Remote Memory Tests Research Articles

Long-term retention of real-world experiences in a patient with profound amnesia

The medial temporal lobe (MTL) is known to be critical for healthy memory function, but patients with MTL damage can, under certain circumstances, demonstrate successful learning of novel information encountered outside the laboratory. Here, we describe a patient, D.C., with extensive but focal bilateral MTL damage centering primarily on his hippocampus, whose memory for real-world experiences was assessed. Tests of remote memory indicated at least some capacity to retrieve specific details. To test his anterograde memory, he was taken on a tour of the NIH Clinical Center, with unique events occurring at each of ten specific locations. His memory for these events was tested after 1 h, and again after fifteen months. Initially, D.C. could not recall having participated in the tour, even when cued with photographs of specific places he had visited. However, he achieved 90% accuracy on a forced choice recognition test of old and new objects he encountered on the tour, and his recognition of these objects remained intact over a year later when he was tested once again. Subsequent recognition memory tests using novel picture stimuli in a standard laboratory-style computer task resulted in chance-level performance across multiple test formats and stimulus categories. These findings suggest a potentially privileged role for natural learning for long-term retention in a patient with severely damaged medial temporal lobes.

“Remote Memory Test Updated Version” for Social Events in Japan since 2010, Using Photographs of Famous People

“Remote Memory Test Updated Version” for Social Events in Japan since 2010, Using Photographs of Famous People

90 Feasibility of Repeated Remote Memory Assessment with Mobile Devices to Detect Subtle Cognitive Decline in Older Adults

Objective:Frequent and remote cognitive assessment may improve sensitivity to subtle cognitive decline associated with preclinical Alzheimer’s disease (AD). The objective of this study was to evaluate the feasibility and acceptability of repeated remote memory assessment in late middle-aged and older adults.Participants and Methods:We recruited participants from a longitudinal aging cohort to complete three medial temporal lobe-based memory paradigms (Object-In-Room Recall [ORR], Mnemonic Discrimination for Objects and Scenes [MDT-OS], Complex Scene Recognition [CSR]) using the neotiv application at repeated intervals over one year. We conducted initial telephone calls to perform screening, consent, and download instructions. Participants were assigned 24 remote sessions on a smartphone or tablet and were alerted via push notification when an assignment was ready to complete. Participants were randomly assigned to: (1) complete memory tests every other week or (2) complete memory tests for multiple days within one week every other month. Each remote session lasts approximately 10 minutes and includes one memory paradigm and brief usability/acceptability questionnaires followed by a delayed retrieval session 90 minutes later. Feasibility metrics examined included participation, retention, compliance, and usability/acceptability.Results:Of 150 participants recruited, 113 consented and were enrolled into the study (participation rate = 75%). Current retention rate is 75%, with 85/113 currently active (n=73) or completed (n=12). Of the 85 active or completed participants, the mean age is 68.7 (range = 4882), 64% are women, 70% used a smartphone (30% tablet), 84 are cognitively unimpaired and 1 has mild cognitive impairment. The primary threat to retention was participants consenting into the study but never registering in the app or completing their first scheduled assignment. After enrollment, 130 telephone calls were made by study staff to facilitate registration into the app or to remind participants to complete tasks. 74-80% of participants completed delayed retrieval tasks within 30 minutes of push notification, but average retrieval time was 125137 minutes post-learning trials. Regarding acceptability/usability, 94% agreed the application was easy to use, 56% enjoyed completing the mobile memory tests (36% felt neutral), 40% prefer remote mobile memory tests to standard in-person paper and pencil tests, and 50% understood the test instructions. 87% felt the frequency of tests assigned was “just right” (13% “too often”) and 90% felt the test length was “just right” (7% too short, 3% too long). Participants who completed all 24 sessions to date (n=12) all endorsed being “satisfied” or “very satisfied” with the platform and visit schedule, as well as recommended continued use of this type of cognitive testing.Conclusions:Remote memory assessment using smartphones and tablets is feasible and acceptable for cognitively unimpaired late middle-aged and older adults. Follow-up by study staff was needed to ensure adequate retention. Comprehension of instructions and compliance with completing delayed retrieval tasks within the expected timeframe was lower than expected. These feedback will be incorporated into an updated version of the app to improve compliance and retention. Longitudinal data collection is ongoing and results will be updated with a larger sample. Results will be compared across frequency schedule groups.

Remote contextual fear retrieval engages activity from salience network regions in rats

The ability to retrieve contextual fear memories depends on the coordinated activation of a brain-wide circuitry. Transition from recent to remote memories seems to involve the reorganization of this circuitry, a process called systems consolidation that has been associated with time-dependent fear generalization. However, it is unknown whether emotional memories acquired under different stress levels can undergo different systems consolidation processes. Here, we explored the activation pattern and functional connectivity of key brain regions associated with contextual fear conditioning (CFC) retrieval after recent (2 days) or remote (28 days) memory tests performed in rats submitted to strong (1.0 mA footshock) or mild (0.3 mA footshock) training. We used brain tissue from Wistar rats from a previous study, where we observed that increasing training intensity promotes fear memory generalization over time, possibly due to an increase in corticosterone (CORT) levels during memory consolidation. Analysis of Fos expression across 8 regions of interest (ROIs) allowed us to identify coactivation between them at both timepoints following memory recall. Our results showed that strong CFC elicits higher Fos activation in the anterior insular and prelimbic cortices during remote retrieval, which was positively correlated with freezing along with the basolateral amygdala. Rats trained either with mild or strong CFC showed broad functional connectivity at the recent timepoint whereas only animals submitted to the strong CFC showed a widespread loss of coactivation during remote retrieval. Post-training plasma CORT levels are positively correlated with FOS expression during recent retrieval in strong CFC, but negatively correlated with FOS expression during remote retrieval in mild CFC. Our findings suggest that increasing training intensity results in differential processes of systems consolidation, possibly associated with increased post-training CORT release, and that strong CFC engages activity from the aIC, BLA and PrL – areas associated with the Salience Network in rats – during remote retrieval.

Betel Quid Dependence Effects on Working Memory and Remote Memory in Chewers with Concurrent Use of Cigarette and Alcohol

Rationale: Betel quid (BQ) is regarded as a human carcinogen by the World Health Organization. Although there are many BQ chewers across Asian-Pacific areas, studies addressing the effects of BQ chewing on memory remain rare. Objective The current study asked whether BQ dependence level could affect working memory (WM) and remote memory for the chewers with concurrent use of cigarettes and alcohol, a common phenomenon in Taiwan. Methods The standardized neuropsychological tests (Wechsler Memory Scale III (WMS-III) and Remote Memory Test) were adopted to address the BQ chewers’ verbal WM, spatial WM and remote memory. The Spatial Span Test and the Digit Span Test from WMS-III and the Remote Memory Test were adopted. The Betel Nut Dependency Scale (BNDS), the Fagerstrom Test for Nicotine Dependence (FTND), and the Alcohol Use Disorders Identification Test (AUDIT) were adopted to measure the dependence levels. Results The BQ dependence level and Last BQ did not affect spatial WM, verbal WM, and remote memory. Last Cigarette is critical in affecting WM; namely, longer interval led to worse performance. Finally, higher alcohol dependence level could lead to better remote memory. Conclusions To our knowledge, there are no BQ studies addressing the effects of concurrent use of cigarettes and alcohol on memory. The current results suggest that cigarette smoking and alcohol drinking, rather than BQ chewing, are critical for memory performance.

Deepened sleep makes hippocampal spatial memory more persistent

Ample evidence has indicated a beneficial role of sleep, and particularly of slow wave sleep (SWS) in memory consolidation. However, how basic features of sleep, its depth and duration, contribute to this process remained elusive. Here, we investigated spatial object-place recognition (OPR) memory in rats, to systematically dissociate effects of sleep depth and duration on the formation of recent and remote hippocampus-dependent memory. Encoding of the spatial configuration was followed by an experimental post-encoding period of either 2 or 4 h, during which the rats had either “regular sleep”, “deeper sleep”, or were kept awake. A deeper sleep was achieved by an extended habituation of the rats to the sleep environment. Retrieval was tested either immediately after the 2-hour post-encoding period (recent memory test) or 1 week later (remote memory test). Deeper sleep expressed itself in a selective increase in the time spent in SWS, and in numbers of slow oscillations, spindles, and hippocampal ripples during SWS, whereas preREM and REM sleep were not affected. At the recent test, OPR memory was preserved only after sleep, but independent of its depth. At the remote test, however, OPR memory was preserved only after deeper sleep, whereas the wake and the regularly sleeping rats did not show remote OPR memory, even with the longer 4-h post-encoding period. Our results indicate that, rather than a longer duration, deeper sleep, i.e., a longer time in SWS together with enhanced oscillatory signatures of mnemonic processing during this sleep stage, occurring within a 2-hour window after encoding, is the factor that makes hippocampus-dependent memory more persistent.

Rewarding deep brain stimulation at the medial forebrain bundle favours avoidance conditioned response in a remote memory test, hinders extinction and increases neurogenesis

Intracranial Self-Stimulation (ICSS) at the medial forebrain bundle consistently facilitates learning and memory in rats when administered post-training or when administered non-concurrent to training, but its scope regarding remote memory has not yet been studied. The present work aims to test whether the combination of these two forms of ICSS administration can cause a greater persistence of the facilitating effect on remote retention and affect neurogenesis in the dentate gyrus (DG) of the hippocampus.Rats were trained in active avoidance conditioning and tested in two retention sessions (10 and 90 days) and later extinction. Subjects received an ICSS session after each of the five avoidance acquisition sessions (post-training treatment) and half of them also received ten additional ICSS sessions during the rest period between retention tests (non-concurrent treatment). All the stimulated groups showed a higher performance in acquisition and retention sessions, but only the rats receiving both ICSS treatments showed greater resistance to extinction. Remarkably, at seven months, rats receiving the non-concurrent ICSS treatment had a greater number of DCX-positive cells in the DG as well as a higher amount of new-born cells within the granular layer compared to rats that did not receive this additional ICSS treatment.Our present findings significantly extend the temporal window of the facilitating effect of ICSS on active avoidance and demonstrate a neurogenic effect of rewarding medial forebrain bundle stimulation.

Neuropeptide Y2 receptors in anteroventral BNST control remote fear memory depending on extinction training.

The anterior bed nucleus of stria terminalis (BNST) is involved in reinstatement of extinguished fear, and neuropeptide Y2 receptors influence local synaptic signaling. Therefore, we hypothesized that Y2 receptors in anteroventral BNST (BNSTav) interfere with remote fear memory and that previous fear extinction is an important variable. C57BL/6NCrl mice were fear-conditioned, and a Y2 receptor-specific agonist (NPY3-36) or antagonist (JNJ-5207787) was applied in BNSTav before fear retrieval at the following day. Remote fear memory was tested on day 16 in two groups of mice, which had (experiment 1) or had not (experiment 2) undergone extinction training after conditioning. In the group with extinction training, tests of remote fear memory revealed partial retrieval of extinction, which was prevented after blockade of Y2 receptors in BNSTav. No such effect was observed in the group with no extinction training, but stimulation of Y2 receptors in BNSTav mimicked the influence of extinction during tests of remote fear memory. Pharmacological manipulation of Y2 receptors in BNSTav before fear acquisition (experiment 3) had no effect on fear memory retrieval, extinction or remote fear memory. Furthermore, partial retrieval of extinction during tests of remote fear memory was associated with changes in number of c-Fos expressing neurons in BNSTav, which was prevented or mimicked upon Y2 blockade or stimulation in BNSTav. These results indicate that Y2 receptor manipulation in BNSTav interferes with fear memory and extinction retrieval at remote stages, likely through controlling neuronal activity in BNSTav during extinction training.

Corticosterone administration after a single-trial contextual fear conditioning does not influence the strength and specificity of recent and remote memory in rats

It is well established that corticosterone (CORT) enhances memory consolidation of emotionally arousing experiences. Despite emotional memories being usually referred to as well remembered for long periods, there are no studies that have investigated the effects of CORT in modulating the duration and specificity of memory. In the present study, we trained Wistar rats in a single-trial contextual fear conditioning protocol and injected CORT (0.3, 1.0 or 3.0mg/kg), immediately after training, to investigate its effects on memory consolidation. Rats were tested 2 and 29days after the training session or only 29days after training to assess recent or remote memory. Our results show that animals tested for recent memory discriminated the training context from a novel one, while those tested only for remote memory generalized the fear response to both contexts. Animals tested for remote memory after being tested for recent memory were able to discriminate both contexts. These results support the literature regarding memory specificity and duration. However, CORT treatment, even at the dose of 1.0mg/kg that effectively enhanced the plasmatic hormone levels, did not affect the strength or the specificity of memory in either recent or remote memory tests. We hypothesize that the lack of effect of CORT treatment could be due to the low arousing training experience of the single-trial protocol which, despite being sufficient to induce significant recent and remote memory consolidation, may not be sufficient to allow the memory-enhancing effect of CORT.

New remote memory test for social events using Japanese famous face photographs

New remote memory test for social events using Japanese famous face photographs

One-year-old fear memories rapidly activate human fusiform gyrus.

Fast threat detection is crucial for survival. In line with such evolutionary pressure, threat-signaling fear-conditioned faces have been found to rapidly (<80 ms) activate visual brain regions including the fusiform gyrus on the conditioning day. Whether remotely fear conditioned stimuli (CS) evoke similar early processing enhancements is unknown. Here, 16 participants who underwent a differential face fear-conditioning and extinction procedure on day 1 were presented the initial CS 24 h after conditioning (Recent Recall Test) as well as 9-17 months later (Remote Recall Test) while EEG was recorded. Using a data-driven segmentation procedure of CS evoked event-related potentials, five distinct microstates were identified for both the recent and the remote memory test. To probe intracranial activity, EEG activity within each microstate was localized using low resolution electromagnetic tomography analysis (LORETA). In both the recent (41-55 and 150-191 ms) and remote (45-90 ms) recall tests, fear conditioned faces potentiated rapid activation in proximity of fusiform gyrus, even in participants unaware of the contingencies. These findings suggest that rapid processing enhancements of conditioned faces persist over time.

Preserved anterograde and remote memory in drug-responsive temporal lobe epileptic patients

PurposeTo investigate cognition, particularly anterograde and remote memory, in patients suffering from unilateral drug-responsive mesial temporal lobe epilepsy (mTLE) patients and to compare their performance with that observed in drug-resistant mTLE patients. MethodsSixteen drug-responsive mTLE patients, with only infrequent seizures in their lifetime, were matched for demographic and clinical variables to 18 patients suffering from drug-resistant unilateral mTLE. A comprehensive neuropsychological examination, including baseline, anterograde memory tasks, and a large range of remote memory tests was carried out. ResultsPatients with drug-responsive epilepsy obtained average scores on every anterograde memory test. Although in general, they obtained lower scores than the healthy controls on remote memory tests, the differences failed to reach significance. Moreover, the drug-responsive group performed significantly better than the drug-resistant group on anterograde recall tests and an episodic autobiographical memory test. Performance was not significantly different between the patient groups in personal semantics or memory for public events. ConclusionOur results show that a mild clinical course of mTLE with no cognitive deficits can occur notwithstanding hippocampal sclerosis. The differences in cognitive function between the two groups are likely due to distinct pathophysiology of the underlying cause of epilepsy. Drug-resistant seizures and cognitive deficits may be the consequence of a more severe underlying cerebral process. Better understanding of the variety of pathogenesis of mTLE could help to answer this open question.

The use of sequential hippocampal-dependent and -non-dependent tasks to study the activation profile of the anterior cingulate cortex during recent and remote memory tests

Recent findings suggest that as time passes, cortical networks become recruited for memory storage. In animal models, this has been studied by exposing rodents to one task, allowing them to form a memory representation for the task then waiting different periods of time to determine, either through brain imaging or region-specific inactivation, the location of the memory representation. A number of reports show that 30days after a memory has been encoded, it comes to be stored in cortical areas such as the anterior cingulate cortex. The present study sought to determine what factors, in addition to the passage of time, would influence whether memory retrieval was associated with cortical activation. To this end, rats were assigned to one of three behavioural groups: (1) Training on one hippocampal-dependent memory task, the water maze (WM); (2) Training on two, different hippocampal-dependent memory tasks, the WM followed by the radial arm maze; (3) Training on one hippocampal-dependent memory task (WM) followed by training on one, non-hippocampal-dependent task, operant conditioning. After training, each group received a recent (2d) or remote (31d) water maze probe test. The group trained on two different hippocampal-dependent tasks and tested 2d later, showed the strongest preference for the platform location during the probe test. This group also displayed a pattern of c-Fos staining in the anterior cingulate cortex similar to the pattern of staining observed in the remotely-tested groups and different from that seen in the other recently-tested groups. These results suggest the formation of multiple hippocampal-dependent memories accelerate the speed at which cortical network recruitment is seen and leads to enhanced behavioural performance in the recent term.

The Australian Remote Memory Battery, 10 Years on

The article reviews research conducted with the Australian Remote Memory Test (ARMB) since its development first reported in 2001. Data from case studies and experimental investigations that have used the ARMB are summarised, and the use made of these data in reviews of the literature is noted. The ARMB has been found sensitive to disease processes such as herpes simplex, stroke, and epilepsy and lesion effects such as temporal lobectomy. The pattern of findings is consistent with current understanding of memory function. The studies have, however, pointed to factors that need to be considered in using the test, including patient medication and education level. Directions for future research with the test are briefly noted.

Peripheral orthopaedic surgery down-regulates hippocampal brain-derived neurotrophic factor and impairs remote memory in mouse

Peripheral orthopaedic surgery induces a profound inflammatory response. This includes a substantial increase in cytokines and, especially, in the level of interleukin (IL)-1β in the hippocampus, which has been shown to impair hippocampal-dependent memory in mice. We have employed two tests of contextual remote memory to demonstrate that the inflammatory response to surgical insult in mice also results in impairment of remote memory associated with prefrontal cortex (PFC). We have also found that, under the conditions presented in the social interaction test, peripheral orthopaedic surgery does not increase anxiety-like behaviour in our animal model. Although such surgery induces an increase in the level of IL-1β in the hippocampus, it fails to do so in the PFC. Peripheral orthopaedic surgery also results in a reduction in the level of hippocampal brain-derived neurotrophic factor (BDNF) and this may contribute, in part, to the memory impairment found after such surgery. Our data suggest that a reduction in the level of hippocampal BDNF and an increase in the level of hippocampal IL-1β following surgery may affect the transference of fear memory in the mouse brain.

Retrograde amnesia after electroconvulsive therapy: A temporary effect?

Although electroconvulsive therapy (ECT) is generally considered effective against depression, it remains controversial because of its association with retrograde memory loss. Here, we assessed memory after ECT in circumstances most likely to yield strong retrograde amnesia. A cohort of patients undergoing ECT for major depression was tested before and after ECT, and again at 3-months follow-up. Included were 21 patients scheduled to undergo bilateral ECT for severe major depression and 135 controls matched for gender, age, education, and media consumption. Two memory tests were used: a verbal learning test to assess anterograde memory function, and a remote memory test that assessed memory for news during the course of one year. Before ECT the patients' scores were lower than those of controls. They were lower again after treatment, suggesting retrograde amnesia. At follow-up, however, memory for events before treatment had returned to the pre-ECT level. Memory for events in the months after treatment was as good as that of controls. The sample size in this study was not large. Moreover, memory impairment did not correlate with level of depression, which may be due to restriction of range. Our results are consistent with the possibility that ECT as currently practiced does not cause significant lasting retrograde amnesia, but that amnesia is mostly temporary and related to the period of impairment immediately following ECT.

Amélioration mnésique postopératoire un an après traitement chirurgical de l’épilepsie du lobe temporal

Several studies have assessed the impact of surgery on both anterograde and remote memory in patients with temporal lobe epilepsy (TLE). The majority of results have shown an extensive memory deficit in patients after temporal resection (TL). However, few protocols have used a prospective longitudinal design. Moreover, the postoperative delays were variable from one study to the next, instead of regular monitoring to identify the potential effect of time elapsed after surgery on memory performance. In addition, some studies have not used strict inclusion criteria to establish homogeneous patient groups. Finally, the impact of surgery on memory has been often assessed by comparing memory skills between epileptic patients and healthy controls. Our aim was to examine the impact of TL on memory in patients with TLE, recruited according to clear-cut clinical criteria. Moreover, we focused on memory performance progression per se in epileptic patients pre- and postoperatively, rather than on memory performance analysis expressed as "deficient" or "normal". We assessed 30 patients with unilateral TLE (17 right TLE and 13 left TLE) on four anterograde memory tests and six remote memory tasks. Patients completed all tests preoperatively, and 5 and 12 months after TL. Five months after surgery, performance was equivalent to the preoperative scores for both groups in anterograde memory tasks and remote memory tests. One year after TL, patients with right TLE showed enhanced performance in the verbal anterograde memory tests and in retrieving recent autobiographical memories. Results for left TL showed improved scores only in a recognition memory test of faces. In the present study, surgical patients were "double winners" gaining seizure freedom and potential of memory stability or recovery. The gain was observed only 12 months after surgery and following temporal resection lateralisation. Our data showed postoperative memory improvement in patients with temporal lobe epilepsy presenting with specific clinical characteristics.

015 Remote memory deficits in transient epileptic amnesia

AimsTransient epileptic amnesia (TEA) is a recently recognised form of temporal lobe epilepsy in which sufferers often complain of irretrievable loss of remote memories. We aimed to answer the following...

Reconstructing the Remote Television Memory Test: Measuring Individual Differences in Long-Term Memory

Memory plays a role in many communications theories; however, few studies consider individual differences in memory. The results are reported here for two original studies designed to reconstruct a previously validated measure for television memory constructed to assess how people forget information over time. The remote television memory test assesses recognition memory for the titles of broadcast television programs canceled after a single season. Results from two studies show that the measure is reliable across repeated administrations among independent samples, exhibits a forgetting curve over time, is uncorrelated with total television viewing, appears to be approximately normally distributed, and predicts social reality estimates typical of the cultivation effect independently from total viewing. More work is needed to further assess the construct validity of the measure. Practical implications of administration also are discussed.

The Formation of Recent and Remote Memory Is Associated with Time-Dependent Formation of Dendritic Spines in the Hippocampus and Anterior Cingulate Cortex

Although hippocampal-cortical interactions are crucial for the formation of enduring declarative memories, synaptic events that govern long-term memory storage remain mostly unclear. We present evidence that neuronal structural changes, i.e., dendritic spine growth, develop sequentially in the hippocampus and anterior cingulate cortex (aCC) during the formation of recent and remote contextual fear memory. We found that mice placed in a conditioning chamber for one 7 min conditioning session and exposed to five footshocks (duration, 2 s; intensity, 0.7 mA; interstimulus interval, 60 s) delivered through the grid floor exhibited robust fear response when returned to the experimental context 24 h or 36 d after the conditioning. We then observed that their fear response at the recent, but not the remote, time point was associated with an increase in spine density on hippocampal neurons, whereas an inverse temporal pattern of spine density changes occurred on aCC neurons. At each time point, hippocampal or aCC structural alterations were achieved even in the absence of recent or remote memory tests, thus suggesting that they were not driven by retrieval processes. Furthermore, ibotenic lesions of the hippocampus impaired remote memory and prevented dendritic spine growth on aCC neurons when they were performed immediately after the conditioning, whereas they were ineffective when performed 24 d later. These findings reveal that gradual structural changes modifying connectivity in hippocampal-cortical networks underlie the formation and expression of remote memory, and that the hippocampus plays a crucial but time-limited role in driving structural plasticity in the cortex.