Attention and successful episodic encoding: an event-related potential study

Effects of peer victimization on cortical processing of social-evaluative stress in patients with major depressive disorder

Peer victimization contributes to the development of major depressive disorders (MDDs). While previous studies reported differentiated peripheral physiological responses in peer-victimized individuals with depression, little is known about potential alterations of cortical event-related potentials (ERPs) in response to social stimuli in depressive patients with a history of peer victimization. Using a social condition paradigm, the present study examined whether peer victimization alters conditioned cortical responses to potentially threatening social stimuli in MDD patients and healthy controls. In the task, we studied ERPs to conditioned stimuli (CSs), i.e. still images of faces, that were coupled to unconditioned socially negative and neutral evaluative video statements. Peer victimization was related to more pronounced P100 amplitudes in reaction to negative and neutral CSs. Attenuated P200 amplitudes in peer-victimized individuals were found in response to negative CSs. Cortical responses to CSs were not influenced by a diagnosis of MDD. The results suggest altered responsiveness to interpersonal information in peer-victimized individuals. Facilitated early processing of social threat indicators may prevent peer-victimized individuals from adaptive responses to social cues, increasing their vulnerability for depression.

Observing memory encoding while it unfolds: Functional interpretation and current debates regarding ERP subsequent memory effects

Our ability to remember the past depends on neural processes set in train in the moment an event is experienced. These processes can be studied by segregating brain activity according to whether an event is later remembered or forgotten. The present review integrates a large number of studies examining this differential brain activity, labeled subsequent memory effect (SME), with the ERP technique, into a functional organization and discusses routes for further research. Based on the reviewed literature, we suggest that memory encoding is implemented by multiple processes, typically reflected in three functionally different subcomponents of the ERP SME elicited by study stimuli, which presumably interact with preparatory SME activity preceding the to be encoded event. We argue that ERPs are a valuable method in the SME paradigm because they have a sufficiently high temporal resolution to disclose the subcomponents of encoding-related brain activity. Implications of the proposed functional organization for future studies using the SME procedure in basic and applied settings will be discussed.

Attentional attenuation (rather than attentional boost) through task switching leads to a selective long-term memory decline

Allocating attention determines what we remember later. Attentional demands vary in a task-switching paradigm, with greater demands for switch than for repeat trials. This also results in lower subsequent memory performance for switch compared to repeat trials. The main goal of the present study was to investigate the consequences of task switching after a long study-test interval and to examine the contributions of the two memory components, recollection and familiarity. In the study phase, the participants performed a task-switching procedure in which they had to switch between two classifications tasks with pictures. After a short vs. a long study-test interval of a week, the participants performed a surprise memory test for the pictures and gave remember/know judgements. The results showed that recognition memory declined after 1 week and this was mainly due to a decrease in "remember" responses. The results also showed that the task-switching effect on memory was enduring. Whereas the results of the immediate test were mixed, the results of the delayed tests showed that the task-switching effect was based on recollection, expressed in more "remember" responses for repeat than for switch trials. As recollection is more sensitive to attention manipulations than familiarity, the results align with the notion that attentional requirements at study determine what we remember, in particular after a long study-test interval.

Passive Elaborative Cueing of Retrieval ProcessesFollowing Traumatic Brain Injury

Purpose: Semantic elaboration is a process in which target information is analyzed in relation to content associated in meaning. The goal of the present study was to examine the use of phrasal cues intended to engage elaborative processes theorized to bolster cognitive performance.Methods: Twenty-two individuals with a history of traumatic brain injury (TBI) and twenty-six neurotypical (NT) individuals were studied. Short phrases intended to elicit elaborative encoding were presented prior to the introduction of a prospective memory task and word-stem completions. Phrases embodied one of three conditions: repeated, semantic, or unrelated information. The stem-completion task was presented between each prospective memory task with fixations serving as cues signaling task completion or functioning as distractors. Event-related potentials (ERPs) were captured during the presentation of word-stems. Following the completion of all word-stems, participants were presented with an old/new recognition task.Results: Linear mixed-effects model analyses revealed a significant effect of condition with respect to word retrieval and recognition memory. Captured ERPs revealed neural signatures resembling a P200.Conclusion: Semantic content increased stimulus saliency, facilitated lexical retrieval, and enhanced retention with the latter process revealing use of semantic cues as a more adept rehearsal strategy than repetition.

Neural correlates of the production effect: An fMRI study

Recognition memory is improved for items produced at study (e.g., by reading them aloud) relative to a non-produced control condition (e.g., silent reading). This production effect is typically attributed to the extra elements in the production task (e.g., motor activation, auditory perception) enhancing item distinctiveness. To evaluate this claim, the present study examined the neural mechanisms underlying the production effect. Prior to a recognition memory test, different words within a study list were read either aloud, silently, or while saying "check" (as a sensorimotor control condition). Production improved recognition, and aloud words yielded higher rates of both recollection and familiarity judgments than either silent or control words. During encoding, fMRI revealed stronger activation in regions associated with motor, somatosensory, and auditory processing for aloud items than for either silent or control items. These activations were predictive of recollective success for aloud items at test. Together, our findings are compatible with a distinctiveness-based account of the production effect, while also pointing to the possible role of other processing differences during the aloud trials as compared to silent and control.

Event-related potentials of episodic encoding after traumatic brain injury in older adults

Episodic memory and attention impairments are frequently observed following a traumatic brain injury (TBI). Older adults are more affected than young adults after a TBI, partly because of the age-related neural and memory changes. Neural mechanisms underlying episodic memory deficits in older adults with chronic TBI remain to be investigated. The current study aimed to investigate the impact of TBI in older adults on the neural mechanisms of episodic encoding. Event-related potentials were recorded while 13 participants with mild-to-severe TBI and 14 matched controls were performing an episodic memory task in which the level of organizational strategy was manipulated through three encoding conditions. Participants were explicitly instructed to memorize words without any semantic relationship (Unrelated condition), words semantically related without any given strategies (Spontaneous condition) and words semantically related with provided category labels and organizational strategy (Guided condition). Behavioral performances indicated that older individuals with a TBI were impaired compared to matched controls whatever the condition. The electrophysiological findings showed a reduction of the P200 and LPC components amplitude in the TBI group relative to control group. Moreover, control participants without any neurological history showed a right frontal sustained activity only in the Spontaneous condition, whereas a right frontal asymmetry was observed in participants with chronic TBI whatever the encoding conditions. This was mainly the result of negative left frontal activity. These findings evidence neural dysfunctions underlying attentional and associative processes involved in memory strategies after a TBI sustained at an older age that are consistent with executive functions impairments.

In search of the proximal cause of the animacy effect on memory: Attentional resource allocation and semantic representations

People recall and recognize animate words better than inanimate words, perhaps because memory systems were shaped by evolution to prioritize memory for predators, people, and food sources. Attentional paradigms show an animacy advantage that suggests that the animacy advantage in memory stems from a prioritization of animate items when allocating attentional resources during encoding. According to the attentional prioritization hypothesis, the animacy effect should be even larger when attention is divided during encoding. Alternatively, the animacy effect could be due to more controlled processing during encoding, and so should be reduced when attention is divided during encoding. We tested the attentional prioritization hypothesis and the controlled processing hypothesis by manipulating attention during encoding in free recall (Experiment 1) and recognition (Experiment 2) but failed to find interactions between word type and attentional load in either free recall or recognition, contrary to the predictions from both hypotheses. We then tested whether the semantic representations of animate and inanimate items differ in terms of number of semantic features, using existing recall data from an item-level megastudy by Lau, Goh, and Yap (Quarterly Journal of Experimental Psychology, 71 (10), 2207-2222, 2018). Animate items have more semantic features, which partially mediated the relationship between animacy status and recall.

Offset-related brain activity in the left ventrolateral prefrontal cortex promotes long-term memory formation of verbal events

BACKGROUND

Recent evidence suggests that brain activity following the offset of a stimulus during encoding contributes to long-term memory formation, however the exact mechanisms underlying offset-related encoding are still unclear.

OBJECTIVES

Here, in three repetitive transcranial magnetic stimulation studies (rTMS) we investigated offset-related activity in the left ventrolateral prefrontal cortex (VLPFC). rTMS was administered at different points in time around stimulus offset while participants encoded visually-presented words or pairs of words. The analyses focused on the effects of the stimulation on subsequent memory performance.

RESULTS

rTMS administered at the offset of the stimuli, but not during online encoding, disrupted subsequent memory performance. In Experiment 1 we found that rTMS specifically disrupted encoding mechanisms initiated by the offset of the stimuli rather than general, post-stimulus processes. Experiment 2 showed that this effect was not dependent upon rTMS-induced somatosensory effects. In a third rTMS experiment we further demonstrated a robust decline in associative memory performance when the stimulation was delivered at the offset of the word pairs, suggesting that offset-related encoding may contribute to the binding of information into an episodic memory trace.

CONCLUSIONS

The offset of the stimulus may represent an event boundary that promotes the reinstatement of the previously experienced event and episodic binding.

EEG-based Identification of Evidence Accumulation Stages in Decision-Making

Dating back to the 19th century, the discovery of processing stages has been of great interest to researchers in cognitive science. The goal of this paper is to demonstrate the validity of a recently developed method, hidden semi-Markov model multivariate pattern analysis (HsMM-MVPA), for discovering stages directly from EEG data, in contrast to classical reaction-time-based methods. To test the validity of stages discovered with the HsMM-MVPA method, we applied it to two relatively simple tasks where the interpretation of processing stages is straightforward. In these visual discrimination EEG data experiments, perceptual processing and decision difficulty were manipulated. The HsMM-MVPA revealed that participants progressed through five cognitive processing stages while performing these tasks. The brain activation of one of those stages was dependent on perceptual processing, whereas the brain activation and the duration of two other stages were dependent on decision difficulty. In addition, evidence accumulation models (EAMs) were used to assess to what extent the results of HsMM-MVPA are comparable to standard reaction-time-based methods. Consistent with the HsMM-MVPA results, EAMs showed that nondecision time varied with perceptual difficulty and drift rate varied with decision difficulty. Moreover, nondecision and decision time of the EAMs correlated highly with the first two and last three stages of the HsMM-MVPA, respectively, indicating that the HsMM-MVPA gives a more detailed description of stages discovered with this more classical method. The results demonstrate that cognitive stages can be robustly inferred with the HsMM-MVPA.

Inhibitory Control of Lexical Selection in Adults who Stutter

PURPOSE

Based on previous evidence that lexical selection may operate differently in adults who stutter (AWS) versus typically-fluent adults (TFA), and that atypical attentional processing may be a contributing factor, the purpose of this study was to investigate inhibitory control of lexical selection in AWS.

METHOD

12 AWS and 12 TFA completed two tasks. One was a picture naming task featuring High and Low Agreement object naming. Naming accuracy and reaction times (RT), and event-related potentials (ERPs) time-locked to picture onset, were recorded. Second was a flanker task featuring Congruent and Incongruent arrow arrays. Push-button accuracy and RTs, and ERPs time-locked to arrow array onset, were recorded.

RESULTS

Low Agreement pictures were named less accurately and slower than High Agreement pictures in both Groups. The magnitude of the Agreement effect on naming RTs was larger in AWS versus TFA. Delta-plot analysis revealed that the Agreement effect was positively correlated with individual differences in inhibition in TFA but not in AWS. Moreover, Low Agreement pictures elicited negative-going ERP activity relative to High Agreement pictures in both Groups. However, the scalp topography of this effect was markedly reduced in AWS versus TFA. For the Flanker task, Congruency affected push-button accuracy and RTs, and N2 amplitudes, similarly between groups.

CONCLUSIONS

Results point to a selective deficit in inhibitory control of lexical selection in AWS. Potential pathways between diminished inhibitory control of lexical selection, speech motor control and stuttering are discussed.

The effect of shared distinctiveness on source memory: An event-related potential study

An illusory correlation (IC) is the erroneous perception that two actually uncorrelated categories are correlated. The Shared Distinctiveness Approach (SDA) explains ICs with heightened accessibility of distinctive category combinations in episodic memory. However, empirical evidence for this approach is heterogeneous. In the present event-related potential (ERP) study, we exploited the fact that more distinctive items elicit larger P300 responses than less distinctive items, which potentially predict subsequent memory performance differences for such items. Distinctiveness at encoding was created by presenting words that differed from frequently presented, positive words in valence, font color, or both. We hypothesized that shared distinctiveness (deviation in both color and valence) would lead to an enhanced P300 subsequent memory effect (SME), better source memory performance, and an overestimation of the frequency of shared distinctive items. Behavioral results indicated the presence of shared distinctiveness effects on source memory and frequency estimation. Unexpectedly, memory also was enhanced for positive items in the frequent color. This pattern also was reflected in the P300 for highly positive and negative items. However, shared distinctiveness did not modulate the P300 SME, indicating that the processing of distinctive features might only indirectly contribute to better encoding. This study shows that shared distinctiveness indeed is associated with better source memory and ICs. Because effects were observed for the most frequent and the least frequent category combination, our results imply that the processing of distinctiveness might involve attention allocation to diametrical category combinations, thereby accentuating the differences between the categories.

The effects of encoding instruction and opportunity on the recollection of behaviourally relevant events

How does attending to a brief, behaviourally relevant stimulus affect episodic memory encoding? In the attentional boost effect, increasing attention to a brief target in a detection task boosts memory for items that are presented at the same time (relative to distractor-paired items). Although the memory advantage for target-paired items is well established, the effects of attending to targets on other aspects of episodic memory encoding are unclear. This study examined the effects of target detection and goal-directed attention on memory for task-irrelevant information from a single event, focusing on the contributions of recollection and familiarity during recognition. In Experiment 1, participants viewed a series of briefly presented faces as they performed a detection task on unrelated squares, pressing the space bar only when the square was a target colour (e.g., blue) rather than a distractor colour (e.g., orange). Half of the participants were told to memorise the faces, and half were told to ignore them. Results indicated that both recollection and familiarity were greater for target-paired faces than for distractor-paired faces, regardless of whether the faces were intentionally encoded. Experiment 2 examined whether these effects are present for single events, replicating the recollection benefit when encoding time is sufficient. Attending to behaviourally relevant targets appears to facilitate both intentional and incidental memory for the background item and the context in which it occurred, boosting subsequent recollection as well as familiarity.

Muscular effort coding in action representation in ballet dancers and controls: Electrophysiological evidence

The present electrophysiological (EEG) study investigated the neural correlates of perceiving effortful vs. effortless movements belonging to a specific repertoire (ballet). Previous evidence has shown an increased heart and respiratory rate during the observation and imagination of human actions that require a great muscular effort. In addition, TMS (transcranial magnetic stimulation) and EEG studies have evidenced a greater muscle-specific cortical excitability and an increase in late event-related potentials during the observation of effortful actions. In this investigation, fifteen professional female ballet dancers and 15 controls with no experience whatsoever with dance, gymnastics, or martial arts were recruited. They were shown 326 short videos displaying a male dancer performing standard ballet steps that could be either effortful or relatively effortless. Participants were instructed to observe each clip and imagine themselves physically executing the same movement. Importantly, they were blinded to the stimuli properties. The observation of effortful compared with effortless movements resulted in a larger P300 over frontal sites in dancers only, likely because of their visuomotor expertise with the specific steps. Moreover, an enhanced Late Positivity was identified over posterior sites in response to effortful stimuli in both groups, possibly reflecting the processing of larger quantities of visual kinematic information. The source reconstruction swLORETA performed on the Late Positivity component showed greater engagement of frontoparietal regions in dancers, while task-related frontal and occipitotemporal visual regions were more active in controls. It, therefore, appears that, in dancers, effort information was encoded in a more refined manner during action observation and in the absence of explicit instruction. Acquired motor knowledge seems to result in visuomotor resonance processes, which, in turn, underlies enhanced action representation of the observed movements.

Across time and space: spatial-temporal binding under stress

Successful episodic memory requires binding of event details across spatial and temporal gaps. The neural processes underlying mnemonic binding, however, are not fully understood. Moreover, although acute stress is known to modulate memory, if and how stress changes mnemonic integration across time and space is unknown. To elucidate these issues, we exposed participants to a stressor or a control manipulation shortly before they completed, while electroencephalography was recorded, an encoding task that systematically varied the demands for spatial and temporal integration. Associative memory was tested 24 h later. While early event-related potentials, including the P300 and Late Positive Component, distinguished different levels of spatiotemporal discontinuity, only later Slow Waves were linked to subsequent remembering. Furthermore, theta oscillations were specifically associated with successful mnemonic binding. Although acute stress per se left mnemonic integration largely unaffected, autonomic activity facilitated object memory and glucocorticoids enhanced detail memory, indicative for mnemonic integration. At the neural level, stress amplified the effects of spatiotemporal discontinuity on early information processing. Together, our results indicate that temporal and spatial gaps recruit early neural processes, providing attentional resources. The actual binding success, however, appears to depend on later processes as well as theta power and may be shaped by major stress response systems.

Neural correlates underlying the effect of reward value on recognition memory

The prioritized encoding and retrieval of valuable information is an essential aspect of human memory. We used electroencephalography (EEG) to determine which of two hypothesized processes underlies the influence of reward value on episodic memory. One hypothesis is that value engages prefrontal executive control processes, so that valuable stimuli engage an elaborative rehearsal strategy that benefits memory. A second hypothesis is that value acts through the reward-related midbrain dopamine system to modulate synaptic plasticity in hippocampal and cortical efferents, thereby benefiting memory encoding. We used a value-directed recognition memory (VDR) paradigm in which participants encoded words assigned different point values and aimed to maximize the point value of subsequently recognized words. Subjective states of recollection (i.e., “remember”) and familiarity (i.e., “know”) were assessed at retrieval. Words assigned higher values at study were recognized more effectively than words assigned lower values, due to increased “remember” responses but no difference in “know” responses. Greater value was also associated with larger amplitudes of an EEG component at retrieval that indexes recollection (parietal old/new component), but had no relationship with a component that indexes familiarity (FN400 component). During encoding, we assessed a late frontal positivity (frontal slow wave, FSW) that has been related to elaborative rehearsal strategies and an early parietal component (P3) thought to index dopamine driven attention allocation. Our findings indicate that the effect of value on recognition memory is primarily driven by the dopamine-driven reward valuation system (P3) with no discernible effect on rehearsal processes (FSW).

The effect of conceptual priming on subsequent familiarity: Behavioral and electrophysiological evidence

Previous studies on the neural mechanisms of how priming influences subsequent recognition memory have mainly focused on repetition priming, whereas the neural mechanisms of how conceptual priming affects subsequent recognition memory is still not clear. The present study investigated the electrophysiological correlates of how conceptual priming influences subsequent recognition memory. The behavioral results showed that conceptual priming only affected subsequent familiarity. The ERP results showed that conceptual priming was associated with reduced N400, and that the N400 conceptual priming effect predicted the behavioral effect of conceptual priming on subsequent familiarity. These results indicated that conceptual priming could influence subsequent familiarity by facilitating semantic processing in the encoding phase.

Electrophysiological evidence of encoding in self-referential effect

Although the self-referential effect was widely supported by several previous studies, there was few event-related potential (ERP) evidence for the encoding mechanism of the self-referential effect. The present study employed ERPs to investigate whether the electrophysiological indices of the encoding processing could predict the retrieval processing in the self-referential paradigm. Behavioral results demonstrated better performance in the self-reference condition than other-reference condition. The N400 and LPP for the subsequent memory effect (the Dm effect) were observed in both self-referential and other-referential trials as shown in the ERP results of the encoding processing. Moreover, the self-referential information had higher amplitudes for subsequently remembered trials. The study also showed correlation between the ERP components in the encoding phase and those in retrieval. These findings suggest that the self-referential effect can be due to more effective encoding process, which in turn predicts better later recall performance.

The electrophysiology of subjectively perceived memory confidence in relation to recollection and familiarity

Subjectively perceived confidence is critically involved in distinguishing recollection from familiarity in episodic memory retrieval. However, the extent to which recollection and familiarity share similar electrophysiological processes associated with subjectively perceived memory confidence remains an open question. In addition, the role of memory encoding in subjectively perceived confidence during retrieval has not yet been investigated. To address these issues, an EEG study was performed in thirty healthy volunteers. During a memory task, participants encoded a subset of words while rating the words on pleasantness. Memory recognition and subjectively perceived confidence concerning these 'old' and additional 'new' words was tested. Results showed that during retrieval, correctly classifying an old item with high subjectively perceived confidence was associated with a parietal ERP and parietal theta power, while frontal theta activity was related to high-confident novelty processing. During the memory encoding phase, a parietal ERP and frontal theta oscillations were related to subsequent subjectively perceived memory confidence. Our findings provide the first evidence that subjectively perceived memory confidence is associated with distinct electrophysiological correlates during both memory encoding and retrieval.

Divided attention and the encoding effects of retrieval

Retrieving from memory both reveals as well as modifies memory. It is important to understand how these encoding effects of retrieval differ from other forms of encoding. One possible difference relates to attention: divided attention is well known to disrupt memory encoding but typically has much less impact on memory retrieval. However, less is known about the relative attentional demands of the encoding consequences of retrieval. The current experiments examined retrieval-based encoding using free recall, a retrieval task purported to require substantial attentional resources. In three experiments, participants studied common category exemplars (Phase 1), restudied or freely recalled the exemplars (Phase 2), and then took a final free-recall test (Phase 3). Phase 2 occurred under full attention (FA) or divided attention (DA). In all three experiments, the negative effect of DA on final recall was significant in the restudy but not retrieval condition. The pattern persisted with short (Experiment 1) or long study lists (Experiment 2), requiring lesser or greater retrieval effort, and with multiple Phase 2 tests, permitting the development of more elaborate retrieval strategies (Experiment 3). The encoding effects of retrieval appear resilient to distraction, even using a memory task that is more effortful and easily disrupted by DA (i.e., free recall). In addition, these results are inconsistent with elaboration and effort accounts of retrieval-based learning.

Divided Attention Selectively Impairs Value-Directed Encoding

In the present study, we examined the effect of value-directed encoding on recognition memory and how various divided attention tasks at encoding alter value-directed remembering. In the first experiment, participants encoded words that were assigned either high or low point values in multiple study-test phases. The points corresponded to the value the participants could earn by successfully recognizing the words in an upcoming recognition memory task. Importantly, participants were instructed that their goal was to maximize their score in this memory task. The second experiment was modified such that while studying the words participants simultaneously completed a divided attention task (either articulatory suppression or random number generation). The third experiment used a non-verbal tone detection divided attention task (easy or difficult versions). Subjective states of recollection (i.e., “Remember”) and familiarity (i.e., “Know”) were assessed at retrieval in all experiments. In Experiment 1, high value words were recognized more effectively than low value words, and this difference was primarily driven by increases in “Remember” responses with no difference in “Know” responses. In Experiment 2, the pattern of subjective judgment results from the articulatory suppression condition replicated Experiment 1. However, in the random number generation condition, the effect of value on recognition memory was lost. This same pattern of results was found in Experiment 3 which implemented a different variant of the divided attention task. Overall, these data suggest that executive processes are used when encoding valuable information and that value-directed improvements to memory are not merely the result of differential rehearsal.

The role of distractor inhibition in the attentional boost effect: evidence from the R/K paradigm

Stimuli presented with targets in a detection task are later recognised more accurately than those presented with distractors, an unusual effect labelled the attentional boost effect (ABE). This effect may reflect an enhancement triggered by target detection, the inhibition of distractor rejection, or some combination of both. To test these possibilities, the present study adopted a baseline similar to that of Swallow and Jiang ([2014b]. The attentional boost effect really is a boost: evidence from a new baseline. Attention, Perception, & Psychophysics, 76(5), 1298-1307); the goal was to separate target-induced enhancements from distractor-induced inhibition. An R/K procedure was applied to further explore the kind of memory that might be affected by target detection or distractor rejection. The results show that the memory advantage for target-paired words was robust relative to that of baseline words; this advantage was mainly observed in R responses. More importantly, a memory reduction was also observed for distractor-paired words relative to baseline words, though this reduction was only observed in R responses. These data led us to conclude that the ABE was triggered by both processes: target-induced enhancement and distractor-induced inhibition. Moreover, both processes were more likely to affect recollection-based recognition.

Hippocampal contributions to serial-order memory

Our memories form a record not only of our experiences, but also of their temporal structure. Although memory for the temporal structure of experience likely relies on multiple neural systems, numerous studies have implicated the hippocampus in the encoding and retrieval of temporal information. This review evaluates the literature on hippocampal contributions to human serial-order memory from the perspective of three cognitive theories: associative chaining theory, positional-coding theory and retrieved-context theory. Evaluating neural findings through the lens of cognitive theories enables us to draw more incisive conclusions about the relations between brain and behavior.

Age-related Differences in Prestimulus Subsequent Memory Effects Assessed with Event-related Potentials

Prestimulus subsequent memory effects (preSMEs)-differences in neural activity elicited by a task cue at encoding that are predictive of later memory performance-are thought to reflect differential engagement of preparatory processes that benefit episodic memory encoding. We investigated age differences in preSMEs indexed by differences in ERP amplitude just before the onset of a study item. Young and older adults incidentally encoded words for a subsequent memory test. Each study word was preceded by a task cue that signaled a judgment to perform on the word. Words were presented for either a short (300 msec) or long (1000 msec) duration with the aim of placing differential benefits on engaging preparatory processes initiated by the task cue. ERPs associated with subsequent successful and unsuccessful recollection, operationalized here by source memory accuracy, were estimated time-locked to the onset of the task cue. In a late time window (1000-2000 msec after onset of the cue), young adults demonstrated frontally distributed preSMEs for both the short and long study durations, albeit with opposite polarities in the two conditions. This finding suggests that preSMEs in young adults are sensitive to perceived task demands. Although older adults showed no evidence of preSMEs in the same late time window, significant preSMEs were observed in an earlier time window (500-1000 msec) that was invariant with study duration. These results are broadly consistent with the proposal that older adults differ from their younger counterparts in how they engage preparatory processes during memory encoding.

Manipulating the focus of attention in working memory: Evidence for a protection of multiple items against perceptual interference

Visual working memory representations can be shielded from interference by selective attentional focusing using retroactive cues (retro-cues). However, it is not clear how many representations can be effectively cued and which neural mechanisms provide the protection from distractors. To address these questions, we manipulated the number of attended items by means of a retro-cue (one, two, or three items) and presented a distractor display during the retention of information in working memory. Analyses of the raw error and a mixture model revealed that a general performance benefit was only present when one item was retro-cued. Nevertheless, a protection of the item representations against subsequent interference occurred also after a two-item cue. ERPs revealed a modulation of the posterior negative slow wave following the retro-cues, reflecting the applied working memory resources dependent on the number of attended representations. Further, the distractor information was encoded into working memory only when the number of attended items was not changed by the retro-cues (neutral and three-item conditions), reflected by a P3b following the distractor display. These results suggest that more than one item can be effectively protected from perceptual interference. We propose that the protective effect of selective attention within working memory is based on both a reduction of the number of focused representations and the attentional refreshing of item context and features.

Verbal Learning and Memory in Cannabis and Alcohol Users: An Event-Related Potential Investigation

Aims: Long-term heavy use of cannabis and alcohol are known to be associated with memory impairments. In this study, we used event-related potentials to examine verbal learning and memory processing in a commonly used behavioral task.

Method: We conducted two studies: first, a small pilot study of adolescent males, comprising 13 Drug-Naive Controls (DNC), 12 heavy drinkers (HD) and 8 cannabis users (CU). Second, a larger study of young adults, comprising 45 DNC (20 female), 39 HD (16 female), and 20 CU (9 female). In both studies, participants completed a modified verbal learning task (the Rey Auditory Verbal Learning Test, RAVLT) while brain electrical activity was recorded. ERPs were calculated for words which were subsequently remembered vs. those which were not remembered, and for presentations of learnt words, previously seen words, and new words in a subsequent recognition test. Pre-planned principal components analyses (PCA) were used to quantify the ERP components in these recall and recognition phases separately for each study.

Results: Memory performance overall was slightly lower than published norms using the standardized RAVLT delivery, but was generally similar and showed the expected changes over trials. Few differences in performance were observed between groups; a notable exception was markedly poorer delayed recall in HD relative to DNC (Study 2). PCA identified components expected from prior research using other memory tasks. At encoding, there were no between-group differences in the usual P2 recall effect (larger for recalled than not-recalled words). However, alcohol-related differences were observed in a larger P540 (indexing recollection) in HD than DNC, and cannabis-related differences were observed in a smaller N340 (indexing familiarity) and a lack of previously seen > new words effect for P540 in Study 2.

Conclusions: This study is the first examination of ERPs in the RAVLT in healthy control participants, as well as substance-using individuals, and represents an important advance in methodology. The results indicate alterations in recognition memory processing, which even if not manifesting in overt behavioral impairment, underline the potential for brain dysfunction with early exposure to alcohol and cannabis.

Masked repetition priming hinders subsequent recollection but not familiarity: A behavioral and event-related potential study

The present study used the masked repetition priming paradigm in the study phase and the R/K paradigm in the test phase to investigate whether repetition priming can hinder recognition memory and which recognition process (familiarity or recollection) is hindered. Event-related potentials (ERPs) in the study and test phase were recorded to explore the temporal course of how repetition priming hinders subsequent recognition memory and which old/new effect (FN400 or LPC) is affected. Converging behavioral and ERP results indicated that masked repetition priming hindered subsequent recollection but not familiarity. The analysis of ERP priming effects in the study phase indicated that primed words were associated with less negative N400 and less positive LPC compared to unprimed words. The analysis of the priming effect as a function of subsequent memory revealed that only the LPC priming effect was predictive of priming effect on subsequent memory, which suggested that the "prediction-error" account might be a possible explanation of how repetition priming affects subsequent recognition memory.

Evidence that disrupted orienting to evaluative social feedback undermines error correction in rejection sensitive women

For individuals high in Rejection Sensitivity (RS), a learned orientation to anxiously expect rejection from valued others, negative feedback from social sources may disrupt engagement with learning opportunities, impeding recovery from mistakes. One context in which this disruption may be particularly pronounced is among women high in RS following evaluation by a male in authority. To investigate this prediction, 40 college students (50% female) answered general knowledge questions followed by immediate performance feedback and the correct answer while we recorded event-related potentials. Error correction was measured with a subsequent surprise retest. Performance feedback was either nonsocial (asterisk/tone) or social (male professor's face/voice). Attention and learning were indexed respectively by the anterior frontal P3a (attentional orienting) and a set of negative-going waveforms over left inferior-posterior regions associated with successful encoding. For women, but not men, higher RS scores predicted poorer error correction in the social condition. A path analysis suggested that, for women, high RS disrupted attentional orienting to the social-evaluative performance feedback, which affected subsequent memory for the correct answer by reducing engagement with learning opportunities. These results suggest a mechanism for how social feedback may impede learning among women who are high in RS.

Age-related differences in subjective recollection: ERP studies of encoding and retrieval

The ability to mentally re-experience past events improves significantly from childhood to young adulthood; however, the mechanisms underlying this ability remain poorly understood, partially because different tasks are used across the lifespan. This study was designed to address this gap by assessing the development of event-related potential (ERP) correlates associated with subjective indices of recollection. Children, adolescents, and adults performed Tulving's () remember/know paradigm while ERPs were recorded during memory encoding (Experiment 1) and retrieval (Experiment 2). Behaviorally, children recognized fewer items than adolescents and adults. All age groups reliably made subjective judgments of recollection, although the ability to make these judgments improved with age. At encoding, the ERP effect associated with recollection was present and comparable across age groups. In contrast, the ERP effect associated with recollection at retrieval differed as a function of age group; specifically, this effect was absent in children, topographically widespread in adolescents, and, consistent with previous literature, maximal over left centro-parietal leads in adults. These findings suggest that encoding processes associated with the subsequent subjective experience of recollection may be similar among children, adolescents, and adults and that age-related improvement in recollection may be primarily attributable to the development of processes that follow the initial encoding of stimuli (i.e., consolidation, storage, retrieval).

The influence of recollection and familiarity in the formation and updating of associative representations

Prior representations affect future learning. Little is known, however, about the effects of recollective or familiarity-based representations on such learning. We investigate the ability to reuse or reassociate elements from recollection- and familiarity-based associations to form new associations. Past neuropsychological research suggests that hippocampal, and presumably recollective, representations are more flexible than extra-hippocampal, presumably familiarity-based, representations. We therefore hypothesize that the elements of recollective associations, as opposed to familiarity-based representations, may be more easily manipulated and decoupled from each other, and facilitate the formation of new associations. To investigate this hypothesis we used the AB/AC learning paradigm. Across two recall studies we observed an advantage in learning AC word pairs if AB word pairs were initially recollected. Furthermore, AB word pairs were more likely to intrude during a final AC test if those AB word pairs were initially familiarity-based. A third experiment using a recognition version of the AB/AC paradigm ruled out the possibility that our findings were due to memory strength. Our results support the idea that elements in recollective associative traces may be more discretely coded, leading to their flexible use, whereas elements in familiarity-based associative traces are less flexible.

Event-related potentials during encoding: Comparing unitization to relational processing

Context details are typically encoded into episodic memory via arbitrary associations to the relevant item, known as relational binding. Subsequent retrieval of those context details is primarily supported by recollection. Research suggests that context retrieval can rely on familiarity if the context details are "unitized" and thereby encoded as features of the item itself in a single new representation. With most investigations into unitization focusing on the contributions of familiarity and recollection during retrieval, little is known about unitization during encoding. In an effort to begin understanding unitization as an encoding process, we used event-related potentials to monitor brain activity while participants were instructed to encode words with color information using relational association or unitization. Results showed that unitization-based encoding elicited significantly more negative potentials in the left parietal region than relational encoding during presentation of the second segment of strategically-specific sentences. This difference continued through presentation of the third sentence segment, becoming less lateralized, and ended before the final two segments were presented. During the mental imagery period, unitization-based encoding elicited significantly more positive potentials than relational encoding in the first 200ms centrally and from 400 through 1000ms in left fronto-temporal and parieto-occipital regions. Our findings indicate that unitization and relational processing diverged at approximately the time that the context item was presented in the relational condition. During mental imagery, unitization diverged from relational processing immediately, suggesting that unitization affected the nature of the item representation, and possibly the brain regions involved, during memory encoding.

Electrophysiological Anomalies in Face-Name Memory Encoding in Young Binge Drinkers

A growing body of evidence indicates that the intake of large amounts of alcohol during one session may have structural and functional effects on the still-maturing brains of young people. These effects are particularly pronounced in prefrontal and hippocampal regions, which appear to be especially sensitive to the neurotoxic effects of alcohol. However, to date, few studies have used the event-related potentials (ERPs) technique to analyze the relationship between binge drinking (BD) and associative memory. The objective of this study was to examine brain activity during memory encoding using the Subsequent memory paradigm in subjects who have followed a BD pattern of alcohol consumption for at least 2 years. A total of 50 undergraduate students (mean age = 20.6 years), i.e., 25 controls (12 females) and 25 binge drinkers (BDs; 11 females), with no personal or family history of alcoholism or psychopathological disorders, performed a visual face-name association memory task. The task used enables assessment of the Difference due to memory effect (Dm), a measure of memory encoding based on comparison of the neural activity associated with subsequent successful and unsuccessful retrieval. In ERP studies, study items that are subsequently remembered elicit larger positive amplitudes at midline parieto-frontal sites than those items that are subsequently forgotten. The Dm effect generally appears in the latency range of about 300-800 ms. The results showed a Dm effect in posterior regions in the 350-650 ms latency range in the Control group. However, in the BD group, no significant differences were observed in the electrophysiological brain activity between remembered and forgotten items during the encoding process. No differences between groups were found in behavioral performance. These findings show that young BDs display abnormal pattern of ERP brain activity during the encoding phase of a visual face-name association task, possibly suggesting a different neural signature of successful memory encoding.

Mismaking Memories

Memory illusions—vivid experiences of events that never occurred—could result from inaccuracies either in retrieving memories or in initially storing them. In two experiments, people studied lists of associated words that either did or did not induce later illusory (false) memories of associated but nonpresented lure words. The amplitude of the electrical brain activity during study of words (~500-1,300 ms) that were themselves later correctly remembered reliably distinguished list words that led to such illusory memories from those that did not. This encoding difference associated with subsequent illusory memory (referred to as a DIM)—presumably reflecting item-specific encoding differences—is a neural precursor of memory illusions.

Familiarity, but not recollection, supports the between-subject production effect in recognition memory

Five experiments explored the basis of the between-subjects production effect in recognition memory as represented by differences in the recollection and familiarity of produced (read aloud) and nonproduced (read silently) words. Using remember-know judgments (Experiment 1b) and a dual-process signal-detection approach applied to confidence ratings (Experiments 2b and 3), we observed that production influences familiarity but not recollection when manipulated between-subjects. This is in contrast to within-subject designs, which reveal a clear effect of production on both recollection and familiarity (Experiments 1a and 2a). Our findings resolve contention concerning apparent design effects: Whereas the within-subject production effect is subserved by separable recollective- and familiarity-based components, the between-subjects production effect is subserved by the familiarity-based component alone. Our findings support a role for the relative distinctiveness of production as a means of guiding recognition judgments (at least when manipulated within-subjects), but we also propose that production influences the strength of produced items, explaining the persistence of the effect in between-subjects designs. (PsycINFO Database Record

Rumination and Rebound from Failure as a Function of Gender and Time on Task

Rumination is a trait response to blocked goals that can have positive or negative outcomes for goal resolution depending on where attention is focused. Whereas “moody brooding” on affective states may be maladaptive, especially for females, “reflective pondering” on concrete strategies for problem solving may be more adaptive. In the context of a challenging general knowledge test, we examined how Brooding and Reflection rumination styles predicted students’ subjective and event-related responses (ERPs) to negative feedback, as well as use of this feedback to rebound from failure on a later surprise retest. For females only, Brooding predicted unpleasant feelings after failure as the task progressed. It also predicted enhanced attention to errors through both bottom-up and top-down processes, as indexed by increased early (400–600 ms) and later (600–1000 ms) late positive potentials (LPP), respectively. Reflection, despite increasing females’ initial attention to negative feedback (i.e., early LPP), as well as both genders’ recurring negative thoughts, did not result in sustained top-down attention (i.e., late LPP) or enhanced negative feelings toward errors. Reflection also facilitated rebound from failure in both genders, although Brooding did not hinder it. Implications of these gender and time-related rumination effects for learning in challenging academic situations are discussed.

Attention demands of language production in adults who stutter

OBJECTIVE

We investigated whether language production is atypically resource-demanding in adults who stutter (AWS) versus typically-fluent adults (TFA).

METHODS

Fifteen TFA and 15 AWS named pictures overlaid with printed Semantic, Phonological or Unrelated Distractor words while monitoring frequent low tones versus rare high tones. Tones were presented at a short or long Stimulus Onset Asynchrony (SOA) relative to picture onset. Group, Tone Type, Tone SOA and Distractor Type effects on P3 amplitudes were the main focus. P3 amplitude was also investigated separately in a simple tone oddball task.

RESULTS

P3 morphology was similar between groups in the simple task. In the dual task, a P3 effect was detected in TFA in all three distractor conditions at each Tone SOA. In AWS, a P3 effect was attenuated or undetectable at the Short Tone SOA depending on Distractor Type.

CONCLUSIONS

In TFA, attentional resources were available for P3-indexed processes in tone perception and categorization in all distractor conditions at both Tone SOAs. For AWS, availability of attentional resources for secondary task processing was reduced as competition in word retrieval was resolved.

SIGNIFICANCE

Results suggest that language production can be atypically resource-demanding in AWS. Theoretical and clinical implications of the findings are discussed.

Fuzzy-Trace Theory and Lifespan Cognitive Development

Fuzzy-trace theory (FTT) emphasizes the use of core theoretical principles, such as the verbatim-gist distinction, to predict new findings about cognitive development that are counterintuitive from the perspective of other theories or of common-sense. To the extent that such predictions are confirmed, the range of phenomena that are explained expands without increasing the complexity of the theory's assumptions. We examine research on recent examples of such predictions during four epochs of cognitive development: childhood, adolescence, young adulthood, and late adulthood. During the first two, the featured predictions are surprising developmental reversals in false memory (childhood) and in risky decision making (adolescence). During young adulthood, FTT predicts that a retrieval operation that figures centrally in dual-process theories of memory, recollection, is bivariate rather than univariate. During the late adulthood, FTT identifies a retrieval operation, reconstruction, that has been omitted from current theories of normal memory declines in aging and pathological declines in dementia. The theory predicts that reconstruction is a major factor in such declines and that it is able to forecast future dementia.

The linguistic context effects on the processing of body-object interaction words: An ERP study on second language learners

Embodied theories of cognition argue that the processing of both concrete and abstract concepts requires the activation of sensorimotor systems. The present study examined the time course for embedding a sensorimotor context in order to elicit sensitivity to the sensorimotor consequences of understanding body-object interaction (BOI) words. In the study, Event-Related Potentials (ERPs) were recorded while subjects performed a sentence acceptability task. Target BOI words were preceded by rich or poor sensorimotor sentential contexts. The behavioural results replicated previous findings in that high BOI words received a response faster than low BOI words. In addition to this, however, there was a context effect in the sensorimotor region as well as a BOI effect in the parietal region (involved in object representation). The results indicate that the sentential sensorimotor context contributes to the subsequent BOI processing and that action-and perception-related language leads to the activation of the same brain areas, which is consistent with the embodiment theory.

La gestion cognitive des connaissances dans les organisations

Depuis les années 1990, le phénomène de la mondialisation s’est accéléré tandis qu’Internet et les nouvelles technologies de l’information et des communications (NTIC) ont accru considérablement la quantité d’informations à gérer. Or des recherches sur les dynamiques de traitement de l’information existent depuis plusieurs dizaines d’années en sciences cognitives et seraient très utiles en gestion des connaissances. Cet article présente un concept qui favorise la fertilisation de la gestion des connaissances par les sciences cognitives : la gestion cognitive des connaissances (GCC). La GCC vise à favoriser l’innovation, l’efficience, la communication, l’adaptation au changement, la prise de décision et la résolution de problèmes des organisations en tirant profit des connaissances de toutes leurs composantes.

Dissociating the effects of semantic grouping and rehearsal strategies on event-related brain potentials

The application of elaborative encoding strategies during learning, such as grouping items on similar semantic categories, increases the likelihood of later recall. Previous studies have suggested that stimuli that encourage semantic grouping strategies had modulating effects on specific ERP components. However, these studies did not differentiate between ERP activation patterns evoked by elaborative working memory strategies like semantic grouping and more simple strategies like rote rehearsal. Identification of neurocognitive correlates underlying successful use of elaborative strategies is important to understand better why certain populations, like children or elderly people, have problems applying such strategies. To compare ERP activation during the application of elaborative versus more simple strategies subjects had to encode either four semantically related or unrelated pictures by respectively applying a semantic category grouping or a simple rehearsal strategy. Another goal was to investigate if maintenance of semantically grouped vs. ungrouped pictures modulated ERP-slow waves differently. At the behavioral level there was only a semantic grouping benefit in terms of faster responding on correct rejections (i.e. when the memory probe stimulus was not part of the memory set). At the neural level, during encoding semantic grouping only had a modest specific modulatory effect on a fronto-central Late Positive Component (LPC), emerging around 650 ms. Other ERP components (i.e. P200, N400 and a second Late Positive Component) that had been earlier related to semantic grouping encoding processes now showed stronger modulation by rehearsal than by semantic grouping. During maintenance semantic grouping had specific modulatory effects on left and right frontal slow wave activity. These results stress the importance of careful control of strategy use when investigating the neural correlates of elaborative encoding.