Neural Mechanisms for Visual Memory and Their Role in Attention

Neural Mechanisms for Visual Memory and Their Role in Attention Robert Desimone

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Neural Mechanisms for Visual Memory and Their Role in Attention 1996 Proceedings of the National Academy of Sciences 10.1073/pnas.93.24.13494 desimone1996-repetition-suppression desimone1996-repetition-suppression.txt, the project's staged copy 99332985f7bd22705e3163175cd474dd7fc03426 personal-copy neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them The neural basis of visual memory, including how repeated stimuli elicit reduced neural responses (repetition suppression). Quotation withheld because this record is not cleared for redistribution. What neural mechanisms support visual memory, and how does repeated experience with a stimulus change neuronal responses? Quotation withheld because this record is not cleared for redistribution. Reviews evidence that neurons in visual cortex respond less to repeated than to novel stimuli (repetition suppression), the neural mechanism underlying repetition priming and implicit memory. Quotation withheld because this record is not cleared for redistribution. mechanism Quotation withheld because this record is not cleared for redistribution. repetition suppression (neural repetition priming) Quotation withheld because this record is not cleared for redistribution. review review Quotation withheld because this record is not cleared for redistribution. THREE COMMONLY OBSERVED NEURONAL EFFECTS IN MEMORY-DEMANDING TASKS ARE REPETITION SUPPRESSION, ENHANCEMENT, AND DELAY ACTIVITY - repeated experience LEADS TO BOTH SHORT- AND LONG-TERM SUPPRESSION, ENHANCEMENT WORKS IN AN OPPOSITE FASHION for OBJECTS WITH LEARNED BEHAVIORAL RELEVANCE, and delay activity holds information ON-LINE Quotation withheld because this record is not cleared for redistribution. and they do not share an anatomy: REPETITION SUPPRESSION APPEARS TO BE AN INTRINSIC PROPERTY OF VISUAL CORTICAL AREAS SUCH AS INFERIOR TEMPORAL CORTEX, whereas ENHANCEMENT AND DELAY ACTIVITY MAY DEPEND ON FEEDBACK TO TEMPORAL CORTEX FROM PREFRONTAL CORTEX Quotation withheld because this record is not cleared for redistribution. the proposed reason suppression happens at all: REPETITION SUPPRESSION IS A BY-PRODUCT OF SHARPENING STIMULUS REPRESENTATIONS IN THE CORTEX - and STIMULUS REPETITION LEADS TO A SMALLER POPULATIONS OF ACTIVATED CELLS Quotation withheld because this record is not cleared for redistribution. Only three short-term mechanisms are covered; long-term plasticity and perceptual learning are left out. Quotation withheld because this record is not cleared for redistribution. Hippocampal and medial temporal lobe memory (events, maps, scenes, episodes) is explicitly outside the scope. Quotation withheld because this record is not cleared for redistribution. The direct test of whether prefrontal feedback causes the IT match-enhancement effect has not been performed. Quotation withheld because this record is not cleared for redistribution. the review declares what it excludes: THE TYPES OF MEMORIES NORMALLY ASSOCIATED WITH THE HIPPOCAMPUS AND MEDIAL TEMPORAL LOBE STRUCTURES, INCLUDING MEMORIES OF MORE COMPLEX BEHAVIORAL EVENTS, MAPS, SCENES, EPISODES, ETC., ARE NOT CONSIDERED what this limits: reading this as an account of memory rather than of STIMULUS MEMORY Quotation withheld because this record is not cleared for redistribution. and that the three are a selection - WE HAVE CONSIDERED ONLY THREE SHORT-TERM MEMORY MECHANISMS IN THIS BRIEF REVIEW, and THESE ARE HARDLY EXHAUSTIVE what this limits: the coverage of the review: WE HAVE CONSIDERED ONLY THREE SHORT-TERM MEMORY MECHANISMS IN THIS BRIEF REVIEW ... THESE ARE HARDLY EXHAUSTIVE Quotation withheld because this record is not cleared for redistribution. half the cells show none of it - FOR ABOUT HALF THE CELLS, RESPONSES TO THE TEST ITEMS WERE APPARENTLY UNAFFECTED BY ANY MNEMONIC ASPECT OF THE TASK what this limits: reading 'IT neurons carry the memory signal' as a statement about IT neurons rather than about half of them Quotation withheld because this record is not cleared for redistribution. the mechanism that would complete the account is the one not established - THERE REMAINS ONE IMPORTANT REQUIREMENT FOR SOLVING THE DMS TASK THAT IS NOT ACCOUNTED FOR BY THE PROPERTIES OF IT NEURONS DESCRIBED SO FAR IN THIS REVIEW - NAMELY, A MECHANISM FOR MAINTAINING THE MEMORY OF THE SAMPLE what this limits: the account of how the DMS task is solved: THERE REMAINS ONE IMPORTANT REQUIREMENT ... NOT ACCOUNTED FOR BY THE PROPERTIES OF IT NEURONS DESCRIBED SO FAR IN THIS REVIEW - NAMELY, A MECHANISM FOR MAINTAINING THE MEMORY OF THE SAMPLE Quotation withheld because this record is not cleared for redistribution. repetition suppression looked for outside the task entirely eliminates: the effect being a product of the animal doing a memory task - REPETITION SUPPRESSION IS ALSO FOUND WHEN STIMULI ARE REPEATED DURING PASSIVE FIXATION AND IN MONKEYS UNDER ANESTHESIA · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. the same effect looked for under a drug that destroys the behavior eliminates: the effect depending on successful performance - REPETITION SUPPRESSION IS ALSO FOUND IN MONKEYS GIVEN SYSTEMIC SCOPOLAMINE, WHICH GREATLY IMPAIRS THEIR BEHAVIORAL PERFORMANCE IN THE DMS TASK · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. prefrontal cortex cooled while recording in temporal cortex eliminates: delay activity in IT being generated there independently - IT DELAY ACTIVITY WAS Quotation withheld · outcome (stated by the tagger, no quotation): partial Quotation withheld because this record is not cleared for redistribution. a task variant built so that one of the two mechanisms cannot solve it eliminates: an ambiguity the standard task leaves open - IN PRINCIPLE, THE ABBA TASK CANNOT BE SOLVED BY AN ANIMAL RELYING ONLY ON THE SUPPRESSIVE MECHANISM · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. prefrontal cortex cooled while recording in temporal cortex [RECOVERED 2026-08-26 from facet_results_clean203.json, written for the retired id Desimone1996-neural-mechanisms-... and merged into this record; 42 of its 45 quote-bearing tags landed and this one did not, because the quote began 'ster et al.' - 'Fuster' cut in half. The gate refuses a mid-word slice, so it was correctly rejected and then lost.] eliminates: delay activity in IT being generated there independently of prefrontal input · outcome: partial Quotation withheld because this record is not cleared for redistribution. repetition priming repetition priming Quotation withheld because this record is not cleared for redistribution. visual memory visual memory Quotation withheld because this record is not cleared for redistribution. THE DIRECTION EVERYONE ASSUMES, REVERSED IN THE SECOND SENTENCE: ATTENTION IS OFTEN THOUGHT OF AS A GATEWAY TO LEARNING AND MEMORY... HOWEVER, THE CONVERSE IS EQUALLY TRUE - MECHANISMS FOR LEARNING AND MEMORY PLAY A CRITICAL ROLE IN THE SELECTION PROCESS THAT DETERMINES WHICH STIMULI... ARE ATTENDED Quotation withheld because this record is not cleared for redistribution. and the conclusion states it as a derivation: ATTENTION DERIVES, AT LEAST IN PART, FROM THE IMPACT OF MEMORY MECHANISMS ON CORTICAL SENSORY MECHANISMS, WHICH ARE INTRINSICALLY COMPETITIVE IN NATURE. `Attention` names an outcome of a competition rather than a process of its own Quotation withheld because this record is not cleared for redistribution. MEMORY DECIDES THE WINNER: ALL OF THESE MNEMONIC EFFECTS ON NEURONAL RESPONSES BIAS THE COMPETITIVE INTERACTIONS THAT TAKE PLACE BETWEEN STIMULUS REPRESENTATIONS IN THE CORTEX WHEN THERE IS MORE THAN ONE STIMULUS IN THE VISUAL FIELD - AS A RESULT, MEMORY WILL OFTEN DETERMINE THE WINNER OF THESE COMPETITIONS AND, THUS, WILL DETERMINE WHICH STIMULUS IS ATTENDED Quotation withheld because this record is not cleared for redistribution. THE TASK DESIGN DECIDES WHICH MECHANISM CAN BE INFERRED, STATED IN 1996: Quotation withheld Twenty-three years before Steinmetz2019 retires go/nogo for the same reason Quotation withheld because this record is not cleared for redistribution. TWO MECHANISMS PULLING AGAINST EACH OTHER, AND AGAINST THE ANIMAL: BECAUSE THE SUPPRESSION MECHANISM BIASED RESPONSES IN FAVOR OF THE NONTARGET STIMULUS (THE ONLY UNIQUE STIMULUS IN THE TRIAL), IT WORKED AGAINST BOTH THE ENHANCEMENT MECHANISM AND, PRESUMABLY, THE ANIMAL'S GOAL IN THE TASK Quotation withheld because this record is not cleared for redistribution. THE THREE EFFECTS DO NOT SHARE AN ANATOMY: Quotation withheld - BY CONTRAST, ENHANCEMENT AND DELAY ACTIVITY MAY DEPEND ON FEEDBACK TO TEMPORAL CORTEX FROM PREFRONTAL CORTEX AND ARE THOUGHT TO BE IMPORTANT FOR WORKING MEMORY Quotation withheld because this record is not cleared for redistribution. SUPPRESSION IS NOT ABOUT THE TASK AT ALL: REPETITION SUPPRESSION IS ALSO FOUND WHEN STIMULI ARE REPEATED DURING PASSIVE FIXATION AND IN MONKEYS UNDER ANESTHESIA - and in MONKEYS GIVEN SYSTEMIC SCOPOLAMINE, WHICH GREATLY IMPAIRS THEIR BEHAVIORAL PERFORMANCE IN THE DMS TASK. The effect survives the removal of the behavior it is supposed to serve Quotation withheld because this record is not cleared for redistribution. and the proposed reason recasts it as a by-product: REPETITION SUPPRESSION IS A BY-PRODUCT OF SHARPENING STIMULUS REPRESENTATIONS IN THE CORTEX Quotation withheld because this record is not cleared for redistribution. SEEING SOMETHING TWICE SHRINKS ITS REPRESENTATION: STIMULUS REPETITION LEADS TO A SMALLER POPULATIONS OF ACTIVATED CELLS, OR SMALLER STIMULUS REPRESENTATIONS IN THE CORTEX Quotation withheld because this record is not cleared for redistribution. and the change may not be temporary: A STUDY BY BROWN AND COLLEAGUES SUGGESTS THAT THESE EFFECTS MAY BE PERMANENT - PRESENTATION OF A SET OF STIMULI ON ONE DAY LEADS TO A REDUCED INCIDENCE OF CELLS ACTIVATED BY THOSE STIMULI ON A SUBSEQUENT DAY Quotation withheld because this record is not cleared for redistribution. HALF THE CELLS SHOW NONE OF IT: FOR ABOUT HALF THE CELLS, RESPONSES TO THE TEST ITEMS WERE APPARENTLY UNAFFECTED BY ANY MNEMONIC ASPECT OF THE TASK Quotation withheld because this record is not cleared for redistribution. A PARTIAL NULL, REPORTED AS ONE: IT DELAY ACTIVITY WAS Quotation withheld. Not present-or-absent - the signal survived and lost its content Quotation withheld because this record is not cleared for redistribution. THE REVIEW NAMES WHAT IT LEAVES OUT: THE TYPES OF MEMORIES NORMALLY ASSOCIATED WITH THE HIPPOCAMPUS AND MEDIAL TEMPORAL LOBE STRUCTURES, INCLUDING MEMORIES OF MORE COMPLEX BEHAVIORAL EVENTS, MAPS, SCENES, EPISODES, ETC., ARE NOT CONSIDERED Quotation withheld because this record is not cleared for redistribution. and that its three mechanisms are a choice: WE HAVE CONSIDERED ONLY THREE SHORT-TERM MEMORY MECHANISMS IN THIS BRIEF REVIEW... THESE ARE HARDLY EXHAUSTIVE Quotation withheld because this record is not cleared for redistribution. AND THE PART THE ACCOUNT CANNOT SUPPLY IS NAMED: THERE REMAINS ONE IMPORTANT REQUIREMENT FOR SOLVING THE DMS TASK THAT IS NOT ACCOUNTED FOR BY THE PROPERTIES OF IT NEURONS DESCRIBED SO FAR IN THIS REVIEW - NAMELY, A MECHANISM FOR MAINTAINING THE MEMORY OF THE SAMPLE Quotation withheld because this record is not cleared for redistribution. the task decomposed before any neuron is discussed: TO SOLVE THE DMS TASK THE MONKEY MUST, IN PRINCIPLE, SOLVE THREE PROBLEMS - DISCRIMINATE AMONG THE DIFFERENT STIMULI, RETAIN THE MEMORY OF THE SAMPLE, AND MAKE A DECISION ABOUT WHETHER THE CURRENT TEST STIMULUS MATCHES Quotation withheld because this record is not cleared for redistribution. A PARTIAL NULL, REPORTED AS ONE: `IT delay activity was Quotation withheld.` Not present-or-absent - the signal survived and lost its content. A result with no place on a binary outcome axis. [RECOVERED 2026-08-26 from facet_results_clean203.json, written for the retired id Desimone1996-neural-mechanisms-... and merged into this record; 42 of its 45 quote-bearing tags landed and this one did not, because the quote began `ster et al.` - `Fuster` cut in half. The gate refuses a mid-word slice, so it was correctly rejected and then lost.] Quotation withheld because this record is not cleared for redistribution. contradicts → studies reporting that IT cells hold a sample stimulus in memory through stimulus-selective maintained delay activity (refs 27-33) Quotation withheld because this record is not cleared for redistribution. extends → Nakamura and Kubota (ref 33) Quotation withheld because this record is not cleared for redistribution. contradicts → the view that attention is the gateway to memory differs in: the direction of the dependence - MECHANISMS FOR LEARNING AND MEMORY PLAY A CRITICAL ROLE IN THE SELECTION PROCESS THAT DETERMINES WHICH STIMULI... ARE ATTENDED Quotation withheld because this record is not cleared for redistribution. critiques → the standard delayed matching-to-sample design as evidence for a particular memory mechanism differs in: which mechanisms the design leaves open - THE STANDARD VERSION OF THE DMS TASK MIGHT BE SOLVED BY A MONKEY RELYING ON EITHER ENHANCEMENT OR SUPPRESSION Quotation withheld because this record is not cleared for redistribution. builds-on → Brown and colleagues, that repetition effects may be permanent status: the paper's own hedge: SUGGESTS THAT THESE EFFECTS MAY BE PERMANENT Quotation withheld because this record is not cleared for redistribution. memory —causes→ attention memory attention strength of the relation: 1 · note: the reversal: MECHANISMS FOR LEARNING AND MEMORY PLAY A CRITICAL ROLE IN THE SELECTION PROCESS THAT DETERMINES WHICH STIMULI OF THE MANY STIMULI IN A COMPLEX ENVIRONMENT ARE ATTENDED Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span says attention derives in part from memory mechanisms; causes is loose. Quotation withheld because this record is not cleared for redistribution. repetition suppression —causes→ priming repetition suppression priming status: SAME SENTENCE, SECOND EDGE: 'Repetition suppression ... Quotation withheld.' One hedged review sentence supplies three 'causes' edges on this record ([3], [4] and [5]), and all three inherit its hedge. · strength of the relation: 1 · note: Quotation withheld Audit 2026-09-28: DOUBTFUL - read against its span and kept, but repetition suppression is thought important for priming; causes states a hypothesis. Quotation withheld because this record is not cleared for redistribution. delay activity —causes→ working memory delay activity working memory status: SAME SENTENCE, THIRD EDGE: 'By contrast, enhancement and DELAY ACTIVITY MAY DEPEND ON feedback' - the weakest clause of the three, carrying 'may depend on' rather than a reported result. · strength of the relation: 1 · note: ENHANCEMENT AND DELAY ACTIVITY... ARE THOUGHT TO BE IMPORTANT FOR WORKING MEMORY Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but enhancement and delay activity 'are thought to be important' for working memory; hedged. Quotation withheld because this record is not cleared for redistribution. prefrontal —causes→ delay activity prefrontal delay activity status: A PARTIAL NULL, AND THE EFFECT IS ON SELECTIVITY RATHER THAN PRESENCE: 'not eliminated ... but it became less selective'. Cooling did not abolish the activity, so prefrontal input is not necessary for delay activity to occur - only for it to carry the stimulus. · strength of the relation: 0.5 — the record marks this weak · note: DIRECTION CORRECTED ON RECOVERY. The unmerged row read 'delay activity -causes-> prefrontal'. The experiment COOLED PREFRONTAL CORTEX and MEASURED IT DELAY ACTIVITY, so the manipulation is prefrontal and the readout is delay activity. The original arrow pointed from the readout to the manipulation. [RECOVERED 2026-08-26 from an internal file, written for the retired id Desimone1996-neural-mechanisms-... and merged into this record; 42 of its 45 quote-bearing tags landed and this one did not, because the quote began 'ster et al.' - 'Fuster' cut in half. The gate refuses a mid-word slice, so it was correctly rejected and then lost.] Audit 2026-09-28: DOUBTFUL - read against its span and kept, but IT delay activity was reduced but not eliminated during prefrontal cooling; causes is loose. Quotation withheld because this record is not cleared for redistribution. about half — the cells whose responses were UNAFFECTED BY ANY MNEMONIC ASPECT OF THE TASK Quotation withheld because this record is not cleared for redistribution. MEMORY WILL OFTEN DETERMINE THE WINNER OF THESE COMPETITIONS AND, THUS, WILL DETERMINE WHICH STIMULUS IS ATTENDED Quotation withheld because this record is not cleared for redistribution. IN PRINCIPLE, Quotation withheld Quotation withheld because this record is not cleared for redistribution. REPETITION SUPPRESSION IS ALSO FOUND WHEN STIMULI ARE REPEATED DURING PASSIVE FIXATION AND IN MONKEYS UNDER ANESTHESIA, and in MONKEYS GIVEN SYSTEMIC SCOPOLAMINE, WHICH GREATLY IMPAIRS THEIR BEHAVIORAL PERFORMANCE Quotation withheld because this record is not cleared for redistribution. STIMULUS REPETITION LEADS TO A SMALLER POPULATIONS OF ACTIVATED CELLS, OR SMALLER STIMULUS REPRESENTATIONS IN THE CORTEX Quotation withheld because this record is not cleared for redistribution. FOR ABOUT HALF THE CELLS, RESPONSES TO THE TEST ITEMS WERE APPARENTLY UNAFFECTED BY ANY MNEMONIC ASPECT OF THE TASK Quotation withheld because this record is not cleared for redistribution. IT DELAY ACTIVITY WAS Quotation withheld Quotation withheld because this record is not cleared for redistribution. BECAUSE THE SUPPRESSION MECHANISM BIASED RESPONSES IN FAVOR OF THE NONTARGET STIMULUS, IT WORKED AGAINST BOTH THE ENHANCEMENT MECHANISM AND, PRESUMABLY, THE ANIMAL'S GOAL IN THE TASK Quotation withheld because this record is not cleared for redistribution. repetition suppression repetition suppression Quotation withheld because this record is not cleared for redistribution. REPEATED EXPERIENCE WITH THE SAME VISUAL STIMULUS LEADS TO BOTH SHORT- AND LONG-TERM SUPPRESSION OF NEURONAL RESPONSES IN SUBPOPULATIONS OF VISUAL NEURONS repetition suppression Quotation withheld because this record is not cleared for redistribution. FOUND IN TASKS IN WHICH ANIMALS ARE REQUIRED TO ACTIVELY HOLD SPECIFIC INFORMATION “on-line” FOR SHORT PERIODS delay activity Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1073/pnas.93.24.13494.