In this research the effects of handedness and depth of processing on the explicit and implicit memory was evaluated. An experimental research was carried out individually on 80 students using computerized measurement tools and Edinburgh Handedness Inventory. The data were analyzed through Variance Analysis Method. Results showed that the difference between examinees under different depths of processing is significant in explicit memory. Moreover, there was also a significant difference in explicit memory between the three groups. Mixed-handed and left-handed participants had better recall performance but there was no significant difference in implicit memory. Better performance of the mixed-handed in explicit memory recall test indicates that explicit memory function is dependent on the interrelation between the two hemispheres.

The neurotransmitter acetylcholine is considered essential for proper functioning of the hippocampus-dependent declarative memory system, and it represents a major neuropharmacological target for the treatment of memory deficits, such as those in Alzheimer's disease. During slow-wave sleep (SWS), however, declarative memory consolidation is particularly strong, while acetylcholine levels in the hippocampus drop to a minimum. Observations in rats led to the hypothesis that the low cholinergic tone during SWS is necessary for the replay of new memories in the hippocampus and their long-term storage in neocortical networks. However, this low tone should not affect nondeclarative memory systems. In this study, increasing central nervous cholinergic activation during SWS-rich sleep by posttrial infusion of 0.75 mg of the cholinesterase inhibitor physostigmine completely blocked SWS-related consolidation of declarative memories for word pairs in human subjects. The treatment did not interfere with consolidation of a nondeclarative mirror tracing task. Also, physostigmine did not alter memory consolidation during waking, when the endogenous central nervous cholinergic tone is maximal. These findings are in line with predictions that a low cholinergic tone during SWS is essential for declarative memory consolidation.

Conceptual priming and familiarity are hot spots of researches on neuro-mechanisms of implicit and explicit memory.Supporters of dual-process theories put forward that brain potentials at pre-frontal areas between 300 and 500ms(FN400) are associated with familiarity.However,supporters of singleprocess theories think that studies supporting FN400 as index of familiarity did not take into account the contamination of conceptual priming on explicit memory.Through a series of studies,Paller and his colleagues proved that FN400 is associated with conceptual priming but not familiarity and that familiarity is indexed by brain potentials at parietal areas between 500 and 800ms(LPC).So far,there are still debates on the nero-mechanism of familiarity and conceptual priming.Further researches should explore new methods to dissociate familiarity and conceptual priming.The neuro-mechanism of effects of fluency on familiarity should also be investigated.

Conceptual priming and familiarity are hot spots of researches on neuro-mechanisms of implicit and explicit memory. Supporters of dual-process theories put forward that brain potentials at pre-frontal areas between 300 and 500ms (FN400) are associated with familiarity. However, supporters of single- process theories think that studies supporting FN400 as index of familiarity did not take into account the contamination of conceptual priming on explicit memory. Through a series of studies, Paller and his colleagues proved that FN400 is associated with conceptual priming but not familiarity and that familiarity is indexed by brain potentials at parietal areas between 500 and 800ms (LPC). So far, there are still debates on the nero-mechanism of familiarity and conceptual priming. Further researches should explore new methods to dissociate familiarity and conceptual priming. The neuro-mechanism of effects of fluency on familiarity should also be investigated.

Evidence from recent studies challenge traditional memory system accounts of separate mechanisms for implicit and explicit memory. The motive behind the present study was to further investigate whether common activations can be detected during explicit and implicit memory performance when using the same procedure for both tasks. Functional magnetic resonance imaging (fMRI) showed separate neural activation to perceptual repetition priming and perceptual recognition of real and nonsense objects, both in terms of the brain regions involved and in the direction of repeated-novel activations. Repetition priming showed deactivation for repeated stimuli in regions not overlapping regions activated in conscious recognition, activation patterns in the two tasks involved largely separate networks. Common activations were observed in three areas, considered as being involved in processes such as stimulus analyses, task monitoring and attention, i.e., processes external to memory. We interpret this as indicating an ...

A wide range of studies have shown that executing the other secondary task during encoding has little influence on implicit memory(repetition priming). Somewhat surprisingly, relatively few studies discussed the effects of interference on implicit memory during retrieval, which was confirmed as a process distinct from encoding, but also important in memory. Furthermore, an open question remains as to whether the retrieval interference could affect implicit memory? The effect of interference during retrieval was assessed by comparing a divide-attention(DA) condition, on which participants carried out a memory task(lexical decision) and an interference task(even-odd decision) simultaneously or successively, with a full-attention(FA) condition, on which participants performed only the memory task or interference task. Each experiment consisted of five parts: a study phase, a distraction phase, twice FA interference phases, and a retrieval phase, which included above two types attention conditions. Thirty-five undergraduate students participated in Experiment 1, which investigated whether synchronous interference task during retrieval could affect implicit memory. Experiment 2 further examined whether asynchronous interference could also change the priming of implicit retrieval. Thirty participants took part in Experiment 3, which was designed to examine whether such interference could affect explicit memory retrieval. Therefore, it replaced the lexical decision with recognition task based on Experiment 1. Participants were instructed to make response to corresponding items by pressing keyboard, and were told that the memory and interference task were equally important. They were asked to perform both tasks as quickly and accurately as possible. The Reaction Time(RT) and Accuracy data in retrieval phase were recorded, in order to assess priming effects, the effect of interference and interference task costs. The results showed that, first, the repetition priming results(the facilitation or bias in processing of studied items) were quite consistent across Experiment 1 and 2 both on RT and Accuracy. It reflected that priming would be impacted by interference task, whatever the distraction and memory stimulus presented synchronously or asynchronously. Second, In Experiment 3, there was non-significant difference across attention conditions in recognition Accuracy. Third, we followed Lozito and Mulligan's(2010) method for examining interference task costs. They proposed two measures to obtain distracting task costs for verifying the effects of interference. One of them would work out global costs, which was assessed by comparing performance on the interference task when performed under DA to FA. We found global costs occurred among three experiments, indicating that attention resource competition happened across dual tasks. But significant specific costs, which comparing performance on interference among DA, was only found in Experiment 3, indicating that explicit retrieval would break secondary task performance, whereas, implicit retrieval seemingly has little impact on interference task, but easily influenced by interference task. In conclusion, results from the current study revealed that implicit memory priming could not be regarded as an automatic form of retrieval with ease. And it's necessary for memory retrieval to catch enough cognitive resources. If limited resource was occupied by the other task, implicit retrieval processing would be impacted.

近三十年来,内隐记忆是认知心理学领域倍受关注的研究方向,吸引了很多专家学者的目光。内隐记忆指的是对先前获得信息的无意识提取,它与对过去经验有意识、有目的回忆的外显记忆是相对应的。关于内隐记忆的影响因素有很多,其中,干扰因素是最为重要的一个因素。当前,很多研究集中于探讨编码干扰对内隐记忆的影响,也得出了较为一致的结论,即编码干扰会影响内隐记忆。然而,关于内隐记忆提取干扰效应的研究很少,而且结论也不一致。 为了进一步探究提取干扰在内隐记忆中所扮演的角色,我们设置了两种不同的干扰任务：知觉干扰、概念干扰,并引入了加工水平这一变量,通过行为实验及事件相关电位(ERP)实验进行研究。行为实验结果表明,在无干扰条件下,词汇判断任务存在着明显的启动效应；而在干扰条件下,这种启动效应受到了影响,知觉干扰条件下深加工启动效应消失,但仍存在浅加工启动效应,概念干扰条件下不存在任何效应。脑电行为结果与行为实验结果一致。ERPs结果表明,无干扰条件下虽没发现浅加工启动效应的ERP成分,然而在深加工启动中,却有明显代表内隐记忆的N400效应；而在干扰条件下,新旧词间的ERPs却没有显著差异。 综合行为与ERP研究结果,我们认为内隐记忆受到了提取干扰的影响,这种影响在不同干扰任务类型中有所差异,概念干扰任务的破坏程度大于知觉干扰任务。

The role of attention during implicit memory retrieval was assessed using a test-phase division of attention. Implicit retrieval is dissociable into perceptual and conceptual forms. Implicit retrieval is further dissociable into tests that involve stimulus identification or stimulus production. The present study used implicit tests that varied on these dimensions. Experiment 1 used a perceptual identification test; Experiment 2 used a word-stem completion test; and Experiment 3 used a category-exemplar production test. Attention was divided with one of several secondary tasks. None of the secondary tasks reduced levels of priming for any of the implicit tests. Furthermore, implicit retrieval generally facilitated secondary task performance rather than producing secondary task costs as is typical with explicit memory. A fourth experiment indicated that explicit recall was negatively affected by most of the secondary tasks, and exhibited a different pattern of secondary task costs. All of the above is consistent with the idea that implicit retrieval is automatic.

以往研究表明在外显记忆中，编码与提取加工存在着非对称性，但在内隐记忆中，二者的关系并不明确，因此该实验采用“学习-再认”范式，考察在编码或提取中分别附加的干扰任务对词汇判断或再认产生的影响。结果证实编码与提取干扰对内隐或外显记忆都具有非对称性的影响，但又存在着差异，即编码干扰会导致随后外显记忆成绩显著减少，而提取干扰对其影响较小，相反，编码干扰对随后内隐测验中启动效应的影响较小，但提取干扰会破坏启动效应，从而为内隐记忆和外显记忆的分离提供了进一步的证据。

Encoding and retrieval are two important phases of memory. Encoding produces memory engraved and re-trieval reactivates previously encoded information. The approach to the relationship between encoding and re-trieval is meaningful for the better understanding of the nature of memory. As for explicit memory, the relation of encoding and retrieval has been investigated by many researchers who have found out that the performance of a secondary task during encoding reduced the later memory performance, but the division of the attention in the same way during retrieval had virtually no effect on memory performance, which indicated an asymmetry be-tween encoding and retrieval processes. With respect to implicit memory, an asymmetry was also found in one of our previous studies (Meng & Guo, 2006), but the asymmetry is somewhat different from that in explicit mem-ory, that is, the performance of a concurrent task during encoding had no effect on later task performance, but interference during retrieval disrupted priming, and reduced task performance. In order to clarify the issues we conducted an ERP experiment. The experiment was conducted with 16 undergraduate students as subjects and Chinese characters as stim-uli. The experiment adopted a study-to-test paradigm, in which participants performed a “shallow” (color) study task or a “deep” (pleasant) study task, followed by either a lexical decision (implicit) test (section 1) or a recog-nition (explicit) test (section 2). In interference task participants were asked to account the total number of “+” in a regulated orientation which appeared with a word, and was performed concurrently with either the encoding or the retrieval phase of the memory task for encoding interference condition or retrieval interference condition. The results showed that: (1) the effects of interference to encoding in implicit memory test were different from that to retrieval. Interference during encoding had virtually no effect on N400 or P600 old/new ERP components, but interference during retrieval significantly reduced N400 old/new and P600 old/new components, which ab-olished behavior priming. (2) The effects of interference to encoding on ERP components in explicit memory test were different from that to retrieval. Interference during encoding had significant influence on later P600 old/new effect, but interference during retrieval did not produce such effect. The results confirmed the finding of Meng & Guo (2006), that is, interference during encoding had effect on explicit memory, but left implicit memory intact. Interference during retrieval affected implicit memory, but had little effect on explicit memory. So the relationship between encoding and retrieval was different between implicit and explicit memory, thus providing further evidence on the dissociation between implicit and explicit memory.

Encoding and retrieval are two important phases of memory.The study investigated the effects of encoding-interference or retrieval-interference on beheavior in implicit memory test and explicit memory test.The results showed that:(1) the effects of interference to encoding on priming in implicit memory test were different from that to retrieval.Compared with encoding-interference,retrieval-interference had more effect on priming,which indicated an asymmetry between encoding and retrieval processes,and the asymmetry was the same between shallow and deep study tasks.(2) The effects of interference to encoding on old/new effect in explicit memory test were different from that to retrieval.Compared with retrieval-interference,encoding-interference had more effect on old/new effect,which indicated an asymmetry between encoding and retrieval processes,and the asymmetry was more distinct on deep study task.The results supported the asymmetric relationship between encoding and retrieval in implicit and explicit memory,and the asymmetric relationship is different between these two Memory types,which indicates the dissociation between encoding and retrieval and the dissociation between implicit and explicit memories.

Abstract Normal aging affects explicit memory while leaving implicit memory relatively spared. Normal aging also modifies how emotions are processed and experienced, with increasing evidence that older adults (OAs) focus more on positive information than younger adults (YAs). The aim of the present study was to investigate how age-related changes in emotion processing influence explicit and implicit memory. We used emotional melodies that differed in terms of valence (positive or negative) and arousal (high or low). Implicit memory was assessed with a preference task exploiting exposure effects, and explicit memory with a recognition task. Results indicated that effects of valence and arousal interacted to modulate both implicit and explicit memory in YAs. In OAs, recognition was poorer than in YAs; however, recognition of positive and high-arousal (happy) studied melodies was comparable. Insofar as socioemotional selectivity theory (SST) predicts a preservation of the recognition of positive information, our findings are not fully consistent with the extension of this theory to positive melodies since recognition of low-arousal (peaceful) studied melodies was poorer in OAs. In the preference task, YAs showed stronger exposure effects than OAs, suggesting an age-related decline of implicit memory. This impairment is smaller than the one observed for explicit memory (recognition), extending to the musical domain the dissociation between explicit memory decline and implicit memory relative preservation in aging. Finally, the disproportionate preference for positive material seen in OAs did not translate into stronger exposure effects for positive material suggesting no age-related emotional bias in implicit memory. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Familiarity is a pervasive memory phenomenon that occurs in its most basic form when someone recognizes a repeated stimulus without recollecting other aspects of the requisite prior learning episode. Theoretical controversy currently abounds with respect to both the cognitive and neural characteristics of familiarity. Here, we show that the extant data, particularly brain-potential data, are insufficient for validating putative neural correlates of familiarity, and we outline strategies for making progress on this problem. Conceptual priming is an implicit-memory phenomenon that often occurs together with familiarity; experiments that conflate the two phenomena can be misleading. Avoiding this conflation is required to understand familiarity and to determine the extent to which the neurocognitive processes that support priming also drive familiarity.

This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually-driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on category exemplar generation priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes.

The present experiments were aimed at determining whether acetylcholine (ACh) plays a role in encoding and retrieval of spatial information using a modified Hebb illiams maze. In addition, the present experiments tested two computational models of hippocampal function during encoding and retrieval using a maze sensitive to hippocampal disruption. Thirty male, Long-Evans rats served as subjects. Chronic cannulae were implanted bilaterally into the CA3 ( n=26) and CA1 ( n=5) subregions of the hippocampus. Rats were tested using a modified Hebb-Williams maze. In the first experiment, rats were injected with either saline or scopolamine hydrobromide 10 min before testing for each day. The number of errors made per day per group was used as the measure of learning. Encoding was assessed by the average number of errors made on the first five trials of Day 1 compared to the last five trials of Day 1, whereas the average number of errors made on the first five trials of Day 2 compared to the last five trials of Day I was used to assess retrieval. No deficit was found for the saline group. The scopolamine group showed a deficit in encoding, but not retrieval. In the second experiment, rats were injected with either saline or physostigmine 10 min before testing each day. In contrast to the scopolamine groups, the physostigmine group showed a deficit in retrieval, but not encoding. To test whether the retrieval deficit was due to a disruption in storage or gaining access to the information two groups of rats received either saline on Day 1 and physostigmine on Day 2 or physostigmine on Day 1 and saline on Day 2. In addition, one group received physostigmine immediately after testing on Day 1. Data indicate that physostigmine causes a disruption of retrieval by means of a disruption in consolidation process. In conclusion, the cholinergic antagonist, scopolamine, disrupts encoding in both CA3 and CA1 subregions of the hippocampus. Furthermore, the cholinesterase inhibitor, physostigmine, boosts ACh action during a time when cholinergic levels need to decline for proper consolidation.

Abstract In the present positron emission tomography (PET) study, we examine the effect of a scopolamine-induced challenge to encoding upon the pattern of regional cerebral blood flow during recognition of a list of abstract visual shapes 3 days after encoding of these shapes. This study was conducted to test hypotheses concerning the fusiform and thalamic contributions to object recognition arising from a previous imaging study of impaired recognition. In that study, we demonstrated that activity in the fusiform cortex and the thalamus during shape recognition was modulated by memory challenges. These memory challenges included, on one hand, impaired storage as a consequence of diazepam administration during encoding, and, on the other hand, impaired retrieval caused by a perceptual challenge. Activation in the fusiform cortex decreased during impaired recognition, irrespective of the type of challenge. In contrast, thalamic activation increased only when the recognition deficit resulted from impaired memory storage. Based on these results, we hypothesized that fusiform activation during recognition reflects the matching of an incoming stimulus with a stored one, whereas thalamic activation reflects retrieval attempts. These hypotheses would receive considerable support if scopolamine, which also impairs memory storage, induced similar modulations of fusiform and thalamic activation. In the present study, we observed that a scopolamine challenge to encoding does indeed modulate the activity in the very same regions that were previously modulated by a diazepam challenge. Hence, a similar memory deficit, although primarily effected through different neurochemical pathways, was paralleled by a similar modulation of activity in the same set of nodes in the shape recognition network. In the fusiform cortex, scopolamine decreased recognition-related activity, as did the sensory challenge of retrieval. Furthermore, covariate analysis demonstrated that the level of fusiform activity linearly correlates with behavioural performance. In the thalamus, activation increased following impaired encoding. This is in accordance with the idea that enhanced thalamic activity reflects increased effort expended in retrieval. In addition, in the intraparietal sulcus, differential activation also increased following impaired memory storage, possibly reflecting enhanced visuospatial attention in an effort to compensate for impaired performance.

A commonly held assumption is that processes underlying explicit and implicit memory are distinct. Recent evidence, however, suggests that they may interact more than previously believed. Using the remember now procedure the current study examines the relation between recollection, a process thought to be exclusive to explicit memory, and performance on two implicit memory tasks, lexical decision and word stem completion. We found that, for both implicit tasks, words that were recollected were associated with greater priming effects than were words given a subsequent familiarity rating or words that had been studied but were not recognised (misses). Broadly, our results suggest that non-voluntary processes underlying explicit memory also benefit priming, a measure of implicit memory. More specifically, given that this benefit was due to a particular aspect of explicit memory (recollection), these results are consistent with some strength models of memory and with Moscovitch's (2008) proposal that recollection is a two-stage process, one rapid and unconscious and the other more effortful and conscious.

Background/Study Context: It has been proposed that effects of aging are more pronounced for explicit than for implicit motor learning. The authors evaluated this claim by comparing the efficacy of explicit and implicit learning of a movement sequence in young and older adults, and by testing the resilience against fatigue and secondary tasking after learning. It was also examined whether explicit learning in older adults can be promoted by alleviating time constraints during learning. Methods: The alternating serial reaction time task (ASRTT) was used. Experiment 1 compared the benefits of receiving full instructions about the stimulus sequence relative to receiving no instructions in young (2025 years) and older (5065 years) adults during retention and during transfer to fatigue and secondary task conditions. Experiment 2 alleviated time constraints during the initial bouts of practice with full instructions. Results: Experiment 1 indicated that the older adults learned on the ASRTT and achieved similar performance as young adults when no instructions were given. In contrast to the young adults, learning was not superior in older adults who received full instructions compared with those who did not. Experiment 2 indicated that alleviating time constraints allowed some of the older adults to gain from instruction but only under relatively low time constraints, but there was no retention with rigorous time constraints. Conclusion: Explicit learning, but not implicit learning, declines in older adults. This is partly due to older adults difficulties to apply explicit knowledge. Less rigorous time constraints can help to ameliorate some of these difficulties and may induce levels of explicit learning in older adults that will result in superior performance compared with implicit learning. Implicit learning did occur under time constraints that prevented explicit learning.

Abstract Implicit memory and explicit memory are fundamentally different manifestations of memory storage in the brain. Yet, conceptual fluency driven by previous experience could theoretically be responsible for both conceptual implicit memory and aspects of explicit memory. For example, contemplating the meaning of a word might serve to speed subsequent processing of that word and also make it seem familiar. We examined electrophysiological correlates of conceptual priming with 180 celebrity faces to determine whether or not they resemble electrophysiological correlates of explicit memory. Celebrity faces are ideal for this purpose because they carry with them preexisting conceptual information (i.e., biographical facts) that can selectively be brought to mind such that conceptual processing can be manipulated systematically. In our experiment, exposure to biographical information associated with only one-half of the celebrities yielded conceptual priming for those faces, whereas all faces were perceptually primed. Conceptual priming was indexed by positive brain potentials over frontal regions from approximately 250 to 500 ms. Explicit memory retrieval was associated with later brain potentials over posterior regions that were strikingly similar to potentials previously associated with pure familiarity for faces (when a face seems familiar in the absence of retrieval of any specific information about previous occurrence). Furthermore, the magnitude of conceptual priming was correlated across subjects with the amplitude of frontal but not posterior potentials, whereas the opposite was true for explicit memory. Distinct brain processes were thus associated with conceptual priming and conscious recognition of faces, thus providing a sharper focus on the border between implicit and explicit memory.