Contextual Reminder Research Articles

Influence of Stress Severity on Contextual Fear Extinction and Avoidance in a Posttraumatic-like Mouse Model.

Posttraumatic stress disorder (PTSD) is a widespread fear-related psychiatric affection associated with fear extinction impairments and important avoidance behaviors. Trauma-related exposure therapy is the current first-hand treatment for PTSD, yet it needs to be improved to shorten the time necessary to reach remission and increase responsiveness. Additional studies to decipher the neurobiological bases of extinction and effects on PTSD-like symptoms could therefore be of use. However, a PTSD-like animal model exhibiting pronounced PTSD-related phenotypes even after an extinction training directly linked to the fearful event is necessary. Thus, using a contextual fear conditioning model of PTSD, we increased the severity of stress during conditioning to search for effects on extinction acquisition and on pre- and post-extinction behaviors. During conditioning, mice received either two or four electrical shocks while a control group was constituted of mice only exposed to the context. Stressed mice exhibited important fear generalization, high fear reaction to the context and selective avoidance of a contextual reminder even after the extinction protocol. Increasing the number of footshocks did not induce major changes on these behaviors.

TDCS-Induced Memory Reconsolidation Effects: Analysis of Prominent Predicting Factors.

BackgroundMemory impairment is among one of the greatest cognitive complaints in midlife and in old age. Considering the importance of good memory functioning in everyday life, it is crucial to study interventions that can reduce the natural decline in this cognitive function. Transcranial Magnetic Stimulation (TMS) studies have demonstrated that the lateral prefrontal cortex (PFC) plays a causal role in enhancing episodic memory recall through reconsolidation. Using a similar paradigm with transcranial direct current stimulation (tDCS) over the left lateral PFC, facilitation effects were observed in delayed memory retrieval in older adults with subjective memory complaints (SMCs) and amnestic Mild Cognitive Impairment (aMCI). However, it remains unclear which potential factors (i.e., tDCS group, cognitive reserve, education level, diagnosis and encoding performance) directly and/or indirectly modulate the tDCS-induced memory reconsolidation effects.MethodsWe reanalyzed data acquired in our previous tDCS studies with 22 SMC and 18 aMCI participants from the perspective of predicting delayed memory retrieval performance. These studies included a learning session on Day 1, a reactivation by a contextual reminder followed by 15 min of tDCS session on Day 2 (24 h after Day 1), and two retrieval sessions (free recall and recognition) tested on Days 3 and 30 (48 h and 30 Days after Day 1).ResultsUnivariate models showed that tDCS group (sham vs. active) significantly predicted memory recognition (but not free recall), evidenced by higher scores in the active tDCS group than in sham group, confirming our previous results. Encoding performance and diagnosis (SMC vs. aMCI) significantly predicted memory retrieval, suggesting higher performances in individuals with SMC than in those with aMCI. Regarding cognitive reserve, higher leisure time activity subscores significantly predicted better memory recognition. Finally, multiple models did not show any tDCS group × predictor interaction effects, indicating that the effects of the predictors on retrieval occurred irrespective of tDCS group.ConclusionOur results shed light on predicting factors of episodic memory retrieval in this reconsolidation paradigm in individuals with SMC and aMCI. The findings suggest that multifactorial interventions program may be most promising to slow cognitive decline and delay the onset of dementia.

TDCS-Induced Memory Reconsolidation Effects and Its Associations With Structural and Functional MRI Substrates in Subjective Cognitive Decline.

Previous evidence suggests that transcranial direct current stimulation (tDCS) to the left dorsolateral prefrontal cortex (l-DLPFC) can enhance episodic memory in subjects with subjective cognitive decline (SCD), known to be at risk of dementia. Our main goal was to replicate such findings in an independent sample and elucidate if baseline magnetic resonance imaging (MRI) characteristics predicted putative memory improvement. Thirty-eight participants with SCD (aged: 60–65 years) were randomly assigned to receive active (N = 19) or sham (N = 19) tDCS in a double-blind design. They underwent a verbal learning task with 15 words (DAY-1), and 24 h later (DAY-2) stimulation was applied for 15 min at 1.5 mA targeting the l-DLPFC after offering a contextual reminder. Delayed recall and recognition were measured 1 day after the stimulation session (DAY-3), and at 1-month follow-up (DAY-30). Before the experimental session, structural and functional MRI were acquired. We identified a group∗time interaction in recognition memory, being the active tDCS group able to maintain stable memory performance between DAY-3 and DAY-30. MRI results revealed that individuals with superior tDCS-induced effects on memory reconsolidation exhibited higher left temporal lobe thickness and greater intrinsic FC within the default-mode network. Present findings confirm that tDCS, through the modulation of memory reconsolidation, is capable of enhancing performance in people with self-perceived cognitive complaints. Results suggest that SCD subjects with more preserved structural and functional integrity might benefit from these interventions, promoting maintenance of cognitive function in a population at risk to develop dementia.

Transcranial direct current stimulation applied after encoding facilitates episodic memory consolidation in older adults.

Episodic memory shows the largest degree of age-related memory decline. There is evidence that consolidation, the process that stabilizes memories after encoding, is reduced in older adults. Previous studies have shown that transcranial direct current stimulation (tDCS) applied during intentional encoding or immediately after a contextual reminder enhanced delayed episodic memory performance, suggesting a potential interaction between tDCS and consolidation or reconsolidation processes. The present randomized, double-blind, sham-controlled study addressed the question whether tDCS applied immediately after verbal encoding enhances episodic memory recall through consolidation in healthy older adults. Twenty-eight participants received tDCS (Active or Sham) over the prefrontal cortex (anode over the left dorsolateral prefrontal cortex and cathode over the contralateral supraorbital region), a brain region contributing to episodic memory function. Verbal recall was tested two days and one month later. The results showed that recall performance at one month was enhanced in the Active tDCS group relative to the Sham group. These findings suggest that tDCS applied off-line immediately after encoding over the prefrontal cortex interacts with the processes promoting consolidation of episodic memories in healthy older adults. Targeting consolidation by means of tDCS might be a novel strategy for reducing episodic memory decline.

Effects of Transcranial Direct Current Stimulation on Episodic Memory in Amnestic Mild Cognitive Impairment: A Pilot Study.

Episodic memory is impaired in amnestic mild cognitive impairment (aMCI), which is posited as a potential prodromal form of Alzheimer's disease. Reactivated existing memories become sensitive to modification during reconsolidation. There is evidence that the lateral prefrontal cortex (PFC) plays causal role in episodic memory reconsolidation. Transcranial direct current stimulation (tDCS) applied to the PFC after a contextual reminder enhanced episodic memory performance up to 1 month, conceivably through reconsolidation, in older adults with subjective memory complaints, a condition that may represent a "pre-mild cognitive impairment" stage. The aim of this pilot study was to test the effect of PFC-tDCS (anode over left lateral PFC, cathode over right supraorbital area) after a contextual reminder on episodic memory in older adults with aMCI. Older adults with aMCI learned a list of words. Twenty-four hours later, tDCS (Active or Sham) was applied after a contextual reminder. Memory retrieval (free recall and recognition) was tested 48 hrs and 1 month after the learning session. Active tDCS enhanced recognition memory relative to Sham stimulation. Modulating reconsolidation with PFC-tDCS might be a novel intervention to enhance episodic memories in aMCI.

Strengthening of Existing Episodic Memories Through Non-invasive Stimulation of Prefrontal Cortex in Older Adults with Subjective Memory Complaints.

Episodic memory is critical to daily life functioning. This type of declarative memory declines with age and is the earliest cognitive function to be compromised in Alzheimer’s disease (AD). Subjective memory complaints are commonly reported by older adults and have been considered a risk factor for developing AD. The possibilities for prevention of memory disorders in older adults have increased substantially in recent years. Previous studies have shown that anodal transcranial Direct Current Stimulation (tDCS) applied over the left lateral prefrontal cortex (PFC) after a contextual reminder strengthened existing verbal episodic memories, conceivably through reconsolidation, in elderly people. In this study, we hypothesized that anodal tDCS applied over the left lateral PFC after a contextual reminder would improve delayed memory retrieval relative to placebo (sham) stimulation in elderly individuals with SMC. Twenty-two subjects learned a list of words. Twenty-four hour later, tDCS (anodal or placebo) was applied over the left lateral PFC after a contextual reminder. Memory retrieval was tested 48h and 30 days later. These findings showed that anodal tDCS over the left lateral PFC strengthened existing episodic memories, a behavioral effect documented by improved recognition up to 30 days, relative to placebo stimulation. This study suggests that tDCS after a contextual reminder can induce long-lasting beneficial effects by facilitating the consolidation processes and opens up the possibility to design specific non-invasive interventions aimed at preventing memory decline in this at-risk population.

Heavy-Ion Physics at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC): Feasibility Studies for Quarkonium and Drell\u2013Yan Production

We outline the case for heavy-ion-physics studies using the multi-TeV lead LHC beams in the fixed-target mode. After a brief contextual reminder, we detail the possible contributions of AFTER@LHC to heavy-ion physics with a specific emphasis on quarkonia. We then present performance simulations for a selection of observables. These show that varUpsilon (nS), J/psi and psi (2S) production in heavy-ion collisions can be studied in new energy and rapidity domains with the LHCb and ALICE detectors. We also discuss the relevance to analyse the Drell–Yan pair production in asymmetric nucleus–nucleus collisions to study the factorisation of the nuclear modification of partonic densities and of further quarkonium states to restore their status of golden probes of the quark–gluon plasma formation.

Intrusions in episodic memory: reconsolidation or interference?

It would be profoundly important if reconsolidation research in animals and other memory domains generalized to human episodic memory. A 3-d-list-discrimination procedure, based on free recall of objects, with a contextual reminder cue (the testing room), has been thought to demonstrate reconsolidation of human episodic memory (as noted in a previous study). Our goal was to replicate the central result, a high intrusion rate during recall of the target list, and evaluate the reconsolidation account relative to an alternative account, based on state-dependent learning and interference. First, replication was not straightforward (Experiment 1). Second, using a very unique, highly salient context (Experiment 2), the method produced a qualitative replication, but it was small in magnitude. A critical assumption of the reconsolidation account, that the target list is reactivated and destabilized during re-exposure to the study context, was not supported (Experiment 3). Although troubling for the reconsolidation account, the findings can be easily accommodated by an alternative account that does not assume additional neurobiological processes underlying the destabilization of consolidated memories, instead explaining intrusion rates simply in terms of well-established cognitive effects, such as item-to-context binding and interference during retrieval.

The Boy and the Whale by Mordicai Gerstein

Reviewed by: The Boy and the Whale by Mordicai Gerstein Deborah Stevenson, Editor Gerstein, Mordicai The Boy and the Whale; written and illus. by Mordicai Gerstein. Roaring Brook, 2017 [40p] ISBN 978-1-62672-505-8 $17.99 Reviewed from galleys R 5-8 yrs Early one morning, a boy looks out to the ocean and spots a struggling whale; he and his father jump into the fishing boat to discover the animal caught in their fishing net. When Papa cries, “I hope we can save it!” he means the precious net, on which their livelihood depends; however, young Abelardo, who remembers the terror of being tangled in the net himself (“I almost drowned”), hopes instead to save the whale. When Papa returns to land to find a replacement net, the boy defiantly heads out on his own, hacking bit by bit at the huge net and persisting through exhaustion to finally free the creature. What could be just a pleasing animal rescue story takes on additional resonance with Gerstein’s contextual reminder that there are multiple lives at stake here; Papa isn’t anti-whale, just sensibly concerned about feeding the family and the safety of his son in the water with an injured and unpredictable animal. Palm trees, sparkling water, the use of the word “panga” for the boat, and the humans’ warm brown skin suggests this takes place in Mexico or Central America. Gerstein’s painterly line and watercolor art is more interested in the sea than the land, however, with compositions employing various strategies to convey the breadth of the ocean, the size of the whale, and the geometric intrusion of the net. An early introduction to the tension between economy and ecology, this will be a talking point for youngsters not ready for the Scientists in the Field series. Copyright © 2017 The Board of Trustees of the University of Illinois

Community Reminder: Participatory contextual reminder environments for local communities

Abstract Many projects have looked at how communities can co-design shared online repositories, such as Wikimapia and Wikipedia. However, little work has examined how local communities can give advice and support to their members by creating context-aware reminders that may include advice, tips and small requests. We developed the Community Reminder environment, a smartphone-based platform that supports community members to design and use context-aware reminders. We have conducted a one-month field study of Community Reminder to crowdsource and deliver safety-relevant information in a local community. The results show the benefits of involving community members in reminder design and connecting different perspectives. We also show that the proposed approach can broaden participation in local communities.

The optimal timing of stimulation to induce long-lasting positive effects on episodic memory in physiological aging

Episodic memory displays the largest degree of age-related decline. A noninvasive brain stimulation technique that can be used to modulate memory in physiological aging is transcranial Direct Current Stimulation (tDCS). However, an aspect that has not been adequately investigated in previous studies is the optimal timing of stimulation to induce long-lasting positive effects on episodic memory function.Our previous studies showed episodic memory enhancement in older adults when anodal tDCS was applied over the left lateral prefrontal cortex during encoding or after memory consolidation with or without a contextual reminder.Here we directly compared the two studies to explore which of the tDCS protocols would induce longer-lasting positive effects on episodic memory function in older adults. In addition, we aimed to determine whether subjective memory complaints would be related to the changes in memory performance (forgetting) induced by tDCS, a relevant issue in aging research since individuals with subjective memory complaints seem to be at higher risk of later memory decline.The results showed that anodal tDCS applied after consolidation with a contextual reminder induced longer-lasting positive effects on episodic memory, conceivably through reconsolidation, than anodal tDCS during encoding. Furthermore, we reported, providing new data, a moderate negative correlation between subjective memory complaints and forgetting when anodal tDCS was applied after consolidation with a contextual reminder.This study sheds light on the best-suited timing of stimulation to induce long-lasting positive effects on memory function and might help the clinicians to select the most effective tDCS protocol to prevent memory decline.

Time‐dependent Development of Social Stress Caused by Repeated Exposures to Aggressors Simulating Features of Post‐traumatic Stress Disorder (PTSD)

A utility criterion of a PTSD mouse model is recruiting a stressor with systematically variable intensity. An ideal stressor should maintain a ‘dose‐response relationship’ with the subjects’ behavioral shift. A typical PTSD model includes a brief exposure to foot or tail shock.We developed a model that involves repeated exposures (either 5‐day or 10‐day) to trained conspecific aggressors (Agg). A contextual reminder study evaluating a cluster of ethogram identified PTSD‐like (acute‐ and persistent‐) syndromes such as incubation, extinction and desensitization of fear responses. Pathophysiological consequences supported the model.This model reflects the combat‐like situation where life‐threatening events occur repeatedly and randomly. The direct relationship of PTSD‐risk with deployment frequency further justifies the model.Agg induced stress intensity can only be elevated by prolonging the exposure. The risk of habituation can thereby defeat the ‘dose‐response’ relationship. We addressed this concern by evaluating the time‐dependent behavioral shift of the subject mice (C57BL/6j). Subsets of subject mice were withdrawn from the Agg‐exposure (Agg‐E) schedule at regular intervals and their psycho‐patho‐physiological characters were evaluated. A regression model elucidated the temporal relationship of Agg‐E stress with the psychological alteration.

Interactions That Trigger Self‐Labeling: The Case of Older Undergraduates

Deviant or stigmatizing labels are associated with various negative outcomes. Although self‐labeling theory proposes that one can self‐label as deviant without first being labeled by others, most labeling research focuses on people whom others have already labeled. Using the case of undergraduates aged twenty‐five and older, I identify three subtle forms of interaction—contextual dissonance, reminder cues, and third‐party communication—that trigger self‐labeling and are associated with negative reactions, even absent others' direct negative feedback or prior labeling. I also show that each form of interaction may systematically relate to specific kinds of negative reactions. I discuss possible reasons for these patterns, as well as how these findings may affect self‐labeling theory and policymaking decisions in higher education.

Remembering when we last remembered our childhood experiences: Effects of age and context on retrospective metamemory judgments

AbstractPeople sometimes exhibit a ‘forgot‐it‐all‐along bias’ in which they claim that they have gone for months or years without thinking about certain childhood experiences despite recently recalling those memories. The present study examines memory for memories of childhood experiences, expanding on prior work by using manipulations that require greater reflection when thinking about remembered experiences and when making retrospective metamemory judgments. Age‐related differences in memory‐for‐memory accuracy were also examined. Young (18–20) and older adults (63–89) recalled various events while focusing on emotional or perceptual details for some, and several weeks later were asked to indicate the last time they had remembered various events. Results showed that young adults were more accurate than older adults overall, though both age groups still exhibited a forgot‐it‐all‐along bias that was reduced but not eliminated when a contextual reminder was provided. Copyright © 2008 John Wiley & Sons, Ltd.

UCS intensity-dependent attenuation of infantile amnesia

Unconditioned stimulus (UCS) reactivation treatments may attenuate infantile amnesia in rats by providing an external reminder cue, creating an internal contextual reminder cue via endogenous hormones, and/or modulating memory retrieval via neurochemical changes from activation of the stress cascade. In the present study, the UCS reactivation treatment and the relationship between intensity at training and intensity at testing were examined. In Experiment 1, 17-day-old Sprague-Dawley rats were given multiple-trial passive-avoidance conditioning with a high-intensity footshock. Those subjects administered a high-intensity reactivation treatment performed significantly better than did subjects that received a low-intensity reactivation treatment, subjects that received no treatment, or pseudo-trained animals. Experiment 2 repeated the first experiment with a low-intensity training footshock. The results indicated that only a high-intensity reactivation treatment attenuated infantile amnesia. These findings suggest that the training UCS need not match the reactivation treatment in terms of intensity and leaves open the possibility that aversive reactivation treatments may be multifaceted, involving external contextual cues, internal contextual cues, and neuromodulatory effects from activation of the stress cascade.

The locus coeruleus and cognitive function: Attempts to relate noradrenergic enhancement of signal/noise in the brain to behavior

Behavioral manipulations that alleviate forgetting in a complex maze task are paralleled by pharmacological manipulations which modulate noradrenergic activity. Increased noradrenergic activity is observed following prior exposure to contextual reminder cues. It is proposed that the facilitated retrieval reflects a conditioned arousal and an enhanced attention to discriminative stimuli mediated by the noradrenergic response. Failure to find learning and memory retrieval deficits in rats that are depleted of noradrenaline is discussed in terms of functional recovery after lesions.