE FEEDBACK SIGNAL IS
THERE.
BUT WE JUST HAVEN'T GOTTEN INTO
THAT YET.
THAT'S WHY EVEN WHEN I THOUGHT
THE IMMUNE SYSTEM WAS SUPER
IMPORTANT, WHAT DID I DO WITH
MICROGLIA, BECAUSE THEY'RE
INSIDE THE BRAIN.
ONCE I GET OUTSIDE THE BRAIN, I
DON'T KNOW WHAT TO DO.
>> THANK YOU FOR YOUR TALK.
QUICK QUESTION ABOUT THE
COGNITIVE IMPLICATIONS OF SLEEP.
SO WE KNOW IT'S IMPORTANT FOR
MEMORY CONSOLIDATION AND OTHER
COGNITIVE FUNCTION.
HOW DOES THIS CAT C CATECHOLAMIE
HYPOTHESIS FIT INTO THIS STUDY?
>> CA CATECHOLAMINE REGULATES
MEMORY PLASTICITY BIG TIME.
I'M NOT SUPER FAMILIAR WITH THE
LITERATURE.
I KNOW THERE ARE A LOT OF PAPERS
STUDYING THOSE BUT I CAN'T GIVE
YOU A COHERENT STUDY ON EXACTLY
WHAT THEY DO, BUT I KNOW THEY
HAVE BIG EFFECTS DEPENDING ON
THE CIRCUITS.
>> HI.
I HAVE -- REGARDING THE
DIFFERENT -- BETWEEN THE PATTERN
OF DIE EURNL AND NOCTURNAL
SPECIES.
DO YOU KNOW IF THE
SUBPOPULATIONS YOU SHOWED, ARE
THEY ACTIVATED IN THE SAME WAY?
>> -- WOULD BE THE GUY TO
ANSWER THAT QUESTION, RIGHT?
I DON'T.
SO UNFORTUNATELY WE'RE LIMITED
TO MICE.
WE HAVEN'T STUDIED ANY DIURNAL
ANIMALS.
>> DO YOU KNOW IF THE SNR IS
RECEIVING ANY INPUTS FROM --
REGIONS OF THE BRAIN?
>> NOT THAT I'M AWARE OF, RIGHT?
[APPLAUSE]