Memory Retrieval Cues Research Articles

Cross-regional coordination of activity in the human brain during autobiographical self-referential processing

For the human brain to operate, populations of neurons across anatomical structures must coordinate their activity within milliseconds. To date, our understanding of such interactions has remained limited. We recorded directly from the hippocampus (HPC), posteromedial cortex (PMC), ventromedial/orbital prefrontal cortex (OFC), and the anterior nuclei of the thalamus (ANT) during two experiments of autobiographical memory processing that are known from decades of neuroimaging work to coactivate these regions. In 31 patients implanted with intracranial electrodes, we found that the presentation of memory retrieval cues elicited a significant increase of low frequency (LF < 6 Hz) activity followed by cross-regional phase coherence of this LF activity before select populations of neurons within each of the four regions increased high-frequency (HF > 70 Hz) activity. The power of HF activity was modulated by memory content, and its onset followed a specific temporal order of ANT→HPC/PMC→OFC. Further, we probed cross-regional causal effective interactions with repeated electrical pulses and found that HPC stimulations cause the greatest increase in LF-phase coherence across all regions, whereas the stimulation of any region caused the greatest LF-phase coherence between that particular region and ANT. These observations support the role of the ANT in gating, and the HPC in synchronizing, the activity of cortical midline structures when humans retrieve self-relevant memories of their past. Our findings offer a fresh perspective, with high temporal fidelity, about the dynamic signaling and underlying causal connections among distant regions when the brain is actively involved in retrieving self-referential memories from the past.

Quantification at a distance and grammatical illusions in French

AbstractRecent research in psycholinguistics supports the hypothesis that retrieval from working memory is a key component of establishing syntactic dependencies in comprehension. This can result in so‐called grammatical illusions. These illusions have been modeled as the result of a content‐addressable retrieval process in sentence comprehension that allows grammatically inaccessible licensing elements to be reactivated, creating a spurious perception of acceptability. This article reports five studies that establish the existence of a new grammatical illusion involving quantification at a distance and the licensing of so‐called de NPs in French. Our results suggest that this grammatical illusion is interestingly constrained by syntactic properties of the licensors. Specifically, quantifiers that independently participate in quantification‐at‐a‐distance constructions were seen to create grammatical illusions to a greater extent than quantifiers that do not participate in that construction. Consistent with previous work on the nature of cues in memory retrieval, we suggest that this is the result of fairly specific abstract syntactic cues that guide retrieval of a licensing element. This article thus brings further evidence that syntax is crucially used to structure working memory over the course of a parse.

Application of an artificial intelligence algorithm model of memory retrieval and roaming in sorting Chinese medicinal materials

In order to capture autobiographical memory, inspired by the development of human intelligence, a computational AM model for autobiographical memory is proposed in this paper, which is a three-layer network structure, in which the bottom layer encodes the event-specific knowledge comprising 5W1H, and provides retrieval clues to the middle layer, encodes the related events, and the top layer encodes the event set. According to the bottom-up memory search process, the corresponding events and event sets can be identified in the middle layer and the top layer respectively; At the same time, AM model can simulate human memory roaming through the process of rule-based memory retrieval. The computational AM model proposed in this paper not only has robust and flexible memory retrieval, but also has better response performance to noisy memory retrieval cues than the commonly used memory retrieval model based on keyword query method, and can also imitate the roaming phenomenon in memory.

Individual differences in the use of motor and visual cues in memory retrieval

Individual differences in the use of motor and visual cues in memory retrieval

A boost of confidence: The role of the ventromedial prefrontal cortex in memory, decision-making, and schemas

The ventromedial prefrontal cortex (vmPFC) has been implicated in a wide array of functions across multiple domains. In this review, we focus on the vmPFC's involvement in mediating strategic aspects of memory retrieval, memory-related schema functions, and decision-making. We suggest that vmPFC generates a confidence signal that informs decisions and memory-guided behaviour. Confidence is central to these seemingly diverse functions: (1) Strategic retrieval: lesions to the vmPFC impair an early, automatic, and intuitive monitoring process (“feeling of rightness”; FOR) often associated with confabulation (spontaneous reporting of erroneous memories). Critically, confabulators typically demonstrate high levels of confidence in their false memories, suggesting that faulty monitoring following vmPFC damage may lead to indiscriminate confidence signals. (2) Memory schemas: the vmPFC is critically involved in instantiating and maintaining contextually relevant schemas, broadly defined as higher level knowledge structures that encapsulate lower level representational elements. The correspondence between memory retrieval cues and these activated schemas leads to FOR monitoring. Stronger, more elaborate schemas produce stronger FOR and influence confidence in the veracity of memory candidates. (3) Finally, we review evidence on the vmPFC's role in decision-making, extending this role to decision-making during memory retrieval. During non-mnemonic and mnemonic decision-making the vmPFC automatically encodes confidence. Confidence signal in the vmPFC is revealed as a non-linear relationship between a first-order monitoring assessment and second-order action or choice. Attempting to integrate the multiple functions of the vmPFC, we propose a posterior-anterior organizational principle for this region. More posterior vmPFC regions are involved in earlier, automatic, subjective, and contextually sensitive functions, while more anterior regions are involved in controlled actions based on these earlier functions. Confidence signals reflect the non-linear relationship between first-order, posterior-mediated and second-order, anterior-mediated processes and are represented along the entire axis.

The hippocampus

The hippocampus

Recording thoughts while memorizing music: a case study.

Musicians generally believe that memory differs from one person to the next. As a result, memorizing strategies that could be useful to almost everyone are not widely taught. We describe how an 18-years old piano student (Grade 7, ABRSM), learned to memorize by recording her thoughts, a technique inspired by studies of how experienced soloists memorize. The student, who had previously ignored suggestions that she play from memory, decided to learn to memorize, selecting Schumann’s “Der Dichter Spricht” for this purpose. Rather than explicitly teaching the student how to memorize, the teacher taught her to record her thoughts while playing by marking them on copies of the score, adapting an approach used previously in research with experienced performers. Over a 6½ week period, the student recorded her thoughts during practice (five times) and while performing from memory for the teacher (three times). The student also video-recorded 3 weeks of practice, three performances, and the reconstruction of the piece from memory after a 9½-weeks break. The thoughts that the student reported were prepared during practice, stable over time, and functioned as memory retrieval cues during reconstruction. This suggests that the student memorized in the same way as the more experienced musicians who have been studied previously and that teaching student musicians to record their thoughts may be an effective way to help them memorize. The speed and durability of her memorization surprised the student, inspiring her to perform in public and to use the same technique for new pieces.

Endogenous-cue prospective memory involving incremental updating of working memory: an fMRI study.

Prospective memory paradigms are conventionally classified on the basis of event-, time-, or activity-based intention retrieval. In the vast majority of such paradigms, intention retrieval is provoked by some kind of external event. However, prospective memory retrieval cues that prompt intention retrieval in everyday life are commonly endogenous, i.e., linked to a specific imagined retrieval context. We describe herein a novel prospective memory paradigm wherein the endogenous cue is generated by incremental updating of working memory, and investigated the hemodynamic correlates of this task. Eighteen healthy adult volunteers underwent functional magnetic resonance imaging while they performed a prospective memory task where the delayed intention was triggered by an endogenous cue generated by incremental updating of working memory. Working memory and ongoing task control conditions were also administered. The 'endogenous-cue prospective memory condition' with incremental working memory updating was associated with maximum activations in the right rostral prefrontal cortex, and additional activations in the brain regions that constitute the bilateral fronto-parietal network, central and dorsal salience networks as well as cerebellum. In the working memory control condition, maximal activations were noted in the left dorsal anterior insula. Activation of the bilateral dorsalanterior insula, a component of the central salience network, was found to be unique to this 'endogenous-cue prospective memory task' in comparison to previously reported exogenous- and endogenous-cue prospective memory tasks without incremental working memory updating. Thus, the findings of the present study highlightthe important role played by the dorsal anterior insulain incremental working memory updating that is integral to our endogenous-cue prospective memory task.

Theta oscillations orchestrate medial temporal lobe and neocortex in remembering autobiographical memories

Remembering autobiographical events can be associated with detailed visual imagery. The medial temporal lobe (MTL), precuneus and prefrontal cortex are held to jointly enable such vivid retrieval, but how these regions are orchestrated remains unclear. An influential prediction from animal physiology is that neural oscillations in theta frequency may be important. In this experiment, participants prospectively collected audio recordings describing personal autobiographical episodes or semantic knowledge over 2 to 7months. These were replayed as memory retrieval cues while recording brain activity with magnetoencephalography (MEG). We identified a peak of theta power within a left MTL region of interest during both autobiographical and General Semantic retrieval. This MTL region was selectively phase-synchronized with theta oscillations in precuneus and medial prefrontal cortex, and this synchrony was higher during autobiographical as compared to General Semantic knowledge retrieval. Higher synchrony also predicted more detailed visual imagery during retrieval. Thus, theta phase-synchrony orchestrates in humans the MTL with a distributed neocortical memory network when vividly remembering autobiographical experiences.

Key Features of Human Episodic Recollection in the Cross-Episode Retrieval of Rat Hippocampus Representations of Space

Author SummarySince Plato and the early cognitive psychologists we have believed that recollection is not a straightforward replay of stored experience; memory can be modified by the subject's experience and or state of mind, sometimes generating knowledge that was never itself experienced. We show in rats that direct neurophysiological evidence that episodic recollection is not a verbatim replay of stored experience; rather retrieval is a constructive process—an intermingling of the stored memory, environmental circumstances, and the subject's state of mind. To monitor internal, neural representations, we recorded the action potential discharge within a network of hippocampal neurons while rats performed two familiar active place avoidance tasks: one where the arena was stable and one where it rotated. Neural representations of the stable and rotating conditions were distinct. However, during the rotating task we intermittently observed intervals that we call “cross-episode retrieval” because discharge resembled the representation of the stable task. The incidence of cross-episode retrieval was higher when the angular position of the rotating arena was similar to that in the stable condition, demonstrating that retrieval is influenced by the environment. Cross-episode retrieval was also more likely when discharge represented the position of the rat in the stationary room rather than when it represented positions that rotate with the arena; this demonstrated that retrieval is influenced by internal cognitive variables that are encoded by hippocampal discharge—a state of mind. Thus novel, key features of constructive human episodic memory can be observed in rat hippocampal discharge.

Context memory in Korsakoff's syndrome.

Memory for contextual information and target-context integration are crucial for successful episodic memory formation and are impaired in patients with Korsakoff’s syndrome. In this paper we review the evidence for the notion that a context memory deficit makes an important contribution to the amnesia in these patients. First, we focus on anterograde memory for contextual (spatial and temporal) information. Next, the use of contextual cues in memory retrieval is examined and their role in retrograde amnesia and confabulation. Evidence on the role of contextual cues and associations in working memory is discussed in relation to the underlying neurocognitive mechanisms and their dissociation from long-term encoding. Finally, we focus on implicit learning of contextual information in Korsakoff patients. It can be concluded that Korsakoff patients are impaired in the explicit processing of contextual information and in target-context binding, both in long-term (retrograde and anterograde) memory and in working memory. These results extend the context memory deficit hypothesis. In contrast, implicit contextual learning is relatively preserved in these patients. These findings are discussed in relation to evidence of dysfunction of the extended diencephalic-hippocampal memory circuit in Korsakoff’s syndrome.

Left and right memory revisited: Electrophysiological investigations of hemispheric asymmetries at retrieval

Hemispheric differences in the use of memory retrieval cues were examined in a continuous recognition design, using visual half-field presentation to bias the processing of test words. A speeded recognition task revealed general accuracy and response time advantages for items whose test presentation was biased to the left hemisphere. A second experiment recorded event-related brain potentials in the same design and replicated these behavioral effects, but found no electrophysiological support for the hypothesis that test words biased to the left hemisphere elicit superior recognition. Instead, successful retrieval was accompanied by memory components of identical strength regardless of test field. That robust visual field effects in response accuracy and speed were not mimicked in memory components that generally do correlate with such behavioral differences suggests that patterns in overt responses may be dominated by the left hemisphere’s superior ability to apprehend words. Differences between the data pattern observed in the present study with lateralized retrieval and that in a prior study with lateralized encoding [Evans, K. M., & Federmeier, K. D. (2007). The memory that’s right and the memory that’s left: Event-related potentials reveal hemispheric asymmetries in the encoding and retention of verbal information. Neuropsychologia 45(8), 1777–1790.] support the notion that hemispheric processing is highly integrated in the intact brain, and highlight the need to treat lateralization at different stages as distinct.

Limits on the role of retrieval cues in memory for actions: Enactment effects in the absence of object cues in the environment

Verb-object phrases (open the umbrella, knock on the table) are usually remembered better if they have been enacted during study (also called subject-performed tasks) than if they have merely been learned verbally (verbal tasks). This enactment effect is particularly pronounced for phrases for which the objects (table) are present as cues in the study and test contexts. In previous studies with retrieval cues for some phrases, the enactment effect in free recall for the other phrases has been surprisingly small or even nonexistent. The present study tested whether the often replicated enactment effect in free recall can be found if none of the phrases contains context cues. In Experiment 1, we tested, and corroborated, the suppression hypothesis: The enactment effect for a given type of phrase (marker phrases) is modified by the presence or absence of cues for the other phrases in the list (experimental phrases). Experiments 2 and 3 replicated the enactment effect for phrases without cues. Experiment 2 also showed that the presence of cues either at study or at test is sufficient for obtaining a suppression effect, and Experiment 3 showed that the enactment effect may disappear altogether if retrieval cues are very salient.

Transfer of old ‘reactivated’ memory retrieval cues in rats

The present studies examined whether the retrieval of an old ‘reactivated’ memory could be brought under the control of new contextual cues. In Experiment 1 rats trained in one context were exposed to different contextual cues either immediately, 60 or 120 min after a cued reactivation of the training memory. When tested in the shifted context, subjects exposed shortly after reactivation treated the shifted context as the original context. This transfer diminished with longer post-reactivation delays. Experiment 2 replicated the basic finding and demonstrated that the transfer of the old retrieval cues was specific to the contextual cues present during exposure. These findings are consistent with previous research [i.e., Briggs, J. F., Fitz, K. I., & Riccio, D. C. (in press). Transfer of memory retrieval cues in rats. Psychonomic Bulletin & Review] showing the transfer of retrieval cues for a new memory, and demonstrating a similarity (in this case) between newly acquired and old reactivated memories.

Alcohol Ataxia Tolerance: Extinction Cues, Spontaneous Recovery, and Relapse

This article reviews ethanol ataxic tolerance experiments with rats that investigate spontaneous recovery after extinction and how extinction-related cues reduce this recovery. Tolerance to the effects of many drugs including ethanol is partly the result of Pavlovian conditioning. Tolerance to the ataxic (and other) effects of ethanol depends critically upon the circumstances in which the drug is administered. Tolerance shows other characteristics common in Pavlovian conditioning, e.g.,. it can be extinguished and is subject to spontaneous recovery. The analogy of spontaneous recovery to instances of relapse in humans potentially makes such spontaneous recovery relevant to both researchers and clinicians. Recently, "extinction cues" have been found to reduce spontaneous recovery and other relapse- like effects in the animal conditioning laboratory. These cues may work in part by activating an association formed during the extinction process, and thus they may serve as memory retrieval cues. Research assessing spontaneous recovery using an ethanol ataxia method, as well as other Pavlovian conditioning methods, has contributed to an understanding of the properties and utility of extinction cues. These topics are addressed and the potential implications of this research for treating substance abusers is considered.

Global and Local Processing of Incidental Information and Memory Retrieval at 6 Months

In five experiments, we examined the role of global and local cues in memory retrieval in infancy. Six-month-old infants were trained at home in a distinctive context (playpen liner) to kick to move a mobile. The liners were yellow and displayed either green stripes, green squares aligned vertically in stripe-like columns, or green squares in a grid pattern. The stripes and columns liners had a similar global configuration but different local components; the columns and grid liners had identical local components but different global configurations. When infants were tested 24 h after training in the presence of context liners that differed from the training context in either global configurations or local features, their memory retrieval was disrupted (Experiments 1 and 2). However, a change from stripes to columns failed to disrupt memory retrieval, even though the reverse change, from columns to stripes, did. Experiments 3, 4, and 5 revealed that this asymmetry was due to the fact that, when discriminative local information is not directly associated with training, a postperceptual strategy enables infants to disregard a mismatch in local information between training and test contexts and to generalize on the basis of a match in global information during the 24-h retention test. Thus, infants encode and remember for substantial periods of time both global configuration information and local component information in the incidental context in which an event occurs and flexibly utilize this information when responding to new events.

Infant memory for place information

The present studies were designed to examine the role of place cues in memory retrieval during early infancy. Three-month-old infants were trained to move a mobile by kicking. Two weeks later, memory retrieval was disrupted if they were reminded in a location or place different from where they had been trained, but not if they were reminded in the same place (Experiment 1A). The same result was obtained even though highly salient cues in their immediate visual surround remained unchanged during reminding (Experiments 1B and 1C). No disruption was seen, however, when retrieval was cued in a different place after only 1 day (Experiment 2). These findings unequivocally demonstrate that infants as young as 3 months encode incidental information about the place where an event occurs and suggest that early memories are buffered against retrieval in potentially inappropriate contexts over the long term.

Odors and the remembrance of things past.

Three experiments, using odors and incidental learning procedures, examined the effectiveness of odors as memory retrieval cues.

Symbolic, identity, and probe delayed matching of sounds by the bottlenosed dolphin

The short-term memory for sounds of the bottlenosed dolphin was tested using symbolic, identity, and probe forms of the delayed matching-to-sample (DMS) task. The forms differed in the number (one or two) or nature (symbolic or identity matches of sample sounds) of postdelay test stimuli available as memory retrieval cues. Although symbolic DMS was difficult to learn, the final performance level was approximately equal to that for identity or probe DMS. On all tasks, the dolphin’s responses were above 80% correct through to delays of 90 sec and, in some cases, through to delays of 180 and 240 sec, the “limits” being governed mainly by the dolphin’s reluctance to continue being tested at long delays. Encoding of sample stimuli into their learned symbolic representation was hypothesized to have reduced symbolic DMS to a recognition memory task, resulting in the observed equivalence of performance with the other two recognition memory tasks. The probe DMS results, unlike those for identity or symbolic DMS, showed no significant proactive interference effects from samples of prior trials. Instead, proactive interference was traceable to the probe value of the prior trial. Overall, the auditory DMS data for the dolphin were functionally similar to results reported for monkeys tested on symbolic, identity, and probe visual DMS tasks.

Ovarian hormones and retention of learned fear in rats

The present series of investigations was designed to evaluate whether naturally occurring or exogenously induced hormonal changes might influence memory in a state-dependent paradigm. Rats in four experiments received Pavlovian fear conditioning to static environmental cues, followed by passive avoidance testing. In Experiment 1 animals were trained and tested in either the same stages of the estrous cycle (E-E, P-P) or in different stages (E-D, D-E, P-D, D-P). In Experiment 2 rats were trained during one stage of pregnancy, and tested for retention when hormonal conditions were presumably similar (same state) or altered (mismatched). No convincing evidence was found which would indicate that naturally occurring changes in hormonal levels associated with either stages of estrous (Exp 1) or stages of pregnancy (Exp 2) modulate retention of fear. Exogenous administrations of progesterone were employed in Experiments 3 and 4 in order to permit more direct experimental control over internal states and to enhance the salience of changes in internal environment. With a 7-day retention interval progesterone manipulations failed to influence retention performance in a state-dependent manner (Experiment 3), but with a 1-day interval asymmetrical state-dependent effects were obtained. Implications of these findings with respect to boundary conditions on the role of internal contextual cues in memory retrieval were discussed.