ERP profiles for face and word recognition are based on their status in semantic memory not their stimulus category

Sensitivity of late ERP old/new effects in source memory to self-referential encoding focus and stimulus emotionality

In episodic memory, the old/new effect, the contrast of the waveforms elicited by the correctly recognized studied items and the correctly rejected novel items, has been broadly concerned. However, the contribution of self-referential encoding to the old/new effect in source memory (i.e., source-SRE), is far from clarification; further, it remains unclear whether the contribution is susceptible to the factor of stimulus emotionality. To address these issues, adopting the event-related potential (ERP) technique, this study applied words of three types of emotional valences (positive, neutral, vs. negative) in the self-focus vs. external-focus encoding tasks. In the course of the test, four ERP old/new effects were identified: (a) the familiarity- and recollection-reflected mid-frontal effect (FN400) and late positive component (LPC) were both independent of source-SRE and stimulus emotionality; (b) the reconstruction-driven late posterior negativity (LPN) exhibited an adverse pattern of source-SRE and was susceptible to the emotional valence by encoding focus; and (c) the right frontal old/new effect (RFE), reflecting post-retrieval process, exhibited a source-SRE in emotional words. These effects provide compelling evidence for the influences of both stimulus valence and encoding focus on SRE in source memory, especially during the late processes. Further directions considering more perspectives are put forward.

Differentiation of the Contribution of Familiarity and Recollection to the Old/New Effects in Associative Recognition: Insight from Semantic Relation

Previous research has revealed two different old/new effects, the early mid-frontal old/new effect (a.k.a., FN400) and the late parietal old/new effect (a.k.a., LPC), which relate to familiarity and recollection processes, respectively. Although associative recognition is thought to be more based on recollection, recent studies have confirmed that familiarity can make a great contribution when the items of a pair are unitized. However, it remains unclear whether the old/new effects are sensitive to the nature of different semantic relations. The current ERP (event-related potentials) study aimed to address this, where picture pairs of thematic, taxonomic, and unrelated relations served as stimuli and participants were required to discriminate the pair type: intact, rearranged, “old + new”, or new. We confirmed both FN400 and LPC. Our findings, by comparing the occurrence and the amplitudes of these two components, implicate that the neural activity of associative recognition is sensitive to the semantic relation of stimuli and depends more on stimulus properties, that the familiarity of a single item can impact the neural activities in discriminating associative pairs, and that the interval length between encoding and test modulates the familiarity of unrelated pairs. In addition, the dissociation between FN400 and LPC reinforces the dual-process models.

How Processing Fluency Contributes to the Old/New Effects of Familiarity and Recollection: Evidence From the Remember/Know Paradigm

Previous investigations have demonstrated FN400 and LPC, 2 event-related potential old/new effects that respectively reflect familiarity- and recollection-based processes in memory. However, it is unclear whether these effects are susceptible to processing fluency, particularly different types of processing fluency. To address this issue, applying a masked priming paradigm, we conducted an event-related potential experiment by manipulating semantic relations between the prime and the target as identical (reflecting perceptual fluency), thematically and taxonomically related (referring to conceptual fluency), and unrelated. A remember/know (R/K) judgment task in the test phase was used to distinguish familiarity- and recollection-based processes. Behaviorally, both task performance and response speed were modulated by the variables of priming condition, item type, and response type. All 4 priming conditions elicited significant FN400 and LPC. Compared with the K response, the R response was more relevant to the recollection-based processes reflected by LPC. Both FN400 and LPC were modulated by whether there was a response of R, K, or new. The former was susceptible only to conceptual fluency, and the latter was sensitive to both perceptual fluency and conceptual fluency, which offered telling evidence for the dual process model. Considerations for future investigations are proposed. See supplemental materials here: https://www.press.uillinois.edu/journals/ajp/media/evidence_in_remember_know_paradigm/

ERP Characteristics of Inducing Rule Validity in Number Series Under Time Pressure

A great deal of research has been devoted to examining the neural mechanisms of inductive reasoning. However, the influences of rule validity and time pressure on numerical inductive reasoning remain unclear. In the current study, we aimed to examine the effects of these variables on the time course of rule identification in numerical inductive reasoning. We designed a 3 (task type: valid, invalid, and anomalous) × 2 (time pressure: with time pressure and without time pressure) within-subject experiment based on electroencephalographic event-related potentials (ERP). Behaviorally, we found significant effects of rule validity and time pressure on rule identification. Neurologically, we considered the elicited N200 ERP to reflect conflict detection and found it to be modulated by rule validity but not time pressure. We considered the induced P300 ERP to be primarily related to updating working memory, affected by both rule validity and time pressure. These findings have new implications for better understanding dynamic information processing within numerical inductive reasoning.

The influence of item familiarization on neural discriminability during associative memory encoding and retrieval

Associative memory requires one to encode and form memory representations not just for individual items, but for the association or link between those items. Past work has suggested that associative memory is facilitated when individual items are familiar rather than simultaneously learning the items and their associative link. The current study employed multivoxel pattern analyses (MVPA) to investigate whether item familiarization prior to associative encoding affects the distinctiveness of neural patterns, and whether that distinctiveness is also present during associative retrieval. Our results suggest that prior exposure to item stimuli impacts the representations of their shared association compared to stimuli that are novel at the time of associative encoding throughout most of the associative memory network. While this distinction was also present at retrieval, the overall extent of the difference was diminished. Overall the results suggest that stimulus familiarity influences the representation of associative pairings during memory encoding and retrieval, and the pair-specific representation is maintained across memory phases irrespective of this distinction.

The influence of negative emotional intensity on dual-processing recognition

Dual-processing theory assumes recognition memory involves two distinct processes: familiarity and recollection. Although the influence of emotional intensity on memory has been investigated, it remains unclear whether the influence of negative stimuli depends on familiarity or recollection. This study recorded event-related potentials as participants performed a modified remember/know procedure with highly negative, mildly negative, and neutral stimuli. The results showed that, relative to highly negative stimuli, mildly negative and neutral stimuli showed increased mean discrimination for responses of 'know' in the following pattern: highly negative < mildly negative < neutral. Neutral stimuli enhanced the frontal old/new effect. Relative to mildly negative and neutral stimuli, highly negative stimuli showed increased mean discrimination for responses of 'remember', and enhanced the parietal old/new effect. These results suggested negative emotional intensity influences recollection and familiarity differently, as recognition of highly negative stimuli depends on recollection, and recognition of neutral stimuli depends on familiarity.

Is color source retrieval sensitive to emotion? Electrophysiological evidence from old/new effects

It has been proved that item memory and source memory are two dissociable processes, as reflected by differential influence at behavioral and electrophysiological levels, the latter being evidenced by the ERP old/new effects. Specially for source memory, the retrieval of color source may be unique from recollecting other types of contextual information, which can be seen from the late posterior negativity (LPN). However, the mediation of emotional valence on the old/new effects for verbal stimuli encoded in colors remains unknown. Adopting words of three emotional valences (i.e., positive, neutral, and negative), with their displayed colors serving as sources, the current experiment aimed to explore the sensitivity of old/new effects to emotion for both item memory and source memory. Results demonstrated that: the FN400 that reflects familiarity was recorded and it was sensitive to emotional valence across both memory tasks; the mediation of emotional valence was absent in recollection-reflected LPC, neither for item memory nor for source memory; an association between LPN and color source retrieval was confirmed, with reliable amplitudes for neutral words but not for emotional words. These data were discussed in terms of the dual-process model and other accounts. Future research directions were recommended.

External (Versus Internal) Facial Features Contribute Most to Repetition Priming in Facial Recognition: ERP Evidence

Previous event-related potential (ERP) research demonstrated four successive ERP components in the repetition priming of human face recognition: P100, N170, N250r, and N400. While these components correspond, respectively, to the four stages proposed by the interactive activation and competition (IAC) model, there has been no emphasis in past research on how internal and external facial features affect repetition priming and the sensitivity of these ERP components to item interval. This study was designed to address these issues. We used faces of celebrities as targets, including completely familiar faces, familiar internal feature faces, and familiar external feature faces. We displayed a target face either immediately following its prime (immediate repetition) or after a delay with interference from a presentation of two other faces (delayed repetition). ERP differences at P100 and N170 were nearly statistically non-significant; familiar faces and familiar external feature faces were associated with reliable ERP signals of N250r and N400 in the immediate repetition condition. For delayed repetition, however, N250r and N400 signals were only preserved for the familiar external feature faces. The differences of these ERP components suggest that, compared with internal facial features, external features of a previously presented face contribute more to brain-based facial repetition priming, particularly during the last two stages of the IAC model.

Unitization of internal and external features contributes to associative recognition for faces: Evidence from modulations of the FN400

Associative recognition requires discriminating between old items and conjunction lures constructed by recombining elements from two different study items. This task can be solved not only by recollection but also by familiarity if the to-be-remembered stimuli are perceived as a unitized representation. In two event-related potential (ERP) studies, we provide evidence for the integration of internal and external facial features by showing that the early frontal old-new effect (considered a correlate of familiarity) is modulated by the specific combination of facial features. Participants studied faces consisting of internal features (eyes, eyebrows, nose, and mouth) paired with external features (hair, head shape, and ears). During the testing phase, intact, recombined, and new faces were presented. Recombined faces consisted of internal and external features taken from two different studied faces. The results showed that at the frontal sites, during the time window from 300 to 500 ms, ERPs to intact faces were more positive than those to new and recombined faces; the latter two did not differ from one another. The late parietal effect was observed only after a more extended study phase in Experiment 2. We take the modulation of the early frontal old-new effect as evidence for the contribution of familiarity to associative recognition for combinations of internal and external facial features.

Sensitivity of Reality Monitoring to Fluency: Evidence from Behavioral Performance and Event-Related Potential (ERP) Old/New Effects

Background

Item memory and source memory are differently processed with both behavioral and event-related potential (ERP) evidence. Reality monitoring, a specific type of source memory, which refers to the ability to differentiate external sources from internal sources, has been drawing much attention. Among factors that have an impact on reality monitoring, fluency has not been well-studied. Therefore, the current study aimed to investigate whether fluency could affect reality monitoring, through observations on both behavioral performance and electrophysiological patterns.

Material/Methods

Adopting ERP techniques, participants were required either to watch the presentation of a name/picture pair, or to imagine a picture for each displayed name, once (low fluency) or twice (high fluency). Later they completed a reality monitoring task of identifying names as perceived, imagined, or novel items. Behavioral performance was measured, and ERP waveforms were recorded.

Results

Behaviorally, high fluency items were faster and more accurately attributed to the sources than low fluency items. ERP waveforms revealed that late positive component (LPC) occurred for all 4 types of items, while imagined items of low fluency did not record a robust FN400 or late frontal old/new effect.

Conclusions

As results revealed, the factor of fluency does influence reality monitoring in terms of accuracy and responding speed. Meanwhile, for imagined items of low fluency, the absence of FN400 and frontal old/new effect also suggests the sensitivity of reality monitoring to fluency, because these representatives of familiarity-based processing and post-retrieval monitoring are inevitably involved in the process of differentiating internal source from external source.

How do word frequency and memory task influence directed forgetting: An ERP study

In daily life, it is important either to remember sometimes or to intentionally forget on other occasions. The issue of forgetting following instructions (i.e. directed forgetting, DF) has been broadly studied; however, whether the frequency of contents would matter in DF remains unclear, and the understanding of its neural mechanism in both circumstances of item memory and source memory requires improvement in depth. For these purposes, the current study manipulated word frequency and memory task to investigate relevant behavioral features and neural activities of DF. Adopting event-related potential (ERP) technique, this study applied two-character Chinese words of two types of word frequency (high vs low) in the item-method DF paradigm. During encoding, we found that the increased frontal positivity, an index of active inhibition, was regulated by both word frequency and memory task, while the enhanced parietal positivity reflecting selective rehearsal didn't fluctuate across conditions. In the course of test, three ERP old/new effects were identified: the familiarity-based FN400 and the recollection-driven LPC were both modulated by word frequency and memory task, but the right frontal old/new effect was significant solely in source memory; also, these effects provided compelling evidence for the influences of word frequency and memory task on DF. Our results reinforce the differentiation between absolute familiarity and relative familiarity in memory, reveal their sensitivity to DF, and also support the dual-process interpretation. Implications are made to examine more influential factors for future research.

Influence of lag length on repetition priming in emotional stimuli: ERP evidence

BACKGROUND

Previous studies have demonstrated both behavioral and neural evidence for the potential mediations of lag length and pre-existing memory representation on repetition priming. However, such mediations on emotional stimuli have not been described.

METHODS

The current experiment intended to disentangle lag length from pre-existing memory representation. A lexical decision task was performed, in which different emotional characters (either normal or transposed) were re-presented either immediately or delayed.

RESULTS

In immediate repetition, one early and two late (ie, N400 and late positive complex) repetition-related event-related potential (ERP) effects were elicited, but these were not sensitive to pre-existing memory representation. The delayed repetition case merely observed the N400.

CONCLUSION

These results suggest that the repetition-related priming effect is neutrally sensitive to lag length. Emotional information potentially exerts early and later influences in the processing underlying stimuli memory.

An item's status in semantic memory determines how it is recognized: Dissociable patterns of brain activity observed for famous and unfamiliar faces

Are all faces recognized in the same way, or does previous experience with a face change how it is retrieved? Previous research using human scalp-recorded Event-Related Potentials (ERPs) demonstrates that recognition memory can produce dissociable brain signals under a variety of circumstances. While many studies have reported dissociations between the putative ‘dual processes’ of familiarity and recollection, a growing number of reports demonstrate that recollection itself may be fractionated into component processes. Many recognition memory studies using lexical materials as stimuli have reported a left parietal ERP old/new effect for recollection; however, when unfamiliar faces are recollected, an anterior effect can be observed. This paper addresses two separate hypotheses concerning the functional significance of the anterior old/new effect: perceptual retrieval and semantic status. The perceptual retrieval view is that the anterior effect reflects reinstatement of perceptual information bound up in an episodic representation, while the semantic status view is that information not represented in semantic memory pre-experimentally elicits the anterior effect instead of the left parietal effect. We tested these two competing accounts by investigating recognition memory for unfamiliar faces and famous faces in two separate experiments, in which same or different pictures of studied faces were presented as test items to permit brain activity associated with retrieving face and perceptual information to be examined independently. The difference in neural activity between same and different picture hits was operationalized as a pattern of activation associated with perceptual retrieval; while the contrast between different picture hits and correct rejection of new faces was assumed to reflect face retrieval. In Experiment 1, using unfamiliar faces, the anterior old/new effect (500–700 ms) was observed for face retrieval but not for perceptual retrieval, challenging the perceptual retrieval hypothesis. In Experiment 2, using famous faces, face retrieval was associated with a left parietal effect (500–700 ms), supporting the semantic representation hypothesis. A between-subjects analysis comparing scalp topography across the two experiments found that the anterior effect observed for unfamiliar faces is dissociable from the left parietal effect found for famous faces. This pattern of results supports the hypothesis that an item's status in semantic memory determines how it is recognized.

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Famous faces are recognized more easily than unfamiliar faces.

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Left parietal ERP old/new effect is observed for famous faces.

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Anterior ERP old/new effect is observed for unfamiliar faces.

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Semantic status determines how faces are recognized.

Auditory enhancement of visual memory encoding is driven by emotional content of the auditory material and mediated by superior frontal cortex

BACKGROUND

The aim of the present study was to investigate how auditory background interacts with learning and memory. Both facilitatory (e.g., "Mozart effect") and interfering effects of background have been reported, depending on the type of auditory stimulation and of concurrent cognitive tasks.

METHOD

Here we recorded event related potentials (ERPs) during face encoding followed by an old/new memory test to investigate the effect of listening to classical music (Čajkovskij, dramatic), environmental sounds (rain) or silence on learning. Participants were 15 healthy non-musician university students. Almost 400 (previously unknown) faces of women and men of various age were presented.

RESULTS

Listening to music during study led to a better encoding of faces as indexed by an increased Anterior Negativity. The FN400 response recorded during the memory test showed a gradient in its amplitude reflecting face familiarity. FN400 was larger to new than old faces, and to faces studied during rain sound listening and silence than music listening.

CONCLUSION

The results indicate that listening to music enhances memory recollection of faces by merging with visual information. A swLORETA analysis showed the main involvement of Superior Temporal Gyrus (STG) and medial frontal gyrus in the integration of audio-visual information.

Elements of person knowledge: Episodic recollection helps us to identify people but not to recognize their faces

Faces automatically draw attention, allowing rapid assessments of personality and likely behaviour. How we respond to people is, however, highly dependent on whether we know who they are. According to face processing models person knowledge comes from an extended neural system that includes structures linked to episodic memory. Here we use scalp recorded brain signals to demonstrate the specific role of episodic memory processes during face processing. In two experiments we recorded Event-Related Potentials (ERPs) while participants made identify, familiar or unknown responses to famous faces. ERPs revealed neural signals previously associated with episodic recollection for identify but not familiar faces. These findings provide novel evidence suggesting that recollection is central to face processing, providing one source of person knowledge that can be used to moderate the initial impressions gleaned from the core neural system that supports face recognition.

Lag-length effect on repetition priming of famous and unfamiliar faces: evidence from N250r and N400

Previous event-related potentials research has reliably identified two repetition priming components in faces, the N250r and the N400, which are believed to reflect, respectively, the accessing to the stored structural representations and the semantic retrieval. However, the effect of lags longer than immediate repetition and shorter than 3 min on the two components has not been described as yet, and the interaction between lag length and familiarity is unclear. The current experiment aims to address these issues. In this experiment, famous and unfamiliar faces were represented after short, medium, or long lags, and participants were required to decide whether each face was known or not. The data showed that the frontal N250r, rather than the temporal counterpart, persisted to the medium lag case for famous faces; for unfamiliar faces, no N250r was observed. The frontal N400 was more regulated by lag length than the centroparietal counterpart. These results suggest that the frontal N250r and the frontal N400 are affected by the lag length; moreover, the former is more sensitive to the pre-experimental familiarity of faces.

Association between polymorphisms in NOS3 and KCNH2 and social memory

Social memory, including the ability to recognize faces and voices, is essential for social relationships. It has a large heritable component, but the knowledge about the contributing genes is sparse. The genetic variation underlying inter-individual differences in social memory was investigated in an exploratory sample (n = 55), genotyped with a chip comprising approximately 200,000 single nucleotide polymorphisms (SNPs), and in a validation sample (n = 582), where 30 SNPs were targeted. In the exploratory study face identity recognition was measured. The validation study also measured vocal sound recognition, as well as recognition of faces and vocal sounds combined (multimodal condition). In the exploratory study, the 30 SNPs that were associated with face recognition at p_uncorrected < 0.001 and located in genes, were chosen for further study. In the validation study two of these SNPs showed significant associations with recognition of faces, vocal sounds, and multimodal stimuli: rs1800779 in the gene encoding nitric oxide synthase 3 (NOS3) and rs3807370 in the gene encoding the voltage-gated channel, subfamily H, member 2 (KCNH2), in strong linkage disequilibrium with each other. The uncommon alleles were associated with superior performance, and the effects were present for men only (p < 0.0002). The exploratory study also showed a weaker but significant association with (non-emotional) word recognition, an effect that was independent of the effect on face recognition. This study demonstrates evidence for an association between NOS3 and KCNH2 SNPs and social memory.

Internal versus external features in triggering the brain waveforms for conjunction and feature faces in recognition

Previous research has found that conjunction faces (whose internal features, e.g. eyes, nose, and mouth, and external features, e.g. hairstyle and ears, are from separate studied faces) and feature faces (partial features of these are studied) can produce higher false alarms than both old and new faces (i.e. those that are exactly the same as the studied faces and those that have not been previously presented) in recognition. The event-related potentials (ERPs) that relate to conjunction and feature faces at recognition, however, have not been described as yet; in addition, the contributions of different facial features toward ERPs have not been differentiated. To address these issues, the present study compared the ERPs elicited by old faces, conjunction faces (the internal and the external features were from two studied faces), old internal feature faces (whose internal features were studied), and old external feature faces (whose external features were studied) with those of new faces separately. The results showed that old faces not only elicited an early familiarity-related FN400, but a more anterior distributed late old/new effect that reflected recollection. Conjunction faces evoked similar late brain waveforms as old internal feature faces, but not to old external feature faces. These results suggest that, at recognition, old faces hold higher familiarity than compound faces in the profiles of ERPs and internal facial features are more crucial than external ones in triggering the brain waveforms that are characterized as reflecting the result of familiarity.