>> GOOD AFTERNOON, EVERYBODY. THANKS FOR COMING. IT'S MY PLEASURE TO INTRODUCE TODAY'S SEMINAR SPEAKER THOMAS EULER I DIDN'T REALIZE THIS BEFORE, THOMAS SPENT HIS ENTIRE LIFE IN A NICE COMPACT AREA OF GERMANY. HE GREW UP IN A TOWN JUST SOUTH OF FRANKFURT AND GOT HIS UNDERGRADUATE DIPLOMA IN BIOLOGY AT THE UNIVERSITY IN MINES. WHICH IS ALSO IN THAT AREA AND THAT'S WHERE HE STARTED WORKING ON THE RETINA WITH HINES VEIS SSLA AS AN RND GRADUATE LOOKING AT BIPOLAR CELLS IN THE RETINA. INITIALLY MORE FROM AN IMMUNE O HISTOCHEMICAL STANDPOINT AND THEN AS A GRADUATE STUDENT WITH HINES VESSLA, AT THE UNIVERSITY, BUT HINES WAS AT THE MAX PLANK INSTITUTE IN FRANKFURT MAKING SOME OF THE FIRST ELECTROPHYSIOLOGICAL RECORDINGS FROM BIPOLAR CELLS I THINK IN THE RAT SLICE AND WITH HINES HE WAS MAINLY LOOKING AT THE KINDS OF RECEPT WERES THAT ON BIPOLAR CELLS AND AFTER HE DID HIS Ph.D. AND DID A SHORT POST DOC WITH HINES HE MOVED TO THE UNITED STATES TO WORK WITH DICK MASLUND AND RECORDED THE FIRST LIGHT-EVOKED RESPONSES FROM ROD BIPOLAR CELLS AND THERE'S 1 PAPER IN PARTICULAR THAT IS A TOTAL CLASSIC IN THE FIELD. AND THEN THOMAS MOOFED BACK TO GERMANY TO WORK WITH WINFRED DENK WHERE HE TOOK HIS EXAMINATION OF THE RETINA FROM THE ELECTROPHYSIOLOGICAL TO THE OPTICAL REALM AND PERFORMED A NUMBER OF LANDMARK STUDIES LOOKING AT SUBCELLULAR VISUAL PROCESSING PRIMARILY IN STARBURST CELLS AND THEN HE BECAME A GROUP LEADER AT THE MAX PLANK INSTITUTE IN HIDELE BERG FOR A FEW QUEERS BEFORE ACCEPTING A POSITION AS A PROFESSOR OF OPHTHALMIC RESEARCH AT THE UNIVERSITY OF TUBBING HAM. AND I WOULD JUST SAY THAT THE DREAM THAT PEOPLE HAVE WITH THE BRAIN INITIATIVE AND SO FORTH IS UNDERSTAND ALL THE CONNECTIONS AND ALL OF THE FUNCTION OF EVERY NEWON IN A CIRCUIT IS PROBABLY CLOSEST TO BEING REALIZED IN THE RETINA. BECAUSE WE HAVE A VERY THOROUGH CONNECTIVITY MAP AND A FEW PEOPLE IN THE WORLD AND THOMAS IS A LEADER IN THAT REGARD ARE TAKING ADVANTAGE OF THIS CONNECTIVITY INFORMATION WE HAVE TO NOT JUST LOOK AT THE INDIVIDUAL CIRCUITS THAT OPERATE IN PARALLEL BUT START TO LOOK AT ALL THOSE CIRCUITS OPERATING AT THE SAME TIME BY RECORDING VISUAL RESPONSES FROM EVERY KIND OF CELL OF A PARTICULAR TYPE AND HIS WORK IS OPENING INCREDIBLE DOORS TO OUR UNDERSTANDING OF RETINA PROCESSING AND IT'S A REAL PLEASURE TO HAVE HIM HERE TODAY, SO THANK YOU THOMAS. [ APPLAUSE ] >> THANK YOU VERY MUCH FOR THE KIND INTRODUCTION AND THE INVITATION. I AM HAPPY TO BE HERE SO I WILL TALK ABOUT OUR WORK ON THE MOUSE RETINA AND BEFORE I STARTED THIS, I WANT TO EXPLAIN A BIT WHY WE ARE INTERESTED IN THE RETINA AND WHY WE THINK THIS IS AN INTERESTING TISSUE. SO THE RETINA, OR THE VISUAL SENSE IS PROBABLY HAS A SPECIFIC POSITION AMONG THE SENSORY SYSTEMS BECAUSE IT HAS PART OF ITS BRAIN ALREADY IN THE SENSORY ORGAN SO THE RETINA IS PART OF THE BRAIN AND IT SITS IN THE SENSORY ORGAN AND IT HAS TO RELAY NNKZ TO THE BRAIN TO THE REMAINING CENTERS OF VISION AND THE QUESTION IS WHY DO YOU NEED A RETINA AT ALL IN THE EYE, WHY NOT CONNECT EVERY PHOTO RECEPTOR FROM THE BRAIN AND LET THE BRAIN DO THE STUFF AND PROBABLY THE MOST CONVINCING EXPLANATION OF THIS IS THE NUMBERS. SO IN OUR RETINA AND IN OUR EYE, WE HAVE 130 MILLION PHOTO RECEPTORS FOR THE CABLE AT THE BRAIN IS ONLY 1 MILLION FIBERS SO YOU CANNOT CONNECT EVERY PHOTO RECEPTOR WITH A FIBER TO THE BRAIN IT WOULD HAVE AN ENORMOUS OPTIC NERVE AND THE MOUSE, THE STUDY ARE VERY SIMILAR SO THE RATIO IS ALSO SOMETHING LIKE 100, 1 TO 50, OR 1 FOCUSED ON A HUNDRED. SO SO THEREFORE THE RETINA IS NOT JUST TAKING PIXEL INFORMATION, IT HAS TO DO PREHERE ALREADY. YOU WANT TO COAT THIS AND SEND IT SO YOU KOOBT DO THIS APPROACH HERE AS I EXPLAINED BUT INSTEAD THE RETINA LOOKS AT LITTLE PARTS OF THE IMAGE AND THEN TRIES TO DETECT FEATURES AND THESE FEATURES ARE SENT TO THE BRAIN ON PARALLEL CHANNELS SO FOR EXAMPLE, IF YOU LOOK AT THIS IMAGE HERE, THE RETINA MIGHT ANALYZE THIS SMALL PORTION OF THE IMAGE AND THEN SEND A DESCRIPTION OF THIS TO THE BRAIN. A DESCRIPTION COULD BE SOMETHING LIKE THERE'S AN ETCH IN THIS REGION, THE EDGE SEPARATES A BROWNISH AND A BLUISH AREA, THE EDGES ARE NOT MOVING IT HAS THIS CERTAIN SLANT HERE AND THIS DESCRIPTION IS MUCH EASIER TO CODE AND SEND TO THE BRAIN. SO THEREFORE, WHAT THE RETINA DOES IS IT BREAKS DIRECTOR OF NATIONAL INSTITUTE THE VISUAL SCENE INTO PARALENS LENS LENS LENS REPRESENTATIONS, PATHWAY GIVESAR LENS LENS LENS LENS MOVES AND THESE MOVIES ARE SENT TO THE BRAIN AND SOME FOCUS ON COLOR, SOME FOCUS ON EDGE, SOME FOCUS ON CONTRAST AND SO ON. AND OUR INTEREST IS TO FIND OUT WHAT ARE THESE CHANNELS AND HOW ARE THEY CREATED IN THE RETINA AND LATER ON, ALSO WHAT THE BRAIN DOES WITH IT TO CREATE OUR VISUAL WORK. AS YOU SAW ALREADY FROM THE TITLE, WE STOLE THE TITLE FROM A FAMOUS PAPER BY COLLEAGUES HERE, WHAT THE FROG'S EYE, TELLS THE FROG'S BRAIN AND THE IDEA THAT THE RETINA IS NOTE CODING PIXEL INFORMATION BUT HAS FEATURE CHANNELS. FEATURE DETECTORS ACTUALLY ARISES ALREADY IN THIS PAPER AND THIS PAPER'S THE 1 THAT INSPIRED US TO LOOK AT THESE KIND OF COMPUTATIONS, IT'S REALLY A GREAT PAPER TO READ. WE'RE NOT WORKING ON FROGS BUT ON THE MOUSE AND MAYBE A FEW WORDS ABOUT THAT. SO WHEN WE STARTED TO ELECTRIC AT THESE THINGS IN MOUSE, REVIEWERS TOLD US, MICE CANNOT SEE, THEY ARE BLIND, WHY DO YOU WORK ON THE VISUAL SYSTEM OF THE MOUSE. SO OF COURSE PRIMATE VISUAL SYSTEM IS MUCH BETTER OR HAS--HAS INTERESTING FEATURES, IF YOU COMPARE THIS TO THE CAMERA IT WOULD BE THIS VERY NICE CAMERA MAYBE AND MOUSE CAMERA AND MOUSE EYE, PEOPLE CONSIDER SOMETHING LIKE THIS. BUT I THINK I--I HOPE TO CONVINCE YOU IN THE END OF MY TALK THAT AT LEAST, THE MOUSE IS SOME KIND OF CAMERA HERE. OKAY. OKAY, SO WE USE PHOTON IMAGING TO IMAGE THE ISOLATED RETINA. SO THIS IS A SCHEMATIC OF A RETINA, THE CHAMBER IS PROFUSED WITH SOLUTION, IT STAYS ALIVE FOR SEVERAL HOURS, 7-8 HOURS AND SO ON AND THE IMAGE ACTIVITY AND THE CHANNELS AND PROJECT LIGHTS, USING A PROJECTOR 32 THE LENS ON TO THE RETINA SO THAT WE CAN EXCITE THE RETINA WITH VISUAL STIMULI AND IMAGE AT THE SAME TIME AND WE--THIS IS DONE BY ARRANGING THE FLUORESCENT BANDS AND THE SIMULATION BANDS IN A WAY THAT WE CAN DO SIMULATION OF THE TISSUE AND WE ARE NOT REFERENCING THE PROCESS TOO MUCH. SO USE THE SPECTRAL SHIFTS HERE AND WE USE THE TEMPORAL ARRANGEMENT TO SEPARATE VISUAL STIMULI FROM OUR DETECTION. IN USING THESE TECHNIQUES WE CAN THEN MEASURE ACTIVITY AT ALL LEVELS IN THE RETINA AND THIS IS AN EXAMPLE OF TRACE, THIS IS RECORDED AT DIFFERENT LEVELS SO WE CAN MEASURE THE OUTPUT OF THE PHOTO RECEPTORS HERE, AND THE SIGNAL AND THE GLUTAMATE RELEASE AND MEASURE HORIZONTAL CELLS, AND PULL THEM WITH DIFFERENT METHODS AND ALSO THE GANGLION CELLS. SO WE CAN LOOK AT THE PROCESS OF THE DECODING OF THE VISUAL SCENE AND ALL THE DIFFERENT LEVELS AND TRY TO UNDERSTAND HOW THE INFORMATION AND REPRESENTATION IS CHANGING UNTIL IT REACHES HERE THE OUTPUT NEURONS OF THE RETINA. OKAY, SO THE FESTER PART, I WANT TO TALK ABOUT IS BRIEFLY, THIS IS A PUBLISHED STUDY ALREADY, HOW MANY OUTPUT CHANNELS ARE THERE, WE KNOW IT'S MORE THAN A COUPLE OF THEM AND ANATOMICAL STUDIES SUGGESTED AT LEAST 20 OR SO, BUT WE WANTED TO APPROACH THIS IN THIS A FUNCTIONAL WAY AND HOW MANY CHANNELS ARE THERE ON A MOUSE FROM THE BRAIN. AND THE STUDY WAS MAINLY PERFORMED BY THESE GUYS HERE ALL OF THE RECORDINGS, I MUST SAY, AND THEY DID SOME ELECTRICAL RECORDINGS, SO THIS IS THEIR WORK, BASICALLY. SO WE'RE LOOKING NOW AT THIS LEVEL OF THE RETINA, AT THE GANGLION CELLS AND WE'RE MEASURING BASICALLY THE OUTPUT OF THE RETINA. SO TO DO THIS, WE TAKE THE RETINA OUT OF THE EYE, AND WE LABEL IT WITH A METHOD CALLED ELECTROPORRATION SO WE PUT SYNTHETIC INDICATOR ON THE RETINA AND THEN WE EXCITE THE RETINA WITH THE ELECTRICAL PULSES BETWEEN 2 ELECTRODES AND THIS PROCESS DRIVES THE DIE INTO THE CELLS THROUGH A MECHANISM& THAT WE DON'T COMPLETELY UNDERSTAND, AND THE RESULT IS THAT YOU HAVE A BEAUTIFULLY LABELED RETINA WHERE ALMOST EVERY CELL IN THE GANGLION CELL IS LABELED SO ALL THE GREEN DOTS ARE GANGLION CELLS AND THE RED ARE BLOOD VESSELS AND THEN WE LABORED MOST OF THE CELLS, IT'S 96 PERCENT ORE SO. AND THE ADAPTIVE RESPONSES ADVANTAGE OVER THIS IS THAT WE CAN DO IT OVER GENETIC METHODS AND WE CAN DO IT IN ALMOST EVERY TISSUE AND WE CAN USE MOST DIFFERENT SPECIES BUT WE CAN ALSO USE MOUSE LINES TO APPLY THIS TECHNIQUE. IN THIS CASE, WE JUST WANT TO MAKE SURE WE LABEL EVERY CELL IN THE GANGLION CELL SO THAT WE DON'T MISS ANY REPRESENTATION. SO THEN WE TAKE THIS PIECE OF RETINA, AND PUT IT UNDER THE MICROSCOPE ASK THEN WE RECORD REGIONS LIKE THIS, SO WE HAVE ABOUT 70 CELLS OR SO UNDER THE MICROSCOPE AND TO COVER A LARGER SPACE UNDER THE MICROSCOPE OF THE RETINA, REPIECE THE PROCESS AT DIFFERENT POSITIONS AND MAKE MONTAGES LIKE THIS AND REACH CELL NUMBERS LIKE 600 CELLS PER RECORDING.& SO TO EACH OF THESE FIELDS WE PRESENT DIFFERENT VISUAL STIMULI AND THEN WE INVITE THIS FIELD INTO CELLS, AND EACH OF THESE MASS CONTAINS 1 CELL. AND I SHOW YOU SOME RECORDINGS OF THIS MASK HERE, SO RED CELL RESPONDS LIKE THIS. THIS IS THE TRACE IN RESPONSE TO THE SLIDE STIMULUS, SO 24 IS THE WHOLE STIMULUS SCREEN IS FLICKERING WITH THE TIME COURSE HERE, CAN YOU SEE THE RESPONSE OF THE CELLS SO THAT WHEN LIGHT GOES OFF HERE, THE RESPONSE IS VERY STRONG THAT THE CELL RESPONDS TO THE INCREASING FREQUENCY FLICKERING AND CONTRAST FLICKERING SO YOU GET SOME IDEA WHAT THE CELL LIKE. IN ADDITION WE PLAY A MOVING PAST HERE TO DIRECT SELECTIVITY, DIRECT SELECTIVITY AND WE PLAY NOISE STIMULUS FOR THE CELLS AND WE ALSO PLAY SOMETHING SO WE LEARN SOMETHING ABOUT THE PROCESSING. SO THIS WE CAN DO--WE CAN ANALYZE ALL THE CELLS IN THE FIELD IN THE SAME WAY AND ALREADY THIS SMALL SET OF VISUAL STIMULI SHOWS YOU THAT THE CELLS DO DIFFERENT THEY THINKS SO AS THE CELL IS INTERESTED IN THE FLICKERRINGS SO WHATEVER HAPPENS THE CELL IS RESPONDING. THIS CELL DOESN'T CARE ANYTHING AT ALL ABOUT THE FEW CHANGES BUT IT RESPONDS QUITE STRONGLY WHEN YOU MOVE A BAR ACROSS THE FIELD BUT THIS CELL IS NOT DIRECTION SELECTIVE BUT THIS CELL FOR EXAMPLE IS, BUT IT ALSO DOESN'T CARE ABOUT MOVEMENTS OR CHANGES BUT HERE RESPONSE BASICALLY WHEN THE MOVEMENT ALL GOES IN 1 DIRECTION. SO THIS WAY WE CAN DISTINGUISH DIFFERENT FUNCTIONS, TYPES OF CELLS IN THE GANGLION CILIA. AND SING THE GANGLION CILIA CONTAINS GINGLION AND ENDOCRINE CELLS WE DIVIDE IT UP SOMEHOW SO WE DO IMMUNE O STAINING, LABEL THE CELL SAYS AND THEN WE SAY OKAY, THESE CELLS ARE GANGLION CELLS CELLS AND WE CAN FOCUS ON THE GANGLION CELL PARTS HERE. SO USING THIS METHOD, I DON'T WANT TO GO INTO THE DETAILS HERE RIGHT NOW. WE USE CLUSTERING METHODS TO START. WE HAVE ABOUT 11,000 CELLS HERE TO SOLVE, TO FUNCTION GROUPS AND THIS IS THE RESULT THAT WE GOT HERE. SO WE HAVE THESE 32 GROUPS OF GANGLION CELLS WHICH WE THINK ARE GANGLION CELL TYPES OR WITH THE SPECIFIC TYPE OF RESPONSE, THE SIZE, PREFERENCE FOR MUTATION AND SO ON. AND IF YOU LOOK AT THIS FIELD HERE, AGAIN, SO THIS IS THE FIELD OF CELLS THAT WE RECORDED AND DOWN THERE'S A MOVIE THAT SHOWS THE CELL ACTIVITY COATED IN COLOR. SO IF WE PLAY THIS, YOU SEE THAT--SORRY. --YOU SIGH THAT THE CELLS PLAY THIS AT DIFFERENT TIMES. SO WE THINK THIS REPRESENTS MOST OF THE CHANNELS THAT THE MOUSE RETINA SENDS TO THE BRAIN. THE QUESTION IS, IS THIS REALLY ALL THAT WE GET THE TOTAL NUMBER OF CELLS AND JUST 1 ARGUMENT THAT WE MIGHT HAVE MISSED SOME CELLS HERE, SO FOR THIS KIND OF RECORDINGS WE GET THE FUNCTIONAL RECEPTOR FIELD OF ALL THE CELLS SO WE CAN MEASURE WHERE THE CELL IS SENSITIVE TO LIVE STIMULI AND WE HAVE ALSO FOR SOME CELLS THE KENNED RETIREDDIC STRUCTURE SO WE CAN CORRELATE THE FUNCTION OF THE FIELD WITH THE DENDRITIC STRUCTURE AND THE EACH CELL HAS TO COVER THE VISUAL SPACE IN ORDER TO HAVE NO GAPS BUT THIS COVERAGE IS SOMETHING ODD TOO, SO THE CELLS ARE NOT TYING THE CELLS PRECISELY BUT THEY'RE OVERLAPPING A LITTLE BIT AND IT HAS BEEN SHOWN THE COVERAGE EFFECT OF 2 SEEMS TO BE TRUE FOR MOST OF THE GANGLION CELLS. SO WE CAN USE THIS IF WE TEST, FOR ALL THE CELLS WE IDENTIFIED AND WE COVER THE SPACE OR WE ALL COVER THE SPACE COMPLETELY. AND IF WE DO THIS, WE FIND THIS KIND OF DATA HERE SO THIS IS FOR ALL THE GROUPS, THE GANGLION CELL TYPES, BASICALLY, 32 TYPES, WE IDENTIFIED HERE, THIS IS THE COVERAGE FACTOR AND WE SEE THAT FOR MOST OF THE TYPES, THE COVERAGE FACTOR IS AROUND 2 SO WE THINK THAT THESE REPRESENT INDEED FUNCTION TYPES BUT IN SOME CASES WE HAVE THE HIGHER COVERAGE HERE AND IN SOME CASES THIS ACTUALLY MAKES SENSE. SO HERE, THIS PEAK HERE, THIS IS OFFGANGLION CELLS AND THEY HAVE BEEN DESCRIBED TO HAVE 4 DIFFERENT DIRECTION TYPES SO GOING DIFFERENT DIRECTIONS OF THE VISUAL FIELD. EACH OF THEM HAS A COVERAGE OF ABOUT 2, AND COVERAGE OF ATS, SO THAT MAKES SENSE, SO THERE ARE THESE 4 DIFFERENT SUBTYPES IN THERE. BUT HERE WE DON'T HAVE THAT EASY EXPLANATION SO THESE ARE CELLS THAT ARE PREFERENTIALLY RESPONDING TO CERTAIN ORIENTATIONS OF THE MOVING BAR. AND HERE WE HAVE MORE THAN THESE 2, AND THERE HAVE BEEN PAPERS IN THE MEAN TIME SINCE WE PUBLISHED THIS, THAT SHOW THAT ORIENTATIONS SEEM TO BE ALSO QUITE VARIABLE OR DIVERSE IN THE RETINA. FINALLY WE HAVE THESE CELLS THAT ARE OPPRESSED BECAUSE WHATEVER WE DO THEY ARE ALWAYS REDUCING THE SPIKING ACTIVITY. AND HERE THESE SEEM TO BE MORE THAN THESE 2 TYPES HERE, PRESCRIBINGENT. SO, WE THINK THAT THE STIMULI THAT WE CHOSE WHICH WORKED NICELY TO SEPARATE THESE GROUPS HERE, JUST ARE NOT WELL ENOUGH CHOSEN TO SEPARATE THESE FURTHER GROUPS HERE. SO THIS JUST THAT WE HAVE NOT ONLY 32 TYPES BUT SOMETHING LIKE 40 TYPES IN THE MOUSE RETINA. AND IN THE MEAN TIME THIS SEEMS TO CORRELATE WHAT OTHER PEOPLE FIND. SO, THE STUDY GAVE US SOME IDEA, ABOUT HOW MANY CHANNELS WE HAVE AND THIS IS OUR CURRENT THINKING THAT ABOUT 40 DIFFERENT CHANNES FROM THE MOUSE EYE TO THE MOUSE BRAIN. SO BUT HOW IS THIS DIVERSITY OF FUNCTION SIGNALING ARISING IN THE RETINA. FOR THIS WE LOOK AT INPUT AND THIS WAS RECENTLY PUBLISHED AS WELL. SO HERE WE NOW START LOOKING AT THE INPUTS TO THE GANGLION CELLS AT THE LEVEL OF THE BIPOLAR CELL, SO THIS SAY CROSS SECTION OF THE RETINA, YOU HAVE THE PHOTO RECEPTORS HERE AND THEY ARE PASSING ON THESE CELLS WHICH RELAY THE OUTPUT OF THE PHOTO RECEPTORS TO THE INNER RETINA AND HERE WE HAVE THE INTERESTING CIRCUITRYS THAT THAT PROBABLY DO ALL THE WORK IN THE FUTURE RECOGNITION IN THE RETINA. SO WE WANT TO UNDERSTAND HOW THE INPUTS FROM THESE BIPOLAR CELLS śWE SEE AT THE GANGLION CELLTHAT LEVEL. BY POLEAR CELLS HAVE THE ADVANTAGE THAT THEY ARE KNOWN VERY WELL ALREADY SO IN THE MOUSE, THEY ARE 14 DIFFERENT TYPES RECOGNIZED AND THERE'S VERY LITTLE ROOM TO ADD MORE TYPES. SO THIS IS VERY LIKELY THE FINAL ACCOUNT FOR THE CELLS AND THERE'S THINGS LIKE HOW MANY CONES THEY CONTACT, HOW BIG THE RECEPTOR FIELDS ARE AND SO, WE HAVE A VERY GOOD UNDERSTANDING OF BIPOLAR CELLS SO FAR. BUT FUMPLEGDZALLY BIPOLAR CELLS HAVE BEEN DESCRIBED IN SEPARATE STUDIES WHEN THEY FOCUS ON SINGLE CELL TYPES AND IT'S NOT EASY TOW COMPARE THE CELLS BECAUSE THEY ARE MAXIMALLY DIFFERENT. SO WE WANT TO HAVE A COMPLET ACCOUNT OF THE SELECTIVITY IN THE RETINA TO GET THE INPUTS THAT THE GANGLION CELLS RECEIVE. AND TO DO SO, WE USED A DIFFERENT APPROACH, WE USE A GLUTAMATE SENSOR, INCLUDING THE SENSOR, CLUE SNIFFER THAT WE EXPRESS UBIQUITOUSLY IN THE RETINA. AND IF YOU DO THIS DUE TO OUR INJECTION TECHNIQUE, YOU SEE THE EXPRESSION HERE IN THE VASAL PART OF THE RETINA BUT WHEN WE LOOK HERE, WE HAVE THE CROSS SECTION OF THE RETINA AND THE LAYER AND THE PART BY THE POLEAR CELLS QUANTIFY AND WE HAVE NICE LABELING HERE AND THIS SIGNALING GIVES US THE GLUTAMATE RELEASE IN THIS PART OF THE RETINA AND SINCE BIPOLAR CELLS, THE THAT ARE THE MAIN EXCITATORY NEURONS IN THIS PART OF THE RETINA WHEN WE MEASURE GLUTAMATE SIGNALS THIS SHOULD REFLECT THE ACTIVITY OF THE EXCITATORY DRIVE IN THE RETINA THROUGH THE BIPOLAR CELLS. AND WE USE IN ADDITION MARKERS TO KNOW WHERE EXACTLY WE ARE IN THE IPL BECAUSE AS YOU CAN SEE HERE THE CELLS STRATIFIED AT DIFFERENT LEVELS SO WE WANT TO KNOW WHAT HAPPENS AT THE LEVEL OF DIFFERENT PILOT PROJECT POLEAR CELL TYPES. SO THEN WE MEASURE THE GLUTAMATE SIGNALS AND THEY LOOK SOMETHING LIKE THIS, SO WE'RE LOOKING AT THIS IPL IN THE STRONG STRIPE, SO YOU SEE THE RESPONSE TO THE FLICKERING CHECKER BOORT AND YOU SEE ACTIVITY SHOWING UP HERE AND HERE AND THESE ARE THE TERMS OF BIPOLAR CELLS LIGHTENING UP AT FIELD. WE CAN THEN USE A METHOD TO IDENTIFY INDIVIDUAL RISE OR TERMINALS SO THIS IS THE SAME FIELD I'VE SHOWN YOU BEFORE AND THE ACTIVITY HAPPEN IN THESE REGIONS HERE AND TO CONVINCE YOU, WE WANT TO CHECK WHETHER THESE ARE REALLY BIPOLAR CELL TERMINALS WE LOOKED INTO THE RECEPTOR FIELDS. SO THIS IS AN EXAMPLE FOR 1 OF THESE LITTLE REGIONS HERE, THIS IS ABOUT 2-MICRONS IN DISCIPLINARY AMTERAND THIS IS THE ACTIVITY IN THE GLUTAMATE LEVEL TO SIMILAR STIMULI AS WE PRESENTED TO THE GANGLION CELLS ALREADY. SO THIS IS THE LOCAL JOB, THIS IS CHANGE IN LIFE LEVEL, FOR FREQUENCY AND CONTRAST BUT? A VERY RESTRICTED SPOT DIRECTLY ON THE POLEAR CELLS, AND THIS IS THE VERSION OF THIS THAT WE SHOWED THAT THE GANGLION CELLS BUT WE ALSO SHOWED NOISE AND OTHER THINGS. SO AS YOU SEE HERE THE SIGNALS ARE BEAUTIFUL. SO THE GLUTAMATE SIGNALS HAVE HIGH NOISE AND A VERY NICE TIME COURSE HERE. SO THIS IS A SIGNAL OF ONLY A FEW PIXELS HERE. AND THEY HAVE VERY SPECIFIC RESPONSES SO THIS IS AN UNRESPONSE TO LIGHT, VERY NICE FREQUENCY RESPONSES. SO NOW IF YOU LOOK AT A DIFFERENT OF THESE VERICOSITYS OR REGION OF INTEREST AND COMPARE THEM, WE FIND THAT THERE'S SOME THAT HAVE VERY SIMILAR RESPONSES. SO ALL THE 1S THAT ARE MARKED IN RED HERE, THIS 1, THIS 1, THIS 1. THEY'RE ALL OVER HERE. SO THE RESPONSE IS ALMOST IDENTICAL. THE ASSUMPTION WOULD BE THAT THEY ALL COME FROM THE SAME BIPOLAR CELL TYPE. SINCE THESE ARE SO CLOSE THEY'RE PROBABLY THE SAME BIPOLAR CELLS AND THIS MIGHT BE DIFFERENT BIPOLAR CELL FROM THE SAME TYPE SO JUST THE NEXT LAYER OF THIS ARRAY HERE AND IN THE OPPOSITE WE HAVE THESE 3 GREEN HERE, AND AGAIN THEY CORRELATE VERY STRONGLY IN THE SIGNALS, BUT THE SIGNAL IS DIFFERENT FROM WHAT WE SEE RED WHICH YOU SEE ESPECIALLY IF YOU LOOK AT THESE RESPONSES HERE, WE LOOK THEA THE SPOT AND THIS RESPONSE IS DIFFERENT FROM THIS WOON AND THIS WAY WE CAN SORT THE CELLS AND CLUSTER THEM BY THOSE TYPES. SO TO TEST IF THIS HYPOTHESIS IS TRUE, THAT THIS IS THE SAME CELL, DIFFERENT CELL IN THERE, DIFFERENT TYPES, WE CAN LOOK AT THE RECEPTOR FIELDS AND THE PREDICTION WOULD BE THESE 2 WOULD HAVE THE SAME RECEPTOR FIELDS, THIS HAS A DIFFERENT 1, AND THESE HERE SHOULD OVERLAP THIS 1 IF THEY ARE DIFFERENT TYPES. --THIS IS PROBABLY THE SAME TYPE OF CELL BUT A DIFFERENT MEMBER OF THE MOSAIC. AND FOR THE GREEN RECEPTOR FIELDS THEY SULSIT ON TOP OF EACH OTHER SO THIS IS PROBABLY PART OF THE SAME TERMINAL SYSTEM. SO THIS WAY WE ACQUIRED MANY RISE OF THREAP THOUSAND CHANNELS AND THIS IS THE DATA FOR THE DIFFERENT STIMULI AND THIS IS A SIMILAR APPROACH TO THE GANGLION CELLS ASK SO WE LOOK AT TEMPORAL FEATURES IN THESE RESPONSES TO CLUSTER THEM AND WE LOOK FOR FEATURES IN A DIFFERENT STIMULI AND WE LOOK HERE FOR 1 FEATER WAS FOR EXAMPLE, IF IT RESPONDED TO THE ONSET OF THE LIGHT POLES OR HOW IT RESPONDED TO THE CONTRAST. AND THIS WAS USED TO FIND THE FUNKDZ TYPES. THE DIFFERENCE OF THE GANGLION CELL IS THAT WE KNOW SOMETHING HERE ABOUT THE ANATOMY. SO HERE IN THIS POINT WE INCLUDE INFORMATION ABOUT THE ANATOMY. THIS IS SHOWN HERE, SO, IF YOU RECORD FOR EXAMPLE, SO FAR THE BIPOLAR CELLS WE KNOW WHERE THEY ARE STRETTIFYING IN THE PILOT PROJECT POLEAR LEVEL, SO WE KNOW THAT THE TYPES OF BIPOLAR CELLS WE CAN MEASURE ONLY INCLUDE TYPE 1 AND TYPE 2. WE NEVER FIND A BIPOLAR CELL TYPE 6 THERE,OT OTHER HAND IF WE RECORD HERE WE MIGHT GET 1 OF THESE TYPE 5S OR THE XL OR TYPE 7 BUT NEVER 1 OF THE TYPE 2 CELLS. SO THIS INFORMATION, WILL BE USED TO INCLUDE INTO THE CLUSTERING PROCESS, AND THE LIMITATION OF THIS IS OF COURSE THAT WE ARE RESTRICTED TO THE NUMBER OF CELL TYPES BECAUSE YOU PUT THE NUMBER OF CELL TYPES THAT WE EXPECT IN THERE,OT OTHER HAND WE KNOW THAT THEY ARE PROBABLY ALREADY COMPLETE. SO THIS INCLUDES ALL THE BIPOLAR CELLS KNOWN. THIS DOESN'T INCLUDE CELLS THAT HAVE BEEN DESCRIBED LATER SO THEY RELEASE GLUTAMATE AND THEIR SIGNALS ARE INCLUDED THERE BUT WE HAVEN'T CONSIDERED THEM. BUT NONETHELESS, THE BIPOLAR CELL GLUTAMATE TRIES THE MOST IMPORTANT COMPONENT IN THIS AREA OF THE RETINA. SO IF YOU USE THIS INFORMATION, THISSEN WE CAN CLUSTER THE DATA INTO THESE TYPES HERE, AND THEN YOU CAN SEE, ALSO THE AVERAGE PROFILES OF THE RESPONSES TO THE DIFFERENT STIMULI, FOR EXAMPLE THIS, IS AN OFF-BIPOLAR CELL, THE POINTING OF THE STRONG RESPONSE TO THE OFFSTEP HERE, THIS IS AN ONBIPOLAR CELL TYPE AND THIS IS THE COMPLETE COLLECTION OF ALL THE BIPOLAR CELL TYPES. MEASURED IN THE SAME TISSUE UNDER THE SAME CONDITIONS. SO IF WE NOW LOOK AT THE INTRIEWKS OF SIGNALS ACROSS THE IPL, THIS IS AN ILLUSTRATION, HOW DO CELLS RESPOND TO THAT STIMULUS BY THAT TYPE, SO THIS IS THE TYPE BIPOLAR CELL 1, THIS IS THE IPL DEPTH AND YOU SEE NOW HOW THE SIGNAL IS CODED SO THIS IS THE INPUT THAT COMES FROM THE BIPOLAR CELLS. TO THIS SLIDE HERE. SO CAN YOU HONESTLY SEE HOW THEY'RE RESPONDING TO DIFFERENT PHAES OF THIS. OKAY, SO, WHEN WE HAD THE DATA RESERVED, WE THOUGHT OH THAT'S GREAT. NOW WE HAVE THE GANGLION CELLS NOW WE CAN CONTINUE BUT WHEN WE LOOK AT RESPONSES HERE, IF WE LOOK AT THE OFFBIPOLAR CELLS THAT WE HAVE THESE 5 TYPES THEY LOOK ALMOST THE SAME WHEN YOU LOOK AT THE STIMULUS, SO HERE YOU SEE BARELY DIFFERENCE, THIS IS MAYBE A BIT MORE SUSTAINED THAN THIS 1. BUT ALSO THE CELLS THAT LOOK ALL THE SAME. SO WHY ARE THEY LOOKING FORWARD TO 14 DIFFERENT BIPOLAR CELLS TO GO OFF THE SIGNALS. BUT WHEN YOU LOOK HERE, THE RESPONSE TO THE BIG STIMULI, HERE THEY BECOME QUITE DIFFERENT. IN THIS WE LOOKED CLOSER. SEE THIS IS AN EXAMPLE, THIS TYPE 6 CELL AND TYPE 9 CELL FOR THE SMALL STIMULUS, THE RESPONSES ARE SIMILAR, SO THAT CORRELATION IS ALMOST--ALMOST 1. IT'S .9. SO THEY RESPOND THE SAME, IF YOU USE THE SMALL POT SPOT ON THE RECEPTOR FIELD. BUT AS SOON AS YOU INCREASE THE SYSTEM, THEN THE STIMULUS FALLS A PART, THEN THIS IS THE TYPE SPOT, THE TYPE 9 AND HERE YOU SEE THE CORRELATION DECREASE IS QUITE A LOT. SO THE SIZE OF THE STIMULUS MAKES THE BIPOLAR CELLS DIFFERENT FROM EACH OTHER. THE SAME IS TRUE FOR THE OFFTYPES HERE, THIS IS OFFTYPE A AND 22. VERY SIMILAR WHEN YOU PLAYED A SMALL SPOT, VERY DIFFERENT WHEN YOU START MAKING A BIGGER [INDISCERNIBLE] AND WE CAN QUANTIFY THIS AND THIS IS TRUE FOR ALL BIPOLAR CELL TYPES. ALL OF THE CELLS BECOME MORE DIFFERENT WHEN YOU USE LARGER STIMULI. SO WHY IS THIS THE CASE? SO WITH THE SMALL SPOT, THIS IS PROBABLY MAINLY STIMULATING THE DEPPED RETIREDDIC THAT COMES SOON AS WE MAKE THE STIMULUS LARGER IT INCLUDES SURROUNDING CIRCUITRYS AS WELL AND THIS IS MAINLY INPUT FROM IMMIGRANT CELLS SO THIS LATERAL INPUT FROM THE ENDOCRINE CELL SEEMS TO MAKE THE CELLS MORE DIFFERENT. THE OWRT PUT OF THE CELLS MORE DIFFERENT. IN THIS YOU CAN LOOK NICELY WITH PHARMACOLOGY IN THE RETINA AT LEAST AND THE MAMMALIAN RETINA, THERE ARE 2 GROUPS OF IMMIGRANT CELLS THAT CAN DIFFERENTIATE REQUEST PHARMACOLOGY, SO THAT WE HAVE THE SMALL FIELD, THE ENDOCRINE CELLS THEY HAVE THE TINY AND YOU CAN BLOCK THEM WITH STRICT 19 FOR EXAMPLE, AND WE HAVE THESE WIDE FIELDS CELLS AND THEY--AND THEIR INPUT CAN BE BLOCKED OR THE TOXIN FOR EXAMPLE. SO, WE CAN DISTINGUISH BETWEEN THEIR 2 INPUTS ON--ADJUST AND MEASURE THEIR INFLUENCEOT BIPOLAR CELL. SO IN THIS CASE, WE APPLIED THIS COMBINATION OF DRUGS, AND THIS DRUGS IN GABA C RECEPTORS SO IT BASICALLY TAKES THE WHITE OUT OF THE CIRCUIT AND WE HAVE ONLY THESE CELLS LEFT HERE. AND WHEN WE DO THIS, WE SEE THAT THE RESPONSE TO THE SMALL SPOTOT LARGE SPOT BECOME MORE SIMILAR. YEAH? SO HERE IN A DIFFERENT THEY BECOME MORE SIMILAR. NOW THESE EBD O KRIN CELLS ARE DETECTED BUT SWITCHED OFF THE ENDOCRINE CELLS NOW THE RESPONSES GET MUCH MORE DIFFERENT. SO THIS IS A RESPONSE BEFORE THE DRUG AND HERE THEY SURROUND RESPONSE WITH THE LARGEST ALMOST AS IT APPEARS COMPLETELY. SO THIS IS THE LARGE CELL,OT BIPOLAR CELLS AND MODULATE RESPONSES AND THIS HAS BEEN SHOWN ALREADY EARLIER. AND THEY ARE REGULATING THE LARGER CELLS SO THEY GATE THE CELLS ON THE BIPOLAR CELLS. SO IN OTHER WORDS WHEN WE LOOK AT THESE RESPONSES AGAIN, BLOCKING THE INHIBITORY SURROUND, SWITCHING OFF THE ENDOCRINE CELLS MAKES THE CELLS VERY SIMILAR. SO THIS IS BEFORE THE TRUCK A RESPONSE TO THE SMALL SPOT AND THE LARGE SPOT, VERY DIFFERENT RESPONSES, WHEN WE BLOCK GABAERGIC CELLS, THE RESPONSES OF THE STIMULI IS ALMOST THE SAME SO THE DIFFERENCES COMPLETELY DISAPPEAR. ON THE OTHER HAND THESE--WHEN WE BLOCK THE SMALL CELLS WITH STRYCHNINE, WE TAKE AWAY ANY INHIBITION ON THE LARGE FIELD OF EPPED O KRIN CELLS CAN COMPLETELY EXHAUST THE EFFECT ON THE CELL TERMINALS SO THE DIFFERENCES BETWEEN THE RESPONSES BECOME EVEN LARGER. SO HERE IN THIS CASE, THEY EVEN SLIGHTLY ANTICORRELATED. SO THE SMALL IMMIGRANT CELLS THEY--THEY REGULATE HOW MUCH LARGE ENDOCRINE CELLS CONTRIBUTE TO THE BIPOLAR CELL RESPONSE AND AGAIN THIS CAN BE QUANTIFIED AND IT'S A SAME FOR ALL OF BIPOLAR CELLS. AND INTERESTINGLY, WE CAN ALSO STIMULATE THE SURROUND ITSELF AND WE GET A STRONG MODULATION OF THE BIPOLAR CELL OUTPUT, SO WHEN YOU ALONG OF BIPOLAR CELLS YOU ALWAYS THINK THEY RECEIVE INPUT FROM THE PHOTO RECEPTORS AND THE RETINA AND THEN, THE ENDOCRINE CELLS MOTTULATE AND SHAPE THIS BUT IT'S MORE SHAPING LIKE--A STRONG INFLUENCE BUT THIS EXPERIMENT SHOWS THAT YOU CAN DRIVE GLUTAMATE RELEASE FROM BIPOLAR CELLS ALREADY BY JUST STIMULATING THE SURROUND. YOU DON'T NEED THE DENDRITES SO CAN YOU DRIVE THE OUTPUT SO THE INTERPLAY BETWEEN THE EXCITATION COMES IN THROUGH THE DENDRITES AND SURROUND INHIBITION AND THIS IS WHAT MAKES BIPOLAR CELL CHANNELS REALLY DIFFERENT AND SPECIFIC. AND IT MAKES SENSE BECAUSE USUALLY IN THE STIMULI, YOU DON'T HAVE LITTLE SPOTS DIRECTLY ON THE BIPOLAR CELLS BUT YOU HAVE LARGER EXTENDED SPOTS AND IF YOU USE LARGE STIMULI OR MORE STRUCTURES STIMULI THAN THE CELLS GET ALSO THE SPECIFIC RESPONSES. SO FROM THIS DATA WE CAN NOW DRAW INFORMATION ABOUT THE DIFFERENT BIPOLAR CELL CHANNELS AND I DON'T WANT TO GO INTO THIS IN DETAIL, I WANT TO POINT OUT 1 THING I FOUND VERY INTERESTING, SO WE HAVE DIFFERENT FACTORS HERE, INDEXES THAT INDICATE WHAT DIFFERENT TYPES AND DIFFERENT LEVELS MUCH THE IPL DO. HERE WE TALK A LOT OF INDICES THAT DESCRIBE THE PROCESSING OF THE CELLS. SO HIGH FREQUENCY INDEX, HOW TRANSIENT THE CELLS ARE IF THERE'S A DELAY IN THE RESPONSE AND THEY ALL VARY ACROSS THE IPL SO FOR THE DIFFERENT TYPES BUT THEY'RE MOSTLY UNCORRELATED SO A SLOW CELL IS NOT NECESSARILY TRANSIENT OR A FAST CELL IS NOT NECESSARILY DISTAINED SO THERE'S A LOT OF TEMPORAL NEVERLINGS IN THE BIPOLAR CELL OUTPUT. AND INTERESTINGLY, IT'S NOT SO MUCH THE INPUT THAT DETERMINING DETERMINING--DETERMINES THE PHOTO RECEPTOR AND DETERMINING THE TEMPORAL PROPERTIES OF THE BIPOLAR OUTPUT BUT IT'S REALLY THE INTERPLAY, THE DIFFERENT TIMING OF EXCITE ATORY INPUT AND INPUT FROM THE ENDOCRINE CELL. OKAY, SO FROM THIS THE SUMMARY CAN BE, WE CAN SHOW THERE ARE DISCORDANT TYPES ARE FUNCTIONALLY DIVERSE AND THESE ARE THE CHANNELS AND THE INTERACTION WLT SURROUND, THE SPATIAL INTERACTION DRIVES IN A WAY THEY BECOME VERY DIFFERENT SO THAT THEY CREATE THIS 14 DIFFERENT FUNCTION CHANNELS. OKAY, SO NOW WE HAVE BIPOLAR CELL INPUTS AND GANGLION CELL OUTPUTS SO WHY DON'T WE MAKE A MODEL AND TRY TO UNDERSTAND HOW WE CAN BUILD THE OUTPUTS FROM DIFFERENT BIPOLAR CELL INPUTS. THIS WOULD BE VERY TEMPTING SO THIS IS THE CIRC CUTRY THAT WE'RE TALKING ABOUT, THE BIPOLAR CELLS GET THE ENDOCRINE CELLS AND THE GANGLION CELLS, AND THIS ACTUALLY INCLUDES ALREADY, THE CELL INPUT THAT GOES DIRECTLY ON TO THE TERMINAL OF THE CELLS AS I SHOWED YOU. AND HERE WE HAVE THE UT PUTS HERE, AND SOMEWHERE WE GET EQUIVALENT OF SMIEKING SO WHAT DO WE NEED TO CONNECT THIS, WE NEED INFORMATION AND WE NEED TO KNOW WHICH BIPOLAR CELL GOES ON WHICH CELL. AND WE NEED TO KNOW WHAT ENDOCRINE CELLS CONTRIBUTE DIRECTLY TO THE GANGLION CELLS BECAUSE THEY ALSO INHIBIT THE CELLS AND WHAT DOES IT DO WITH THE SIGNAL. SO WHAT DOES THE DENDRITIC CELL RIDDIC CELL DO TO THE SIGNAL BEFORE IT ENDS UP AS A SPIKING OUTPUT. AND THE DIFFICULTY, IT SOUNDS EASY BUT THE DIFFICULTY IS MAINLY HERE IN THE ENDOCRINE CELL CONTRIBUTION. AND THE REASON FOR THIS IS, SHOWN HERE, SO THIS IS A PART OF THE MOUSE RETINA. CONES, RODS, VERY SIMPLE, 2 TYPES OF CONES 1 TYPE OF ROD, 1 TYPE, VERY GOOD. BIPOLAR CELLS ARE VERY GOOD. 14 TYPES, GANGLION CELLS, PROBABLY SOMETHING LIKE 45. [INDISCERNIBLE] I LOST THE MIC. THEY ARE PROBABLY EASY MANY TYPES OF ENDOCRINE CELLS AS THERE ARE TYPES OF GANGLION CELLS AND HERE WE DON'T HAVE A GOOD HANDLE FOR THIS YET. WE CAN SWITCH ON CERTAIN GROUPS AND WE CAN LOOK AT CERTAIN TRANSGENIC TYPES BUT THERE'S NO METHOD YET TO UNDERSTAND TO GET FOR EXAMPLE, THIS DIFFUSION OF INHIBITION ACROSS THE IPL, AND THIS IS SOMETHING THAT WE'RE VERY INTERESTED TO LOOK AT. SO OUR HUNDRED APPROACH TO THIS IS TRYING TO--I DESCRIBE THIS NOW. THIS IS NOW VERY EARLY DAYS, THIS IS MOST OF THE FETUS HAPPENED--MAYBE LAST WEEK SO PLEASE BE NICE TO ME. SO THE QUESTION IS HERE, WE TAKE THIS TYPE OF CELL, IT'S A CELL THAT'S PRESENT IN MOST MEMOS, WE HAVE A COMPLETE FUNCTION PROFILE OF IT, SO HOW CAN WE KNOW WHICH BIPOLAR CELLS HAVE INPUT IN HERE, SO WE--HERE THIS IS 1 EXAMPLE. THIS IS A COLLABORATION WITH RACHEL'S GROUP AND SHE LABELS GANGLION CELLS AND BIPOLAR CELLS WITH THE DIFFERENT UNIVERSE AND THE MARKERS AND THESE ARE PICTURES THAT ILLUSTRATE THIS, THIS IS PRESYNAPTIC MARKERS, THIS IS THE SPECIFIC TYPE OF BIPOLAR CELL AND SHE CAN LOOK FOR CONNECTIONS BETWEEN THIS TYPE OF BIPOLAR CELL ANDLET GANGLION CELL AND HERE FOR EXAMPLE, YOU SEE THE CONTEXT OF THIS TYPE, BIPOLAR CELL MAKES TO THIS TRANSIENT OF OF CELLS SO VERY LITTLE IF YOU LOOK AT A DIFFERENT CELL TYPE, YOU FIND MANY CONNECTIONS AND THIS WAY YOU GET A CONTRIBUTION PROFILE SO MOST OF THIS GETS TYPE 3 A AND SOME INPUT FROM TYPE 4, SO THIS WE CAN USE BUT WE CAN ALSO USE THE CONNECTOMIC DATA AVAILABLE THROUGH HERE, WE CONSTRUCTION. SO THIS WOULD BE NOW THE CONTRIBUTION OF THE BIPOLAR CELLS, THAT WE GET INTO THE CIRCUITRY AND HERE'S THE OUTPUT. SO HOW CAN WE CONNECT THIS NOW? SO NOW WHAT WE TRY TO DO IS IMAGE THE CELLS TO UNDERSTAND HOW THE BIPOLAR CELL AND THE ENDOCRINE CELL THAT GOES IN THERE, IS SHAPING THE SIGNAL SO WE CAN USE THIS AS A FUNCTION TO CONNECT THIS OUTPUT TO THIS OUTPUT HERE AND THIS IS AS I SAID VERY EARLY PRELIMINARY DATA. THIS DATA WAS MAINLY COLLECTED BY YANG LI, SHE A PROMISING Ph.D. STUDENT IN MY LAB AND IT'S IN COLLABORATION WITH [INDISCERNIBLE] AS WELL. SO WHAT SHE DOES, SHE FILLS GANGLION CELLS WITH OGB, THE INDICATOR WITH SHARP ELECTRODES WITH THE METHOD SHE LEARNED FROM CHAD'S LAB AND WE ARE THANKFUL FOR THAT. SO THIS IS A BEAUTIFUL CELL AND YOU CAN IMAGE THE ACTIVITY QUITE NICELY AND SHE TAKES THESE REGIONS OF THIS RECORDING FIELDS AND MEASURES ACTIVITY OF THESE DENDRITES AND DISPLAYS THIS NOISE, AND THIS IS AN EXAMPLE SIGNAL AND THEN SHE CONSTRUCTS THE WHOLE CELL AND GETS A 3D MODEL SO THAT SHE CAN LOCATE THE REGION OF INTERESTOT DENDRITES AND STUDY THE RELATIONSHIP. AND THIS IS COMPARISON HERE FOR THE PROFILE FROM THE EARLY WORK. THEN SHE CAN GET THE RECEPTOR FIELD STRUCTURE OF EACH OF THESE AND DESCRIBE THIS HERE AS IT FITS AND SHE CAN LOOK AT TIME ANALYSIS AND SHE LOOKS CLOSELY SO THIS IS A TYPICAL CELL IN THIS CASE AND THE COLOR INDICATES HOW FAR THIS IS FROM THE STUDIES OF MULTIPLE ENDOCRINE AYELLOW ARE 1S FROM FIRST AWAY FROM THE STUDIES OF MULTIPLE ENDOCRINIA AND THE BLUE 1S ARE VERY CLOSE. AND NOW CAN YOU LOOK AT RECEPTOR FIELDS OF ALL THESE AND THERE'S 1 THING THAT COMES TO MIND IMMEDIATELY AND THEY LOOK AT THE CLOSER YOU GET TO THE TIPS, IF WE COMPARE FOR EXAMPLE RECEPTOR FIELDS HERE, TO THIS 1 HERE THIS IS MUCH BIGGER HERE COMPARED TO THIS 1 RECORDED AT THIS POSITION, AND MAYBE IF WE GO FURTHER TO THE TIP, WE MEASURE THE BIPOLAR CELL AND WHEN WE LOOK AT THE AREA OF THE RECEPTOR FIELD AS A FUNCTION OF DISTANCE OF THE RIDE TO THE STUDIES OF MULTIPLE ENDOCRINIA, SO THIS IS IN THE REGION SO THE RECEPTOR FIELDS ARE CLOSER TO THE STUDIES OF MULTIPLE ENDOCRINIA AND THEY GET SMALL AND THEN THEY GET TO A PLATEAU AND THE TYPICAL SIZE OF RECEPTOR FIELD SMSHED WITH TECHNIQUES--MEASURED WITH TECHNIQUE SYSTEM SOMEWHERE IN HERE. SO WE'RE GETTING CLOSER TO THE BIPOLAR AREA. SO HERE WE MIGHT INDGREAT JUST THE MORE--THE FURTHER YOU GO, THE MORE THEY ARE INTEGRATED. SO WE LOOKED AT DIFFERENT CELLS AS WELL AND IT'S HARD TO FIND THE SIMILAR THING, SO THIS IS A SMALL BIPOLAR GANGLION CELL AND TRY TO FIND WHERE THE TRANSIENT CELL IS STRATIFYING AND IT'S PROBABLY A MINICELL THAT WE DISCOVERED IN THIS LARGE SEARCH AND HERE, RECEPTOR FIELDS LOOK MUCH DIFFERENT. SO THEY ALL SHIFTED TOWARDS THE STUDIES OF MULTIPLE ENDOCRINIA, NO MATTER HOW FAR YOU GO OUT TO THE DENDRITIC CELL RIDDIC TIP AND THEY ARE ALSO VERY SIMILAR IN SIZE, SO THESE CELLS SEEM TO PROCESS INFORMATION ON THE DENDRITES DIFFERENT COMPARED TO THIS LARGER CELL HERE. AND WE CAN QUANTIFY THIS, WITH THE 6 CELLS HERE, THERE IS TYPICAL DECREASE IN DENDRITIC OR IN RECEPTOR FIELD SIZE, OVER THE DISTANCE FROM THE STUDIES OF MULTIPLE ENDOCRINIA AND HERE ARE 3 OF THESE SMALL CELLS AND HERE THE RECEPTOR FIELD SIZE STAYS MAINLY THE SAME. IT'S VERY--NOT THIS DROP HERE IN THIS SIZE SO THORS LOOK, THIS IS THE MORPHOLOGYS IN A MORE SYSTEMATIC WAY, SO THEY ALL DIGITIZED AND WE CAN DETERMINE ALSO THE DISTANCES BETWEEN 2 EYES ALONG THE STUDIES OF MULTIPLE ENDOCRNAL OR USE INSTEAD OF USE--USE INSTEAD OF THE RADIO DISTANCE AND SO ON. AND WE ALSO LOOK AT OVERLAP BETWEEN RECEPTOR FIELDS OF 2 FOR EXAMPLE, AS DEFINED HERE. THIS IS DISTANCE BETWEEN THESE AND WE NOW WANT TO LOOK AT TO DESCRIBE WHAT HAPPENS IN THESE CELLS. THERE'S ANOTHER BETWEEN THE 2. SO 1 INTERESTING OUTCOME ALREADY IS A PLOT I SHOWED YOU BEFORE, AND HERE'S A RECEPTOR FIELD WITH THE AREA DISTANCE AND THE DIRECT LINE FROM THIS TO THE STUDIES OF MULTIPLE ENDOCRINIA AND THE ESTIMATE OF THE RECEPTOR FIELD SIZE WAS [INDISCERNIBLE] TO THE REST OF THE FIELD SO WHEN WE DO THIS NOW. WITH RECEPTOR FIELDS BUT THEY MAY BE PIE SHAPED AND SO ON. BUT IF YOU USE THE DISTANCE, AND NOT THE DIRECT DISTANCE, THE SHAPE LOOKS DIFFERENT IT'S THE MUCH BIGGER DIFFERENCE BETWEEN THE LARGE CELLS HERE AND THE SMALL CELLS HERE. ANOTHER REPRESENTATION WE'RE PLAYING WITH, IS PLAYING WITH THE OVERLAP INDEX AND SO YELLOW MEANS HIGH OVERLAP BETWEEN THE RECEPTOR FIELDS, LIKE HERE FOR EXAMPLE, AND THIS DARK COLOR MEANS OVERLOAD THE NEXT AS A FUNCTION OF ANGLE BETWEEN THE DENDRITES AND THE DENDRITIC CELL RIDDIC DISTANCE TO THE STUDIES OF MULTIPLE ENDOCRINIA. SO THIS IS--TRYING TO UNDERSTAND LIKE HERE, THE CELLS ARE ON THE SAME BRANCH SO THE ANGLE IS SMALL. AND IF THEY ARE ON THE SAME BRANCH AND THIS CELL, THEY ALWAYS OVERLAP RECEPTOR FIELDS. THIS ACTS--THIS IS THE SAME BRANCH THIS, IS DIFFERENT BRANCH, THIS IS CLOSE TO THE STUDIES OF MULTIPLE ENDOCRINIA HERE, THIS IS JUST THE DENDRITE SO IF THEY'RE CLOSE TO THE STUDIES OF MULTIPLE ENDOCRINIA OR IN THE SAME BRANCH, THEY LARGELY OVERLAPPED THE RECEPTOR FIELDS. IF YOU LOOK FOR THIS AT THE SMALL CELL HERE, WE ALMOST ALWAYS HAVE OVERLAP BETWEEN THE RECEPTOR FIELDS AND AND EVERYTHING IS COMPRESSED HERE. SO THIS--SUGGESTS THAT THERE THERE'S A DIFFERENT DENDRITIC PROCESS OF THE CELLS. AND WE ALSO LOOK AT DIFFERENT FACTORS AND THIS IS THE DENDRITIC DISTANCE WEAN 2 SO YOU CAN PUT ALL SORTS OF THINGS NOW AND WE'RE TRYING TO MAKE SENSE OF THIS. OKAY SO WHAT WE HOPE ARE THESE KINDS OF MEASUREMENTS, HOW TO COMBINE THE CELLULAR INPUT IN A WAY WE CAN EXPLAIN GANGLION CELL OUTPUT AND THAT WE ALSO UNDERSTAND A LITTLE BIT ABOUT THE CONTRIBUTION OF ENDOCRINE CELLS THAT SHOULD BE REPRESENTED HERE IN THIS DENDRITIC MEASUREMENT, TO UNDERSTAND WHETHER WE CAN DESCRIBE THE CIRCUITRYS. HOW AM I ON TIME? STILL? --MICE ARE NOT VERY UNIFORM. AND THE FACT THAT EVERY SPECIES HAVE DIFFERENT NEEDS AND YOU HAVE TO CONSIDER THE ANIMAL IN THE ECOLOGICAL ENVIRONMENT AND THE VISUAL STIMULI THEY NEED TO DEIT ECTOMYOSIN AND IN THIS CASE, ALL WE NEED TO SEE IS THE MOUSE AND THE GRASS, SO IT NEEDS HIGH SPATIAL RESOLUTION AND THIS WANTS TO SEE A PREDATOR SHOWING UP ON THIS GUY. SO THE FOLLOWING SLIDES I WANT TO SHOW A BIT THAT WE ARE--WE HAVE TO BE CAREFUL INTERPRETING THE CELLS AND WE HAVE TO THINK MORE ABOUT WHERE WE RECORDOT RETINA. SO THIS IS THE DIFFERENCE IN THE SPECIES. THIS IS ALSO DIFFERENT IN THE SPECIES AND IMPLEMENTATION OF SURGERY AND THIS IS GREAT WORK FROM CHAD'S LAB IN COMBINATION WITH KEVIN A LAB WHERE THEY SHOWED THAT THE SAME COMP CUEITATION WORK, IN THE RETINA, LIKE DIRECTIONS AND SELECTIVITY AND THE PROFILE, SO THE RANGE OF DETECTED SPEEDS ACROSS THE IMENT LESMATION NEEDS TO BE CHANGED WITH SPECIES BECAUSE DIFFERENT SPECIES HAVE DIFFERENT EYE SIZES SO NOT ONLY THE NEEDS OF THE SPECYINGS NEED TO BE TAKE KNOW INTO CONSIDERATION BUT ALSO COMMON DIFFERENCES LIKE DIFFERENCES IN EYE SIGHT. SO IF YOU FIND THE IN YOUITATIONS OF THE [INDISCERNIBLE], IT DOESN'T MEAN THERE ARE ALSO DIFFERENT FUNCTIONS THAT MIGHT JUST REFLECT THE NEED OF THE IMPLEMENTATION. SO, MICE WHAT MAKES MICE COMPLICATED IS THAT THEY ARE ONLY THE DORSAL RETINA LOOKS LIKE THE NORMAL MAMMALIAN RETINA. YOU HAVE A SMALL NUMBER OF CONES AND MOST OF THE CONES ARE GREEN. BUT FURTHER YOU GO TO THE VENTRAL HALF OF THE RETINA, THEY EXPRESS BOTH OF THOSE SO BECOME MOST SENSITIVE. SO IN TERMS OF COLOR VISION, THIS AREA LOOKS NORMALLY HERE, THERE'S SOMETHING COMPROMISED SO WHY DOES THE MOUSE RETINA, HAVE THIS HIGH EXPRESSION OF THEOXIN IN THE VENTRAL RETINA AND THIS IS NOT TYPICAL OF THE MOUSE, IT EXISTS IN RABBITS AND HIGHINAS AND SO ON. SO WHY DO YOU NEEZ THIS INTRIEWKS--DISTRIBUTION IN THE VENT RAM RETINAL. IT USES TO DETECT THE GRASS BECAUSE IT'S GREEN AND SKY BECAUSE IT'S BLUE, AND SO SO MIGHT BE USED TO DETECT AND THAL WAY, AND SOME TIME AGO, WE LOOKED AT PHOTO RECEPTOR OUTPUT ESPECIALLY FOR THIS QUESTION TO SEE WHETHER THERE'S SOMETHING IN THE OUTPUT OF THE BLUE CONES THAT ARE HERE IN THE VENTRAL RETINA, THAT MAKE THIS IS TASK HIT EASIER. AND I WANT TO SHOW THE MEASUREMENTS IN THE DETAIL BUT THE RESULT WAS IF WE DISPLAY DIFFERENT SPOTS FOR POTENT STATE O RECEPTORS SO DARK SPOT MEANING SOMETHING LIKE A DARK PREDATOR FOR THIS KIND, SMM NEVER FIND A BRIGHT BIRD IN FRONT OF THE SKY, THIS WOULD BE--THIS WOULD BE REPRESENT SENTED BY THE BRIGHT SPOT HERE. SO THE M-CONES SITTING HERE, THEY RESPOND SYMMETRICALLY, THEY RESPOND THE SAME WAY. SO THEY'RE LOOKING. BUT IF WE LOOK AT THESE THAT LOOK UP TO THE SKY, THEY PREFERENTIALLY ENCODE THE DARK CONTRAST SO THEY RESPOND TO THIS KIND OF CONTRAST MUCH BETTER AND THIS KIND OF CONTRAST. SO IT SUGJEFFS ALREADY THE CONES IN THIS PART OF THE RETINA THEY'RE TUNED TO DETECT SOMETHING IN SOME CONTRAST ON THIS TYPE. AND WE LOOKED INTO--REPRESENTATION OF THESE KIND OF FIELDS AND WE LOOK THROUGH THE FILTERS THAT MOUSE CONES OFFER SO THIS IS THE MOUSE VIEW OF THIS SCENE HERE OF A WOOD SCENE CLOSE TO A FIELD, THE MICE ROLL AROUND AND IF YOU LOOK AT THE CONTRAST, IN THE BLUE BAND OF THE FET O RECEPTORS, VERSUS THE GREEN BAND, THERE'S ACTUALLY A SHIFT TO DARK CONS TRAOF THE. SO THE NATURAL CONTAIN A DARK CONTRAST SHIFT TOWARDS THIS KIND. AND THIS ACTUALLY FITS TO THE PHOTO RECEPTORS. SO THIS HERE IN THE RETINA, THEY LOOK AT THE SKY MUCH BETTER THIS KIND OF CONTRAST DISTRIBUTION AND THESE CONES HERE LOOKING AT THE GROUND MATCH THIS CONTRAST SCRIEWKS. SO NOW IF YOU TAKE THE CELL, THAT'S INTERESTED IN BIRTHS AND W3 CELL THAT HAVE BEEN SUGGESTED IN MANY STUDIES THAT ARE RESPONDED TO SMALL BIRDS FLYING IN THE SKY, WE FIND THE CELL ALSO IN OUR STUDY, SO THEY ARE OUR--GOOD POPULATION. THEY'RE PROBABLY LOCATED HERE IN THE VENTRAL RETINA AS A HIGH CONCENTRATION HERE, SO IF YOU PUT THESE ALTOGETHER, YOU CAN MAYBE START THINK BEING WHRA CERTAIN CELLS SEND TO THE BRAIN OF THE MOUSE. SO THIS WOULD BE THE SCENE IN A HUMAN VIEW, MOUSE LOOKING AT THIS BIRD OF PREY HERE SO WE TAKE AWAY THE RED SCONES AND TOOK THE V-CONES AND THE GREEN CONES HERE AND WE HAVE TAKE INTO ACCOUNT THE THAT THE BLUE CONES PROBABLY DETECT DARK CONTRAST BETTER AND BRIGHT CONTRAST, THIS WOULD BE ENHANCING THE CONTRAST HERE AND WE TAKE THE CELL THAT RESPONDS TO SMALL MOVING OBJECTS HERE LOOKING ALSO AT THE SKY, THIS MIGHT BE A CHANNEL--GANGLION CELL CHANNEL THAT IS IMPORTANT FOR THE MOUSE TO DETECT THE PREDATOR ON THIS. SO THIS IS SUMMARY OF WHAT I SHOWED YOU TODAY, THERE ARE MANY CHANNELS GOING FOR THE MOUSE TO THE BRAIN, APPROXIMATELY 40. SOME OF THIS DIVERSTY IS GENERATED AT THE INTERPLAY BETWEEN POLEAR CELLULAR OUTPUTS AND ENDOCRINE CELL AND INPUT TO THE SIDE SO THIS GABAERGIC AND INDO KRINERGIC CELLS AND WE START TO LOCK AT INTEGRATION PROFILES OF THE CELLS AND WE FIND THEY ARE QUITE INTERESTING DIFFERENCES BETWEEN CELLS THAT ARE CERTIFY THE SAME LEVEL AND THEY ALSO INTEGRATE BIPOLAR CELLS IN A DIFFERENT WAY. WITH THIS I WOULD LIKE TO THANK ALL MY COLLABORATORS. SO THE LATESTEST WORK I SHOWED YOU IS BY LEE RON HERE ON THE BIPOLAR AND GANGLION CELLS AND KATHLEEN STARTED HER OWN GROUP AND SHE STAYED IN TUBING WHICH IS VERY LUCKY FOR ME BUT SHE STARTED HER OWN GROUP WHICH IS GREAT AND MY LONG TIME COLLABORATORS HERE AT THE UNIVERSITY OF SUSSEX, AND ALSO THOSE WHO PROVIDED THE NEW DATA AND I THANK YOU VERY MUCH FOR COMING AND FOR LYNCHING. --LISTENING. [ APPLAUSE ] >> THANK YOU THOMAS ARE THERE ANY QUESTIONS? WE ASK THAT YOU USE THE MICROPHONES? SO EVERYBODY CAN HEAR THE QUESTION. >> GREAT TALK THOMAS SO QUICK QUESTION JUST TO CLARIFY FOR THE LAST BIT, THE VENTRAL PART, YOU ARE LOOKING AT CONE OUTPUT FROM CONES THAT EXPRESS BOTH SOPs AND MOPSYN, SO IT DOES HAVE OPSIN, SO HOW DOES THE RESPONSE GET LOST THERE? >> I THINK THE S-OPSIN IS DOMINATING THE EXPRESSION OF THE CODE A LOT. THE MORE YOU GO TO--THE MOST VENTRAL CODES THEY JUST HAVE S-OPSIN, AND THEY SHOW--THE LEVELS, THERE'S ALMOST NOTHING IN TERMS OF OPSIN, BUT IT'S RIGHT. I'M ALWAYS--THIS IS A PART THAT WE DON'T UNDERSTAND, BECAUSE FROM THE EVOLUTIONARY POINT OF VIEW, THESE CONES IN THE VENTRAL RETINA ARE M-CONES AND THEY JUST FOR SOME REASON EXPRESS ALSO THE S-OPSIN, BUT THEY'RE DIFFERENT. SO I'M NOT SURE WHERE IT'S COMING FROM, BUT IN TALKING ABOUT THIS AGAIN, WE DIDN'T FIND SO FAR A DIFFERENCE BECAUSE IF YOU LOOK AT THE TRUE S-CONES AND THE DORGSAL RETINAL THEY'RE NOT BEHAVING THAT WAY. >> IN THE RESPONSE DOES HAVE INGREDIENTS OR IT'S KIND OF A BINARY FOR SWITCHING? >> GRADEIENT. >> QUICK QUESTION, FOR THE FIRST PART GANGLION CELL TYPE, BRAD SCHWARTZ DESCRIBED A LONG DELAY, VERY UNIQUE, TYPE I DON'T KNOW IF YOU SEE THAT IN YOUR CLASSIFICATION? ABOUT 300 MILLI SECOND DELAY ON RESPONSE, IF THE [INDISCERNIBLE] IS SHORT, YOU MIGHT CLASSIFY IT AS OFF? >> YEAH, IT'S POSSIBLE WE DISCARDED THE CELL BUYS WE TRIED TO COVER THE CELLS, EVERYTHING THAT RESPONDED SLOWLY WE THROUGH OUT AND THEN OF COURSE, THE S-OPSIN STAINING, I THINK WE HAVE 1 OF THE CELLS WE DISCARDED BASED ON NOISE OR NOT RESPONDING TO OUR STIMULI AND IT'S POSSIBLE [INDISCERNIBLE]. YEAH. I'LL ASK A QUESTION WHILE PAUL IS GOING TO CHRIS--GLIES NERNLGIC ENDOCRINE CELLS ARE REGULATING THE FUNCTION OR INHIBITING WIDE FIELD GABAERGIC AMARKRIN CELLS AND I'M CURIOUS DO YOU IMAGINE THIS REGULATION IS LOCAL OR IS IT HAVING--IS IT THIS POTENTIA WILY EXPANDING THE RANGE OF INFLUENCE OF A NARROW FIELD GLIESINERGIC AMAKRIN CELL. >> YOU ARE ASKING IF THIS IS ALSO REGULATED CELLS? >> NO I'M TRYING TO GET A SPATIAL EXTENT OF THIS AND IF YOU LOOK AT THE FUNCTION OF THE GABAERGIC CELL AND THEN HAVE YOU A NARROW FIELD AMIA KRIN CELLS, AND THIS IS LOCAL INFLUENCE OR COULD THIS BE MORE GLOBALLY EFFECTING THE ENTIRE GABAERGIC AMIA KRIN SO HOW DO YOU PICTURE THAT HAPPENING. >> THAT'S A GOOD QUESTION. WE IMAGINE ALWAYS THAT IT'S A LOCAL--LOCAL--IT HAPPENS LOCALLY AT THE SITE WHETHE THE WHITE CELLS INFLUENCE THE RECORDED BIPOLAR CELL. BUT YOU'RE RIGHT, IT COULD ALSO REGULATE THE INPUT ALREADY, COULD REGULATE THE ACTIVITY OF THE WHITE FLAME ENDOCRINE CELLS BUT WE HAVEN'T TESTED THIS, NO. THAT'S A GOOD POINT. >> MY QUESTION'S SORT OF CONTINUES ALONG THE SAME LINE SO IN THE EXPERIMENT YOU REMOVE THE GABAERGIC INPUT BUT NOT THE GLIESAERGIC INPUT AND LOOKED IN THE FIELD OF STIMULUS, THERE'S ALMOST ADHERENCE BETWEEN THE 2, YOUR OVERLAYS LOOK PERFECTLY IDENT DAL IN THE ABSENCE OF THE GABAERGIC TRANSMISSION SO THE REQUESTY IS ARE ALL GABAERGIC TRANSMISSION CREATED EQUALLY IN THAT CIRCUIT IS THAT 1 SERVED BY 1 CELL TYPE AND IN THEIR STIMULUS TRAIN, YOU HAVE AN ON AND OFF AND THEN HAVE YOU DIFFERENT FREQUENCIES ARE EACH OF COMPONENT OF THAT STIMULI ALTERED EQUIVALENTLY, OR DOES GABA SHAPE DIFFERENT ASPECTS OF THAT? >> THAT'S A GOOD QUESTION. WE HAVEN'T LOOKED INTO THE DETAILS ALONG THE TRACE, WHETHER IT'S IN CERTAIN POSITIVE TRAITS, BUT BUT I THINK WE WILL FIND DIFFERENT ASPECTS BECAUSE IT ALSO NOT ONLY DEPENDS ON THE TYPE OF CELL, THAT THE BIPOLAR CELL YOU INPUT FROM, ALSO WHAT TYPE OF BIPOLAR CELLS ARE TRYING THESE CELLS. AND WE DID ALSO--WE ALSO DID BOTH AT THE SAME TIME AND THEN THE RESPONSES COME A BIT WEIRD WHICH MAY BE DUE TOO THE EFFECT THAT YOU'RE REMOVING TOO MUCH INHIBITION AND THE CIRCUITRY, GETS UNBALANCED SOMEHOW. IT LOOKS ALSO AS IF IN SOME BIPOLAR CELLS, ENDOCRINE TRIGGERED FROM THE SAME TYPE AND OTHERS YOU GET SPECIFICALLY FROM DIFFERENT TYPES AND THIS OF COURSE COULD ADD INTERESTING TEMPORAL PROPERTIES. YEAH, THAT'S A GOOD POINT. >> I HAVE 2 MORE TECHNIDAL QUESTIONS. THE FIRST 1 IS TO DO YOU BLOCK SODIUM CHANNEL WHEN IS YOU MEASURE THE RESPONSES IN YOUR EXPERIMENTS? >> NO. >> JUST ASKING BECAUSE THEY CAN PROPAGATE INFLUENCE THE PERCEIVED MOLECULE SIZE AND THAT MAY EXPLAIN THE LARGER SIZE YOU SEE-- >> YEAH, SO THE DIFFERENCE MAY BE EXPLAINED BY THE DIFFERENT CHANNEL TYPES WE HAVEN'T STARTED THIS BUT WE WOULD HAVE TO INCLUDE SOME BLOCKER INTO THE ELECTRODES TO LEAVE EVERYTHING ELSE INTACT, THIS IS SOMETHING ON THE TO DO LIST BUT WE HAVEN'T DONE THIS YET. I'M NOT SURE HOW WELL YOU CAN SHOP THE ERKTS LECT LEBLGHT RODES BUT YOU HAVE TO TRY THAT. >> AND THE SECOND QUESTION IS IN THE SHOW THE INDICATORS THAT HAVE TD SLOW TIME SCALE DO YOU COMPENSATE FOR THIS SLOW DOWN OF THE SIGNAL WHEN YOU TIE TO THE BULB ALL THE TIME FOR THE RESPONSE. >> YEAH WE DO THIS WHEN WE LOOK AT TIME RESPONSE. IN THIS CASE WE HAVEN'T LOOKED AT THE TEMPORAL PROPERTIES YET, BUT WE--YEAH, THIS IS A SERIOUS PROBLEM. WE TRY TO DEAL WITH THIS CURRENTLY IN A DIFFERENT ASPECT SO WE HAVE DATA RECORDINGS FROM GANGLION CELLS WITH OGB AND WE CANNOT MATCH THE CELLS VERY WELL, FOR THESE 2 INDICATOR TYPES SO WE HAVE TO FIND SOME WAY OF GETTING A COMMON CURRENCY TO COMPARE THE RESPONSES SO IT MIGHT BE SPIKES IN THE ENDS, THAT YOU WANT TO JUST CALCULATE SPIKES FROM THE OTHER TRACES THAT HAS A CERTAIN RISK OR YOU CALCULATE THE CALCIUM SIGNAL AND THIS WOULD BE NECESSARY TO COMPARE THE TEMPORAL ASPECTS AND ALSO THE COMPARISON. >> THOMAS I KIND OF THINK OF THE RETINA AS BEING THE FIND--IT'S THE BETA TEST FOR CONECTOMYOSIN OHMICS AS I SAID IN THE INTRODUCTION AND 1 OF THE THINGS WE LEARNED FROM THE CEREAL BLOCK FACE EM IS THAT LOOKING AT THE CONTACT BETWEEN CELLS AND YOU NEED TO HAVE MORE INFORMAION ABOUT SYNAPTIC STRUCTURE SO THE SECOND LESSON YOU'RE SHOWING NOW, IS THAT THE RESPONSE PROPERTIES OF CELLS CAN BE VERY DIFFERENT DEPENDING ON FOR EXAMPLE, WHETHER YOU HAVE FULL FIELD STIMULUS VERSUS A NARROW STIMULUS AND I'M WONDERING WHAT YOU THINK ABOUT THAT PROJECTING THAT ONTOLOOKING AT THIS IN THE AMYGDALA OR SOMETHING? IT SEEMS VERY DAUNTING NOW TO THINK ABOUT WHETHER WE'RE LOOKING AT A BRAIN CIRCUIT IN THE RIGHT STATE OR WITH THE RIGHT SET OF INPUTS THE PROPER SET OF INPUTS COMING IN, OR WHETHER WE RUN THE RISK OF SEEING ONLY A VERY SPECIFIC TYPE OF RESPONSE IN A NETWORK OF CELLS. >> YEAH, THIS IS--I THINK THIS IS A BIG RISK AND--BUT THIS PROBLEM IS INTRODUCED ALREADY BY DIFFERENT PREPARATIONS, DIFFERENT STAINING METHODS, DIFFERENT WAYS OF KEEPING RETINA ALIVE AND SO ON. I MEAN, EVEN IF YOU KEEP THIS ALL CONSTANT AND WHAT WE IGNORE HERE COMPLETELY, AT LEAST WE CAN CHANGE THE STIMULUS, BUT WHAT WE CAN DO COMPLETELY IS THE NEURAL MODULATION STATE OF THE TISSUE, YEAH SO THE ADAPTATION IS CAN ALSO BE CONTROLLED BUT WHAT'S ALSO HAPPENING IN THE CIRCUITRY, WHEN YOU TAKE IT OUT OF THE TISSUE, WHAT CHANGES THE CIRCUITRY, I THINK NEUROMODDULATION IS AN ANYTHING ASPECT HERE, AND THEY ARE OTHER PARTS OF THE BRAIN MAY ALREADY FURTHER THAN IN THE RETINA, CONCERNING THE CONNECTOMICS, I MEAN NEUROMODDULATION WOULD BE DIFFICULT TO TEST AS WELL BUT WHAT SHOULD BE THE NEXT DATA SET SHOULD BE [INDISCERNIBLE] JUNCTIONS, SOMETHING WE'RE NOT TAKING INTO ACCOUNT RIGHT NOW. AND THAT MIGHT BE FEASIBLE TO SEEK THE CHANGES. >> OKAY, THANK YOU VERY MUCH. >> THANK YOU. [ APPLAUSE ]