Recognition Memory Task Research Articles

Motor-related oscillations reveal the involvement of sensorimotor processes during recognition memory

Certain object properties may render an item as more memorable than others. One such property is manipulability, or the extent to which an object can be interacted with using our hands. This study sought to determine if the manipulability of an item modulates memory task performance on both a behavioural and neural level. We recorded electroencephalography (EEG) from a large sample of right-handed individuals (N = 53) during a visual item recognition memory task. The task contained stimuli of both high and low manipulability. Analysis focused on activity in the theta rhythm (3.5–7 Hz), which has been implicated in sensorimotor integration, and the mu rhythm (8–14 Hz), the primary oscillation associated with sensorimotor related behaviours. At both encoding and retrieval, theta oscillations were greater over the left motor region for high manipulability stimuli, suggesting that an item’s sensorimotor properties are assessed immediately upon presentation. Manipulability did not affect activity in the mu rhythm. However, mu oscillations over the left motor region were lower during the retrieval of old versus new items and response time was faster for old items, aligning with the cortical reinstatement hypothesis. These results collectively reveal an association between motor oscillations and memory processes, highlight the involvement of sensorimotor processing at both encoding and retrieval.

Behavioral and electrophysiological evidence for preserved specific associative episodic memory in older adults

Aging is often linked to a decline in associative memory. Prior research has shown that older adults have difficulty retrieving specific associative memory but can retrieve gist associative memory when deliberately differentiating test pairs with different levels of specificity during associative recognition. In this study, we utilized the context reinstatement paradigm to examine whether older adults could retrieve specific memory in situations where associations do not necessarily need to be voluntarily retrieved. Thirty-five older adults were directed to intentionally link objects with unique background scenes during encoding. Subsequently, test objects were presented against either the reinstated or similar background scenes during a recognition memory task, where participants were required to identify whether the objects were old or new regardless of their background contexts. Event-related potentials (ERP) were recorded to uncover the electrophysiological correlates of specific associative episodic memory. Behavioral results revealed higher memory sensitivity for object recognition when the background scenes were reinstated than when those were similar in older adults. ERP results indicated that older adults exhibited a more prominent fronto-centrally distributed positivity during object recognition in the reinstated than in similar contexts. Our results suggest that older adults may preserve their ability to retrieve specific memory for associations through an involuntary, spontaneous recollection process, which holds important theoretical implications for age-related associative memory deficits.

Overgeneralization of autonomic defensive reactions in obesity

Generalizing defensive responses to new stimuli resembling learned threats is an adaptive process within an ever-changing environment. However, evaluation mechanisms excessively biased toward generalization (i.e., overgeneralization) may underlie anxiety-related symptoms. In the context of obesity, fear memory and fear generalization processes have never been investigated. In this study, participants with obesity and healthy participants as controls underwent a single-cue auditory fear conditioning paradigm and recognition memory tasks. We analyzed the autonomic reactions evoked by threat-predictive and new stimuli, as well as the recognition performance towards the same cues. We found that participants with obesity displayed similar autonomic defensive responses to a learned fearful stimulus, but enhanced reactions to new stimuli, when compared with the controls. We detected no significant differences between groups in recognition abilities. Our results provided the first evidence that obesity may widen fear generalization patterns. This alteration may encourage future research in investigating the link between emotional dysregulation and clinical anxiety-related symptoms in obesity.

Cognitive function and brain structure in COVID-19 survivors: The role of persistent symptoms

Persistent COVID-19 symptoms post-acute state have been shown to have a significant negative impact on brain structure and function. In this study, we conducted magnetic resonance imaging (MRI) of the whole brain in 43 working-age adults (mean age: 44.79±10.80; range: 24–65 years) with a history of COVID-19 (731.17±312.41 days post-diagnosis), and also assessed their cognitive function (processing speed, attention, working memory, executive function, and recognition memory), mental health, and sleep quality. MRI data were processed using FSL to derive regional volumes for bilateral nucleus accumbens, caudate, pallidum, putamen, thalamus, amygdala, and hippocampus, and total grey matter, white matter, and cerebral spinal fluid volume, and analysed in relation to persistent COVID-19 symptom load, mental health, and sleep quality. Higher persistent COVID-19 symptom load was significantly associated with smaller putamen volume, lower response accuracy on working memory, executive function, and recognition memory tasks, as well as a longer time to complete the executive function task, and poorer mental health and sleep quality. Smaller putamen fully mediated the relationship between persistent COVID-19 symptom load and lower executive function. Further research is required to confirm whether reduced putamen volume and its association with poor executive function persists in COVID-19 survivors in the long term.

Subjective cognitive decline is associated with altered patterns of brain activity and connectivity during performance of an old/new recognition memory task

IntroductionSubjective Cognitive Decline (SCD) is considered a preclinical stage within the AD continuum. Knowledge about the functional changes in the brain associated with episodic memory retrieval and novelty recognition in people with SCD is currently very limited. MethodThe study aimed to evaluate behavioural and neurofunctional changes in individuals with SCD, measured relative to a control group, during successful episodic memory retrieval and novelty recognition, as well as to compare the functional connectivity patterns related to these cognitive processes within the Default Mode Network (DMN) in both groups. Participants performed an old/new recognition memory task with words while the BOLD signal was acquired. ResultsNo between-group differences were observed in the performance of the episodic memory task. However, during the successful recognition of old words, the SCD group showed brain hypoactivity in the right rolandic operculum and reduced functional connectivity between the DMN and the fronto-parietal control network (FPCN). During the correct identification of new words, the SCD group also showed reduced connectivity between the DMN and the FPCN, and lower connectivity within the DMN. ConclusionDespite the absence of objective evidence of cognitive impairment, people with SCD display several changes in brain activity and connectivity associated with episodic memory retrieval and novelty recognition.

The anxiogenic drug yohimbine is a reinforcer in male and female rats.

The indole alkaloid yohimbine is an anxiogenic drug that activates stress-responsive systems in the brain. However, because yohimbine also elicits approach behaviors, this study employed male and female Sprague-Dawley rats to explore its potential reinforcing effects. Thus, it was first determined if intravenous (IV) infusions of yohimbine (0.25 mg/kg/infusion) could maintain lever pressing, whether intake could be modulated by dose/infusion, and if lever pressing would persist in the absence of yohimbine or yohimbine-paired cues. Next, to assess yohimbine's effect on memory consolidation, 0.3, 1.25 or 3 mg/kg yohimbine was administered post-training using an object recognition memory task. Finally, place conditioning assessed whether doses of yohimbine that elevate blood serum corticosterone levels (1.25 or 3 mg/kg) couldelicit a conditioned place preference. It was found that both sexes acquired yohimbine IV self-administration, that intake was modulated by dose/infusion, and that lever pressing persisted during extinction and in the absence of the yohimbine-paired cue. As well, post-training injections of 1.25 mg/kg yohimbine enhanced consolidation of object memory, and 1.25 and 3 mg/kg elevated corticosterone levels and elicited a place preference in both sexes. Finally, in behavioral tests of psychomotor functions, acute yohimbine increased lever pressing for a visual cue and elevated locomotor activity. These findings reveal a profile of yohimbine's behavioral effects that is consistent with that of psychostimulant reinforcing drugs.

Visual long-term memory is not made more precise with medial-frontal direct-current stimulation

ABSTRACT Previous research suggests that applying anodal transcranial direct-current stimulation (tDCS) to the medial-frontal cortex can improve how quickly subjects learn to make simple discriminations (i.e., red from blue). Here, we tested the idea that this enhanced task learning is attributable to superior encoding of relevant information into visual long-term memory. Thirty subjects completed an anodal stimulation session and a sham session, with order counterbalanced across subjects, before performing recognition-memory tasks using pictures of real-world objects and visually presented words or nonwords. These tasks allowed us to detect potential memory differences across types of memoranda. Contrary to the hypothesis that the medial-frontal cortex helps control encoding fidelity, we found that anodal tDCS delivered over this brain region did not significantly improve subjects’ memory for visual stimuli, regardless of stimulus type. Our findings show no evidence that targeting medial-frontal cortex with tDCS changes the fidelity of our visual long-term memories.

Associations of prenatal maternal urinary concentrations of triclosan and benzophenone-3 with cognition in 7.5-month-old infants

BackgroundEndocrine-disrupting chemicals (EDCs) have been linked to adverse health outcomes and prenatal exposure is known to impact infant and child development. However, few studies have assessed early developmental consequences of prenatal exposure to two common phenolic compounds, benzophenone-3 (BP-3) and triclosan (TCS). ObjectiveWe evaluated the relationship of prenatal exposure to BP-3 and TCS with infant cognition at 7.5 months via performance on a visual recognition memory (VRM) task. MethodsDrawing from the Illinois Kids Development Study (IKIDS) cohort, prenatal exposure to BP-3 and TCS was assessed in pools of five urine samples collected from each woman across pregnancy. Cognition was measured in 310 infants using a VRM task assessing information processing speed, attention, and recognition memory through infrared eye-tracking. Generalized linear regression estimated exposure-outcome associations, followed by stratification to investigate modification of associations by infant sex and stimulus set. ResultsSampled mothers were more likely to be white, college educated, and middle or high income relative to the US population. Mean chemical exposures were significantly higher than those of adult women in the NHANES cohort. In models adjusted for income, gestational age at birth, and testing age, prenatal BP-3 exposure was associated with an increase in run duration (average time spent looking at the stimuli before looking away) (β = 0.0011, CI -0.0001:0.0022), indicating slower information processing speed, while TCS was associated with significantly longer time to familiarization (time to accrue a total of 20 s of looking time to the stimuli) (β = 0.0686, CI 0.0203:0.1168, p < 0.01), indicating poorer attention. Stratum-specific analyses isolated both effects to male infants who viewed the second of two stimulus sets. ConclusionHigher prenatal exposure to triclosan was associated with poorer attention in infancy, while benzophenone-3 may be associated with slower information processing speed, particularly among males.

Distress reactions and susceptibility to misinformation for an analogue trauma event

Accuracy of memory is critical in legal and clinical contexts. These contexts are often linked with high levels of emotional distress and social sources that can provide potentially distorting information about stressful events. This study investigated how distress was associated with susceptibility to misinformation about a trauma analogue event. We employed an experimental design whereby in Phase 1, participants (N = 243, aged 20–72, 122 females, 117 males, 4 gender diverse) watched a trauma film (car crash) and heard an audio summary that contained misinformation (misled items), true reminders (consistent items), and no reminders (control items) about the film. Participants rated their total distress, and symptoms of avoidance, intrusions, and hyperarousal, in response to the film. They then completed cued recall, recognition, and source memory tasks. One week later in Phase 2, participants (N = 199) completed the same measures again. Generalised linear mixed models were used. A significant misinformation effect was found, and importantly, participants with higher distress levels showed a smaller misinformation effect, owing to especially poor memory for consistent items compared to their less distressed counterparts. Distress was also associated with improved source memory for misled items. Avoidance of the film’s reminders was associated with a smaller misinformation effect during immediate retrieval and a larger misinformation effect during delayed retrieval. Findings suggest that distress is associated with decreased susceptibility to misinformation in some cases, but also associated with poorer memory accuracy in general. Limitations are discussed, and the need for further research is highlighted.

Untangling the threads of motivated memory: Independent influences of reward and emotion.

Motivational and emotional influences on memory have been studied extensively; however, despite the link between these constructs, they have been studied in separate lines of research, with very little work examining their effects concurrently. The current study takes a novel approach to manipulate motivational and emotional influences orthogonally, and within the same task, to test their interplay on intentional memory formation. If emotion and reward motivation are tightly linked, they may rely on overlapping cognitive mechanisms, thus we would not expect emotion and reward to interact in memory. Alternatively, they could be distinct constructs and therefore would boost memory when both are included in the same experimental trial, above and beyond additive effects. To test these competing predictions, in Experiment 1, participants (n = 180) completed an old/new recognition memory task with emotional (negative, positive) and neutral words intentionally encoded with high or low reward anticipation cues. In Experiment 2, participants (n = 159) encoded emotional and neutral words with a high or low reward cue, but memory was tested with free recall using study-test blocks. The findings from both experiments converged. There were main effects of emotion and reward in generally hypothesized directions, but no evidence of an interaction between these factors. This is in line with the prediction that emotion and reward motivation are similar constructs. Their combination within a trial does not boost memory above and beyond either of these factors alone perhaps indicating these constructs have similar cognitive mechanisms.

Successful retrieval is its own reward.

The ability to successfully remember past events is critical to our daily lives, yet the neural mechanisms underlying the motivation to retrieve is unclear. Although reward-system activity and feedback-related signals have been observed during memory retrieval, whether this signal reflects intrinsic reward or goal-attainment is unknown. Adjudicating between these two alternatives is crucial for understanding how individuals are motivated to engage in retrieval and how retrieval supports later remembering. To test these two accounts, we conducted between-subjects recognition memory tasks on human participants undergoing scalp electroencephalography and varied test-phase goals (recognize old vs. detect new items). We used an independently validated feedback classifier to measure positive feedback evidence. We find positive feedback following successful retrieval regardless of task goals. Together, these results suggest that successful retrieval is intrinsically rewarding. Such a feedback signal may promote future retrieval attempts as well as bolster later memory for the successfully retrieved events.

Goal-directed attention transforms both working and long-term memory representations in the human parietal cortex.

The abundance of distractors in the world poses a major challenge to our brain's limited processing capacity, but little is known about how selective attention modulates stimulus representations in the brain to reduce interference and support durable target memory. Here, we collected functional magnetic resonance imaging (fMRI) data in a selective attention task in which target and distractor pictures of different visual categories were simultaneously presented. Participants were asked to selectively process the target according to the effective cue, either before the encoding period (i.e., perceptual attention) or the maintenance period (i.e., reflective attention). On the next day, participants were asked to perform a memory recognition task in the scanner in which the targets, distractors, and novel items were presented in a pseudorandom order. Behavioral results showed that perceptual attention was better at enhancing target memory and reducing distractor memory than reflective attention, although the overall memory capacity (memory for both target and distractor) was comparable. Using multiple-voxel pattern analysis of the neural data, we found more robust target representation and weaker distractor representation in working memory for perceptual attention than for reflective attention. Interestingly, perceptual attention partially shifted the regions involved in maintaining the target representation from the visual cortex to the parietal cortex. Furthermore, the targets and distractors simultaneously presented in the perceptual attention condition showed reduced pattern similarity in the parietal cortex during retrieval compared to items not presented together. This neural pattern repulsion positively correlated with individuals' recognition of both targets and distractors. These results emphasize the critical role of selective attention in transforming memory representations to reduce interference and improve long-term memory performance.

Skills and cautiousness predict performance in difficult search.

People differ in how well they search. What are the factors that might contribute to this variability? We tested the contribution of two cognitive abilities: visual working memory (VWM) capacity and object recognition ability. Participants completed three tasks: a difficult inefficient visual search task, where they searched for a target letter T among skewed L distractors; a VWM task, where they memorized a color array and then identified whether a probed color belonged to the previous array; and the Novel Object Memory Test (NOMT), where they learnt complex novel objects and then identified them amongst objects that closely resembled them. Exploratory and confirmatory factor analyses revealed that there are two latent factors that explain the shared variance among these three tasks: a factor indicative of the level of caution participants exercised during the challenging visual search task, and a factor representing their visual cognitive abilities. People who score high on the search cautiousness tend to perform a more accurate but slower search. People who score high on the visual cognitive ability factor tend to have a higher VWM capacity, a better object recognition ability, and a faster search speed. The results reflect two points: (1) Visual search tasks share components with visual working memory and object recognition tasks. (2) Search performance is influenced not only by the search display's properties but also by individual predispositions such as caution and general visual abilities. This study introduces new factors for consideration when interpreting variations in visual search behaviors.

Complement C5a receptor 1 blockade reverses cognitive deficits following cranial radiation therapy for brain cancer.

Cranial radiation therapy (RT) for brain cancers leads to an irreversible decline in cognitive function without an available remedy. Radiation-induced cognitive deficits (RICD) are particularly a pressing problem for the survivors of pediatric and low grade glioma (LGG) patients who often live long post-RT. Radiation-induced elevated neuroinflammation and gliosis, triggered by the detrimental CNS complement cascade, lead to excessive synaptic and cognitive loss. Using intact and brain cancer-bearing mouse models, we now show that targeting anaphylatoxin complement C5a receptor (C5aR1) is neuroprotective against RICD. We used a genetic knockout, C5aR1 KO mouse, and a pharmacologic approach, employing the orally active, brain penetrant C5aR1 antagonist PMX205, to reverse RICD. Irradiated C5aR1 KO and WT mice receiving PMX205 showed significant neurocognitive improvements in object recognition memory and memory consolidation tasks. C5aR1 inhibition reduced microglial activation, astrogliosis, and synaptic loss in the irradiated brain. Importantly, C5aR1 inhibition in the syngeneic, orthotopic astrocytoma, and glioblastoma-bearing mice protected against RICD without interfering with the therapeutic efficacy of RT to reduce tumor volume in vivo . PMX205 is currently in clinical trials for amyotrophic lateral sclerosis (ALS). Thus, C5aR1 inhibition is a translationally feasible approach to address RICD, an unmet medical need.

Everyday amnesia: Residual memory for high confidence misses and implications for decision models of recognition.

Despite studying a list of items only minutes earlier, when reencountered in a recognition memory test, undergraduate participants often say with total confidence that they have not studied some of the items before. Such high confidence miss (HCM) responses have been taken as evidence of rapid and complete forgetting and of everyday amnesia (Roediger & Tekin, 2020). We investigated (a) if memory for HCMs is completely lost or whether a residual memory effect exists and (b) whether dominant decision models predict the effect. Participants studied faces (Experiments 1a, 2, and 3) or words (Experiment 1b), then completed a single-item recognition memory task, followed by either (a) a two-alternative forced-choice recognition task, in which the studied and nonstudied alternatives on each trial were matched for their previous old/new decision and confidence rating (Experiments 1 and 2) or (b) a second single-item recognition task in which the targets and foils were HCMs and high confidence correct rejections, respectively (Experiment 3). In each experiment, participants reliably distinguished HCMs from high-confidence correct rejections. The unequal variance signal detection and dual-process signal detection models were fit to the single-item recognition data, and the parameter estimates were used to predict the memory effect for HCMs. The dual-process signal detection model predicted the residual memory effect (as did another popular model, the mixture signal detection theory model). However, the unequal variance signal detection model incorrectly predicted a negative, or no, effect, invalidating this model. The residual memory effect for HCMs demonstrates that everyday amnesia is not associated with complete memory loss and distinguishes between decision models. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Retrieval of contextual memory can be predicted by CA3 remapping and is differentially influenced by NMDAR activity in rat hippocampus subregions.

Episodic memory is essential to navigate in a changing environment by recalling past events, creating new memories, and updating stored information from experience. Although the mechanisms for acquisition and consolidation have been profoundly studied, much less is known about memory retrieval. Hippocampal spatial representations are key for retrieval of contextually guided episodic memories. Indeed, hippocampal place cells exhibit stable location-specific activity which is thought to support contextual memory, but can also undergo remapping in response to environmental changes. It is unclear if remapping is directly related to the expression of different episodic memories. Here, using an incidental memory recognition task in rats, we showed that retrieval of a contextually guided memory is reflected by the levels of CA3 remapping, demonstrating a clear link between external cues, hippocampal remapping, and episodic memory retrieval that guides behavior. Furthermore, we describe NMDARs as key players in regulating the balance between retrieval and memory differentiation processes by controlling the reactivation of specific memory traces. While an increase in CA3 NMDAR activity boosts memory retrieval, dentate gyrus NMDAR activity enhances memory differentiation. Our results contribute to understanding how the hippocampal circuit sustains a flexible balance between memory formation and retrieval depending on the environmental cues and the internal representations of the individual. They also provide new insights into the molecular mechanisms underlying the contributions of hippocampal subregions to generate this balance.

Top-Down Task Goals Induce the Retrieval State.

Engaging the retrieval state (Tulving, 1983) impacts processing and behavior (Long and Kuhl, 2019, 2021; Smith et al., 2022), but the extent to which top-down factors-explicit instructions and goals-versus bottom-up factors-stimulus properties such as repetition and similarity-jointly or independently induce the retrieval state is unclear. Identifying the impact of bottom-up and top-down factors on retrieval state engagement is critical for understanding how control of task-relevant versus task-irrelevant brain states influence cognition. We conducted between-subjects recognition memory tasks on male and female human participants in which we varied test phase goals. We recorded scalp electroencephalography and used an independently validated mnemonic state classifier (Long, 2023) to measure retrieval state engagement as a function of top-down task goals (recognize old vs detect new items) and bottom-up stimulus repetition (hits vs correct rejections (CRs)). We find that whereas the retrieval state is engaged for hits regardless of top-down goals, the retrieval state is only engaged during CRs when the top-down goal is to recognize old items. Furthermore, retrieval state engagement is greater for low compared to high confidence hits when the task goal is to recognize old items. Together, these results suggest that top-down demands to recognize old items induce the retrieval state independent from bottom-up factors, potentially reflecting the recruitment of internal attention to enable access of a stored representation.

The ownership memory self-reference effect shifts recognition criterion but not recognition sensitivity

Information referenced to the self is retrieved more accurately than information referenced to others, known as the memory self-reference effect. It is unclear, however, whether social context (identity of the other) or task factors alter decision-making processes. In a virtual object allocation task, female participants sorted objects into their own or another’s (stranger or mother) basket based on a colour cue. Subsequently, they performed a recognition memory task in which they first indicated whether each object was old or new, and then whether it had been allocated to themselves or to the other. We obtained owner-specific hit rates and false-alarm rates and applied signal detection theory to derive separate recognition sensitivity (d’) and recognition criterion parameters (c) for self- and other-owned objects. While there was no clear evidence of a recognition self-reference effect, or a change in sensitivity, participants adopted a more conservative recognition criterion for self- compared with other-owned objects, and particularly when the other-referent was the participant’s mother compared with the stranger. Moreover, when discriminating whether the originally presented objects were self- or other-owned, participants were biased toward ascribing ownership to the ‘other’. We speculate that these findings reflect ownership-based changes in decisional processing during the recognition memory self-reference paradigm.

GlyT1 Inhibition by NFPS Promotes Neuroprotection in Amyloid-β-Induced Alzheimer's Disease Animal Model.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-β, leading to N-methyl-D-aspartate (NMDA) receptor-dependent synaptic depression, spine elimination, and memory deficits. Glycine transporter type 1 (GlyT1) modulates glutamatergic neurotransmission via NMDA receptors (NMDAR), presenting a potential alternative therapeutic approach for AD. This study investigates the neuroprotective potential of GlyT1 inhibition in an amyloid-β-induced AD mouse model. C57BL/6 mice were treated with N-[3-([1,1-Biphenyl]-4-yloxy)-3-(4-fluorophenyl)propyl]-N-methylglycine (NFPS), a GlyT1 inhibitor, 24h prior to intrahippocampal injection of amyloid-β. NFPS pretreatment prevented amyloid-β-induced cognitive deficits in short-term and long-term memory, evidenced by novel object recognition and spatial memory tasks. Moreover, NFPS pretreatment curbed microglial activation, astrocytic reactivity, and subsequent neuronal damage from amyloid-β injection. An extensive label-free quantitative UPLC-MSE proteomic analysis was performed on the hippocampi of mice treated with NFPS. In proteomics, KEGG enrichment analysis revealed increased in dopaminergic synapse, purine-containing compound biosynthetic process and long-term potentiation, and a reduction in Glucose catabolic process and glycolytic process pathways. The western blot analysis confirmed that NFPS treatment elevated BDNF levels, correlating with enhanced TRKB phosphorylation and mTOR activation. Moreover, NFPS treatment reduced the GluN2B expression after 6h, which was associated with an increase on CaMKIV and CREB phosphorylation. Collectively, these findings demonstrate that GlyT1 inhibition by NFPS activates diverse neuroprotective pathways, enhancing long-term potentiation signaling and countering amyloid-β-induced hippocampal damage.

Response-locked theta dissociations reveal potential feedback signal following successful retrieval

Abstract Successful memory retrieval relies on memory processes to access an internal representation and decision processes to evaluate and respond to the accessed representation, both of which are supported by fluctuations in theta (4-8Hz) activity. However, the extent to which decision making processes are engaged following a memory response is unclear. Here, we recorded scalp electroencephalography (EEG) while human participants performed a recognition memory task. We focused on response-locked data, allowing us to investigate the processes that occur prior to and following a memory response. We replicate previous work and find that prior to a memory response theta power is greater for identification of previously studied items (hits) relative to rejection of novel lures (correct rejections; CRs). Following the memory response, the theta power dissociation ‘flips’ whereby theta power is greater for CRs relative to hits. We find that the post-response ‘flip’ is more robust for hits that are committed quickly, potentially reflecting a positive feedback signal for strongly remembered experiences. Our findings suggest that there are potentially distinct processes occurring before and after a memory response that are modulated by successful memory retrieval.