Emotion enhanced retention of cognitive skill learning

Ample evidence suggests that emotional arousal enhances declarative/episodic memory. By contrast, there is little evidence that emotional enhancement of memory (EEM) extends to procedural skill based memory. We examined remote EEM (1.5-month delay) for cognitive skill learning using the weather prediction (WP) probabilistic classification task. Participants viewed interleaved emotionally arousing or neutral pictures during WP acquisition. Arousal retarded initial WP acquisition. While participants in the neutral condition showed substantial forgetting of WP learning across the 1.5-month delay interval, the arousal condition showed no evidence of forgetting across the same time period. Thus, arousal during encoding determined the mnemonic fate of cognitive skill learning. Emotional enhancement of WP retention was independent of verbally stated knowledge of WP learning and EEM for the picture contexts in which learning took place. These results reveal a novel demonstration of EEM for cognitive skill learning, and suggest that emotional arousal may in parallel enhance the neural systems that support procedural learning and its declarative context.     

Distributed learning enhances relational memory consolidation

It has long been known that distributed learning (DL) provides a mnemonic advantage over massed learning (ML). However, the underlying mechanisms that drive this robust mnemonic effect remain largely unknown. In two experiments, we show that DL across a 24 hr interval does not enhance immediate memory performance but instead slows the rate of forgetting relative to ML. Furthermore, we demonstrate that this savings in forgetting is specific to relational, but not item, memory. In the context of extant theories and knowledge of memory consolidation, these results suggest that an important mechanism underlying the mnemonic benefit of DL is enhanced memory consolidation. We speculate that synaptic strengthening mechanisms supporting long-term memory consolidation may be differentially mediated by the spacing of memory reactivation. These findings have broad implications for the scientific study of episodic memory consolidation and, more generally, for educational curriculum development and policy.     

Forgetting of recently acquired or recently reactivated memories

Four experiments compared the rates of forgetting following acquisition of a conditioned aversion and following a reactivation treatment given long after conditioning had been completed. The “reactivation treatment” consisted of a single presentation of the unconditioned stimulus, a procedure known to reinstate, following substantial forgetting, the behavior seen immediately after conditioning. It was first determined that the decrement in performance 1, 3, or 7 days later tended to be more rapid just after original conditioning than following a reactivation treatment given 27 days after conditioning. Subsequent experiments confirmed that the forgetting seen 3 or 7 days after original conditioning was in fact greater than forgetting 3 or 7 days after the reactivation treatment that had followed conditioning by 27 days; also, tests permitted rejection of the hypothesis that this effect could be attributed to nonassociative (systemic) consequences of the conditioning situation. Finally, tests indicated that retention 24 hr after a reactivation treatment was significantly better if the reactivation treatment followed conditioning by 27 days than if it were given just 3 min or 24 hr after conditioning. The central observation emerging from this study, that forgetting is more rapid following original learning than following a temporally remote reactivation treatment, was discussed in terms of potential interactions between the age (or accessibility) of a memory and processes that might be instigated by a reactivation treatment.     

Gone but not forgotten: the transient nature of retrieval-induced forgetting

Recent research has demonstrated that the act of remembering can prompt temporary forgetting or, more specifically, the inhibition of particular items in memory. Extending work of this kind, the present research investigated some possible boundary conditions of retrieval-induced forgetting. As expected, a critical determinant of temporary forgetting was the interval between guided retrieval practice and a final recall test. When these two phases were separated by 24 hr, retrieval-induced forgetting failed to emerge. When they occurred in the same testing session, however, retrieval practice prompted the inhibition of related items in memory (i.e., Experiment 1). A delay of 24 hr between the encoding of material and guided retrieval practice reduced but did not eliminate retrieval-induced forgetting (i.e., Experiment 2). These findings are considered in the wider context of adaptive forgetting.     

Temporal lobe epilepsy and the selective reminding test: the conventional 30-minute delay suffices

Conventional memory assessment may fail to identify memory dysfunction characterized by intact recall for a relatively brief period but rapid forgetting thereafter. This study assessed learning and retention after 30-min and 24-hr delays on auditory and visual selective reminding tests (SRTs) in right (n=20) and left (n=22) temporal lobe epilepsy (TLE) patients and controls (n=49). The left TLE group performed significantly worse than controls on all 3 trials of both tests. The right TLE group differed from the controls on all 3 visual SRT trials and on learning for the auditory SRT. There were no between-groups differences in rate of information lost at the 30-min versus the 24-hr delay. At the individual level, there was no difference in the percentage of patients versus controls who demonstrated isolated memory impairment at the 24-hr delay. Accelerated forgetting over 24 hr is uncommon in TLE patients.     

Age and forgetting rate with pictorial stimuli

The rate of forgetting standardized line drawings of common objects was assessed in groups of young (M age = 22 years) and older (M age = 70.5 years) subjects. The two groups forgot equal quantities of pictorial stimuli over successive intervals of 10 min, 2 hr, and 48 hr, after being matched for original learning. In contrast, the older subjects showed the expected age decrement in reproduction of geometric designs from memory. These findings indicate that aging does not affect retention of pictures when differences in learning and retrieval abilities are controlled.     

定向遗忘的编码加工机制

有目的的遗忘(定向遗忘)需要耗费认知努力吗?有研究发现, 定向遗忘可能是被动衰减的结果, 即F项目(需要遗忘的项目)未获得有效复述是选择性复述了R项目(需要记住的项目)造成的, 这一加工过程不需要认知努力; 但也有研究表明, 定向遗忘过程可能是遗忘线索诱发的对记忆加工的主动抑制, 需要耗费认知努力, 脑认知研究中发现的前额叶ERPs成分为这一机制提供了证据。还有一种观点认为, 定向遗忘编码过程可能同时包含主动抑制与被动衰减, 但是尚不清楚两种加工机制相互作用的方式。为进一步澄清定向遗忘编码阶段的认知机制, 未来研究需要将非认知因素纳入考察, 并关注不同人群的定向遗忘特征, 在此基础上尝试解决理论争议。     

New evidence on the suggestibility of memory: the role of retrieval-induced forgetting in misinformation effects

Extending recent work that has demonstrated that the act of remembering can result in the inhibition of related items in memory, the present research examined whether retrieval-induced forgetting could provide a mechanism for explaining misinformation effects. Specifically, the authors found in their first study that the inhibition of critical items rendered the recollection of postevent information more likely in a subsequent test of memory. The authors established in their second study that when guided retrieval practice and final recall tests were separated by 24 hr, retrieval-induced forgetting failed to emerge and misinformation effects were absent. In contrast, a delay of 24 hr between initial encoding and guided retrieval practice produced not only retrieval-induced forgetting but also misinformation effects.     

The differential effects of emotional salience on direct associative and relational memory during a nap

Relational memories are formed from shared components between directly learned memory associations, flexibly linking learned information to better inform future judgments. Sleep has been found to facilitate both direct associative and relational memories. However, the impact of incorporating emotionally salient information into learned material and the interaction of emotional salience and sleep in facilitating both types of memory is unknown. Participants encoded two sets of picture pairs, with either emotionally negative or neutral objects paired with neutral faces. The same objects were present in both sets, paired with two different faces across the sets. Baseline memory for these directly paired associates was tested immediately after encoding, followed by either a 90-min nap opportunity or wakefulness. Five hours after learning, a surprise test assessed relational memory, the indirect association between two faces paired with the same object during encoding, followed by a retest of direct associative memory. Overall, negative information was remembered better than neutral for directly learned pairs. A nap facilitated both preservation of direct associative memories and formation of relational memories, compared to remaining awake. Interestingly, however, this sleep benefit was observed specifically for neutral directly paired associates, while both neutral and negative relational associations benefitted from a nap. Finally, REM sleep played opposing roles in neutral direct and relational associative memory formation, with more REM sleep leading to forgetting of direct associations but promoting relational associations, suggesting that, while not benefitting memory consolidation for directly learned details, REM sleep may foster the memory reorganization needed for relational memory.     

Two critical periods of protein and glycoprotein synthesis in memory consolidation for visual categorization learning in chicks

A protein synthesis inhibitor, anisomycin (ANI), and an inhibitor of glycoprotein synthesis, 2-deoxygalactose (2-D-gal), were used to investigate memory consolidation following visual categorization training in 2-day-old chicks. ANI (0.6 micromole/chick) and 2-D-gal (40 micromoles/chick) were injected intracerebrally at different time intervals from 1 hr before to 23 hr after the training. Retention was tested 24 hr post-training. Both ANI and 2-D-gal injections revealed two periods of memory sensitivity to pharmacological intervention. ANI impaired retention when injected from 5 min before to 30 min after the training or from 4 hr to 5 hr post-training, thus demonstrating that consolidation of long-term memory in this task requires two periods of protein synthesis. 2-D-Gal first produced an amnesia when it was injected in the interval from 5 min before to 5 min after the training. Injections made between 5 min and 5 hr post-training were without effect on the retention. The second period of memory impairment by 2-D-gal started at 5 hr post-training and lasted until 21 hr after the training. Administration of 2-D-gal made 23 hr after the training did not influence retention in the test at either 24 hr or 26 hr. These results are consistent with the hypothesis that two waves of protein and glycoprotein synthesis are necessary for the formation of long-term memory. The prolonged duration of performance impairment by 2-D-gal in the present task might reflect an extended memory consolidation period for a categorization form of learning.     

记忆抑制在正常人群与抑郁人群中的研究进展

抑郁症认知障碍的突出表现之一为患者的负性记忆偏向。已有研究常关注患者对负性信息自下而上的选择性注意,往往忽略了自上而下执行控制障碍对记忆的影响。近年研究提示,抑郁症患者和抑郁状态个体的记忆抑制缺陷在其负性记忆偏向的形成和维持中起到了重要作用,无法有效地主动抑制负性记忆可能是患者持续性负性反刍的主要原因。从抑郁症自上而下的执行控制缺陷入手,研究患者的记忆抑制障碍与其主要症状－负性反刍间的相关性,不仅能从理论上丰富Beck的抑郁症认知模型,还能指导临床建立更准确的预后评估指标,同时制定更有效的治疗方案。本文分别介绍了健康成人及抑郁症患者和抑郁状态个体的记忆抑制研究现状,并就当前在抑郁人群研究领域亟待解决的三个问题进行了探讨。     

Do subjective measures of attention and memory predict actual performance? Metacognition in older couples

Older individuals who recognize their cognitive difficulties are more likely to adjust their everyday life to their actual cognitive functioning, particularly when they are able to estimate their abilities accurately. We assessed self- and spouse-ratings of memory and attention difficulties in everyday life of healthy, older individuals and compared them with the respective test performance. Eighty-four older individuals (women's age, M = 67.4 years, SD = 5.2; men's age, M = 68.5 years, SD = 4.9) completed both the self and the spouse versions of the Attention Deficit Questionnaire and the Everyday Memory Questionnaire and completed two neuropsychological tests. Using the residual score approach, subjective metacognitive measures of memory and attention were created and compared with actual test performance. Significant associations between subjective and objective scores were found only for men and only for episodic memory measures. Men who underreported memory difficulties performed more poorly; men who overreported memory difficulties performed better. Men's recognition performance was best predicted by subjective measures (R2 = .25), followed by delayed recall (R2 = .14) and forgetting rate (R2 = .13). The results indicate gender-specific differences in metacognitive accuracy and predictive validity of subjective ratings.     

Absence of adult age differences in forgetting in the Brown-Peterson Task

Despite some recent evidence to the contrary, no reliable age differences in proactive interference (PI) or retroactive interference (RI) were found in a cross-sectional study of adults aged 18-29 and 63-75. Individual memory span was used as the list length in the Brown-Peterson Task in order to achieve stimulus equivalence of memory loads across individuals and age groups. Data from rehearsers were excluded from the analyses in order to isolate age differences in passive forgetting processes from those in rehearsal. PI was manipulated by presenting categorized or uncategorized memory lists. RI was manipulated, holding distractor task difficulty constant, by using words or tones in a signal detection distractor task. It is concluded that age differences are minimal to nonexistent in passive RI-related processes such as decay and perturbation and in passive PI-related processes such as set effects in semantic encoding.     

Experimental evidence for spatial learning on octopuses (octopus bimaculoides)

Octopuses forage far from temporary home dens to which they return for shelter. Spatial tasks may assess learning. Octopuses (Octopus bimaculoides) were placed in a novel arena, and their movements were tracked for 72 hr. Movements around the arena decreased across time, consistent with exploratory learning. Next, octopuses were given 23 hr to move around an arena; after a 24-hr delay, their memory of a burrow location was tested. Most remembered the location of the open burrow, demonstrating learning in 1 day. Finally, octopuses were trained to locate a single open escape burrow among 6 possible locations. Retention was tested after a week and was immediately followed by reversal training (location rotated 180 degrees ). Octopuses learned the original location of the burrow, remembering it for a week. Path lengths increased significantly after reversal, gradually improving and showing relearning. Octopuses show exploratory behavior, learning, and retention of spatial information.     

Activity engagement is related to level, but not change in cognitive ability across adulthood

It is unclear whether the longitudinal relation between activity participation and cognitive ability is due to preserved differentiation (active individuals have higher initial levels of cognitive ability), or differential preservation (active individuals show less negative change across time). This distinction has never been evaluated after dividing time-varying activity into its two sources of variation: between-person and within-person variability. Further, few studies have investigated how the association between activity participation and cognitive ability may differ from early to older adulthood. Using the PATH Through Life Project, we evaluated whether between- and within-person variation in activity participation was associated with cognitive ability and change within cohorts aged 20-24 years, 40-44 years, and 60-64 years at baseline (n = 7,152) assessed on three occasions over an 8-year interval. Multilevel models indicated that between-person differences in activity significantly predicted baseline cognitive ability for all age cohorts and for each assessed cognitive domain (perceptual speed, short-term memory, working memory, episodic memory, and vocabulary), even after accounting for sex, education, occupational status, and physical and mental health. In each case, greater average participation was associated with higher baseline cognitive ability. However, the size of the relationship involving average activity participation and baseline cognitive ability did not differ across adulthood. Between-person activity and within-person variation in activity level were both not significantly associated with change in cognitive test performance. Results suggest that activity participation is indeed related to cognitive ability across adulthood, but only in relation to the starting value of cognitive ability, and not change over time.     

Who benefits from memory training?

Cognitive training programs can have significant benefits. However, their efficacy is often reduced for individuals of advanced age or lower cognitive ability. Using older adult subjects, we examined the role of self-initiation of cognitive control in a training program that targets recollection memory. Relative time spent on an open-ended, intentional encoding task that requires the self-initiation of cognitive control was highly predictive of improvement in the training task, and fully accounted for individual differences related to age and crystallized intelligence. Analyzing training programs from the perspective of cognitive theory may help clarify how these programs have their effects and suggest ways to optimize such programs for the individuals who need them most.     

When can we choose to forget? An ERP study into item-method directed forgetting of emotional words

Emotionally arousing information is treated in a specialised manner across a number of different processing stages, and memory for affective events is often found to be heightened by virtue of this. However, in some cases, emotional experiences might be the very ones that we would like to forget. Here, two item-method directed forgetting studies are presented which investigate people's ability to intentionally forget affective words when stimuli and memory instructions are presented simultaneously. In the first experiment an interaction between task instruction and emotional content was evident in a diminished directed forgetting effect for emotional words, suggesting that they may be relatively resistant to deliberate forgetting. The interaction between instruction and emotion appeared both in free recall of words and in a yes-no recognition task. In the second study, an ERP procedure was utilised to investigate whether emotion modulates the effects of instruction during the initial encoding of stimuli. Recognition data again showed a clear interaction between instruction and emotion, with a reduced directed forgetting effect for emotional words. The ERP data demonstrated evidence for individual effects of both emotion and instruction during encoding; however, despite this, no evidence for an interaction between these factors was evident in the ERP data. As such, we conclude that even when study items are presented simultaneously with their associated memory instructions, neither does emotion prevent differential processing of directed forgetting instruction, nor does memory instruction prevent differential processing of emotion during early encoding. Implications are discussed in relation to the directed forgetting literature and more broadly with respect to circumstances under which emotion and cognitive processing work in parallel or in competition with each other.     

On the course of forgetting in very long-term memory

For practical reasons, little information is available about memory across very long learning-retention intervals. To determine the time course of forgetting in very long-term memory, a memory test was constructed that sampled events (former one-season television programs) that had occurred during a single year from 1 to 15 years ago. Updated versions of the test were administered each year for 9 consecutive years, and a forgetting curve was then calculated by superimposing the results from the nine tests. The best fitting function to the curve was monotonic and nonlinear. The findings show that forgetting in very long-term memory can be gradual and continuous for many years after learning.     

Idazoxan, an alpha-2 antagonist, facilitates memory retrieval in the rat

The role of the noradrenergic system in cognitive function was studied by using the alpha-2 adrenoceptor antagonist idazoxan to increase noradrenergic activity. Rats were trained in a complex maze task for food reward. They were left undisturbed for a 4-week "forgetting" period and were treated with idazoxan, just before the retention test. The dose of idazoxan used had previously been shown to enhance firing of units of the locus coeruleus and to increase noradrenaline (NE) turnover in the forebrain. This pharmacological treatment effectively alleviated forgetting, while control rats showed significant decrement compared to their performance at the last training trial. A control experiment showed that the facilitative effect was not on learning or on ongoing performance of the task, since there was no effect on simple acquisition. The results are taken as support for the notion that NE plays a role in memory retrieval processes.     

Risk- and protective factors for memory plasticity in aging

ABSTRACT

Risk and protective factors for cognitive function in aging may affect how much individuals benefit from their environment or life experiences by preserving or improving cognitive abilities. We investigated the relations between such factors and outcome from episodic-memory training in 136 healthy young and older adults. Tested risk factors included carrying the ?4 variant of the apolipoprotein E allele (APOE), age, body mass index, blood pressure, and cholesterol. Protective factors included higher levels of education, intelligence quotient (IQ), physical activity, fatty acids, and vitamin D. Average increases in memory performance were seen after training, with ample variation between individuals. Being young, female, and having higher IQ were positive predictors of memory improvement. No other relationships were observed. Similar benefit was observed across APOE allelic variation. This indicates that beyond IQ, age, and sex, known risk -and protective factors of cognitive function in aging were not significantly related to memory plasticity.