Memory Recollection Research Articles

BACE1 Translation: At the Crossroads Between Alzheimer's Disease Neurodegeneration and Memory Consolidation.

Human life unfolds not only in time and space, but also in the recollection and interweaving of memories. Therefore, individual human identity depends fully on a proper access to the autobiographical memory. Such access is hindered under pathological conditions such as Alzheimer’s disease, which affects millions of people worldwide. Unfortunately, no effective cure exists to prevent this disorder, the impact of which will rise alarmingly within the next decades. While Alzheimer’s disease is largely considered to be the outcome of amyloid-β (Aβ) peptide accumulation in the brain, conceiving this complex disorder strictly as the result of Aβ-neurotoxicity is perhaps a too straight-line simplification. Instead, complementary to this view, the tableau of molecular disarrangements in the Alzheimer’s disease brain may be reflecting, at least in part, a loss of function phenotype in memory processing. Here we take BACE1 translation and degradation as a gateway to study molecular mechanisms putatively involved in the transition between memory and neurodegeneration. BACE1 participates in the excision of Aβ-peptide from its precursor holoprotein, but plays a role in synaptic plasticity too. Its translation is governed by eIF2α phosphorylation: a hub integrating cellular responses to stress, but also a critical switch in memory consolidation. Paralleling these dualities, the eIF2α-kinase HRI has been shown to be a nitric oxide-dependent physiological activator of hippocampal BACE1 translation. Finally, beholding BACE1 as a representative protease active in the CNS, we venture a new perspective on the cellular basis of memory, which may incorporate neurodegeneration in itself as a drift in memory consolidating systems.

The functional organisation of the hippocampus along its long axis is gradual and predicts recollection

Understanding the functional organisation of the hippocampus is crucial for understanding its role in cognition and disorders in which it is implicated. Different views have been proposed of how function is distributed along its long axis: one view suggests segregation, whereas the alternative view postulates a more gradual organisation. Here, we applied a novel ‘connectopic mapping’ data-analysis approach to the resting-state fMRI data of participants of the Human Connectome Project, and demonstrate that the functional organisation of the hippocampal longitudinal axis is gradual rather than segregated into parcels. In addition, we show that inter-individual variations in this gradual organisation predict variations in recollection memory better than a characterisation based on functional parcellation. These results present an important step forward in understanding the functional organisation of the human hippocampus and have important implications for translating between rodent and human research.

Recollection of Memory and Stupidity of Love in Julian Barnes’s The Sense of an Ending

Recollection of Memory and Stupidity of Love in Julian Barnes’s The Sense of an Ending

Echoes of Emotions Past: How Neuromodulators Determine What We Recollect

We tend to re-live emotional experiences more richly in memory than more mundane experiences. According to one recent neurocognitive model of emotional memory, negative events may be encoded with a larger amount of sensory information than neutral and positive events. As a result, there may be more perceptual information available to reconstruct these events at retrieval, leading to memory reinstatement patterns that correspond with greater memory vividness and sense of recollection for negative events. In this commentary, we offer an alternative perspective on how emotion may influence such sensory cortex reinstatement that focuses on engagement of the noradrenergic (NE) and dopaminergic (DA) systems rather than valence. Specifically, we propose that arousal-related locus coeruleus-norepinephrine (LC-NE) system activation promotes the prioritization of the most salient features of an emotional experience in memory. Thus, a select few details may drive lower-level sensory cortical activity and a stronger sense of recollection for arousing events. By contrast, states of high behavioral activation, including novelty-seeking and exploration, may recruit the DA system to broaden the scope of cognitive processing and integrate multiple event aspects in memory. These more integrated memory representations may be reflected in higher-order cortical reinstatement at retrieval. Thus, the balance between activation in these neuromodulatory systems at encoding, rather than the valence of the event, may ultimately determine the quality of emotional memory recollection and neural reinstatement.

Misremembrance of Things Past: Depression Is Associated With Difficulties in the Recollection of Both Specific and Categoric Autobiographical Memories.

Impaired retrieval of specific, autobiographical memories of personally experienced events is characteristic of major depressive disorder (MDD). However, findings in subclinical samples suggest that the reduced specificity phenomenon may reflect a broader impairment in the deliberate retrieval of all autobiographical memory types. This experiment (N = 68) explored this possibility by requiring individuals with and without MDD to complete a cued-recall task that required retrieval of specific, single-incident memories to a block of cues; retrieval of categoric, general memories to a block of cues; and to alternate between retrieval of specific and general memories for a block of cues. Results demonstrated that relative to never-depressed controls, individuals with MDD experience reduced recall of both specific (d = 0.48) and general memories (d = 1.00) along with reduced flexibility in alternating between specific and general memories (d = 0.90). Findings support further development of autobiographical memory–based interventions that target a range of retrieval deficits rather than specificity alone.

Direct Stimulation of Human Hippocampus During Verbal Associative Encoding Enhances Subsequent Memory Recollection.

Previous studies have reported conflicting results regarding the effect of direct electrical stimulation of the human hippocampus on memory performance. A major function of the hippocampus is to form associations between individual elements of experience. However, the effect of direct hippocampal stimulation on associative memory remains largely inconclusive, with most evidence coming from studies employing non-invasive stimulation. Here, we therefore tested the hypothesis that direct electrical stimulation of the hippocampus specifically enhances hippocampal-dependent associative memory. To test this hypothesis, we recruited surgical patients with implanted subdural electrodes to perform a word pair memory task during which the hippocampus was stimulated. Our results indicate that stimulation of the hippocampus during encoding helped to build strong associative memories and enhanced recollection in subsequent trials. Moreover, stimulation significantly increased theta power in the lateral middle temporal cortex during successful memory encoding. Overall, our findings indicate that hippocampal stimulation positively impacts performance during a word pair memory task, suggesting that successful memory encoding involves the temporal cortex, which may act together with the hippocampus.

The relevance of the first two eye fixations for recognition memory processes

ABSTRACTStimuli can be recognised based on information from only one or two eye fixations. With only one fixation, item recognition is typically above chance level and performance generally saturates by the second fixation. Thus, the first two eye fixations play an important role for recognition memory performance. However, little is known about the involved processes. Therefore, two experiments were conducted to investigate hypotheses regarding the role of the first two eye fixations for specific recognition memory processes, that is, familiarity and recollection. In addition, we looked in detail at the unique contributions of (a) longer input duration and (b) additional information provided by a second fixation for familiarity- and recollection-based recognition, using a gaze-contingent stimulus presentation technique. The experiments showed that recollection- but not familiarity-based recognition increased with two compared to only one fixation, and that the second fixation boosted recollection both due to longer availability of the input and additional stimulus information gathered.

Increasing Dopamine and Acetylcholine Levels during Encoding Does Not Modulate Remember or Know Responses during Memory Retrieval in Healthy Aging—a Randomized Controlled Feasibility Study

The retrieval of information from long-term memory can be associated with information regarding sources or context (recollection) or without further context (familiarity). The retrieval type depends on how information has been encoded previously, and this encoding process is supposed to be modulated by the neurotransmitters dopamine and acetylcholine. For example, acetylcholine levels in the hippocampus increase when one is confronted with novel information allowing for better encoding and, presumably, for retrieval of more detailed memories (recollection). On the other hand, a dopaminergic deficit such as in Parkinson’s disease has been shown to induce deficits in familiarity rather than in recollection-based retrieval. It is, however, unclear whether this finding arises from alterations in encoding, retrieval, or both. Moreover, other research has challenged this clear-cut dichotomy and linked dopamine to both familiarity and recollection, and acetylcholine to unspecific enhancement of memory for novel information. Thirty-nine healthy seniors (age range 62–77) participated in a remember/know task in which scenes that were presented with different repetition rates had to be encoded and retrieved on the following day. Neurotransmitter levels were modulated during encoding by administrating either levodopa (100 mg, N = 13) or galantamine (8 mg, N = 13) to one of two experimental groups. A third group received a placebo (N = 13). Across all groups, recognition memory increased as a function of stimulus repetition, and this effect was specifically pronounced for remember relative to know answers. Importantly, the drugs had no effect on recollection, familiarity, or overall recognition memory. The findings argue against a simple dichotomy of dopaminergic and cholinergic contributions to either recollection- or familiarity-based memory retrieval.

The role of reference frames in memory recollection.

In this commentary on Bastin et al., we suggest that spatial context plays a critical role in the encoding and retrieval of events. Specifically, the translation process between the viewpoint-independent content of a memory and the viewpoint-dependent stimuli activating the retrieval (mental frame syncing) plays a critical role in spatial memory recollection. This perspective also provides an explanatory model for pathological disturbances such as Alzheimer's disease.

A Pre-Experimental Study to Evaluate the Effectiveness of Structured Reminiscence Psychotherapy on the Level of Depression among Elderly Residing in Old Age Home

Depression is not a sign of weakness. It can happen to anyone, at any age, no matter your background or your previous accomplishments in life. Depression is common problem in older adults. And its symptoms affect every aspect of life, including energy, appetite, sleep and interest in work, hobbies and relationships. Elderly people are highly prone to mental morbidities due to aging of the brain, problems associated with physical health, socioeconomic factors such as break down of the family support systems, decrease in economic independence. Reminiscence refers to recollection of memory from the past. Reminiscence involves exchanging memories with the old and young, friends and relatives, with care giver and professional, passing on information, wisdom and skills, therapeutic reminiscence not only enhances the cure of souls in early old age; it also help to close the gap between the depressing expectation of younger generation and the reality of continued growth in the last half of life. Elderly adults gain satisfaction, confidence and sense of identity from reminiscing. “A pre-experimental study to evaluate the effectiveness of structured reminiscence psychotherapy on the level of depression among elderly residing in old age home at selected areas of tricity.” Total 60 elderly adults of age group 60–80 years were taken by using convenient sampling technique. The pre-test was done by using standardized Beck's Depression Inventory on the level of depression, it contained 21 items. Structured reminiscence psychotherapy was administered to reduce the level of depression. The post-test was conducted by using same depression scale. Collected data was analyzed by descriptive and inferential statistics. The results showed that the level of depression was assessed with Beck's Depression Inventory with 21 items. The level of depression was classified according to severity. In pre-test 28 (46.7%) subjects were moderate level of depression, 26(43.3%) had severe level of depression, 6(10%) had mild mood disturbance and none of them had borderline clinical depression and extreme level of depression. The analysis revealed that the mean value of pre-test was 28.016 with Standard Deviation 6.593 and the mean value of post-test was 21.366 with Standard Deviation 6.436 with t-value 5.834. So there was significant difference between the mean pre-test and post-test scores at p>;0.01 level. Thus it was evident that after intervention the score of post-test was less from pre-test score. It indicates that the structured reminiscence psychotherapy was an effective psychotherapy to reduce the level of depression among elderly.

기억의 재현과 미학의 문제: 영화 <임을 위한 행진곡>과 <외롭고 높고 쓸쓸한>

기억의 재현과 미학의 문제: 영화 <임을 위한 행진곡>과 <외롭고 높고 쓸쓸한>

Higher sleep spindle activity is associated with fewer false memories in adolescent girls.

Sleep facilitates the extraction of semantic regularities amongst newly encoded memories, which may also lead to increased false memories. We investigated sleep stage proportions and sleep spindles in the recollection of adolescents' false memories, and their potential sex-specific differences. 196 adolescents (mean age 16.9 y; SD = 0.1, 61% girls) underwent the Deese, Roediger & McDermott (DRM) false memory procedure and overnight polysomnography, with free recall the following morning. Sleep was scored manually into stages 1, 2, 3 and REM. Stage 2 sleep spindle frequency, density, and peak amplitude were used as measures of spindle activity for slow (10-13 Hz) and fast (13-16 Hz) ranges. In girls, a lower number of critical lures was associated with higher spindle frequency (p ≤ 0.01), density (p ≤ 0.01), and amplitude (p = 0.03). Additionally, girls' longer sleep duration was associated with more intrusion words (p = 0.03), but not with critical lures. These associations survived adjustment for age, pubertal status, and intelligence. No significant results emerged in boys. In adolescent girls, higher spindle activity was associated with fewer critical lures being falsely recalled in the DRM paradigm. Unlike studies using adult participants, we did not observe any association between slow-wave sleep and false memory recollection.

The Archetypal Analysis of Tomorrow by Graham Swift

This study entitles the Archetypal Analysis of the text Tomorrow by Graham Swift. This psychoanalytical study explores the entire personality of the protagonist of the novel on the basis of Jung’s theory of Unconscious and Archetypes. This study dissects the character of protagonist through the revelation of personal, collective unconscious, and repressed desire. Also, it draws its attention towards different kinds of archetypes as suggested by Jung and its universal application on the protagonist of the novel. The qualitative method was used for this research work that laid its emphasis upon the continual flow of protagonist’s thoughts and memories. The recollections of memories of the protagonist will help better to scrutinize the text by applying Jung’s theory. Jung’s theory will attest that an individual just like the novel’s protagonist can bring its unconscious mind into his consciousness through a mental effort of recalling.

Of molecules, memories and migration: M1 acetylcholine receptors facilitate spatial memory formation and recall during migratory navigation.

Many animals use complex cognitive processes, including the formation and recall of memories, for successful navigation. However, the developmental and neurological processes underlying these cognitive aspects of navigation are poorly understood. To address the importance of the formation and recollection of memories during navigation, we pharmacologically manipulated turtles (Chrysemys picta) that navigate long distances using precise, complex paths learned during a juvenile critical period. We treated freely navigating turtles both within and outside of their critical learning period with a specific M1 acetylcholine receptor antagonist, a drug known to disrupt spatial cognition. Experienced adult turtles lost all navigational ability under the influence of the drug, while naive juveniles navigated successfully. We retested these same juveniles the following year (after they had passed their critical period). The juveniles that initially navigated successfully under the influence of the antagonist (but were unable to form spatial memories) were unable to do so subsequently. However, the control animals (who had the opportunity to form memories previously) exhibited typical navigational precision. These results suggest that the formation of spatial memories for navigation occur during a critical period, and successful navigation after the critical period is dependent upon the recall of such memories.

Event-related potential correlates of recognition memory in asymptomatic individuals with CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common form of hereditary stroke disorder and is caused by mutations of the NOTCH3 gene. Cognitive decline in CADASIL is characterized by early impairments of attention, memory, and executive functions. Studying asymptomatic individuals with CADASIL offers a unique genetic model to understand preclinical vascular cognitive impairment and dementia. This study aimed at examine whether early preclinical physiological changes could be observed in asymptomatic individuals with CADASIL, who will go on to develop vascular cognitive impairment and dementia later in life. Twenty-nine individuals (mean age: 54.1 years old) were included in the study; five CADASIL NOTCH3 mutation carriers and twenty-five age-matched non-carriers. Participants underwent a comprehensive clinical evaluation and neuropsychological testing. Event-related potentials (ERPs) were recorded during a picture recognition memory task. Analyses focused on the early frontal effect and parietal effect ERP components associated with familiarity and recollection memory. There were no differences between groups in behavioral performance during recognition memory discrimination or cognitive performance. Compared to non-carriers, CADASIL carriers had decreased amplitudes in both ERP components for hits and correct rejections. Among mutation carriers, lower amplitude at 500–600 ms in the left parietal region of interest for correct rejections was correlated with worse performance on measures of semantic fluency and inhibitory control. We conclude that cognitively unimpaired CADASIL carriers showed abnormalities in the neural correlates of recognition memory, years before clinical onset. Early disruptions of fronto-subcortical networks may explain preclinical changes in brain function during recognition memory. This work also demonstrates the potential usefulness of ERP brain correlates as preclinical markers of vascular dementia.

Effect of emotional enhancement of memory on recollection process in young adults: the influence factors and neural mechanisms

Emotional enhancement of memory (EEM) is thought to modulate memory recollection rather than familiarity. However, the contributing factors and neural mechanisms are not well understood. To address these issues, we investigated how valence, arousal, and the amount of devoted attention influence the EEM effect on recollection. We also compared the topological properties among hippocampus- and perirhinal and entorhinal cortex-mediated emotional memory processing networks. Finally, we evaluated the correlations between emotional memory/EEM and inherent properties (i.e., amplitude of low-frequency fluctuation and node degree, efficiency, and betweenness) of the hippocampus and perirhinal and entorhinal cortices in 59 healthy young adults by resting-state functional magnetic resonance imaging. EEM was elicited by incidental encoding, negative images, and positive high-arousal images. The hippocampus was correlated with recollection sensitivity and EEMnegative-high-arousal. The emotional memory processing network mediated by the hippocampus had higher clustering coefficient, local efficiency, and normalized characteristic path length but lower normalized global efficiency than those mediated by the perirhinal and entorhinal cortices. The entorhinal cortex was associated with both recollection and familiarity sensitivity, but showed different correlation patterns. The perirhinal cortex was highly correlated with familiarity sensitivity of negative low-arousal stimuli. These results demonstrate that the EEM effect on memory recollection is influenced by valence, stimulus arousal, and amount of attention involved during encoding. Moreover, the hippocampus and perirhinal and entorhinal cortices play distinct roles in the recollection and familiarity of emotional memory and the EEM effect.

Interactivity of Neural Representations for Perceiving Shared Social Memory

Although the concept of “common sense” is often taken for granted, judging whether behavior or knowledge is common sense requires a complex series of mental processes. Additionally, different perceptions of common sense can lead to social conflicts. Thus, it is important to understand how we perceive common sense and make relevant judgments. The present study investigated the dynamics of neural representations underlying judgments of what common sense is. During functional magnetic resonance imaging, participants indicated the extent to which they thought that a given sentence corresponded to common sense under the given perspective. We incorporated two different decision contexts involving different cultural perspectives to account for social variability of the judgments, an important feature of common sense judgments apart from logical true/false judgments. Our findings demonstrated that common sense versus non-common sense perceptions involve the amygdala and a brain network for episodic memory recollection, including the hippocampus, angular gyrus, posterior cingulate cortex, and ventromedial prefrontal cortex, suggesting integrated affective, mnemonic, and social functioning in common sense processing. Furthermore, functional connectivity multivariate pattern analysis revealed that interactivity among the amygdala, angular gyrus, and parahippocampal cortex reflected representational features of common sense perception and not those of non-common sense perception. Our study demonstrated that the social memory network is exclusively involved in processing common sense and not non-common sense. These results suggest that intergroup exclusion and misunderstanding can be reduced by experiencing and encoding long-term social memories about behavioral norms and knowledge that act as common sense of the outgroup.

Unitization mitigates interference by intrinsic negative emotion in familiarity and recollection of associative memory: Electrophysiological evidence.

Emotion exerts varied influences on memory. While task-relevant item memory is oftenenhanced by emotion, associative memory is generally impaired. Unitization is known to improve associative memory, but its effects and mechanisms in protecting associative memory from emotional interference are rather obscure. The current study investigated associative memory by employing experimental manipulation of unitization (vs. nonunitization) encoding strategy and stimulus emotion (neutral, intrinsic negative, and extrinsic negative), combined with event-related potential (ERP) signatures of familiarity (FN400 old/new effects) and recollection (parietal late positive component/LPC old/new effects) in memory recognition. Both behavioral and ERP indices of associative recognition from the nonunitization group confirmed emotional interference in associative memory. Importantly, it was primarily intrinsic (vs. extrinsic) emotion that impeded associative memory. Unitization encoding improved memory performance in general, accompanied by enhanced recollection process and induction of familiarity process, which is typically not involved in associative memory recognition and was indeed absent in the nonunitization group. Importantly, unitization helped to preserve behavioral performance (specifically, response speed though not recognition strength) from interference by intrinsic emotion while largely reversed the detriment of intrinsic emotion on ERP indices of familiarity and recollection processes. Interestingly, a synergy between intrinsic emotion and unitization encoding was observed, which could underpin the facilitation of familiarity process in associative recognition of emotional pairs. Overall, current findings highlight interference by intrinsic emotion in associative memory, which is nonetheless responsive to mitigation by unitization encoding.

Alcohol and pharmacologically similar sedatives impair encoding and facilitate consolidation of both recollection and familiarity in episodic memory

ABSTRACTAlcohol and other pharmacologically similar sedatives (i.e., GABAA positive allosteric modulators or PAMs) impair the encoding of new episodic memories but retroactively facilitate the consolidation of recently encoded memories. These effects are consistent for recollection (i.e., the retrieval of details) but some mixed results have been reported for familiarity (i.e., a feeling of knowing a stimulus was presented). Here, with dual-process models, we reanalyzed prior work testing the effects of GABAA PAMs at encoding or consolidation. Contrary to previous conclusions, we show that GABAA PAMs at encoding consistently impair both recollection and familiarity when an independence correction is applied to familiarity-based responses. These findings were further confirmed and extended in a dual-process signal detection analysis of a recent study on the effects of alcohol during encoding or consolidation: Alcohol at encoding impaired both recollection and familiarity, whereas alcohol at consolidation enhanced both recollection and familiarity. These findings speak to the ability of alcohol and other GABAA PAMs to induce ‘blackouts,’ highlighting the importance of dual-process approaches when analyzing drug manipulations at different phases of episodic memory.

A Pilot Study of Hippocampal Activity During a Verbal Memory Task in Depressed Young Adults

Background: Hippocampal volume is reduced in Major Depressive Disorder (MDD), but the extent to which hippocampal function is altered in the context of MDD, particularly in young adults, is not well established. The hippocampus is important in recollection memory, a cognitive domain that is often impaired in depressed adults. Objective: This pilot functional Magnetic Resonance Imaging (fMRI) study aimed to assess hippocampal activity during a verbal memory task in unmedicated young adults with MDD (18-24 years of age) relative to healthy age-matched Controls. Method: Brain activity was measured in hippocampal regions during verbal encoding and retrieval, and compared between groups (N=11 in each group); exploratory whole-brain assessments were also carried out. Results: Greater right hippocampal activity during verbal memory encoding (vs. retrieval) was apparent in Controls. Further, in the MDD group, left hippocampal activity during encoding (vs. retrieval) was positively related to depression symptom severity and number of previous depressive episodes. Conclusion: This pilot study is a stepping stone in examining the effect of depression on hippocampal function in young adults. Keywords: Depression, fMRI, hippocampus, memory, youth, MDD.