>> OKAY, I THINK WE'LL GET STARTED. I'M BRUCE COMINGS IN THE LABORATORY OF RESEARCH, IT'S MY GREAT PLEASURE TO INTRODUCE OUR SPEAKER. I HAVE FOND MEMORIES OF EYAL NUMBER OF VIGOROUS DISCUSSION THERE IS AND IT MADE IT CLEAR THAT HE WAS SOMEONE WHO THOUGHT DEEPLY ABOUT HIS PROBE DEVELOPMENTS. HE WENT ON TO DO THE POST DOC AT THE INSTITUTE WHERE HE WAS 1 OF THE PEOPLE WHO PIONEERED THE APPLICATION OF OPTICAL IMAGES TECHNIQUES TO AWAKE MONKEES. THEN HE MOVED BACK AT THE UNIVERSITY OF TEXAS IN AUSTIN IN 2 WHERE 002. WHERE HE'S BEEN PURSUING THE USE OF THESE MONKEES IN A--MONKEYS THAT NO 1 ELSE DID, MAINLY IN WHICH HE STUDIED POPULATIONS LIKE THIS, WHEN YOU TRY TOPBD THE HOW SIGNALS IN THE BRAIN SUPPORT THE PERFORMANCE OF THRESHOLD PROTECTION, AND HOPEFULLY HE'LL SHOW US HOW THAT HAS COMPLIMENTED PREVIOUS WORK TODAY. AND HIS TITLE IS DECISION RELATED ACTIVITY AND TOP DOWN INTENTIONAL MODULATIONS IN PRIMATE. IT'S A PLEASURE TO HAVE YOU HERE. >> HOPE LEGAL, YOU CAN HERE ME, IT'S A GREAT PLEASURE IS HONOR TO BE INVITED TO TALK HERE. AS BRUCE MENTIONED, I WAS TRAINED IN HERE IN THIS LAB. SO IT'S A DOUBLE PLEASURE AND HONOR TO BE TALKING HERE WHERE MANY OF THE TECHNIQUES THAT I'M USING IN MY LAB HAVE BEEN DEVELOPED. SO, THE BIG QUESTION, THE GOAL OF RESEARCH IN MY LAB IS TO TRY TO UNDERSTAND HOW SIMPLE PERCEPTUAL DECISIONS ARE FORMED IN THE BRAIN BASED ON NEURAL SIGNALS AND EARLY SENSORY POLITICAL AREAS. THE SYSTEM THAT I'M STUDYING IS THE VISUAL SYSTEM. AND THE FIRST SLIDE SHOWS THE HUMAN VISUAL SYSTEM, IN WHAT I WANTED TO DO IN THIS SLIDE IS TO SHOW YOU SOMEWHAT OF A SIMPLE MINDED REPRESENTATION OF THE STAGES OF PROCESSING THAT MUST TAKE PLACE. WHEN A SUBJECT PERFORMS A PERCEPTUAL TASK. SO SENSORY SIGNALS, VISUAL SIGNALS ARE SENT FROM THE RETINA TO THE BACK OF THE BRAIN, THE PRIMARY VISUAL CORTEX WHICH IS THE AREA THAT I'M STUDY NOTHING MY LAB CURRENTLY. AND THEN FROM THE PRIME VISUAL CORTEX, SIGNALS ARE SENT THROUGH MULTIPLE STAGES TO VARIOUS ASSOCIATION CORTICALE AREAS THAT ARE INVOLVED IN FORMING THE PERCEPTUAL DECISIONS AND THEN BASICALLY FORMING, DECISIONS BASED ON THESE DECISIONS, PLANNING MOVEMENTS AND EXECUTING THESE MOVEMENT. SO AS A FIELD FOUR GOAL IS TO UNDERSTAND HOW PERCEPTUAL DECISIONS ARE FORMED, WE HAVE TO ADDRESS 3 BASIC QUESTIONS. FIRST OF ALL WE HAVE TO UNDERSTAND THE ENCODING PROCESS, AND IN THE CONTEXT OF THE VISUAL SYSTEM, OUR GOAL IS TO UNDERSTAND THE ENCODING TO THE POINT THAT GIVEN A VISUAL STIMULUS, WE CAN PREDICT WHAT WILL BE THE PATTERN OF THE RESPONSES IN THE EARLY SENSORY CORTICALE AREAS TO THE SIGNALS, AND SIMILARLY, GIVEN THE RESPONSES IN THE CORTEX, WE SHOULD BE ABLE TO PREDICT WHAT THE STIMULUS WAS ON THE STREET OR IN THE REAL WORLD. SO THAT'S 1 IMPORTANT QUESTION, ANOTHER IMPORTANT QUESTION HAS TO DO WITH DECODING, SO WHEN WE PERCEIVE THE WORLD AT LEAST IN VISION, MOST IF NOT ALL THE SENSORY INFORMATION THAT IS AVAILABLE FOR THE HIGHER AREAS OF FORMED PERCEPTION HAVE TO BE REPRESENTED BY PATTERNS OF NEURAL ACTIVITY IN THE EARLY CORTICALE AREAS PARTICULARLY E-1. SO THE QUESTION IS HOW ARE THESE SIGNALS REPRESENTED HERE BY PATTERNS OF NORMAL RESPONSES READ OUT OR DECODED BY THESE SUBSEQUENT PROCESSING STAGES. AND OF COURSE, THE SYSTEM IS NOT SIMPLY FEET FORWARD LINEAR 1 MAJOR STEP IS THE ENCODING PROCESS, EARLY ENCODING PROCESS IS FIXED AND TO WHAT EXTENT IT IS CAST DEPENDENT BY WAY OF TOP DOWN INFLUENCES. SO THESE ARE THE 3 GENERAL QUESTIONS THAT I THINK THE FIELD IS TRYING TO ADDRESS AND WHAT I WANT TO DO TODAY IS TO GIVE YOU A LITTLE BIT OF TASTE OF HOW WE STUDY THESE 3 QUESTIONS, IN MY LAB, NOW MUCH OF WHAT WE KNOW ABOUT THESE BASIC QUESTIONS COMES FROM WORK USING SINGLE UNIT, SINGLE RECORDING SINGLE NEURONS OR WAKE OR THESE TYPES OF ANIMALS OTHER AND 1 OF THE THINGS I HOPE TO CONVINCE YOU, I MAY NOT HAVE TO CONVINCE YOU BUT YOU KNOW THAT ALREADY, THAT PERCEPTION OF EVEN THE SIMPLEST MOST LOCALIZED STIMULUS AND LIKELY TO INVOLVE THE COORDINATEINATED ACTIVITY OF THE LARGE POPULATIONS OF NEURONS AND BECAUSE OF THAT, I THINK THERE'S A GROWING APPRECIATION IN THE FIELD THAT IN ORDER TO EXTEND THESE QUESTIONS, WE NEED TO COMPLEMENT THIS WITH TECHNIQUES THAT WILL ALLOW US TO RECORD POPULATIONS OF NEURONS, IDEALLY IN AN AWAKE AND BEHAVING SUBJECT. SO, THE WAY THAT WE ACHIEVE THIS IN MY LAB AS BRUCE MENTION SIDE BY USING OPTICAL IMAGES TECHNIQUES. OUR SUBJECTS ARE ARE AWAKE AND BEHAVING MONKEYS, THIS IS PROBABLY NOT NECESSARY IN THIS AUDIENCE BUT THESE MACAQUE MONKEYS ARE IDEAL FOR STUDYING VISION FOR 2 PRIMARY REASONS: ONE, THEIR VISUAL SYSTEM IS REMARKABLILY--REMARKABLY SIMILAR TOEURS AND WE--OURS AND WE CAN TRAIN THEM SIMILAR TO THE 1S THAT WE'VE BEEN STUDYING FOR HUMAN VISION FOR DECADES. SO WE TRAIN THESE MONKEY TO PERFORM SER SEPTORSUAL TASK AND THEN TO MEASURE BRAIN ACTIVITY, WHAT WE DO IS IMPLANT A CHAMBER, WINDOW OVER THE BRAIN, THE OCCIPITAL LOBE. WE BASICALLY OPEN A WINDOW INTO THE BRAIN AND WHAT WE DO WHICH IS FAIRLY UNIQUE IS WE REPLACE THE LAY THEY'RE PROTECTS THE BRAIN WITH THIS ARTIFICIAL CURIA THAT IS MADE OF SILICONE AND IS TRANSPARENT AND BY DOING THAT WE BASICALLY HAVE DIRECT OPTICAL ACCESS TO THE BRAIN OF THESE MONKEYS, WE CAN MAINTAIN THESE CHAMBERS STERILE AND CLEAN FOR MANY, MANY MONTHS AND SOMETIMES MORE THAN A YEAR. AND DURING THIS PERIOD, IN ORDER TO MEASURE BRAIN RESPONSES, THE MAIN TOOL THAT WE USE IN MY LAB, IN ADDITION TO ELECTROPHYSIOLOGY IS VOLT AND SENSITIVE DIE IMAGING. SO FOR EACH EXPERIMENT, WE TAKE THE ANIMALS, AWAKE, SITTING IN THE CHAIR, WE APPLY THE DIE TOPICALLY OVER THE CORTEX, THE DIES BASICALLY PENETRATE INTO THE TISSUE AND IN THE TISSUE, THEY ACTAs MOLECULAR TRANSDUCERS, TRANSDUCING ESSENTIALLY INSTANTANEOUSLY AND LINEARLY, CHANGES IN MEMORY RESPONSE AND VOLTAGE IN CHANGES AND FLUORESCENCE THATEE CAN PICK WITH A SENSITIVE CAMERA. SO THIS TECHNIQUE HAS SEVERAL IMPORTANT ADVANTAGES, 1, I THINK KEY ADVANTAGE OF THIS TECHNIQUE OVER OTHER TECHNIQUE SYSTEM THAT IT ALLOWS US TO DIRECTLY MEASURE CHANGES IN VOLTAGE. AND THAT GIVES THE TECHNIQUE TEMPORAL RESOLUTION. ANOTHER IMPORTANT ADVANTAGE FROM THE PERSPECTIVE OF THE PROJECTS THAT I'LL TALK ABOUT TODAY IS THAT IT HAS A LARGE FIELD OF OF VIEW. SO THIS CHAMBER HAS A DIAMETER OF ABOUT 18-MILLIMETERS OUR IMAGES AREA IS TYPICALLY 14 BY 14-MILLIMETERS SO WE CAN LOOK AT A FAIRLY LARGE REGION IN THE CORTEX AND WHAT I HOPE TO SHOW YOU TODAY IS THAT IF YOU WANT TO MEASURE THE RESPONSES FROM THE ENTIRE POPULATION OF NEURONS IN B-1 THAT REFOND A SMALL LOCALIZED STIMULUS, YOU HAVE TO HAVE A LARGE FIELD OF VIEW. NOW, THE TECHNIQUE HAS LIMITATIONS AS ANY OTHER TECHNIQUES, 1 MAJOR LIMITATION IS THAT, RATHER THAN LOOKING AT THE ACTIVITY OF INDIVIDUAL NEURONS, NOW WE'RE LOOKING AT POPULATIONS OF NEURONS. AND WE RECENTLY COMPLETED A STUDY WHERE WE LOOK AT SORT OF THE SPACIAL SUMMATION PROPERTIES OF THIS TECHNIQUE, OUR ESTIMATE IS THAT WHEN WE MEASURE THE RESPONSES FROM A SINGLE PIXEL IN OUR CAMERA WE'RE PULLING ACTIVITY FROM A REGION WITH A RADIUS OF ABOUT 200-MICRONS. THE REASON FOR THIS IS THAT THAT YOU'REONS IN THE CORTEX SEND PROPHECYS TO NEIGHBORING LOCATIONS SO WHEN WE RECORD FROM A SINGLE PIXEL, THAT PIXEL CONTAIN DENDRITES AND AXONS THAT BELONG TO CELLS OHM A FEW HUNDRED MICRONS AWAY. SO THAT CAUSES A BLURRING OF THE SIGNAL BUT IN A SECOND, DESPITE THE PLURIPOTENT PLURIPOTENT BLURRING WE CA N RECEIVE SIGNALS WITH GOOD RESOLUTION DOWN TO THE CUMULATIVE RESOLUTION FOR SURE. I'LL SHOW THAT IN A SECOND. SO ANOTHER LIMITATION IS THAT WE CAN MEASURE THINGS ONLY FROM THE SUPERFICIAL LAYERS FROM THE CORTEX, THE LAYERS ARE COMING FROM LAYERS 2, 3, LAYER 2, AND 3, CONTAIN APPLICATIONSICCAL DENDRITES OF NEURONS LOCATED DEEPER IN THE CORTEX. SO IN THAT SENSE, WE'RE GETTING A SENSE OF THE CORTEX. SO WHEY WANT TO DO TODAY IS TELL YOU ABOUT A COUPLE OF STUDIES WHERE WE LOOK AT PERFORM ANSWER OF MONKEYS, MONKEYS PERFORMING PROTECTION TASK WHILE WE'RE IMAGING THE BRAIN AND BEFORE DOING THAT, 1 OF THE KEY FEATURES OF PRIMARY VISUAL CORTEX AS WELL AS OTHER CORTICALE AREAS IS THE FACT THAT IT'S TOP GRAPHICALLY ORGANIZED AND INFORMATION IS REPRESENTED TOP GRAPHICALLY SO IN THE FIXTURE FEW SLIDES I WANT TO SHOW YOU HOW USING THIS TECHNIQUE FOR THE IMAGES WE CAN ACTUALLY MEASURE THE LAY OUT OF THE TOPPOGRAPHIC MAP IN EACH OF THE CHAMBERS WE'RE STUDYING, VERY QUICKLY AND RELIAISONNABLILY, SO JUST TO DEMONSTRATE WHAT WE CAN DO WITH THIS TECHNIQUE, THE FIRST THING IS THAT PRIMARY CORTEX CONTAINED A MAP OF VISUAL SPACE, THAT MEANS THAT POINTS THAT ARE NEARBY IN THE VISUAL SPACE WILL MAP WHAT'S NEARBY IN THE CORTEX AND WE CAN CHARACTERIZE THIS MAP WHICH IS CALLED THE TOPIC MAP, BY TAKING ADVANTAGE OF THE FAST TIME COURSE, THE HIGH TEMPORAL RESOLUTION OF THE TECHNIQUE, WE KNOW THAT THIS PORTION OF THE VISUAL CORTEX, THIS IS HERE AT THE BACK OF THE MONKEY'S BRAIN, THE BORDER BETWEEN THE IMAGES CLOSER PRIMARY VISUAL CORTEX AND THE SECONDARY VISUAL CORACLE AREA AND THIS REGION REPRESENTS LOWER VISUAL FIELD IN THIS GENERAL SO THIS CHUNK OF CORTEX OVER HERE ROUGHLY REPRESENTS A WEDGE SHAPED REGION IN THE LOWER VISUAL FIELD. THESE REPRESENT THE 2 ACCENTS NORMAL TO THE B-1 OR 2 BORDER REPRESENTS POLAR ANGLE AND THE ACCESS PARAHREL TO THE BORDER, REPRESENTS THIS FROM THE CENTER OF GAZE. SO TO GET THESE MAPS HA WE DO IS THE FOLLOWING, WE PRESENT THE MONKEYS WITH VERY FAST SWEEPING STIMULUS IN BARS IN WEDGES OR RINGS AND WE BASICALLY TRACK THE ACTIVITY IN THE CORTEX, SO I HAVE THIS DEMO THAT HOPEFULLY WILL WORK. SO BASICALLY AS A STIMULUS SWEEPS THROUGH THE INDIVIDUAL FIELD IT CREATES A PATTERN OF ACTIVITY THAT TRAVEL THROUGH THE CORTEX NO THE TIME SCALE HERE, EACH 1 OF THESE IS 2 SECONDS SO THERE ARE 5 SWEEPS PER SECOND SO IN EVERY TRIAL WE CAN HAVE 5 TO 10 OF THESE SWEEPS, IT'S ENOUGH TO AVERAGE LESS THAN 10 TRIALS TO GET A RELIABLE ESTIMATE OF THE TIMING OF THE RESPONSE AT EACH LOCATION. THE NEXT CLIP SHOWS THE RESPONSE TO RINGS, MOVING IN THIS CASE, INWARDS, TOWARDS THE CENTER OF GAZE, AND AGAIN WE SEE THIS VERY NICE WAVE FRONT TRAVELING THROUGHOUT THE CORTEX AT A SPEED THAT CORPONDS, AND SO FROM THIS, WE CAN GET A VERY RELIABLE MAP OF THE VISUAL SPACE SO HERE, YOU SEE THE REPRESENTATION ALONG THE CORTEX, POLAR I THINKLE IN RED, THIS--DISTANCE FROM THE CENTER OF GAZE IN GREEN. AND WE'VE ESTIMATED, WE CAN ACTUALLY RESOLVE THIS MAP DOWN TO SOMETHING IN THE ORDER OF A HUNDRED MICRONS IN THE CORTEX. NOW YOU PROBABLY ALL KNOW THAT IN ADDITION TO THIS LARGE SCALE TOP GRAPHIC MAP, WHEN WE LOOK AT A SMALL IT HAS A FINE SCALE MAP OF THIS OF THIS THEY ARE A FEW HUNDRED MICRONS IN DIAMETER. SO WE CAN ZOOM IN ON THE SMALLER REGION AND IN USING THIS TECHNIQUE WE CAN MEASURE THESE MAPS SO THIS SHOWS THE RESPONSE IN EYE 5 BY 5-MILLIMETER OF CORTEX TO BARS, AT DIFFERENT ORIENTATIONS, THIS IS JUST A SUBSET OF ORKWREBTATIONS THAT WE USE? AND YOU CAN SEE THESE PATCHES AND DARK PATCHES BASICALLY RESPONSE, LIFE PATCHS AND DARK PATCHES RESPOND LESS THAN THESE AND THESE PATCHES ARE 300-MICRONS IN DIAMETER. AND WE CAN LOOK THESE SHOULD BE INDUCE BIDE ORIENTATION AND MAPS PRODUCED BY NEARBY SIMILAR POSITIVELY CORRELATED AS WE MAKE THE DIFFERENCE BETWEEN THE ADDITIONS LARGER AND CORRELATION SHOULD DROP AND EVENTUALLY WHEN WE GET TO ORKWREBTATION AND WHAT WE SEE THE CROSS CORRELATION BETWEEN MAPS AND FUNCTION OF LIMITATION. CORRELATION, 0 FOR 45-DEGREES ORIENTATION AND NEGATIVE CORRELATION FOR ORIENTATION THAT ARE 90-DEGREES APART AND USING THIS WE CAN CREATE A COLOR MAP OF EACH ORIENTATION OF EACH IMAGED AREA, AND BASICALLY THE COLOR HERE IS REPRESENTING PREFERRED ORIENTATION, SATTURATION IS THE ORIENTATION, AND WE SLEEP APNEA AND OBESITY WHAT IS KNOWN AROUND THE POINTS, WHERE THE ORIENTATION IS WEEK, AND THEN, ORIENTATION VARIES IN A CIRCLE AROUND THE SIMILARITY POINT, SOMETIMES LOCK WIDE DIRECTION AND SOMETIMES IN COUNTER CLOCK WIDE DIRECTION. IF HAVING THESE CHARACTERIZATIONS IN THE ANIMAL GIVES US THE FOUNDATION ABOUT ASKING FOR ENCODING AND DECODING IN THE BRAIN. FOR THE REST OF THE TALK I WON'T FOCUS ON THE SIGNALS OF THE COLUMBUS SCALE, BUT I WILL FOCUS ON THE LARGE TOPIC, AND ALL STUDIES I'LL DESCRIBE TODAY USE SIMPLE DETECTION TASK AS BRUCE MENTIONED REALLY WE ARE THE ONLY LAB SO FAR THAT HAVE SUCCEEDED IN COMBINING THRESHOLD TYPE OF PHYSICS WITH THIS TECHNIQUE IN THE WAKE BEHAVING MONKEY. SO IT WAS IMPORTANT TO START WITH A SIMPLE TASK AND THAT'S WHY WE STARTED WITH THE DETECTION TASK. MONKEE, FIXATES AT THE CENTER OF THE SCREEN AND THEN AT SOME POINT OFFICIAL TARGET MAY APPEAR. THE VISUAL TARGET IS AN ORIENTED STIMULUS OPTIMIZED FOR A CELLS IN V1. THESE ARE TYPICALLY SMALL ORIENTED THAT ARE SMALLER THAN THE AVERAGE SIZE OF THE FIELD IN V1. THESE ARE HIGHLY SENSITIVE TO THESE STIMULI AND BECAUSE OF THAT, WE THINK THAT REALLY THE QUALITY AND THE NATURE OF SIGNALS IN V1 WILL DICTATE PERFORMANCE IN THIS TASK. SO IT APPEARS ONLY ON HALF THE TRIALS, THE DIFFICULTY OF THE TASK IS THE CONTRAST OF THE TARGET SO TARGET CAN BE EASILY VISIBLE ORA WE LOWER CONTRAST, THEY BECOME HARDER AND HARDER. AND MOST OF THE TIME WE SPENT BASICALLY AT OR AROUND ANIMALS DETECTION THRESHOLD. SO HERE'S THE SEQUENCE OF EVENTS WITHIN A TRIAL. THE MONKEY ESTABLISHES FIXATION AT THE CENTER OF THE SCREEN, AT SOME POINT THE FIXATION POINT DIDN'T AND THAT TELLS THE ANIMAL THAT 3 NANNY MOLARS LATER A TARGET MAY APPEAR WITH A 50%. AT THE FIXED LOCATION, IF THE TARGET APPEARED THEN THEY'RE REQUIRED TO MOVE THE EYES TO THE TARGET LOCATION RAPIDLY, AND HOW THAT'S SEEING THE TARGET BUT IF IT DID NOT APPEAR, THEN IT MAINTAINS FIXATION IN ORDER TO GET THE REWARD. AND WE ALLOW THE ANIMAL TO APERIOD OF OF 600 NANO MOLARS TO REPORT SEEING THE TARGETS. OKAY, SO WHAT I WANT TO DO NOW IS GIVE YOU A BRIEF OVERVIEW OF WHAT I'LL TALK ABOUT, AND RATHER THAN TALKING IN DETAIL ABOUT 1 STUDY, WHAT I WANT TO DO, HOPEFULLY THIS WILL WORK IS GIVE YOU A BRIEF OVER SEW VIEW OF 3 PROJECTS DEALING WITH THIS, THE DECODING AND TOP YOU DOWN MODULATIONS SO BECAUSE OF THAT, I WILL BE FAIRLY BRIEF ON EACH 1 OF THESE PROJECTS. BUT PLEASE BE SURE TO ASK QUESTIONS. SO FIRST I'LL TALK ABOUT THE ENCODING AND THIS IS A STUDY THAT IS ALREADY BEEN PUBLISHEDs FOR A COUPLE OF YEARS AND I WILL TALK ABOUT IT FOR A BACKGROUND FOR THE NEXT 2 PROGYS AND WHAT WE ASK IN THIS PROJECT IS HOW WELL WE CAN PREDICT IN THE STIMULUS WAS PRES EPT OR ABSENT ON THE RESPONSES IN V1 DURING THIS BRIEF FORWARD WHERE THE ANIMAL DECIDES WAS THE TARGET PRESENT FOR OR ABSENCE. SO BY DOING THAT WE'RE TRYING TO CHARACTERIZE THE QUALITY OF THE CIGNAS AND THE LEVEL POPULATION. SECOND PROJECT WAS TO LEARN TO DECORRODE THE MECHANISMS AND HOW WELL WE CAN PREDICT THE CHOICE THAT THE ANIMAL WILL, AND SO NOW WE'RE FIXING THE STIMULUS AND ASKING HOW WE CAN PREDICT THAT ON THIS PARTICULAR TRIAL THE MONKEY WOULD EFFECT THE TRIAL SUCCESSFULLY AND ON THIS TRIAL, THE MONKEY WOULD FAIL. THIS TELLS US ABOUT THE MAJOR CODING MECHANISM AND THE HOPE, AND THE THIRD PROJECT THAT I'LL TALK ABOUT, IS A PROJECT WHERE WE MANIPULATED MODULATIONS, AND WE LOOK AT THE EFFECTS OF V1. BASED ON VIEWING THE RESPONSES, POPULATION RESPONSES, WE HAVE TO ADDRESS 2 BASIC QUESTIONS. ONE OF THEM WHAT IS THE AVERAGE STIMULUS RESPONSE IN V1 TO THESE TARGETS. THAT'S BASICALLY WHAT WE'RE LOOKING FOR IN THE RESPONSE OF V1 ON A GIVEN TRIAL AND IN ORDER TO DECIDE IF THE TARGET WAS PRESENT OR ABSENT, THE OTHER IS AND GO TO TRIAL AND NOW WE CHARACTERIZE IN ORDER TO DECIDEOT TRIAL WHETHER IT WAS PRESENT OR NOT. SO LET ME FIRST SHOW YOU, THE AVERAGE STIMULUS OF A RESPONSE, AND TARGET OR V1 AND ADVANTAGE OF HAVING THE RETINAL LOCATION NOLL TOPIC MAP, WE KNOW EXACTLY WHERE TO POSITION THE TARGET SO THAT IT WILL FOLLOW IN THE CENTER OF THE AREA WE'RE IMAGING. SO THE SCALE BAR IS MILLIMETERS AND CHECK OUT THE RESPONSE, SO THE SPACE CONSTANT IS ABOUT 2-MILLIMETERS O THE FULL EXTENT IS SOMETHING LIKE 8-MILLIMETERS IN THE CORTEX. >> [INDISCERNIBLE]. >> THANKS FOR ASKING. THE STIMULUS IS ON FOR UP TO 300 MILLISECONDS, BUT TELL TERMINATE WHEN THE ANIMAL MOVES ITS EYE. AFTER STIMULUS ONSET, AND NEVER INCLUDE PERIOD THAT S&P BEFORE THIS, SO WE TERMINATE OUR INTEGRATION. SO THIS IS SHORTLY AFTER STIMULUS ONSET, THE FIRST STRIKINGOR SURPRISING RESULT IS THAT, DESPITE THE FACT THAT THIS IS REALLY LOCALIZED BOTH IN SPACE, AND IN SPECIAL FREQUENCY AND ORIENTATION, IT ACTIVATES MANY MILLIMETERS, SQUARE MILLIMETERS OF CORTEX, CONTAINS MILLIONS OF NEURONS SO IN PRINCIPLE, THERE ARE MILLIONS OF NEURONS IN V1 THAT COULD POTENTIALLY PROVIDE USEFUL INFORMATION FOR THIS TASK. THE NOW THE REASON WE GET A LARGE SPREAD IS PRIMEAR IMPEDIMENTSY DETERMINED BY--PRIMARILY DETERMINED BY THE SIZE AND SCATTER OF OF THE FIELDS. V1 HAVE FIELDS THAT EXTEND OVER SPACE. SO WHEN WE MOVE FROM THE CENTER, IF WE MOVE TO NEURONS OVER HERE THAT THERE'S CENTER DOESN'T OVERLAP THE STIMULUS, BECAUSE THE RECEPTOR FIELDS ARE EXTEND OVER SPACE, THEY STILL OVERLAP AND THEREFORE THEY STILL RESPOND TO THE STIMULUS. SO THIS IMPLIES THAT BASICALLY WE'RE SEEING HERE IS WITH PEOPLE WILL PULL A POINT IMAGE SO THIS IS THE SMALLEST REGION IN V1 THAT WE CAN ACTIVATE. AND AS I TOLD YOU BEFORE, MEASURING MEMBER POTENTIAL DONE RECENT WORK IN THE LAB CHARACTERIZING IN THE LAB BETWEEN SIGNALS AND ACTIVITY AND WHAT WE FIND IS THAT AS EXPECTED, THE SPIKING ACTIVITY IN V1 IS NARROWER THAN THE DIE RESPONSES BUT NOT DRAMATICALLY NARROWER. THE DIFFERENCE IS ABOUT 50%. SO THE RADIUS IS 50% SMALLER FOR SPIKES, STILL ENCOMPASSING MULTIPLE SQUARE MILLIMETERS AND BASICALLY MILLIONS OF NEURONS EVEN AT THE LEVEL OF OUTPUT FROM V1, IT'S MORE THE INPUT OF THE SUPERFICIAL LAYERS IN V1 RECEIVE. IT'S ONLY ABOUT 50% MORE. SO TO ANSWER OUR QUESTION: HOW WELL CAN WE PREDICT THE ANSWER OF THE TARGETOT GIB TRIAL. BASICALLY WHAT WE DO IS AVERAGE OR INTEGRATE SIGNALINGS OVER THE TIME OR OVERALL STRATEGY A SHORT PERIOD BEFORE THE ANIMAL MADE THIS DECISION AND WHAT WE ASKED WAS IF WE WERE TO COMBINE THESE SIGNALS OVERSPACE, WHAT IS THE OPTIMAL WAY TO PULL THESE SIGNALS IN ORDER TO PERFORM THE TASK, IN TERMS OF THE NOISE, VARIABILITY, I'M NOT GOING TO SHOW DATA, I'LL JUST MENTION THAT THE A KEY PROPERTY OF THE VARIABILITY IS THAT IT'S HIGHLY CORRELATED OVER SPACE. SO WHEN THE RESPONSE ON A GIVEN TRIAL HAPPENS TO BE ABOVE THE CENTER, TELL BE ABOVE THE MEAN FOR A LARGE REGION AROUND THE CENTER, SO WE GET STRONG POSITIVE SPECIAL CORRELATION AND THAT HAS LARGE IMPACT ON HOW WE PULL THE SIGNALS IN ORDER TO PERFORMA THE TASK. THIS SHOWS THE AVERAGE RESPONSE, IT LOOKS LIKE A TKPWHRALSION WITH A 1 IS HALF TO 2 THESE ARE WEIGHTS PULLING THIS WITH BILL GUISELER WHERE WE TRY TO CHARACTERIZE THE WEIGHTS AND THE WEIGHTS ARE INTERESTING. THEY HAVE POSITIVE CENTER WHERE THE RESPONSE IS STRONG AND THEY HAVE LARGE NEGATIVE LOBES THAT EXTEND OR A LARGER REGION, THE REASON THESE ARE OPTIMAL FOR PERFORMING THESE TASK SYSTEM BECAUSE OF THE TORALATED NOISE. WHAT THIS PULLING ALEGORITHMS DOES IS IT ESTIMATES THE NOISE IN THE SURROUND WHERE WE HAVE STRONG LORA RODRIGUEZICATION WITH THE CENTER BUT NOT A LOT OF SIGNAL, AND THEN, SUBJECT THIS MODEL OF THE NOISE FROM THE CENTER, WHERE WE HAVE THE STRONG STIMULUS RESPONSE AND BY DOING THAT IT'S DOING A SIMPLE NOISE CANCELLATION. SO THESE WAVES, ARE OPTIMIZED FOR SEPARATING TARGET PRESENT TRIALS FROM A*RGET ABSENT TRIALS. SO NOW WE HAVE THIS ALEGORITHMS, WE CAN BASICALLY COMPARE THE PERFORMANCE OF THIS ALEGORITHMS TO A PERFORMANCE OF OTHER ALDORIT IMPEDIMENTSS FROM PULLING THEM FOR V1, AVERAGING THE RESPONSES OVER THIS ENTIRE REGION AND COMPARE THE PERFORMANCE TO THE MONK NEUROECTODERMAL THIS TASK AND ALL THIS COMPARISON IS DONE IN CROSS VALIDATED FASHION. AND THE SURPRISING RESULT WAS THAT IF WE LOOK AT THE PERFORMANCE OF OUR MODEL, MINUS THE PERFORMANCE OF THE MONKEY OVERALL ACCURACY OR CORRECTNESS OF THE ANIMAL, VERSES THE MODEL, WHAT WE SEE ACROSS 8 EXPERIMENTS FROM 2 ANIMALS THAT THE OPTIMAL DECODER USING THESE WEIGHTS, WE CAN ACTUALLY CONSISTENTLY OUTPERFORM THE MONKEY IN THIS DETECTION TEST. SO, WHILE IF WE USED OTHER POTENTIAL PULLING RULES, OF COURSE, WE CAN DO WORSE. SO LET ME JUST BRIEFLY SUMMARIZE THE FIRST PART. WHAT WE FOUND WAS THAT WE CAN OFFER FROM THE MONKEY IN THIS TASK USING A SINGLE TRIAL RESPONSE FROM THE DIE, THIS IMPLIES THAT THERE IS MORE INFORMATION IN V1 THAN THE ANIMAL CAN USE EFFECTIVELY. WHICH THEREFORE IMPLIES THAT THERE HAVE TO BE DOWN STREAM INEFFICIENCIES THAT SPHREUPB WHY THE ANIMAL IS NONAPOPTOTIC DOING THAT WELL AND THESE DOWN STREAM INEFFICIENCIES CAN HAVE 2 POSSIBLE SOURCES, 1 OF THEM IS THAT FOR WHATEVER REASON THE ANIMAL MAY BE LIMITED AND MAY NOT BE ABLE TO USE THE OPTIMAL DECODER AND OF COURSE THAT COULD BE GREAT PERFORMANCE. ANOTHER 1 WHICH I HOPE TO CONVINCE YOU IS ACTUALLY DIFFERENT IS THAT THE ANIMAL COULD BE PULLING THE SIGNALS IN V1 OPTIMALLY BUT AS THE SIGNALS PROPAGATE FROM V1 TO SUBSEQUENT PROCESSING STAGES INDEPENDENT NOISE ACCOUNTED BE ADDED AND THAT NOISE COULD DEGRADE PERFORMANCE. YES? BUT THAT AREA IS HIGHLY CORRELATED. THAT BY ITSELF WOULD NOT CHANGE SIGNALS. SO IF YOU PUT THIS THROUGH THE NONLINEARITY, THE SIGNAL ITSELF WOULD BE THE SAME AS THE SIGNAL TO NOISE THAT YOU HAVE PRIOR TO THE SUBTHRESHOLD LEVEL. WE DIDN'T TRY THAT IN THE MONKEY BUT EVERYTHING IS GOING TO BE MORE RESTRICTIVE. EVERYTHING WILL BE RESTRICTIVE BUT YOU WILL HAVE THIS CORRELATION, YOU WILL DECODE BETTER THAN TH-T MONKEY. IN PRINCIPLE THIS NULL LINEARITY SHOULDN'T HAVE LARGE IMPACT ON THE WAY THAT YOU WANT TO PULL THE SIGNALS. OKAY SO DIFFERENCES IN THESE POSSIBILITIES. SO 1 POTENTIAL DIFFERENCE IS THAT IF THE MONKEY IS USING THE SUBOPTICALOPTIMAL DECODER THAT'S THE MAIN REASON FOR THE INEFFICIENCY, THEN, END MOST OF THE CHOICE LIMITING, BEHAVIORIAL LIM EU9ING NOISE IMPRESSED IN V1 THAN IN PRINCIPLE IF WE CAN ACCESS TO THE SIGNALS IN V1 AND IF WE KNOW SOMETHING ABOUT THE DECODER, WE SHOULD BE ABLE TO PREDICT THE CHOICES THE ANIMAL MAKES ON THE TRIAL BY TRIAL BASIS QUITE RELIAISONNABLY. ON THE OTHER HAND IF THERE'S DOWN STREAM VARIABILITY THAT WE DON'T HAVE ACCESS TO IN V1. THAT WILL PUT A LIMIT ON HOW WELL WE CAN PREDICT THE CHOICES THAT THE ANIMAL WILL MAKO A GIVEN TRIAL ON THE RESPONSES. SO THIS LEADS ME TO THE SECOND PROJECT THAT AGAIN I'LL BRIEFLY MENTION. AND IN THAT PROJECT WE ASK THE FULL QUESTION: IS PERCEPTION LIMITED PRIMARILY IN THIS TASK, PRIMARILY BYINIZE IN V1, OR BY NOISE DOWN STREAM FROM V1. INDEPENDENT NOISE? AND NOW NOW TO ANSWER THAT IS WE CAME UP WITH THE SIMPLE MODEL FOR THE WHOLE PROCESS. SO THE MODEL S&P SORT OF A STANDARD MODEL, LIKE A PHYSICS IDEA AND WHEN THE SUBJECT PERFORMS THE TASK, THE SUBJECT FORMS THE INTERNAL DECISION VARIABLE AND ASSUMPTION WAS THAT INTERNAL DECISION VARIABLE IS NORMALLY DISTRIBUTED AND THEN THE SUBJECT IS COMPARING THIS INTERNAL DECISION VARIABLE IN A TRIAL BY TRIAL WITH A CRITERION, IF THE VARIABLE EXCEED THE CRITERION THEN THE SUBJECT WILL REPORT TARGET EXPRESSING IF IT FOLDS BELOW, THE SUBJECT WILL REPORT THAT THE SUBJECT IS ABSENT. AND THE DECISION VARIABLE OVER HERE, THE MODEL IS MADE OF--THE VARIABILITY AT THE LEVEL OF DID THE CISION IS MAY HAVE HAD WHO COMPONENTS, IT'S IT IS SUM OF 2 COMPOPENTS, SENSORY VARIABILITY, VARIABILITY AT THE LEVEL OF SENSORY ENCODING CHARACTERIZED BY THIS SIGMA AND DOWN STREAM INDEPENDENT VARIABILITY WHICH WE INDICATE BY THE SIGMA SUBD, SO SO SIGMA IS THE SUM OF THE SQUARES OF THIS AND THAT. SIMILARLY AS EXPERIMENTERS WE CAN TAKE THE SIGNALS FROM THE V1 AND WE CAN PULL THEM USING DIFFERENT POSSIBLE DECODERS, AND WE WILL END UP WITH SIGNALS THAT ARE ALSO ROUGHLY NORMALLY DISTRIBUTED AND THOSE SIGNALS WILL HAVE VARIABILITY AND THAT VARIABILITY AGAIN WILL BE THE SUM OF 2 COMPONENTS, SENSORY VARIABILITY AND VARIABILITY THAT COMES FROM VARIOUS SOURCES OR INDEPENDENT OF THE CHOICE FOR EXAMPLE, FROM INSTRUMENT NOISE. SO THE CIGNA IS CHARACTERIZED BY THE DOWN STREAM AND THE MEASUREMENT SIGMA AND TOGETHER WITH JONATHAN IT'S THE MAXIMUM LIKELIHOOD METHOD THAT TAKES ALL OF OUR DATA, TAKES THE STIMULUS ON ANY GIVEN TRIAL, THE CHOICE THAT THAT MAKES ON GO ANY GIVEN TRIAL AND THE NEURAL RESPONSE THAT WE MEASURE, AFTER TRYING DIFFERENT POSSIBLE DECODERS AND USING THAT, IS FOR THE MAXIMUM LIKELIHOOD, ESSENCE OF D AND SIGMA OF M, AND THAT'S BASICALLY ANSWERING ANOTHER PART QUESTION, BECAUSE THE--THE QUESTION IS HOW BIG IS SIGMA SUBS, VERSES SIGMA SUBD IN THIS MODEL. I DON'T HAVE TIME TO GO IN DETAIL THROUGH THIS MODEL, BUT WHAT I WANT TO DO IS GIVE YOU AN INTUITION ABOUT WHAT ARE THE PREDICTIONS IF IT'S REALLY THE CASE THAT IS DOMINANT AND THIS IS NEGLIGIBLE. SO THIS IS A SIMPLE NOTE, ON ANY GIVEN TRIAL THE ANIMAL WILL SAY YES, THE TARGET WAS PRESENT OR NO, THE TARGET WAS ABNORMALITIES SEPTORS AND WE HAVE 2 POSSIBLE STIMULI, WE HAVE TARGET PRESENT OR ABSENT. THIS GIVES RISE OF THE 4 STANDARD CATEGORIES IN THE DETECTION TASK AND HERE ARE THE PREDICS AND MOST RELATED VARIABILITY IS IN V1. THE PREDICTION IS INTUITIVE, THIS IMPLIES WHEN WE LOOK AT RESPONSES TO THE SAME PHYSICAL STIMULUS, AND TARGET PRESENT WE SHOULD SEE RELIABLE DIFFERENCES IN THE RESPONSES BASED ON THE CHOICE THAT THE ANIMAL MADE. SO IF REALLY WHAT'S DRIVING THE CHOICE OF THE ANIMAL, THE VARIABILITY IN V1 THEN THE RESPONSES AND MISSES AND SIMILARLY RESPONSES IN FALSE ALEM SHOULD LOOK SIMILAR TO REJECTED 1S. THAT'S INTUITIVE. SECOND IF WE LOOK AT RESPONSES DURING FALSE ALARM TRIALS THOSE SHOULD BE ALARMED. SO THIS IS COUNTER INTUITIVE. THIS IS TELLING US THE RESPONSES IN V1 SHOULD CORRESPOND MORE CLOSELY THAN THE CHOICE THE ANIMAL MAKES RATHER THAN THE STIMULUS ON THE SCREEN BUT THIS IS SORT OF, NECESSARY, WITHIN THIS FRAMEWORK. IMAGINE LET'S SAY THAT WE DON'T HAVE ANY DOWN STREAM VARIABILITY, ALL VARIABILITY THAT IS DRIVING DECISION IS IN V1 AND PERDEFINITION ON A TRIAL IN WHICH THE ANIMAL, A FALSE ALARM TRIAL WHERE THE ANIMAL REPORTED THE TARGET PRESENT. WE KNOW THAT THE SIGNALS MUST HAVE EXCEEDED THE TRI KERRIA, AND THE DECISION HAD TO EXCEED THE CRITERION. AND ON A MISTRIAL, WHERE THE TARGET WAS PRESENT BUT THE ANIMAL REPORTED NOT SEEING IT, IT HAD TO BE BELOW THE CRITERION. SO IN THIS EXTREME CASE IT'S CLEAR THE FALSE ALEMS HAD TO EXCEED THE MISSES AND BASICALLY THE WAY THE MODEL BEHAVES, AS WE ADD DOWN STREAM VARIABILITY, THESE TUMOR RESPONSES GET CLOSER AND CLOSER AND EVENTUALLY THEY'LL REVERT, THE RESPONSES WILL GET STRONGER IF THEY'RE DOMINATED BY V1, THEN THEY WILL FOLLOW THESE AND IMPORTANT 3, THIS PREDICTION, THE SECOND PREDICTION, IS INSENTATIVE TO MEASUREMENT NOISE WHICH IS KEY FOR OUR EXPERIMENTS BECAUSE WE HAVE A LOT OF SOURCES OF NOISE THAT ARE CHOICE UNRELATED. SO LET ME SHOW YOU DATA. HERE AGAIN AVERAGE RESPONSES OVER A INSURED PERIOD AFTER STIMULUS ONSET BEFORE THE ANIMAL MEETS POSITION ON ALL THE PRESENT TRIALS AND TARGET ABSENT TRIALS AND AGAIN THESE ARE LOW, LOW, CONTRAST WELL BELOW MY THRESHOLD, PERCEPTUAL THRESHOLD AND THE KEY QUESTION IS WHAT HAPPEN WHEN IS WE SPLIT THESE HITS AND MISSES OVER HERE. IN THE DRAMATIC RESPONSES SO STIMULUS TRIALS AND RESPONSES IN HITS ARE MUCH STRONG STRONGER IN THE RESPONSE IN THE MISSS AND SIMILARLY WE LOOK AT FALSE ALARM TRIALS. THE RESPONSES ARE QUITE DIFFERENT FROM THE RESPONSES IN INJECT AND IMPORTANTLY FOR WHAT I JUST TOLD YOU. RESPONSES IN THE FALSE ALARMS ARE TIRED IN THE RESPONSES IN THE MISTRIALS. AND ANOTHER IMPORTANT FEATURE HERE IS THAT, WHEN WE LOOK AT THE CHOICE RELATED VARIABILITY IN CHOICE RELATED ACTIVITY, RATHER THAN HAVING A REALLY SMALL REGION AT THE CENTER, WHERE WE GET THE STRONGEST RESPONSE, BE CORRELATED WITH A CHOICE, WE SEE CHOICE RELATED ACTIVITY OVER MUCH LARGER REGION, SUPPORTING THE IDEA THAT THE MONKEY IS USING RELATIVELY LARGE POOL OF NEURONS TO FORM THE DECISION. SO, LET ME JUST SUMMARIZE THIS PART, OUR RESULTS SHOW THERE IS A ROBUST CHOICE RELATED ACTIVITY IN THE RESPONSES, AND WHEN WE TAKE THESE RESULTS AND WE PUT THEM INTO OUR MODEL, UNDER THE MODEL ASUFPBLGZ FOR VARIOUS TYPES OF DECODERS, WE FIND THAT THE VAST MAJORITY OF THE VARIABILITY, THE MODEL SUGGEST THAT THE VAST MAJORITY OF THE VARIABILITY IS PRESCRIBINGENTENT IN V1. MAJORITY PRESENT IN V1. AND THIS SUGGESTS THAT THE REASON THE MONKEYS ARE NOT PERFORMS OPTIMALLY IS PRIMARILY INEFFICIENCY OR SUBOPTIMAL PULLING RATHER THAN A LOT OF DOWN STREAM VARIABILITY. NOW IN THIS PROJECT WE QUANTIFY THE VARIABILITY IN V1 BUT WE DIDN'T ASK OR WE COUNTERED WITH THE QUESTION: WHERE IS THIS VARIABILITY COMING FROM. AND 1 POSSIBILITY IS THIS IS A BOTTOM UP SENSORY ACCUMULATING FROM THE RETINAL RETINA AND ANOTHER POSSIBILITY IS THAT THIS OR SOME OF THIS COULD BE DUE TO TOP DOWN MECHANISMS AS SUGGESTED BY RECENT ELKPWAPBT STUDY BY BRUCE. SO I DON'T THINK WE REALLY ADDRESS THIS QUESTION, USING OUR TECHNIQUE. ONE THING THEY SHOULD MENTION IS THAT WHEN YOU LOOK AT THE TIME COURSE OF THESE CHOICE RELATED RESPONSES THE TIME COURSE OF THE CHOICE, AND WE DON'T SEE CHOICE RELATED ABILITY FOREVER THE STIMULUS APPEARED AND DON'T SEE DELAYED STIMULUS ONSET, THAT'S AN INTERESTING POINT TO CONSIDER. THE LAST PROJECT I'LL DESCRIBE ACTUALLY TRIES OR PARTIALLY MOTIVATED BY THIS RESULT, WE WANT TO CHARACTERIZE WHAT TOP DOWN MECHANISMS COULD DO AT THE LEVEL OF V1. SO IN THIS PROJECT, WE ASKED, TOP DOWN MODULATE AND USING IMAGING IN THE MONKEY SO THIS WAS THE FIRST QUESTION. SO WHAT WE WANT TO KNOW IS IF WE CAN SEE TOP DOWN MODULATIONS IN V1. WHAT ARE THE SPACIAL TEMPORAL DYNAMICS. WE HAVE THIS GOOD SPACIAL TEMPORAL RESOLUTION, WE MIGHT BE ABLE TO ADDRESS THAT QUESTION AND ANOTHER REALLY IMPORTANT GOAL THAT HI, THIS IS SOMETHING THAT I--I REALLY WANTED TO ADDRESS SINCE MY PH DD WORK WITH BILL--Ph.D. WORK WITH BILL NEWS ON ORDER OF MICRONS AND 1 OF THE THINGS I THOUGHT WAS FULLY ADDRESSED IS WHAT THE PURPOSE OF ATTENTION. TWO POSSIBLE, WHAT I HOPE TO CONVINCE YOU IS THAT THERE ARE 2 POSSIBLE THINGS ATTENTION COULD BE DOING IN THE SENSORY AREA. ONE OF THEM IS RELATED TO THIS IDEA, PREVALENT IN THE FIELD THAT WE HAVE LIMITED SENSORY PRESENTATION. LIMITED TO CAPABILITY AND THE GOAL OF ATTENTION IS TO ALLOCATE THESE LIMITED RESOURCES TO THE AND WHEN WE FOCUS WE APPLY A LOT OF RESOURCES BUT WHEN WE APPLY, WE HAVE TO DISTRIBUTE THESE RESOURCES AND SEE A DIFFERENCE IN PERFORMANCE SO THIS IS 1 POSSIBILITY. ANOTHER POSSIBILITY IS THOSE ARE NOT MUTUALLY EXCLUSIVE IS THAT THE MAIN PURPOSE OF ATTENTION IS IN THE CASE OF SPACIAL ATTENTION IS TO SPACIALLY GAUGE SIGNALS BASED ON SIGNIFICANCE. SO IF WE HAVE THINGS THAT ARE IRRELEVANT FOR OUR BEHAVIOR AT A GIVEN TASK, THE MAIN GOAL OF ATTENTION IS TO NOT LET THESE AFFECT THEIR BEHAVIOR. SO THE WAY WE DESIGN THIS IS THAT THEY'RE DISTINGUISHED BETWEEN THESE POSSIBILITYS AND THESE EFFECTS ARE RELATED TO THIS OR TO THIS. NOW I THEN IS A LITTLE BIT TRICKY SO I TAKE BODY THIS WITH BILL GEISLER, SO HE SUGGESTED THE FULL ILLUSTRATION TO SHOW THESE FUNCTIONS. SO LET ME WALK YOU THROUGH THE EXAMPLE IS PLEASE STOP ME IF SOMETHING'S NOT CLEAR. SO HERE'S A AN EXAMPLE, TO ILLUSTRATE THESE POSSIBILITIES. SO IN THIS TOY EXAMPLE, WHAT YOU'RE DO SUGGEST YOU'RE FACE WIDE A SIMPLE TASK, ON EVERY TRIAL YOU'RE SEEING 4 POINTS IN THIS CONFIGURATION AND YOUR GOAL IS TO REPORT WHETHER THERE THEY'RE AHEAD OR IF THERE IS A HEAD, WHERE IT'S LOCATED SO ON HALF OF THE TRIALS THERE WILL BE 4 TAILS, ON HALF OF THE TRIALS TELL BE A SINGLE HEAD, AND YOUR GOAL IS TO REPORT WHERE IT IS. NOW THIS A TRIVIAL TASK BUT WHAT MAKES THE TASK DIFFICULT IS THAT YOU DON'T HAVE ACCESS TO THE POINTS. YOU HAVE ACCESS TO THE NOISIER REPRESENTATION. AND BECAUSE OF THIS, THERE'S A CERTAIN PROBABILITY THAT WHAT YOU'RE SEEING, WHAT YOU'RE EXPERIENCING IS DIFFERENT FROM THE TRUE STATE OF THE COIN. AND WE REPRESENT THIS BY WHAT WE CALL A SPONTANEOUS FLIP. FOR A ABILITY OF SPONTANEOUS SLIP WHICH IS INVERSELY PROPORTIONAL TO THE FIDELITY, AND THE NEURAL FIDELITY IS HIGH, THEN THERE'S LOW PROBABILITY OF A FLIP SPONTANEOUS, IF THE FIDELITY IS LOW, THAN THE PROBABILITY IS HIGHER. THIS IS REPRESENTED HERE BY THIS RED BAR IN OUR EXAMPLE, THIS IS 10%. OKAY? EMPLOY NOW YOU PERFORM THIS, THIS COULD CONTAIN THE TRUE HELP. OR, UNDER THE DISTRIBUTED ATTENTION MODE WHERE ALL 4 LOCATIONS ARE INVALID AND IT'S EASY TO APPRECIATE THAT, WHEN YOU KNOW THAT THIS IS THE ONLY RELEVANT LOCATION, THEN YOU DON'T CARE ABOUT THE OTHER LOCATION AND YOUR PERFORMANCE WILL BE 90% CORRECT BECAUSE IF YOU SEE A HEAD HERE, REPORT IT'S A HEAD, YOU ARE RIGHT 90% OF THE TIME. IF YOU SEE A, YOU REPORT THAT YOU'RE RIGHT 90% OF THE TIME. HOWEVER IF WE GO TO THIS CASE, THIS IS GOING TO BE MUCH HARDER. WHAT I SHOULD HAVE MENTIONED IS THAT, IN THIS CASE, WE ASSUME THAT THERE IS NO RESOURCE LIMITS. AND THE REASON THAT THERE IS NO RESOURCE LIMIT OR BECAUSE THERE'S NO RESOURCE LIMIT, THE FLIP ABILITY FOR EACH 1 OF THE COIN SYSTEM--COINS IS STILL .1. HAD I SHOWN YOU THIS EARLIER, TPHREPB THE FLIP ABILITY WOULD BE 1, HERE YOU HAVE TO ALLOCATE IT TO 1 LOCATION, HERE YOU DISTRIBUTE IT. BUT IN THIS CASE THERE IS NO RESOURCE LIMIT. BESPITE THE FACT THERE'S NO RESOURCE LIMIT, YOU COULD REP RESENT 1 TARPGET AND SAME WITH A FIDELITY AND THIS IS A MUCH HARDER. ONE REASON TO SHOW THIS IS IMAGINE THAT YOU'RE SEEING 2 HEADS, 1 HERE AND 1 HERE. IN THIS CASE, UNDER FOCAL ATTENTION YOU KNOW THIS IS A SPONTANEOUS SLIP. YOU ONLY CONSIDER THIS LOCATION, YOU CONSIDER THERE IS A HEAD AND YOU WILL BE RIGHT 90% OF THE TIME. IN THIS CASE, YOU DON'T KNOW WHICH 1 OF THE 2 MAY CONTAIN THE TRUE HEADS. SO EVEN IF YOU SAY, CORRECTLY THAT THERE IS A HEAD, YOU STILL HAVE TO GUESS WHICH OF THE 2 LOCATIONS CONTAIN IT, SO YOUR PERFORMANCE IS 50% WORSE. AND IT'S FAIRLY EASY TO WORK OUT WHOO IS THE OPTIMAL STRATEGY IN THIS TASK UNDER THE DISTRIBUTED ATTENTION AND YOU CAN SHOW THE BEST YOU CAN DO IN THIS TASK IS 71% CORRECT. SO, DESPITE THE FACT THAT THERE IS NO RESOURCE LIMIT, PERFORMANCE WILL BE MUCH WORSE UNDER DISTRIBUTED ATTENTION THAN UNDER FOCAL ATTENTION SO THE FIRST TAKE HOME MESSAGE FOR THIS EXAMPLE IS THAT SEEING DIFFERENCES IN BEHAVIOR BETWEEN FOLK AT AND DISTRIBUTED DOESN'T NECESSARILY MEAN THERE'S A LIMITED RESOURCE INVOLVED. NOW OF COURSE WE GO TO A CASE WHERE WE HAVE A RESOURCE IN THE MIX, NOW THE FLIPPABILITY WHILE IT WAS 10% HERE GOES UP TO 20% HERE, WE ARE GOING TO GET ANOTHER HIT IN OUR PERFORMANCE AND THE BEST PERFORMANCE THAT WE CAN HAVE NOW IS 60%. SO THE KEY EVIDENCE FOR A LIMITED RESOURCE IS DIFFERENT IN THE FIDELITY OF THE REPRESENTATION OF A COIN UNDER FOCAL ATTENTION VERSES THE DISTRIBUTOR ATTENTION AND THIS FIDELITY DIFFERENCE COULD BEING REFLECTED IN A CHANGE BY THE SIGNAL AND SIGNALS ARE STRONGER HERE THAN HERE OR BY CHANGING THE NOISE. NOISE IS LOWER HERE, THAN HERE. OR BY BOTH. NOW ATTENTION ACCOUNTED BE DOING ANOTHER THING, IN THIS TASK, ANOTHER THING IT COULD SOMEHOW TAG FOR SUBSEQUENT PROCESSING STAGES WHICH LOCATIONS ARE RELEVANT AND WHICH LOICATIONS ARE IRRELEVANT. SO IN OUR TASK, IN THE FOCAL ATTENTION TASK THERE IS ONLY 1 COIN THAT IS RELEVANT, THE OTHER COINS ARE IRRELEVANT TO THE TASK. SO THE WAY WE INDICATED THIS, THIS IS BY THE COLOR OF THE COIN. THE GOLD COIN IS RELEVANT, THE SILVER COINS ARE IRRELEVANT, AND THE OTHER THING THAT ATTENTION COULD BE DOING IS SOMEHOW BIAS OR TAG RELEVANT LOCATIONS RELATIVE TO IRRELEVANT LOCATION. THIS IS REALLYALATED TO THIS IDEA OF--RELATED TO THE IDEA OF A GATING MECHANISM, SO THE DEFICIENCY WOULD BE INDTENDED LOCATIONS LOCATIONS AND IGF NORRED LOCATIONS IN V1. I HOPE THIS HELPS YOU APPRECIATE THESE POSSIBILITIES AND THEIR PREDICTIONS. SO WE DESIGNED THE TASK TO THIS, IT'S SIMILAR TO THE DETECTION TASK TAKEN--THEY YOU HAVE ORIGINALLY, BUT IT HAS 2 MAJOR DIFFERENCES. THE FIRST IS THAT THE PARTY COULD APPEAR, COULD APPEAR IN THE 4 QUADRANTS AND THEN WE MIX TRIALS IN WHICH WE TELL THE ANIMAL IN ADVANCE, WHICH LOCATION IS RELEVANT AND TRIALS IN WHICH THE ANIMAL WAS ASKED TO ATTEND TO ALL LOCATIONS. SO THE WAY WE WERE TELLING THE ANIMAL WHAT WE'RE TO ATTEND IS THERE'S A THIN CIRCULAR OR WHILE CIRCLE THAT EXTENDS KWRAUBD THE AREA THAT WE'RE IMAGING BUT MARKS THAT TAGS THAT LOCATION AS BEING RELEVANT. SETHERE'S EITHER A SINGLE CUE OR MULTIPLE CUES THAT THE ANIMAL HAS TO ATTACH TO ALL OF THEM. THERE'S ONLY A 50% CHANCE THAT THE ANIMAL APPEARS AND THEY WILL HAVE TO MOVE THEIR EYES TO THAT LOCATION AND THERE WILL BE NO TARGET IN WHICH THE ANIMAL MAINTAINS FIXATION. CUE IS ALWAYS VALID AND THEN AFTER A RAPD ORDER OF MICRONS DELAY AFTER A FEW OFFSETS THERE'S A RANDOM DELAY IN WHICH THE ANIMAL FIXATES AND THE POSITION--THE KEY DIFFERENCE IN HAVING UNIFORM BACKGROUND, WE DID THIS EXPERIMENT BY HAVING 4 ORIENTED STIMLIEU LIE THAT WE CALL MASKS THAT APPEAR ON EVERY TRIAL. SO THIS IS THE BACKGROUND ON WHICH THE TARGET WILL APPEAR AND THE MASKS ARE MODERATE OR MEDIUM CONTRAST, VIRTUAL MACHINE CALIFORNIA STIMULI AND THE TARGET IN THIS EXAMPLE IS LO CONTRAST HORIZONTAL, SO THERE ARE 2 POSSIBLE STIMULI, EITHER THEY'RE 4 MASKS OR 4 VERTICAL MASKS ON THAT TRIAL OR THERE WILL BE 4 MASKS AND A TARGET ON TOP OF THE MASK WHICH IS SHOWN HERE. THIS WAS EXAGGERATED IN TERMS OF THE CONTRAST, IT'S VERY, VERY HARD. THE ANIMAL REPORTS SEEING THE TARGET [INDISCERNIBLE] OF THE PICTURE. SO I'M SORT OF RUNNING LATE. I'M GOING TO RUN, I'LL JUST MENTION THAT BEHAVIORIALLY, WE SEE CLEAR EFFECTS OF THE TASK FOR THE MONKEY'S PERFORMING BETTER UNDER THE FOCAL ATTENTION THAN OTHER DISTRIBUTED ATTENTION IN TERMS OF ACRASE MODEL SCHEIN TERMS OF REACTION TIME. BUT HERE IS THE KEY EXPERIMENTAL RESULT. SO, IN THIS EXPERIMENT, SWRAOE 2 POSSIBLE STIMULI, EITHER MATH ONLY OR MATH PLUS TARGET IN THE REGION WE'RE IMAGING AND THEN WE HAVE 3 POSSIBLE INTENTIONAL STATES. THIS IS INDICATED HERE BY THIS CARTOON AT THE TOP SO THE COLOR WILL BE CONTINUED THROUGHOUT THE REST OF THE PRESENTATION, GREEN MEANS THAT WHILE THE RECEPTIVE FIELD HERE IS AT THE BOTTOM LEFT, THE KEY WAS SOMEWHERE ELSE. IN THIS CASE, IT'S A SINGLE CUE AND THE RECEPTIVE FIELD LOCATION IS IRRELEVANT SO WE CALL THIS UNATTENDED CONDITION. WE COULD HAVE AN ATTEND-IN CONDITION WHERE THE KEY WAS IN THE FIELD THAT WE'RE IMAGING AND ATTEND IN. OR WE CAN HAVE AN INTENDED [INDISCERNIBLE]. AND IF YOU FOLD MY EXAMPLE, HERE ARE THE PREDICTIONS, IF THE MAIN PURPOSE OF THE ATTENTION IN THIS TASK IS TO ALLOCATE LIMITED RESOURCES, THEN WE SHOULD SEE A DIFFERENCE BETWEEN THE RESPONSES IN V1 UNDER THE DISTRIBUTED THIS THAT END. SO DIFFERENCE HERE IN SIGNAL TO NOISE IN THE SENSITIVITY WILL INDICATE A LIMITED RESOURCE. DIFFERENCE HERE BETWEEN ATTEND IN AND ATTEND OUT WILL EVIDENCE GATING. OF COURSE WE CAN SEE BOTH. BUT NOW WE'RE TESTING FOR THEM INDEPENDENTLY. SO THIS IS A GOOD POINT TO TAKE A QUICK SURVEY AND THOSE WHO HAVEN'T READ THE PAPER, HOW MANY OF YOU THINK WE'LL SEE EVIDENCE FOR LIMITED RESOURCES, ONLY GATING ONLY, OR BOTH. I GIVE YOU A HINT. ONE OF THEM IS A PICTURE. HOW MANY THINGS JUST LIMITED RESOURCE. NO 1. HOW MANY THINK LIKE 80? QUITE A FEW. AND HOW MANY THINK BOTH? OKAY. SO, PEOPLE ARE SPLIT BETWEEN EITHER BOTH OR JUST THE GATING. SO HERE ARE THE RESULTS. WHEN WE COMPARE THE RESPONSES, THESE ARE RESPONSES AVERAGE OVER SHORT PERIOD, WE SEE QUITE SIGNIFICANT DIFFERENCES BETWEEN THIS POSITION AND THE IN-POSITION, YOU CAN SEE THIS IN THE COLORS, THEY ARE DARKER THAN AVERAGE HERE AND THAT DIFFERENCE IS QUITE RELIABLE. SO THE ATTENTION FOR THE GATING MECHANISM. IF WE COMPARE THEM, THEY ARE VIRTUALLY IDENTICAL. WE SEE NO DIFFERENCE AT ALL IN THESE 2 POSITIONS INCONSISTENT WITH A LIMIT THE RESOURCE IN THIS PARTICULAR TASK. SO TO QUANTIFY THIS, 1 WAY TO QUANTIFY THIS IS TO AGAIN TAKE THE CENTER OF THE RESPONSE AND THIS IS SHOWN HERE FOR THE TARGET ABSENCE, AND THE TARGET PRESENT TRIALS. REMEMBER THE CONTRAST OF THE TARGET IS VERY LOW AND THE MASK HAS HAY HIGHER CONTRAST O THE RESPONSE IS DOMINATED BY THE RESPONSE OF THE MASK WHAT YOU CAN APPRECIATE LEER IS THAT IN THE DISTRIBUTED--IN THAT SENSE, THE RESPONSE IS ELEVATED, RELATIVELY THEY TEND OUT, PRETTY MUCH THROUGHOUT THE ENTIRE AREA WE'RE IMAGING, 10-MILLIMETERS OF CORTEX, THE BASELINE BY THE WAY IS DEFINED BY TRIALS WHERE WE DID NOT PRESENT ANY STIMULUS. SO, IN THE 10th OUT, THE BASELINE IS ACTUALLY CLOSE TO 0 AND THE THAT'S DISTRIBUTED IN AN ELEVATED BASELINE OVER THE ENTIRE AREA. BOTH FOR THE NO TARGET AND WITH A TARGET. BECAUSE THESE WERE VERY SIMILAR, WE COMBINED THESE 2 AND WE QUANTIFIED THE EFFECT BY FITTING THE RESPONSES WITH A 2 DIMENSIONAL TKPWALSION, TO INDICATE THE TKPWALSION RESOPBS AND THE UNIFORM SPACIAL PEDESTAL TO INDICATE THAT BASELINE ELEVATION AND WHEN WE QUANTIFY THE RESPONSES, THE INTERESTING RESULT IS THAT BE RESULT FROM 1 MONK SCHETHE OTHER MONKEY WE SEE NO EFFECTIVE ATTENTION ON THIS 2 DIMENSIONAL TKPWALSION. THE STIMULUS RESPONSE LOOKS IDENTICAL UNDER THE 3 ESSENTIAL STATES BUT WHERE WE DO SEE SIGNIFICANT DIFFERENCE SYSTEM IN THE BASELINE, THE BASELINE IS ELEVATED IN THE TURNED IN AND SIMILARLY ELEVATED, AND THERE'S NO BASELINE ELEVATION RELATIVE TO PREDICTION TO THE BLIND TRIALS IN THIS END OUT. AND THE DASH LINE HERE BY THE WAY REPRESENTS THE AVERAGE STIMULUS RESPONSE, THE MAG NIFEUD OF THE TARGET RESPONSE, THE DIFFERENCE WOULD BE MASK ONLY AND MASK TPHRUFBG TARGET AND YOU CAN SEE THE EFFECTS ARE LARGER THAN THE TARGETED RESPONSE SO THEY'RE NOT NEGLIGIBLE AND THE LAST THING I'LL SHOW YOU HERE IS THAT WHEN WE ELECTRIC AT THE TIME COURSE OF THIS POTENTIAL EFFECT, IF WE LOOK AT THE DIFFERENCE IN THE BASELINE IN THE ATTEND IN AND ATTEND--DISTRIBUTED VERSES 10th OUT, STARTS TO BUILD UP ABOUT A HUNDRED SECONDS BEFORE THE STIMULUS APPEARS, SO IT'S AN ANTICIPATORY EFFECT AND REMEMBER THE GIVE THE ANIMAL A CUE, OF THE FIXATION POINT TELLS THEM THAT 3 SECONDS LATER THE TARGETS WILL APPEAR, SO ABOUT A HUNDRED SECONDS BEFORE THE TARGET APPEAR WAOES SEE THE BUILD UP IN THE ACTIVITY THAT IS UNIFORM SPACIALLY AND TO SHOW YOU THE COURSE OF THE PART AS YOU EXPECT THAT BUILDS UP ON THE AFTER-STIMULUS. SO, LET ME QUICKLY SUMMARIZE, THIS, WE SEE EVIDENCE FOR SPACIAL GATING BUT NOT FOR LIMITED RESOURCES, THE INTENTIONAL MODULATIONS OPERATE OVER A LARGER SPACIAL SCALE, LARGER THAN THE SCALED RESPONSE AND ANTICIPATORY IN NATURE. AND WHAT WE THINK IS THAT THE PURPOSE OF THESE EFFECTS COULD BE TO HELP TO GATE LOCATIONS THAT ARE IRRELEVANT, BIAS, FURTHER PROCESS NOTHING FAVOR OF THE LOCATIONS THAT ARE RELEVANT TO THE ANIMAL VERSES LOCATIONS THAT ARE IRRELEVANT. SO JUST TO CONCLUDE, IN THE FIRST PART I SHOWED YOU THERE IS NOR INFORMATION IN V1 THAT THE ANIMALS CAN ACTUALLY USE IS THIS SUGGESTS THAT THERE IS SOME KIND OF INEFFICIENCY DOWN STREAM. SECOND PROJECT SHOWS THERE'S CHOICE RELATED ACTIVITY IN V1 BASED ON THE DATA AND THE MODEL THE SEFDZ THAT THE CHOICE RELATED VARIABILITYS ARE PRESENT IN V1 WHICH WOULD IMPLY THAT THE MAIN LIMITATION HAS TO DO WITH INEFFICIENT DECODING AND WE'RE CURRENTLY TRYING TO UNDERSTAND THE NATURE OF THIS INEFFICIENT DECODING. EMPLOY THIS IS AN ACTIVE AREA OF RESEARCH IN THE LAB. AND THEN IN THE THIRD PART I SHOWED YOU THAT THERE ARE TOP DOWN MODULATIONS IN V1 AND APPEARS TO BE RELATED TO SPACIAL GAINING AND NOT ALLOCATION OF LIMITED RESOURCES. SO LET ME THANK MY COLLABORATORS. YUSY CHEN. A POST DOC IN THE LAB, NOW A SCIENTIST. HE TRIBUTED THROUGH ALL PROJECTS BUT PRIMARILY IN THE FIRST AND THIRD. CHUCK MICHAEL SON, WORKED IN THE SECOND PROJECT, MY COLLABORATORS HERE. AND THEN, PAST AND PRESENT LAB MEMBERS AND OF COURSE, SUPPORT FROM NEI AND OTHER INSTITUTIONS. ONE THING I WANTED TO DO WHILE I ANSWERED QUESTION, I DIDN'T HAVE TIME TO TALK ABOUT IT BUT NICHOLAS PRIVY AND I DEVELOPED TECHNIQUES FOR DOING INTRACELLULAR RECORD NOTHING OUR WAKE BEHAVING MONKEYS AND I WE HAVE DATA THAT ARE INTERESTING THIS WILL GIVE US ANOTHER NEW PERSPECTIVE ON POPULATION RESPONSE IN THE CORTEX, NOW FROM THE PERSPECTIVE OF A SINGLE V1 NEURON AND THE INPUTS THAT IT RECEIVES FROM THE POPULATION OF PRESYNAPTIC INPUT. SO I THINK, WHAT I WANT TO DO WHILE I'M ANSWERING QUESTION IS SHOW YOU THIS LITTLE CLIP. LET'S SEE IF I SUCCEED IN DOING THAT. SO THIS SHOWS THE GAZE OF THE MONKY, THIS WILL SHOW YOU WHERE THE MONK SELOOKING AT AND THE VISUAL STIMULUS THE MONK SELOOKING AT AND THE BOTTOM WILL SHOW YOU THE INTRACELLULAR RECORD PROGRESS A SINGLE CELL IN V1 AND THIS IS A SIMPLE CELL SO AS THE STIMULUS SWEEPS IT SWEEPS AT 4-HERTZ. IT 4 CYCLES OF MODULATIONS IN V1. SO I'LL START RUN THANKSGIVING MOVE SCHEHERE YOU SEE IN THE SECOND STIMULUS APPEARS AND HERE ARE THE 4 CYCLES OF THEY ROBINSON SPONSE TO THE STIMULUS. SO WHILE I ANSWER QUESTIONS, YOU CAN LOOK AT THIS. THIS WILL DISTRACT YOU SO YOU WON'T ASK HARD QUESTIONS. THANK YOU VERY MUCH FOR THE ATTENTION. [ APPLAUSE ] >> --YOU SHOULD IS BE ABLE TO BOTH OF THESE BECAUSE THERE'S NO LIMITED RESOURCE IN YOUR--[LAUGHTER] >> HAVE YOU TRIED A CASE WHERE THE ANIMAL DIDN'T--WHERE YOU DIDN'T GET THE ANIMAL PRECISE TEMPORAL CUE BECAUSE IT WOULD BE INTERESTING TO KNOW WHETHER THE CHANGE IN BASELINE ACTIVITIES ARE TIME DEPENDENT [INDISCERNIBLE]--TO WHERE WE KNOW WHAT HAPPENED AS YOU'RE WAITING TO [INDISCERNIBLE]--IT WOULD BE INTERESTING TO KNOW? >> THE TIMING? WE EVAPORATE DONE THAT. THERE'S TECHNICAL LIMITATIONS BUT IN PRINCIPLE, THIS IS DOABLE. WE CAN ADD JITTER TO THE TIMING AND SEE HOW THAT EASTS THE BUILD UP UP OF ACTIVITY BUT WE HAVEN'T DONE THAT. THAT WOULD BE INTERESTING. >> BASICALLY SAME QUESTION, ON EVERY FILE [INDISCERNIBLE]-- >> HALF OF THE TRIALS. HALF OF THE TRIALS. ONLY WHEN THERE IS A TARGET, WHEN HE THINKS THERE IS A TARGET. IF NOT HE'LL MAINTAIN FIXATION. >> [INDISCERNIBLE]. >> THIS BUILD UP AND IRRESPECTIVE WHETHER HE WILL GO OR NOT. >> [INDISCERNIBLE] CROSS LINKING SO WE COULD HAVE THE ANIMALS RECORD BY GOING SOMEWHERE ELSE, WE WILL SEE THIS MODULATION, THAT WILL BE INTERESTING TO TRY. WE HAVEN'T DONE THAT OF COURSE. BUT THIS IS AN INTERESTING SUGGESTION. YEAH. >> [INDISCERNIBLE]. >> YEAH, EVERYTHING IS SINGLE TRIAL. WE WORKED OUT WHAT I SHOWED YOU, JUST OPTIMAL SPACIAL POOLING, WE WORKED OUT OPTIMAL DYNAMIC POINT WHERE YOU TAKE THE SIGNALS AS THEY COME AND YOU FORM 2 DECISIONS, 1 IS SHOULD I GO OR NOT AND TO WHEN SHOULD I GO. AND SO, THESE ARE BOTH INTERESTING STUDIES, WHAT I SHOWED YOU, BUT EVERYTHING IS DONE ON A SINGLE TRIAL AND EVERYTHING IS DONE IN CROSS VALIDATED FASHION. SO THE ALEGORITHMS QUOTE IS SEEING A NEW TRIAL IT HASN'T SEEN BEFORE AND HAS TO DECIDE WHEN TO RESPOND AND THEN WE COMPARE THE PERFORMANCE AND THE ALEGORITHMS CAN DO BETTER THAN THE MONK SCHEDO IT FASTER THAN THE MONKEY. >> ALSO HAVE A QUESTION ABOUT THE SUBOPTIMAL POOLING, FROM YOUR FIRST STUDY, YOU DESCRIBED IT MAKES IT LOOK LIKE IT MAY NOT BE TERRIBLY OPTIMAL BUT IN THE MODEL AS YOU ADD MORE NOISE, YOU HAVE TO DO MORE AND MORE DECODED. SO CAN YOU SAY HOW [INDISCERNIBLE] THAT IS? HOW MUCH INFORMATION IS LOST BY THE DECODING IN THE MODEL WITH THE MEASUREMENT NOISE? >> MEASUREMENT NOISE WILL NOT EFFECT THE EFFICIENCY OF THE DECODING BUT IN A SENSE IT WOULD BECAUSE IT WOULD IMPLY THAT THE SIGNALS TO THOSE PRIOR PRIOR THAT WOULD SRO BEEN BETTER. I'LL HAVE TO THINK ABOUT IT. I'M NOT SURE I HAVE A GOOD ANSWER TO THAT--TO THAT QUESTION. BUT THAT'S THE KIND OF THING WE'RE TRYING TO DO NOW. AND WE THINK THAT--WE HAVE SOME IDEA ABOUT THE POTENTIAL SOURCE OF INENTIOUS FICIENCY. WE THINK THAT WHAT COULD BE AFFECTING THE ANIMALSER FORMANCE IS IS THAT WHILE OUR ANIMAL KNOWS EXACTLY WHERE THE STIMULUS IS, EXACTLY THE TIMULOUS RESPONSES, WE HAVE BEHAVIORIAL DATA, BEHAVIORIAL EVIDENCE IS BOTH FOR MONKEYS AND HUMANS THAT SUGGEST THERE IS A CERTAIN AMOUNT OF UNCERTAINTY ABOUT LOCATION IN THIS TASK, AND THAT'S THE MAJOR SOURCE OF INEFICIENT THAT LIMITS THEM--INEFFICIENCY THAT LIMITS THE ANIMAL'S PERFORMANCE. SO IN THAT CONTEXT, WE CAN ACTUALLY MODEL EVERYTHING INCLUDING THE MEASUREMENT NOISE AND OUR RESULTS SUGGEST THAT PERFORMANCE PROBABLY WOULD HAVE BEEN EVENT BETTER THAN WHAT WE GET RIGHT NOW, HAD WE NOT HAD THE MEASUREMENTS, OR HAD NO MEASUREMENTS. STH-RBGS-- >> [INDISCERNIBLE]. >> YEAH IN GENERAL MY IMPRESSION FROM THESE RECORDINGS, I'M NOT SURE WHERE IT'S COMING FROM, SPIKING RATES ARE FAIRLY LOW SO I DON'T KNOW IF THIS IS A SAMPLING ISSUE, OR THE INTRACELLULAR WITH LOWER CELLS WAS LOWER FIRING RATES, BUT IT'S DIFFERENT FROM EXTRA CELLULAR RECORDING WHERE THEY'RE FIRING SPONTANEOUSLY AND HAVE HIGHER SPONTANEOUS RATES SO WE DON'T KNOW WHETHER THAT'S THE ISSUE OR SOMEHOW THE INTRACELLULAR RECORDING IS ACTUALLY AFFECTING THE SPIKE THRESHOLDS MECHANISM. ONE INTERESTING THING FOR ME, WAS REALLY SURPRISING AND INTERESTING IS THAT WE DEFINITELY HAVE EPISODES IN THE AWAKE BEHAVING MONKEY WHERE THE MONKEY IS FIXATING, WE SEE NO MOVEMENTS OF THE EYE AND IT VARIES FROM CELL TO CELL BUT WE CAN SEE LARGE FLUCTUATION SPONTANEOUSLY THAT ARE SIMILAR IN SOME CELLS OF THE STIMULUS RESPONSE, SO EVEN IN THE AWAKE ANIMAL, YOU HAVE THESE LARGE FLUCTUATIONS SPONTANEOUSLY THAT ARE COMPARABLE TO THE THINGS OF THE RESPONSE WHICH I FOUND QUITE SURPRISING. >> [INDISCERNIBLE]. >> BASICALLY IT'S A DEFINITION, WE DEFINE ANYTHING DOWN STREAM THAT IS INDEPENDENT OF WHAT WE CAN MEASURE. SO IN A SENSE, THAT'S WHY I SAID, WE'RE AGNOSTIC WHEN WE'RE MEASURING, IN V1, WE'RE--THIS IS--WE THINK BECAUSE THIS IS A REACTION TIME TASK IT'S A BRIEF PERIOD WE SEE WHAT WE'RE MEASURING IS R*EPB CODING, THE EVIDENCE OF ANIMALS USING TO PERFORM THE TASK WHETHER OR NOT THAT IS CONTAMINATED BY TOP DOWN SIGNAL SYSTEM AN IMPORTANT QUESTION, BUT ANYTHING IN V1 WE CALL ENCODING EVEN IF IT'S COMING FROM TOP DOWN. AND THEN ANYTHING THAT IS INDEPENDENT OF WHAT WE'RE SEE SUGGEST V1. THAT'S WHAT WE CLASSIFY AS DOWN STREAM. IT'S A DEFINITION. >> AGAIN IT'S A MATTER OF DEFINITION. WE'RE NOT CLAIMING THAT THE VARIABILITY OF V1 IS NECESSARILY THERE. IT COULD HAPPEN, BUT, WHAT WE THINK THINK IS THAT WE'RE LOOKING INTO EVIDENCE THAT WE'RE USING AND THAT EVIDENCE OF ENCODING COULD HAVE TOP DOWN CONTRIBUTIONS. --TO IT. SO THE QUESTION AGAIN IS, HOW MUCH OF THE CHOICE RELATED ABILITY THAT WE'RE SEEING IN THE BEHAVE HAIR IS DO THE--BEHAVIOR IS PRESCRIBINGINENT V1 AND HOW MUCH IS DUE TO VARIABILITY IN V1 AND INDEPENDENT OF WHAT'S HAPPENING IN VIVO. >> OKAY, I'D LIKE TO THANK AL FOR A VERY INTERESTING TALK. [ APPLAUSE ]