Picture superiority doubly dissociates the ERP correlates of recollection and familiarity

Icono: a universal language that shows what it says

This article lays out the foundation of a new language for easier written communication that is inherently reader-friendly and inherently international. Words usually consist of strings of sounds or squiggles whose meanings are merely a convention. In Icono, instead, they typically are strings of icons that illustrate what they stand for. "Train," for example, is expressed with the icon of a train, "future" with the icon of a clock surrounded by a clockwise arrow, and "mammal" with the icons of a cow and a mouse-their combination's meaning given by what they have in common. Moreover, Icono reveals sentence structure graphically before, rather than linguistically after, one begins reading. On smartphones and computers, writing icons can now be faster than writing alphabetic words. And using simple pictures as words helps those who struggle with conditions like dyslexia, aphasia, cerebral palsy, and autism with speech impairment. Because learning its pronunciation or phonetic spelling is optional rather than a prerequisite, and because it shows what it says, Icono is bound to be easier to learn to read-and then easier to read-than any other language, including our own.

Temporal Expectation Improves Recognition Memory for Spatially Attended Objects

Recent evidence suggests that temporal expectation is beneficial to memory formation. Rhythmic presentation of stimuli during encoding enhances subsequent recognition and is associated with distinct neural activity compared with when stimuli are presented in an arrhythmic manner. However, no prior study has examined how temporal expectation interacts with another important form of facilitation-spatial attention-to affect memory. This study systematically manipulated temporal expectation and spatial attention during encoding to examine their combined effect on behavioral recognition and associated ERPs. Participants performed eight experimental blocks consisting of an encoding phase and recognition test, with EEG recorded throughout. During encoding, pairs of objects and checkerboards were presented and participants were cued to attend to the left or right stream and detect targets as quickly as possible. In four blocks, stimulus presentation followed a rhythmic (constant, predictable) temporal structure, and in the other four blocks, stimulus onset was arrhythmic (random, unpredictable). An interaction between temporal expectation and spatial attention emerged, with greater recognition in the rhythmic than the arrhythmic condition for spatially attended items. Analysis of memory-specific ERP components uncovered effects of spatial attention. There were late positive component and FN400 old/new effects in the attended condition for both rhythmic and arrhythmic items, whereas in the unattended condition, there was an FN400 old/new effect and no late positive component effect. The study provides new evidence that memory improvement as a function of temporal expectation is dependent upon spatial attention.

How do students with intellectual disabilities tell stories? An investigation of narrative macrostructure and microstructure

Individuals with intellectual disability may have limited narrative skills. The novelty of this study lies in the examination of strengths and weaknesses which may enable a more facilitative approach to narrative and other storytelling‐based methodologies among adults with intellectual disability who study in an academic enrichment program in comparison to typical students with the same chronological age. Seventeen adult students with intellectual disability and 16 typically developing students, produced narratives which were examined for microstructure (e.g., length, lexis, grammaticality, and complexity) macrostructure (e.g., goals, attempts, and outcomes) and Internal state terms (ISTs). The findings indicate that in spite of weakness of adults with intellectual disability in terms of coherence, syntactic complexity, and grammatical sentences, they exhibit strengths in narrative macrostructure story scheme and use IST. With increasing age, narratives performance of adults with intellectual disability continues to advance possibly due to maturity, life experience and indirect exposure to the environment.

Spatiotemporal Dynamics of Affective and Semantic Valence Among Women

As an important dimension of emotional assessment, valence can refer to affective valence reflecting an emotional response, or semantic valence reflecting knowledge about the nature of a stimulus. A previous study has used repeated exposure to separate these two similar cognitive processes. Here, for the first time, we compared the spatiotemporal dynamics of the affective and semantic modes of valence by combining event-related potentials with repeated exposure. Forty-seven female participants were assigned to the feeling-focused and semantic-focused groups and thereafter repeatedly viewed the pictures selected for the study. Self-report behavioral results showed that post-test scores were significantly lower than pre-test scores in the feeling-focused group, while the differences between the two tests were not significant in the semantic-focused group. At the neural level, N2 amplitudes decreased and early late positive potential amplitudes increased in both groups, suggesting that the participants perceived the repeated pictures more fluently and retrieved the traces of the stimulus spontaneously regardless of the valence they judged. However, the late positive potential amplitudes in anterior areas and the activity of the middle frontal gyrus were attenuated in the feeling-focused group; however, this component in posterior areas and the activity of the precentral gyrus were increased in the semantic-focused group. Therefore, the processes of affective and semantic valence are similar in the early stages of image perception and retrieval, while in the later stage of valence judgment, these processes show different brain activation patterns. The results provide electrophysiological evidence for the differences in psychological processes when judging the two modes of valence.

Usefulness of familiarity signals during recognition depends on test format: Neurocognitive evidence for a core assumption of the CLS framework

Familiarity-based discrimination between studied items and similar foils in yes/no recognition memory tests is relatively poor. The complementary learning systems (CLS) framework explains this with the small difference in familiarity strength between targets and foils. The framework, however, also predicts that familiarity values of targets and corresponding similar foils are directly comparable - as long as they are presented side by side in a forced-choice corresponding (FCC) test. This is because in each trial, targets tend to be more familiar than their corresponding foils. In contrast, when forced-choice displays contain non-corresponding foils (FCNC) which are similar to other studied items, familiarity values are not directly comparable (as in yes/no-tasks). In a recognition memory task with pictures of objects, we found that the putative ERP correlate of familiarity, the mid-frontal old/new effect for targets vs. foils, was significantly larger in FCC compared to FCNC displays. Moreover, single-trial target-foil amplitude differences predicted the accuracy of the recognition judgment. This study supports the assumption of the CLS framework that the test format can influence the diagnostic reliability of familiarity. Moreover, it implies that the mid-frontal old/new effect does not reflect the difference in the familiarity signal between studied and non-studied items but the task-adequate assessment of this signal.

Acute effects of naturalistic THC vs. CBD use on recognition memory: a preliminary study

The ratio of ∆9-tetrahydrocannabinol (THC) to cannabidiol (CBD) varies widely across cannabis strains. CBD has opposite effects to THC on a variety of cognitive functions, including acute THC-induced memory impairments. However, additional data are needed, especially under naturalistic conditions with higher potency forms of cannabis, commonly available in legal markets. The goal of this study was to collect preliminary data on the acute effects of different THC:CBD ratios on memory testing in a brief verbal recognition task under naturalistic conditions, using legal-market Colorado dispensary products. Thirty-two regular cannabis users consumed cannabis of differing THC and CBD levels purchased from a dispensary and were assessed via blood draw and a verbal recognition memory test both before (pretest) and after (posttest) ad libitum home administration in a mobile laboratory. Memory accuracy decreased as post-use THC blood levels increased (n = 29), whereas performance showed no relationship to CBD blood levels. When controlling for post-use THC blood levels as a covariate, participants using primarily THC-based strains showed significantly worse memory accuracy post-use, whereas subjects using strains containing both THC and CBD showed no differences between pre- and post-use memory performance. Using a brief and sensitive verbal recognition task, our study demonstrated that naturalistic, acute THC use impairs memory in a dose dependent manner, whereas the combination of CBD and THC was not associated with impairment.

Evaluating the Association of High Trait Anxiety With a Bias in Familiarity-Based Recognition of Emotional Stimuli

Abstract. In the past decades the role of cognitive biases as maintaining factors of anxiety has been widely researched. This theoretical framework assumes that vulnerability self-referential thoughts promote a hyper-vigilant mode of processing environmental stimuli. In this mode, threatening information increases attentional capture and therefore encoding and retrieval of such stimuli is enhanced. Although this attentional bias has been confirmed, the evidence concerning the memory bias is contradictory. Our hypothesis is that the bias in memory is expressed through the pattern of recognition. Particularly, the aim of this study was to evaluate the association of anxiety with familiarity, a deficient form of recognition which consists only in the identification of the item without retrieval of contextual information. Two groups of 17 participants with low and high anxiety levels performed an experimental task of visual recognition memory, using neutral, positive, and negative pictures. The experiment had two test phases, with a 24-hour interval, to evaluate possible effects of consolidation. The pattern of recognition was measured, behaviorally (through an independent Remember/Know paradigm) and through event-related potentials (ERP). Participants with higher levels of anxiety developed a bias in recognition of arousing stimuli (positive and negative) compared with the control group. This bias was observed behaviorally through an increase of familiarity-based recognition, and was associated with a positive modulation of a right parietal late positive component (LPC) at approximately 600 ms of latency. Participants with higher levels of anxiety are capable of recognizing arousing stimuli but lack efficiency in retrieving past contextual information compared to lower level anxiety participants. A recognition bias can be the first step in cognitive distortions that generate anxiety. This is, to our knowledge, the first study to explore the association of anxiety with familiarity-based recognition, using an independent Remember/Know paradigm combined with electrophysiological data. Further studies with bigger samples and more recording channels are needed to confirm the electrophysiological findings.

Is bad news on TV tickers good news? The effects of voiceover and visual elements in video on viewers’ assessment

In our experiment, we tested how exposure to a mock televised news segment, with a systematically manipulated emotional valence of voiceover, images and TV tickers (in the updating format) impacts viewers’ perception. Subjects (N = 603) watched specially prepared professional video material which portrayed the story of a candidate for local mayor. Following exposure to the video, subjects assessed the politician in terms of competence, sociability, and morality.

Results showed that positive images improved the assessment of the politician, whereas negative images lowered it. In addition, unexpectedly, positive tickers led to a negative assessment, and negative ones led to more beneficial assessments. However, in a situation of inconsistency between the voiceover and information provided on visual add-ons, additional elements are apparently ignored, especially when they are negative and the narrative is positive. We then discuss the implications of these findings.

Electrocortical indices of subjectively perceived confidence in episodic memory

Electrophysiological studies on recognition memory have identified several brain signals that are associated with subjective perceived confidence. However, the extent these brain signals reflect a generic process and are independent of the type of information recognized remains an open question. To address this issue, twenty-seven healthy volunteers performed an episodic memory task while their electro-encephalogram (EEG) was recorded. Participants encoded a set of abstract pictures, and subsequently rated their confidence on recognition decisions. Similar to results reported in previous studies using concrete words, we found retrieval-related theta power, FN400 and late positive component (LPC) effects. In contrast to previous studies using verbal material, a subsequent memory effect for encoding-related evoked theta power, sensitive to subjectively perceived memory confidence, was observed. Our findings suggest that brain signals that are associated with subjectively perceived confidence reflect specific encoding, but generic retrieval processes.

Rhythmic Temporal Structure at Encoding Enhances Recognition Memory

Presenting events in a rhythm has been shown to enhance perception and facilitate responses for stimuli that appear in synchrony with the rhythm, but little is known about how rhythm during encoding influences later recognition. In this study, participants were presented with images of everyday objects in an encoding phase before a recognition task in which they judged whether or not objects were previously presented. Blockwise, object presentation during encoding followed either a rhythmic (constant, predictable) or arrhythmic (random, unpredictable) temporal structure, of which participants were unaware. Recognition was greater for items presented in a rhythmic relative to an arrhythmic manner. During encoding, there was a differential neural activity based on memory effect with larger positivity for rhythmic over arrhythmic stimuli. At recognition, memory-specific ERP components were differentially affected by temporal structure: The FN400 old/new effect was unaffected by rhythmic structure, whereas the late positive component old/new effect was observed only for rhythmically encoded items. Taken together, this study provides new evidence that memory-specific processing at recognition is affected by temporal structure at encoding.

Listening to the Picture-Superiority Effect

The picture-superiority effect (PSE) refers to the finding that, all else being equal, pictures are remembered better than words ( Paivio & Csapo, 1973 ). Dual-coding theory (DCT; Paivio, 1991 ) is often used to explain the PSE. According to DCT, pictures are more likely to be encoded imaginally and verbally than words. In contrast, distinctiveness accounts attribute the PSE to pictures' greater distinctiveness compared to words. Some distinctiveness accounts emphasize physical distinctiveness ( Mintzer & Snodgrass, 1999 ) while others emphasize conceptual distinctiveness ( Hamilton & Geraci, 2006 ). We attempt to distinguish among these accounts by testing for an auditory analog of picture superiority. Although this phenomenon, termed the auditory PSE, occurs in free recall ( Crutcher & Beer, 2011 ), we were unable to extend it to recognition across four experiments. We propose a new framework for understanding the PSE, wherein dual coding underpins the free-recall PSE, but conceptual distinctiveness underpins the recognition PSE.

Briefly Flashed Scenes Can Be Stored in Long-Term Memory

The capacity of human memory is impressive. Previous reports have shown that when asked to memorize images, participants can recognize several thousands of visual objects in great details even with a single viewing of a few seconds per image. In this experiment, we tested recognition performance for natural scenes that participants saw for 20 ms only once (untrained group) or 22 times over many days (trained group) in an unrelated task. 400 images (200 previously viewed and 200 novel images) were flashed one at a time and participants were asked to lift their finger from a pad whenever they thought they had already seen the image (go/no-go paradigm). Compared to previous reports of excellent recognition performance with only single presentations of a few seconds, untrained participants were able to recognize only 64% of the 200 images they had seen few minutes before. On the other hand, trained participants, who had processed the flashed images (20 ms) several times, could correctly recognize 89% of them. EEG recordings confirmed these behavioral results. As early as 230 ms after stimulus onset, a significant event-related-potential (ERP) difference between familiar and new images was observed for the trained but not for the untrained group. These results show that briefly flashed unmasked scenes can be incidentally stored in long-term memory when repeated.

The production effect and the generation effect improve memory in picture naming

The production effect (better memory for words read aloud than words read silently) and the picture superiority effect (better memory for pictures than words) both improve item memory in a picture naming task (Fawcett, J. M., Quinlan, C. K., & Taylor, T. L. (2012). Interplay of the production and picture superiority effects: A signal detection analysis. Memory (Hove, England), 20(7), 655-666. doi: 10.1080/09658211.2012.693510 ). Because picture naming requires coming up with an appropriate label, the generation effect (better memory for generated than read words) may contribute to the latter effect. In two forced-choice memory experiments, we tested the role of generation in a picture naming task on later recognition memory. In Experiment 1, participants named pictures silently or aloud with the correct name or an unreadable label superimposed. We observed a generation effect, a production effect, and an interaction between the two. In Experiment 2, unreliable labels were included to ensure full picture processing in all conditions. In this experiment, we observed a production and a generation effect but no interaction, implying the effects are dissociable. This research demonstrates the separable roles of generation and production in picture naming and their impact on memory. As such, it informs the link between memory and language production and has implications for memory asymmetries between language production and comprehension.

Sentence Context and Word-Picture Cued-Recall Paired-Associate Learning Procedure Boosts Recall in Normal and Mild Alzheimer's Disease Patients

Introduction

The aim of this study was to employ the word-picture paradigm to examine the effectiveness of combined pictorial illustrations and sentences as strong contextual cues. The experiment details the performance of word recall in healthy older adults (HOA) and mild Alzheimer's disease (AD). The researchers enhanced the words' recall with word-picture condition and when the pair was associated with a sentence contextualizing the two items.

Method

The sample was composed of 18 HOA and 18 people with mild AD. Participants memorized 15 pairs of words under word-word and word-picture conditions, with and without a sentence context. In the paired-associate test, the first item of the pair was read aloud by participants and used to elicit retrieval of the associated item.

Results

The findings suggest that both HOA and mild-AD pictures improved item recall compared to word condition such as sentences which further enabled item recall. Additionally, the HOA group performs better than the mild-AD group in all conditions.

Conclusions

Word-picture and sentence context strengthen the encoding in the explicit memory task, both in HOA and mild AD. These results open a potential window to improve the memory for verbalized instructions and restore sequential abilities in everyday life, such as brushing one's teeth, fastening one's pants, or drying one's hands.

Complementarity in false memory illusions

For some years, the DRM illusion has been the most widely studied form of false memory. The consensus theoretical interpretation is that the illusion is a reality reversal, in which certain new words (critical distractors) are remembered as though they are old list words rather than as what they are-new words that are similar to old ones. This reality-reversal interpretation is supported by compelling lines of evidence, but prior experiments are limited by the fact that their memory tests only asked whether test items were old. We removed that limitation by also asking whether test items were new-similar. This more comprehensive methodology revealed that list words and critical distractors are remembered quite differently. Memory for list words is compensatory: They are remembered as old at high rates and remembered as new-similar at very low rates. In contrast, memory for critical distractors is complementary: They are remembered as both old and new-similar at high rates, which means that the DRM procedure induces a complementarity illusion rather than a reality reversal. The conjoint recognition model explains complementarity as a function of three retrieval processes (semantic familiarity, target recollection, and context recollection), and it predicts that complementarity can be driven up or down by varying the mix of those processes. Our experiments generated data on that prediction and introduced a convenient statistic, the complementarity ratio, which measures (a) the level of complementarity in memory performance and (b) whether its direction is reality-consistent or reality-reversed. (PsycINFO Database Record

Development of a tool to facilitate real life activity retraining in hand and arm therapy

Introduction

Successful recovery of upper extremity function after stroke is more likely when the affected limb is used regularly in daily life. We developed an iPad (Apple) application called the ‘Aid for Decision-Making in Occupation Choice for Hand’ to facilitate daily upper extremity use. This study examined the suitability of items and pictures in the Aid for Decision-Making in Occupation Choice for Hand, and tested a paper prototype of the application (which has since been produced).

Method

We used a Delphi method with 10 expert occupational therapists to refine the items in the aid. Next, we prepared pictures of items in the aid and confirmed their suitability by testing them with 10 patients (seven stroke, three cervical spondylotic myelopathy). Nine occupational therapists conducted field tests with a paper prototype of the aid in clinical practice to examine its utility.

Results

After four Delphi rounds, we selected 130 items representing activities of daily living, organized into 16 categories. Of 130 pictures, 128 were recognizable to patients as representing the intended activities. Based on testing of the paper prototype, we found the Aid for Decision-Making in Occupation Choice for Hand process was suitable for clinical practice, and could be organized into six steps.

Conclusion

The Aid for Decision-Making in Occupation Choice for Hand process may promote daily upper extremity use. This application, since developed, now needs to be clinically tested in its digital form.

Format change and semantic relatedness effects on the ERP correlates of recognition: old pairs, new pairs, different stories

In this event-related potential (ERP) study, we investigated the effects of format change and semantic relatedness in a recognition task using pairs composed of a word and a line drawing. The semantic relatedness of the pairs (related: rabbit-carrot; unrelated: duck-artichoke) influenced their associative properties and corresponding distinctiveness, while format change refers to the switching of an item from the verbal form to the line drawing form between study and recognition (e.g., the word "egg" is associated with a drawing of a hen at study, and a line drawing of an egg is associated with the word "hen" at test). Study-test format change thus prevents visual matching while maintaining conceptual matching. While the N300 potential was only modulated by the semantic relatedness of the pair, both factors modulated recognition performance and corresponding ERP old/new effects with larger mid-frontal N400 old/new effect (300-500 ms) and larger parietal old/new effect (500-800 ms) in the same compared to the different-format condition, as well as for related compared to unrelated pairs. Furthermore, the semantic relatedness of correctly recognized old pairs modulated the anterior N400 while it modulated the posterior N400 for correctly rejected pairs. These results suggest that semantic relatedness and familiarity related to the amount of change between study and test present distinct ERP signatures in the N400 window. They suggest also that the distinctiveness and the ease of the retrieval of the pair could be determining for the parietal old/new effect.

Recollection is delayed under changed viewing conditions: A graded effect on the latency of the late posterior component

Object recognition is a central human ability. In everyday life, the conditions under which objects have to be recognized are usually not perfect. Often, viewing conditions change in between two encounters with an object; typical are changes in illumination or in the object-observer distance. With such changes, object recognition sometimes feels slightly delayed. We examined this phenomenon empirically by measuring the latency of the well-established electrophysiological correlate of recollection, the late posterior component (LPC), in an object-recognition task. Although the cognitive processes underlying successful recognition are well examined, thus far the consequences of changed viewing conditions on the timing of these processes have not been investigated. The ERP technique is well suited for investigating this question, because it allows differentiating between processes contributing to recognition times (in particular, recollection from familiarity as indexed by the FN400 component) and measuring their time course with high temporal precision. In the present study, participants' task was to differentiate previously studied (old) objects from a set of new objects. Viewing conditions for old objects changed slightly, changed strongly, or remained identical between learning and test. We found that the latency of the LPC in response to an old object was delayed whenever viewing conditions changed. Moreover, this delay in LPC latency scaled with the size of the change. These effects were absent for the FN400. This is the first examination of effects of changes in viewing conditions on the latency of recollection and the first dissociation of FN400 and LPC latencies.

Repetition and ERPs during emotional scene processing: A selective review

A set of studies are reviewed that investigate the effects of repetition during scene perception on event-related potentials, elucidating perceptual, memory and emotional processes. Repetition suppression was consistently found for the amplitude of early frontal N2 and posterior P2 components, which was greatly enhanced for massed, compared to distributed, repetition. Both repetition suppression and enhancement of the amplitude of a centro-parietal positive potential (LPP) were found in specific contexts. Suppression was reliably found following a massive number of repetitions of few items, whereas enhancement is found when repetitions are spaced; enhancement was apparent both during simple free viewing as well as on an explicit recognition test. Regardless of repetition, an enhanced LPP was always found for emotional, compared to neutral, scenes. Taken together, the data suggest that different effects of massed and distributed repetitions on specific ERP components index perceptual priming, habituation, and spontaneous episodic retrieval.

Visual event-related potential studies supporting the validity of VARK learning styles' visual and read/write learners

The validity of learning styles needs supports of additional objective evidence. The identification of learning styles using subjective evidence from VARK questionnaires (where V is visual, A is auditory, R is read/write, and K is kinesthetic) combined with objective evidence from visual event-related potential (vERP) studies has never been investigated. It is questionable whether picture superiority effects exist in V learners and R learners. Thus, the present study aimed to investigate whether vERP could show the relationship between vERP components and VARK learning styles and to identify the existence of picture superiority effects in V learners and R learners. Thirty medical students (15 V learners and 15 R learners) performed recognition tasks with vERP and an intermediate-term memory (ITM) test. The results of within-group comparisons showed that pictures elicited larger P200 amplitudes than words at the occipital 2 site (P < 0.05) in V learners and at the occipital 1 and 2 sites (P < 0.05) in R learners. The between-groups comparison showed that P200 amplitudes elicited by pictures in V learners were larger than those of R learners at the parietal 4 site (P < 0.05). The ITM test result showed that a picture set showed distinctively more correct responses than that of a word set for both V learners (P < 0.001) and R learners (P < 0.01). In conclusion, the result indicated that the P200 amplitude at the parietal 4 site could be used to objectively distinguish V learners from R learners. A lateralization existed to the right brain (occipital 2 site) in V learners. The ITM test demonstrated the existence of picture superiority effects in both learners. The results revealed the first objective electrophysiological evidence partially supporting the validity of the subjective psychological VARK questionnaire study.

The Effects of Age on the Neural Correlates of Recollection Success, Recollection-Related Cortical Reinstatement, and Post-Retrieval Monitoring

Functional magnetic resonance imaging (fMRI) was used to investigate whether age-related differences in episodic memory performance are accompanied by a reduction in the specificity of recollected information. We addressed this question by comparing recollection-related cortical reinstatement in young and older adults. At study, subjects viewed objects and concrete words, making 1 of 2 different semantic judgments depending on the study material. Test items were words that corresponded to studied words or the names of studied objects. Subjects indicated whether each test item was recollected, familiar, or novel. Reinstatement of information differentiating the encoding tasks was quantified both with a univariate analysis of the fMRI signal and with a multivoxel pattern analysis, using a classifier that had been trained to discriminate between the 2 classes of study episode. The results of these analyses converged to suggest that reinstatement did not differ according to age. Thus, there was no evidence that specificity of recollected information was reduced in older individuals. Additionally, there were no age effects in the magnitude of recollection-related modulations in regional activity or in the neural correlates of post-retrieval monitoring. Taken together, the findings suggest that the neural mechanisms engaged during successful episodic retrieval can remain stable with advancing age.

Separating the FN400 and N400 potentials across recognition memory experiments

There is a growing debate as to whether frontally distributed FN400 potentials reflect familiarity-based recognition or are functionally identical to centro-parietal N400 reflecting semantic processing. We conducted two experiments in which event-related potentials (ERPs) associated with semantic priming and recognition were recorded, either when priming was embedded within a recognition test (Experiment 1), or when these two phases were separated (Experiment 2). In Experiment 1, we observed 300-500 ms differences between primed and unprimed old words as well as differences between old and new primed words, but these two effects did not differ topographically and both showed midline central maxima. In Experiment 2, the N400 for priming was recorded exclusively during encoding and again showed a midline central distribution. The ERP component of recognition was only found for unrelated words (not primed previously during encoding), and also showed a midline central maximum, but, in addition, was present in the left frontal area of the scalp. Conversely, the priming effect was absent in the left frontal cluster. This pattern of results indicate that FN400 and N400 potentials share similar neural generators; but when priming and recognition are not confounded, these potentials do not entirely overlap in terms of topographical distribution and presumably reflect functionally distinct processes.

Increasing N200 Potentials Via Visual Stimulus Depicting Humanoid Robot Behavior

Achieving recognizable visual event-related potentials plays an important role in improving the success rate in telepresence control of a humanoid robot via N200 or P300 potentials. The aim of this research is to intensively investigate ways to induce N200 potentials with obvious features by flashing robot images (images with meaningful information) and by flashing pictures containing only solid color squares (pictures with incomprehensible information). Comparative studies have shown that robot images evoke N200 potentials with recognizable negative peaks at approximately 260[Formula: see text]ms in the frontal and central areas. The negative peak amplitudes increase, on average, from [Formula: see text]V, induced by flashing the squares, to [Formula: see text]V, induced by flashing the robot images. The data analyses support that the N200 potentials induced by the robot image stimuli exhibit recognizable features. Compared with the square stimuli, the robot image stimuli increase the average accuracy rate by 9.92%, from 83.33% to 93.25%, and the average information transfer rate by 24.56[Formula: see text]bits/min, from 72.18[Formula: see text]bits/min to 96.74 bits/min, in a single repetition. This finding implies that the robot images might provide the subjects with more information to understand the visual stimuli meanings and help them more effectively concentrate on their mental activities.

Improvement of encoding and retrieval in normal and pathological aging with word-picture paradigm

OBJECTIVES

During the aging process, there is a progressive deficit in the encoding of new information and its retrieval. Different strategies are used in order to maintain, optimize or diminish these deficits in people with and without dementia. One of the classic techniques is paired-associate learning (PAL), which is based on improving the encoding of memories, but it has yet to be used to its full potential in people with dementia. In this study, our aim is to corroborate the importance of PAL tasks as instrumental tools for creating contextual cues, during both the encoding and retrieval phases of memory. Additionally, we aim to identify the most effective form of presenting the related items.

METHOD

Pairs of stimuli were shown to healthy elderly people and to patients with moderate and mild Alzheimer's disease. The encoding conditions were as follows: word/word, picture/picture, picture/word, and word/picture.

RESULTS

Associative cued recall of the second item in the pair shows that retrieval is higher for the word/picture condition in the two groups of patients with dementia when compared to the other conditions, while word/word is the least effective in all cases.

CONCLUSION

These results confirm that PAL is an effective tool for creating contextual cues during both the encoding and retrieval phases in people with dementia when the items are presented using the word/picture condition. In this way, the encoding and retrieval deficit can be reduced in these people.

Mental Schemas Hamper Memory Storage of Goal-Irrelevant Information

Mental schemas exert top-down control on information processing, for instance by facilitating the storage of schema-related information. However, given capacity-limits and competition in neural network processing, schemas may additionally exert their effects by suppressing information with low momentary relevance. In particular, when existing schemas suffice to guide goal-directed behavior, this may actually reduce encoding of the redundant sensory input, in favor of gaining efficiency in task performance. The present experiment set out to test this schema-induced shallow encoding hypothesis. Our approach involved a memory task in which faces had to be coupled to homes. For half of the faces the responses could be guided by a pre-learned schema, for the other half of the faces such a schema was not available. Memory storage was compared between schema-congruent and schema-incongruent items. To characterize putative schema effects, memory was assessed both with regard to visual details and contextual aspects of each item. The depth of encoding was also assessed through an objective neural measure: the parietal old/new ERP effect. This ERP effect, observed between 500–800 ms post-stimulus onset, is thought to reflect the extent of recollection: the retrieval of a vivid memory, including various contextual details from the learning episode. We found that schema-congruency induced substantial impairments in item memory and even larger ones in context memory. Furthermore, the parietal old/new ERP effect indicated higher recollection for the schema-incongruent than the schema-congruent memories. The combined findings indicate that, when goals can be achieved using existing schemas, this can hinder the in-depth processing of novel input, impairing the formation of perceptually detailed and contextually rich memory traces. Taking into account both current and previous findings, we suggest that schemas can both positively and negatively bias the processing of sensory input. An important determinant in this matter is likely related to momentary goals, such that mental schemas facilitate memory processing of goal-relevant input, but suppress processing of goal-irrelevant information.

Massed and distributed repetition of natural scenes: Brain potentials and oscillatory activity

Neural measures of repetition can result in either repetition suppression or enhancement effects, with enhancement sometimes interpreted as indicating episodic retrieval, rather than stimulus habituation. Here, we manipulated whether repetitions were massed (consecutive) or distributed (intermixed) and measured event-related potentials and oscillatory activity, investigating the question of whether there is evidence of "spontaneous" episodic retrieval for distributed, but not massed, repetition. Results showed that distributed repetition uniquely prompted a significant centroparietal old-new effect as well as enhanced theta, compared to either novel presentations or massed repetitions, consistent with a hypothesis of spontaneous retrieval. Massed repetition, on the other hand, prompted repetition suppression and reduction of the N2/P2. Taken together, the data suggest that distributed repetition may facilitate later memory performance because it spontaneously retrieves prior representations.

Sometimes we have to intentionally focus on the details: Incidental encoding and perceptual change decrease recognition memory performance and the ERP correlate of recollection

Prior studies suggest that memory retrieval is based on two independent processes: Recollection and familiarity. Here, we investigated the role of incidental and intentional encoding, and specifically whether perceptual changes between study and test affects behavioral and electrophysiological correlates of both retrieval processes. During retrieval, participants distinguished between identical and changed exemplars as well as novel distractors. Following incidental encoding, participants had difficulty identifying changed exemplars; item and feature recognition increased after intentional encoding, in particular for changed exemplars. Reflecting this increase in memory performance, the ERP correlate of recollection was larger after intentional encoding and for identical item repetitions, whereas the ERP correlate for familiarity was largely unaffected. Pre-response old/new effects corresponding to later aspects of recollection (700-1000 ms relative to stimulus onset) were larger in response-compared to stimulus-locked averages, but also of similar magnitude for identical and changed exemplars. These results corroborate previous findings suggesting that the electrophysiological signature of recollection is modulated as a function of memory performance. The role of task characteristics and material retrieved from memory for modulations in familiarity-based retrieval processes is discussed.

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.

Basic perceptual changes that alter meaning and neural correlates of recognition memory

It is difficult to pinpoint the border between perceptual and conceptual processing, despite their treatment as distinct entities in many studies of recognition memory. For instance, alteration of simple perceptual characteristics of a stimulus can radically change meaning, such as the color of bread changing from white to green. We sought to better understand the role of perceptual and conceptual processing in memory by identifying the effects of changing a basic perceptual feature (color) on behavioral and neural correlates of memory in circumstances when this change would be expected to either change the meaning of a stimulus or to have no effect on meaning (i.e., to influence conceptual processing or not). Abstract visual shapes (“squiggles”) were colorized during study and presented during test in either the same color or a different color. Those squiggles that subjects found to resemble meaningful objects supported behavioral measures of conceptual priming, whereas meaningless squiggles did not. Further, changing color from study to test had a selective effect on behavioral correlates of priming for meaningful squiggles, indicating that color change altered conceptual processing. During a recognition memory test, color change altered event-related brain potential (ERP) correlates of memory for meaningful squiggles but not for meaningless squiggles. Specifically, color change reduced the amplitude of frontally distributed N400 potentials (FN400), implying that these potentials indicated conceptual processing during recognition memory that was sensitive to color change. In contrast, color change had no effect on FN400 correlates of recognition for meaningless squiggles, which were overall smaller in amplitude than for meaningful squiggles (further indicating that these potentials signal conceptual processing during recognition). Thus, merely changing the color of abstract visual shapes can alter their meaning, changing behavioral and neural correlates of memory. These findings are relevant to understanding similarities and distinctions between perceptual and conceptual processing as well as the functional interpretation of neural correlates of recognition memory.

The time course of episodic associative retrieval: electrophysiological correlates of cued recall of unimodal and crossmodal pair-associate learning

Little is known about the time course of processes supporting episodic cued recall. To examine these processes, we recorded event-related scalp electrical potentials during episodic cued recall following pair-associate learning of unimodal object-picture pairs and crossmodal object-picture and sound pairs. Successful cued recall of unimodal associates was characterized by markedly early scalp potential differences over frontal areas, while cued recall of both unimodal and crossmodal associates were reflected by subsequent differences recorded over frontal and parietal areas. Notably, unimodal cued recall success divergences over frontal areas were apparent in a time window generally assumed to reflect the operation of familiarity but not recollection processes, raising the possibility that retrieval success effects in that temporal window may reflect additional mnemonic processes beyond familiarity. Furthermore, parietal scalp potential recall success differences, which did not distinguish between crossmodal and unimodal tasks, seemingly support attentional or buffer accounts of posterior parietal mnemonic function but appear to constrain signal accumulation, expectation, or representational accounts.

Repetition and brain potentials when recognizing natural scenes: task and emotion differences

Repetition has long been known to facilitate memory performance, but its effects on event-related potentials (ERPs), measured as an index of recognition memory, are less well characterized. In Experiment 1, effects of both massed and distributed repetition on old-new ERPs were assessed during an immediate recognition test that followed incidental encoding of natural scenes that also varied in emotionality. Distributed repetition at encoding enhanced both memory performance and the amplitude of an old-new ERP difference over centro-parietal sensors. To assess whether these repetition effects reflect encoding or retrieval differences, the recognition task was replaced with passive viewing of old and new pictures in Experiment 2. In the absence of an explicit recognition task, ERPs were completely unaffected by repetition at encoding, and only emotional pictures prompted a modestly enhanced old-new difference. Taken together, the data suggest that repetition facilitates retrieval processes and that, in the absence of an explicit recognition task, differences in old-new ERPs are only apparent for affective cues.

Using pictures and words to understand recognition memory deterioration in amnestic mild cognitive impairment and Alzheimer's disease: a review

Difficulty recognizing previously encountered stimuli is one of the earliest signs of incipient Alzheimer's disease (AD). Work over the last 10 years has focused on how patients with AD and those in the prodromal stage of amnestic mild cognitive impairment make recognition decisions for visual and verbal stimuli. Interestingly, both groups of patients demonstrate markedly better memory for pictures over words, to a degree that is significantly greater in magnitude than their healthy older counterparts. Understanding this phenomenon not only helps to conceptualize how memory breaks down in AD, but also potentially provides the basis for future interventions. This review critically examines recent recognition memory work using pictures and words in the context of the dual-process theory of recognition and current hypotheses of cognitive breakdown in the course of very early AD.

Identical versus conceptual repetition FN400 and parietal old/new ERP components occur during encoding and predict subsequent memory

This Event-Related Potential (ERP) study investigated whether components commonly measured at test, such as the FN400 and the parietal old/new components, could be observed during encoding and, if so, whether they would predict different levels of accuracy on a subsequent memory test. ERPs were recorded while subjects classified pictures of objects as man-made or natural. Some objects were only classified once, while others were classified twice during encoding, sometimes with an identical picture, and other times with a different exemplar from the same category. A subsequent surprise recognition test required subjects to judge whether each probe word corresponded to a picture shown earlier, and if so whether there were two identical pictures that corresponded to the word probe, two different pictures, or just one picture. When the second presentation showed a duplicate of an earlier picture, the FN400 effect (a significantly less negative deflection on the second presentation) was observed regardless of subsequent memory response; however, when the second presentation showed a different exemplar of the same concept, the FN400 effect was only marginally significant. In contrast, the parietal old/new effect was robust for the second presentation of conceptual repetitions when the test probe was subsequently recognized, but not for identical repetitions. These findings suggest that ERP components that are typically observed during an episodic memory test can be observed during an incidental encoding task, and that they are predictive of the degree of subsequent memory performance.

Electrophysiological distinctions between recognition memory with and without awareness

The influence of implicit memory representations on explicit recognition may help to explain cases of accurate recognition decisions made with high uncertainty. During a recognition task, implicit memory may enhance the fluency of a test item, biasing decision processes to endorse it as "old". This model may help explain recognition-without-identification, a remarkable phenomenon in which participants make highly accurate recognition decisions despite the inability to identify the test item. The current study investigated whether recognition-without-identification for pictures elicits a similar pattern of neural activity as other types of accurate recognition decisions made with uncertainty. Further, this study also examined whether recognition-without-identification for pictures could be attained by the use of perceptual and conceptual information from memory. To accomplish this, participants studied pictures and then performed a recognition task under difficult viewing conditions while event-related potentials (ERPs) were recorded. Behavioral results showed that recognition was highly accurate even when test items could not be identified, demonstrating recognition-without-identification. The behavioral performance also indicated that recognition-without-identification was mediated by both perceptual and conceptual information, independently of one another. The ERP results showed dramatically different memory related activity during the early 300 to 500ms epoch for identified items that were studied compared to unidentified items that were studied. Similar to previous work highlighting accurate recognition without retrieval awareness, test items that were not identified, but correctly endorsed as "old," elicited a negative posterior old/new effect (i.e., N300). In contrast, test items that were identified and correctly endorsed as "old," elicited the classic positive frontal old/new effect (i.e., FN400). Importantly, both of these effects were elicited under conditions when participants used perceptual information to make recognition decisions. Conceptual information elicited very different ERPs than perceptual information, showing that the informational wealth of pictures can evoke multiple routes to recognition even without awareness of memory retrieval. These results are discussed within the context of current theories regarding the N300 and the FN400.

Neurophysiological evidence for a recollection impairment in amnesia patients that leaves familiarity intact

In several previous behavioral studies, we have identified a group of amnestic patients that, behaviorally, appear to exhibit severe deficits in recollection with relative preservation of familiarity-based recognition. However, these studies have relied exclusively on behavioral measures, rather than direct measures of physiology. Event-related potentials (ERPs) have been used to identify putative neural correlates of familiarity- and recollection-based recognition memory, but little work has been done to determine the extent to which these ERP correlates are spared in patients with relatively specific memory disorders. ERP studies of recognition in healthy subjects have indicated that recollection and familiarity are related to a parietal old-new effect characterized as a late positive component (LPC) and an earlier mid-frontal old-new effect referred to as an 'FN400', respectively. Here, we sought to determine the extent to which the putative ERP correlates of recollection and familiarity are intact or impaired in these patients. We recorded ERPs in three amnestic patients and six age matched controls while they made item recognition and source recognition judgments. The current patients were able to discriminate between old and new items fairly well, but showed nearly chance-level performance at source recognition. Moreover, whereas control subjects exhibited ERP correlates of memory that have been linked to recollection and familiarity, the patients only exhibited the mid-frontal FN400 ERP effect related to familiarity-based recognition. The results show that recollection can be severely impaired in amnesia even when familiarity-related processing is relatively spared, and they also provide further evidence that ERPs can be used to distinguish between neural correlates of familiarity and recollection.

Memorial familiarity remains intact for pictures but not for words in patients with amnestic mild cognitive impairment

Understanding how memory breaks down in the earliest stages of Alzheimer's disease (AD) process has significant implications, both clinically and with respect to intervention development. Previous work has highlighted a robust picture superiority effect in patients with amnestic mild cognitive impairment (aMCI). However, it remains unclear as to how pictures improve memory compared to words in this patient population. In the current study, we utilized receiver operating characteristic (ROC) curves to obtain estimates of familiarity and recollection for pictures and words in patients with aMCI and healthy older controls. Analysis of accuracy shows that even when performance is matched between pictures and words in the healthy control group, patients with aMCI continue to show a significant picture superiority effect. The results of the ROC analysis showed that patients demonstrated significantly impaired recollection and familiarity for words compared controls. In contrast, patients with aMCI demonstrated impaired recollection, but intact familiarity for pictures, compared to controls. Based on previous work from our lab, we speculate that patients can utilize the rich conceptual information provided by pictures to enhance familiarity, and perceptual information may allow for post-retrieval monitoring or verification of the enhanced sense of familiarity. Alternatively, the combination of enhanced conceptual and perceptual fluency of the test item might drive a stronger or more robust sense of familiarity that can be accurately attributed to a studied item.

Examining ERP correlates of recognition memory: evidence of accurate source recognition without recollection

Recollection is typically associated with high recognition confidence and accurate source memory. However, subjects sometimes make accurate source memory judgments even for items that are not confidently recognized, and it is not known whether these responses are based on recollection or some other memory process. In the current study, we measured event related potentials (ERPs) while subjects made item and source memory confidence judgments in order to determine whether recollection supported accurate source recognition responses for items that were not confidently recognized. In line with previous studies, we found that recognition memory was associated with two ERP effects: an early on-setting FN400 effect, and a later parietal old-new effect [late positive component (LPC)], which have been associated with familiarity and recollection, respectively. The FN400 increased gradually with item recognition confidence, whereas the LPC was only observed for highly confident recognition responses. The LPC was also related to source accuracy, but only for items that had received a high confidence item recognition response; accurate source judgments to items that were less confidently recognized did not exhibit the typical ERP correlate of recollection or familiarity, but rather showed a late, broadly distributed negative ERP difference. The results indicate that accurate source judgments of episodic context can occur even when recollection fails.