Declarative Memory Research Articles

Memories are One-to-Many Mapping Alleviators in Talking Face Generation.

Talking face generation aims at generating photo-realistic video portraits of a target person driven by input audio. According to the nature of audio to lip motions mapping, the same speech content may have different appearances even for the same person at different occasions. Such one-to-many mapping problem brings ambiguity during training and thus causes inferior visual results. Although this one-to-many mapping could be alleviated in part by a two-stage framework (i.e., an audio-to-expression model followed by a neural-rendering model), it is still insufficient since the prediction is produced without enough information (e.g., emotions, wrinkles, etc.). In this paper, we propose MemFace to complement the missing information with an implicit memory and an explicit memory that follow the sense of the two stages respectively. More specifically, the implicit memory is employed in the audio-to-expression model to capture high-level semantics in the audio-expression shared space, while the explicit memory is employed in the neural-rendering model to help synthesize pixel-level details. Our experimental results show that our proposed MemFace surpasses all the state-of-the-art results across multiple scenarios consistently and significantly.

Neither fifty percent slow-wave sleep suppression nor fifty percent rapid eye movement sleep suppression does impair memory consolidation

Establishing well-defined relationships between sleep features and memory consolidation is essential in comprehending the pathophysiology of cognitive decline commonly seen in patients with insomnia, depression, and other sleep-disrupting conditions.Twenty-eight volunteers participated in two experimental sessions: a session with selective SWS suppression during one night and a session with undisturbed night sleep (as a control condition). Fifteen of them also participated in a third session with REM suppression. Suppression was achieved by presenting an acoustic tone. In the evening and the morning, the participants completed procedural and declarative memory tasks and the Psychomotor vigilance task (PVT). Heart rate variability analysis and salivary cortisol were used to control possible stress reactions to sleep interference.SWS and REM suppression led to more than 50 percent reduction in the amount of these stages. Neither vigilance nor memory consolidation was impaired after SWS or REM suppression. Unexpectedly, a beneficial effect of selective SWS suppression on PVT performance was found. Similarly, after a night with SWS suppression, the overnight improvement in procedural skills was higher than after a night with REM suppression and after a night with undisturbed sleep.Our data brings into question the extent to which SWS and REM are truly necessary for effective memory consolidation to proceed. Moreover, SWS suppression may even improve the performance of some tasks, possibly by reducing sleep inertia associated with undisturbed sleep.

Lifestyle, Environment, and Dietary Measures Impacting Cognitive Impairment: The Evidence Base for Cognitive Subtypes

: Cognition includes all phases of valid functions and processes, e.g., sensitivity, judgment, assessment, and decision-making. Thinking is also a cognitive procedure since it involves considering potential opportunities. There are various types of cognition. Hot cognition involves mental procedures where emotion plays a role, while cold cognition includes mental processes that do not include feelings or emotions. Cognitive memories of various types include sensor memory, sensing touch, smell, and sight; short-term memory allows one to recall, e.g., what one had for lunch a few days ago; working memory includes remembering telephone numbers or directions to a destination; and long-term memory comprises of major milestones in life and recalling one’s childhood events. These are further classified as episodic, e.g., the first day in primary school, and semantic memories, such as recalling the capital city of a country and filling out crossword puzzles. Declarative memories include remembering significant past events, such as global information. Cognition is affected by factors, such as nutrition, aging, addiction, environment, mental health, physical activity, smoking, and keeping the brain active. Consumption of plant- based foods plays a prominent role in the prevention of cognitive memory. Playing games and instruments, reading books, and being socially active make life more satisfying, thus assisting in the preservation of mental function and slowing mental decline.

A comparative analysis of partial sleep restriction versus split sleep regimen on cognitive processing, declarative memory, and affective behaviour in nursing students

Objectives: Sleep plays a regulatory role in functions such as abstraction, fluid intelligence, and declarative memory. This research seeks to assess the influence of two sleep restriction schedules—partial nocturnal sleep restriction and a split sleep (SS) regimen—on fluid intelligence and various memory functions (including encoding, consolidation, and retrieval) in shift-working nurses. Materials and Methods: The research involved 46 4th-year nursing students (23 males and 23 females) assigned to night duties, categorised into two groups: Partial sleep restriction (5 h of night sleep with 4 h of daytime recovery sleep) and SS (5 h of night sleep with 1.5 h of an afternoon nap and recovery sleep of 2.5 h following the tests). Instruments such as the Pittsburgh sleep quality index (PSQI), Karolinska sleepiness scale (KSS), and Raven’s Progressive Matrices were utilised to evaluate sleep quality, sleepiness levels, overall mood, benefits of daytime naps, and fluid intelligence. Memory-related activities comprised a picture-encoding task and a factual knowledge task, evaluated through subjective assessments and two alternative choice questions. Results: The PSQI global scores highlighted notable differences, with female nursing students in the partial sleep group scoring lower (9 ± 2.311) than their counterparts in the SS group (5 ± 1.09). Sleepiness, gauged by the KSSKSS score, was higher in the partial sleep group (7 ± 3.2) compared to female nursing students in the SS regimen (5 ± 5.8). Results from Raven’s progressive matrices pointed to delayed abstraction in the partial sleep restriction group (9.31 ± 6.24) in contrast to the SS group (9.01 ± 5.59), indicating poorer performance in visual attentive tasks. Positive and negative affect schedule scores unveiled heightened negativity in mood due to sleep restriction in the partial sleep group, with less hostility observed in those with an afternoon nap, albeit not reaching statistical significance. Positive moods exhibited fluctuation, with attentiveness declining in the partial sleep group. The study affirmed the advantages of a daytime nap on long-term memory. Female nurses in the SS regimen displayed statistically significant picture encoding accuracy (78 ± 3.65) with faster reaction times (2 ± 6.37) compared to the partial sleep group. Males in the SS regimen recorded a higher percentage of hits (88 ± 5.16). Learning sessions at 3 pm, coinciding with the circadian dip, affected the partial sleep groups, whereas the nap mitigated such effects for the SS group. Allowing a 1.5-h afternoon nap synchronised with the circadian dip enhanced memory in the SS group. Conclusion: By comparing partial nocturnal sleep restriction and a SS regimen, this study unveils their distinct effects on fluid intelligence and memory processes among shift-working nurses. The results provide valuable insights into the degree of dependence of basic cortical functions on sleep for healthcare professionals navigating demanding schedules, underscoring the significance of accounting for both nocturnal sleep duration and daytime naps to optimise cognitive performance.

Ketamine differentially affects implicit and explicit memory processes in rats.

Ketamine, a non-competitive NMDA receptor antagonist, produces antidepressant effects at subanesthetic doses. The therapeutic effect, however, is often accompanied by cognitive side effects, including memory impairments. Yet, the specific effects of ketamine on different processes of implicit and explicit memory remain to be elucidated. We examined the effect of an antidepressant dose of ketamine (10mg/kg, IP) on the encoding, retrieval, and modulation processes of fear memory and spatial memory in adult Wistar rats. Ketamine was administered before the fear acquisition, retrieval, or extinction procedures in a Pavlovian fear conditioning task. In another set of experiments, it was administered before the training, probe trial, or reversal training phases of the Morris Water Maze (MWM). The antidepressant dose of ketamine partially impaired fear extinction when administered before the acquisition or retrieval. In contrast, it facilitated memory modulation and decreased the escape latency in the first day of reversal training in the MWM when administered before the training or reversal training sessions. Encoding or retrieval performance in either type of memory was not affected. These findings show that ketamine does not impair the acquisition or retrieval processes of cued fear or spatial memory; but exerts differential effects on memory modulation of these implicit and explicit memory paradigms, by disrupting fear extinction and facilitating reversal spatial learning.

Low-Frequency Deep Brain Stimulation in Non-Rapid Eye Movement Sleep Modifies Memory Retention in Parkinson's Disease.

Memory impairment is a frequent and debilitating symptom in neurodegenerative disorders. The objective of this study was to provide proof-of-principle that deep brain stimulation during sleep can modify memory consolidation in people with Parkinson's disease depending on the stimulation frequency that is applied. Twenty-four patients with Parkinson's disease who were treated with deep brain stimulation of the subthalamic nucleus were included in this single-blind pilot study. Six patients had to be excluded because of insomnia on the night of testing. Patients were randomized (1:1 ratio) to receiving either low frequency deep brain stimulation (4 Hz) or clinically used high frequency deep brain stimulation (130 Hz) during early non-rapid eye movement (NREM) sleep. The main outcome measure was overnight memory retention as measured by a validated declarative memory task. Patients receiving low frequency deep brain stimulation during early NREM sleep (n = 9, 4 females, mean age 61.1 ± 4.3 years) showed improved overnight memory retention (z = 2.549, P = 0.011). Patients receiving clinically used high frequency deep brain stimulation (n = 9, 2 females, mean age 62.2 ± 7.1) did not show any improvement (z = 1.023, P = 0.306) leading to a significant difference between groups (z = 2.214, P = 0.027). Stronger improvement in memory function was correlated with increased cortical low frequency activity after low frequency deep brain stimulation as measured by electroencephalography (ρ = 0.711, P = 0.037). These results provide proof-of-principle that memory can be modulated by frequency-specific deep brain stimulation during sleep. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

On the Modeling of Inverse Memristor With Completely Explicit Memory Description: A Memorized Dielectric Relaxation Analogy‐Based Approach

ABSTRACTIn this work, a memorized dielectric relaxation analogy‐based model of inverse memristor has been proposed. In contrast to the previous models, a completely explicit memory description of the inverse memristor can be achieved by ours. The proposed model has been found to be well applicable to the practical inverse memristors of both current and voltage‐controlled types where the basic properties of inverse memristor have been preserved and the strong agreements between the model‐based results and their circuit‐based benchmarks can be observed. Based on our model, a rigorous analysis of inverse memristor has been performed to give a mathematical discussion on the simulation results. The power and energy consumption aspects have also been analyzed. In addition, the effect of parasitic element has been explored and it has been found that the inverse memristor realized based on our model is more robust to such undesired effect than those realized based on the others. This is another virtue of the proposed model. The realization methodology of the inverse memristor circuit based on our model with off‐the‐shelf components and the extension of the model toward the inverse memcapacitor and inverse meminductor have also been given.

The Discursive Journey of Meta-Awareness: Literacy (Teacher) Identity Within Preservice Teacher Preparation

The purpose of this study is to examine preservice teachers’ (PTs) meta-awareness related to their developing literacy (teacher) identities and examine the discursive belief systems and patterns embedded within this context. In this instrumental case study, we aim to determine the relationship(s) between meta-awareness and PTs’ literacy (teacher) identities through how they demonstrate their knowledge of literacy instruction and envision future literacy practices. The findings include PTs’ demonstration of their meta-awareness of literacy through their use of evaluative language, explicit memories, and content appropriation. Because personal and professional identities draw deeply from one another in shaping how PTs demonstrate their learning, our discussion expands upon this duality. Implications for teacher educators include recontextualizing one's past experiences as a reader and writer in literacy methods coursework as a means of moving toward agentic redress and responsive instruction.

EXPRESS: Do Motor Representations Influence Declarative Memory for Graspable Objects? A Test with Action Priming and Short-Term Hand Nonuse.

The present study addressed the role of motor representations in declarative memory (i.e., semantic and episodic). Based on embodied and grounded theories of cognition, it is often suggested that motor representations contribute to declarative memory. According to the action priming effect, graspable objects are categorized faster when primed by pictures of a congruent hand grip, as motor representations (how to grasp it) and semantic information (what it is) are closely related. Moreover, motor representations may contribute to episodic memory functioning. We immobilized participants' dominant hand for 24 hours to impair their processing of hand-related motor representations. This method is known to elicit rapid updating of cortical hand representations, and a slowdown in cognitive tasks linked to hand-related motor cognition. We expected to observe a decreased action priming effect following short-term hand nonuse. We further predicted that in a subsequent recognition task, objects that had been encoded following congruent action priming would be recognized faster by controls, but not by previously immobilized participants. Results did not show any effect of hand nonuse on action priming, suggesting that motor representations are not a decisive factor for this effect. Nonetheless, prime congruence influenced subsequent recognition. Immobilized participants were slower to recognize objects previously seen with an unrelated hand grip prime compared to a congruent one. This result suggests a contribution of motor representation to declarative memory, in particular when the sensorimotor system has previously been impaired.

Sleep oscillations and their relations with sleep-dependent memory consolidation in early course psychosis and first-degree relatives

Sleep spindles mediate sleep-dependent memory consolidation, particularly when coupled to neocortical slow oscillations (SOs). Schizophrenia is characterized by a deficit in sleep spindles that correlates with reduced overnight memory consolidation. Here, we examined sleep spindle activity, SO-spindle coupling, and both motor procedural and verbal declarative memory consolidation in early course, minimally medicated psychosis patients and non-psychotic first-degree relatives. Using a four-night experimental procedure, we observed significant deficits in spindle density and amplitude in patients relative to controls that were driven by individuals with schizophrenia. Schizophrenia patients also showed reduced sleep-dependent consolidation of motor procedural memory, which correlated with lower spindle density. Contrary to expectations, there were no group differences in the consolidation of declarative memory on a word pairs task. Nor did the relatives of patients differ in spindle activity or memory consolidation compared with controls, however increased consistency in the timing of SO-spindle coupling were seen in both patients and relatives. Our results extend prior work by demonstrating correlated deficits in sleep spindles and sleep-dependent motor procedural memory consolidation in early course, minimally medicated patients with schizophrenia, but not in first-degree relatives. This is consistent with other work in suggesting that impaired sleep-dependent memory consolidation has some specificity for schizophrenia and is a core feature rather than reflecting the effects of medication or chronicity.

Effects of dietary proteins on cognitive performance and brain vascular function in adults: a systematic review of randomised controlled trials.

The incidence of cognitive decline is rising, leading to increased attention on the preventive role of healthy foods on brain function. Previous reviews including primarily observational studies suggested that dietary proteins may improve cognitive performance, but evidence from individual randomised controlled trials (RCT) is less consistent. Therefore, this systematic review examined the long-term effects of dietary proteins from RCT, considering both their amount and type, on cognitive performance (psychomotor speed and attention, executive function, memory and global cognition). Alterations in cerebral blood flow (CBF) - a validated brain vascular function marker - were also considered. A total of 4747 studies were identified through a systematic search, resulting in twenty-three included papers reporting effects on cognitive performance (n = 23) and CBF (n = 3). Improvements were observed in three out of the nine studies that evaluated psychomotor speed which compared a dietary protein intervention with a non-protein or lower-protein control. Of the six beneficial observations on working memory (n = 12), declarative memory (n = 10) and visuospatial memory (n = 10), five were nut interventions from three different trials. Limited studies focusing on global cognition suggested that specific target populations, namely subacute stroke or dementia, may benefit more than healthy individuals from increased dietary protein intake. From the three studies involving CBF, improvements in regional blood flow were associated with most cognitive performance outcomes. The comparative effects of different protein types warrant further investigation. Overall, this review encourages additional research into protein-rich foods or supplements which could potentially prevent or mitigate cognitive decline.

How predictability and individual alpha frequency shape memory: Insights from an event-related potential investigation

Prediction and memory are strongly intertwined, with predictions relying on memory retrieval, whilst also influencing memory encoding. However, it is unclear how predictability influences explicit memory performance, and how individual neural factors may modulate this relationship. The current study sought to investigate the effect of predictability on memory processing with an analysis of the N400 event-related potential in a context extending beyond language. Participants (N = 48, females = 33) completed a study-test paradigm where they first viewed predictable and unpredictable four-item ‘ABCD’ sequences of outdoor scene images, whilst their brain activity was recorded using electroencephalography. Subsequently, their memory for the images was tested, and N400 patterns during learning were compared with memory outcomes. Behavioural results revealed better memory for images in predictable sequences in contrast to unpredictable sequences. Memory was also strongest for predictable images in the ‘B’ position, suggesting that when processing longer sequences, the brain may prioritise the data deemed most informative. Strikingly, greater N400 amplitudes during learning were associated with enhanced memory at test for individuals with low versus high individual alpha frequencies. In light of the relationship between the N400 and stimulus predictability, this finding may imply that predictive processing differs between individuals to influence the extent of memory encoding. Finally, exploratory analyses provided evidence for a later positivity that was predictive of subsequent memory performance. Ultimately, the results highlight the complex and interconnected relationship between predictive processing and memory, whilst shedding light on the accumulation of predictions across longer sequences.

EXPRESS: The lexical boost is not an automatic part of sentence production: Evidence from Japanese structural priming.

The lexical boost is an increase in structural priming with overlapping elements like verbs. Residual activation priming theories argue that the boost is an automatic side effect of sentence planning. In contrast, explicit memory theories of the boost argue that it is the result of a non-automatic explicit memory retrieval. These theories were contrasted in Japanese by including a prime memory task in a structural priming study. Structural priming was found for both datives and passives, but no lexical boost was found and one possible reason was that explicit memory for the prime structure was weak. In a follow-up study, priming was found in a sentence completion task, but there was no lexical boost. The existence of abstract priming and the lack of a lexical boost in these studies falsifies theories that argue that verb overlap automatically creates a boost under conditions that exhibit abstract priming.

Modulation of memory by prism adaptation in healthy subjects

Recent findings suggest that prism adaptation can extend its effects beyond spatial attention, modulating the performance of different cognitive tasks by acting on cerebellar, parietal and temporal-frontal networks. We tested groups of healthy subjects to investigate the effects of rightward vs. leftward prism adaptation vs. neutral lenses exposure in a series of memory tasks, probing either short-term (Digit span, Corsi span) or long-term memory (Supraspan verbal and spatial learning). In the short-term memory tasks, leftward prism adaptation selectively increased verbal span, while rightward prism adaptation increased spatial span. In the long-term memory tasks, leftward prism adaptation selectively increased verbal supraspan, i.e., increased the number of digits in the correct sequence reproduced and reduced the number of repetitions needed to learn the supraspan sequence. On the other hand, rightward prism adaptation selectively increased spatial supraspan, i.e. it increased the number of spatial positions in the correct sequence reproduced and reduced the number of repetitions needed to learn the supraspan sequence. Moreover, rightward, but not leftward, prism adaptation selectively increased supraspan recall after a delay interval, regardless of the stimulus material, i.e., it increased the number of digits or spatial positions recalled after a delay interval. Neutral lenses exposure did not influence any memory task. These findings suggest that prism adaptation can induce both modality/hemispheric-specific and process-specific effects on short-term and long-term explicit memory.

Executive control can query hidden human memories.

When we try to retrieve a representation from visual long-term memory there is a chance that we will fail to recall seeing it even though the memory is stored in our brain. Here we show that although mechanisms of explicit memory retrieval are sometimes unable to retrieve stored memories, that mechanisms of executive control can quickly query memory and determine if a representation is stored therein. Our findings suggest that the representations stored in human memory that cannot be accessed explicitly at that moment are nonetheless directly accessible by the brain's higher level control mechanisms.

Temporal recall in the shadow of emotion: separate emotional contexts during encoding enhance the temporal source memory retrieval.

Episodic memory, with its emphasis on temporal-spatial contexts, has been a longstanding focus in memory research. While previous studies have investigated the role of emotion in temporal source memory using emotionally charged stimuli, such as emotional words or images, the influence of a separated emotional context remains less explored. This study sought to understand the impact of separate emotional contexts on temporal source memory. Participants were shown Chinese characters alongside separate emotional contexts (i.e. a neutral or negative picture) and then engaged in either a retrieval practice or a control condition. Finally, they were tested for recognition, temporal source memory, and emotional source memory for all the learned characters. Results revealed that a negative emotional context, unlike a neutral setting, enhanced the accuracy of temporal memory for adjacent neutral characters. However, this negative context reduced the accuracy of recalling the associated emotion. Importantly, the boost in temporal memory due to the emotional context remained even when participants were unsure or mistaken about the associated emotion. This study demonstrates the complex interplay between emotion and temporal memory, underscoring the enhancement effect of separated emotional contexts on temporal recall, irrespective of explicit emotional memory retrieval.

Impaired Sleep-Dependent Memory Consolidation in Pediatric Narcolepsy Type 1.

Disrupted nighttime sleep (DNS) is common in pediatric Narcolepsy type 1, yet its cognitive impact is unknown. As N2 sleep spindles are necessary for sleep-dependent memory consolidation, we hypothesized that Narcolepsy Type 1 impairs memory consolidation via N2 sleep fragmentation and N2 sleep spindle alterations. We trained 28 pediatric Narcolepsy Type 1 participants and 27 healthy controls (HC) on a spatial declarative memory task before a nocturnal in-lab polysomnogram and then gave them a cued recall test upon awakening in the morning. We extracted wake and sleep stage bout numbers and N2 spindle characteristics from the polysomnogram and conducted mixed model analysis of sleep-dependent memory consolidation to identify group differences. Narcolepsy Type 1 participants had shorter N2 bout durations and associated shorter N2 spindles vs. HC, but other N2 spindle features were similar. Narcolepsy Type 1 participants had worse memory performance post-sleep than HCs after adjusting for age and gender (mean memory consolidation HC: -3.1% ± 18.7, NT1: -15.6 ± 24.8, main effect group x time of testing F=5.3, p=0.03). We did not find significant relationships between sleep-dependent memory consolidation and N2 spindle characteristics. Notably, increased N1% was associated with worse sleep-dependent memory consolidation with results driven by the Narcolepsy Type 1 group. Sleep-dependent memory consolidation is mildly impaired in youth with Narcolepsy Type 1 and findings may be attributed to increases in N1 sleep. Further studies are needed to determine if these findings are generalizable and reversible with sleep-based therapies.

Measuring Socioeconomic and Stress Disparities in Infant Declarative Memory Using the Visual Paired Comparison Task.

Research suggests that socioeconomic circumstances and stress predict memory skills in adults and older children, yet few studies have addressed this question in infancy. The current study used the visual-paired comparison paradigm to examine whether socioeconomic circumstances, maternal perceived stress, and/or maternal physiological stress, all measured prenatally, predict memory performance among 6-month-old infants. We found no significant associations between infant memory and any measure of socioeconomic circumstance or stress. Potential explanations for these null findings are discussed.

Explicit information and working memory in second-language acquisition of the Spanish subjunctive: A replication and extension of Fernández (2008)

Abstract An important issue in second-language acquisition concerns the role of explicit information (EI) and how it is affected by individual differences. The present study explored this question through a partial replication and extension of Fernández (2008: Experiment 2), which investigated the effects of EI in processing instruction (PI) for the Spanish present subjunctive. This replication compared training with EI (PI) to training without it (structured input; SI). In addition to methodological changes that balance the amount of exposure between groups, this study also includes a control group that received exposure to the target form (C+). Extending the original study, we also assessed the durability of training and whether its effects interact with individual differences in working memory (WM). Results indicate advantages for the PI group during training, supporting Fernández’s conclusions. Immediate post-tests show advantages for the PI group that are not sustained on delayed post-tests. Analyses also indicate benefits for higher WM but only for the PI and C+ groups, although this was only sustained for the C+ group. Thus, findings indicate that when paired with SI, EI and high WM may influence the initial learning of the Spanish subjunctive, but their influence may dissipate over time.

A Matter of Memory? Age-Invariant Relative Clause Disambiguation and Memory Interference in Older Adults.

Past research suggests that Working Memory plays a role in determining relative clause attachment bias. Disambiguation preferences may further depend on Processing Speed and explicit memory demands in linguistic tasks. Given that Working Memory and Processing Speed decline with age, older adults offer a way of investigating the factors underlying disambiguation preferences. Additionally, older adults might be subject to more severe similarity-based memory interference given their larger vocabularies and slower lexical access. Nevertheless, memory interference and sentence disambiguation have not been combined in studies on older adults before. We used a self-paced reading paradigm under memory load interference conditions. Older (n=30) and Younger (n=35) readers took part in the study online; reading times were recorded and measures of comprehension accuracy and load recall were collected. This setup allowed for the implicit measurement of attachment biases and memory interference effects interactively. Results show that similarity-based interference affected both age groups equally, but was more pronounced in NP2-biased structures, which took participants generally longer to read. Attachment preferences did not differ by group and were unaffected by Working Memory span. However, accuracy on recall prompts was predicted by Working Memory span in both groups. Findings of greater interference in syntactically dispreferred structures support unified processing models where parsing constraints naturally interact. The lack of age differences on our measures further aligns with research finding age-invariant implicit language processing.