ERP indices of emotionality and semantic cohesiveness during recognition judgments

Event-related potentials (ERPs) were used to examine the impact of emotionality on false recognition. In Experiment 1, participants discriminated previously studied words from neutral and negatively valenced emotional foils. Emotional words elicited a more positive ERP than did neutral words and emotional foils were falsely recognized more often than neutral foils. In Experiment 2, the hypothesis that emotionality-based false recognition is due to the semantic cohesiveness of emotional words was tested by including a highly associated but emotionally neutral category (animals). It was emotional and not animal foils that elicited greater positivity in the ERP and increased false positive response. These data provide little support for semantic cohesiveness as the basis for false recognition effects, but are consistent with the view that the salience of emotional words can be falsely attributed to familiarity in the context of a recognition task.     

True and false memories in adolescents with psychosis: Evidence for impaired recollection and familiarity

Introduction. Psychotic patients are impaired on recall and recognition of studied items (true memory) and typically make more false recall (intrusions) and false recognition than controls, reflecting greater susceptibility to false memory. The functional mechanisms underlying these deficits are poorly understood. The aim of this study was to examine recollection and familiarity in true and false memory in psychotic adolescents without long-term exposure to medication and repeated hospitalisations.

Methods. Seventeen adolescents with psychosis and 17 matched controls were tested on a DRM false memory paradigm combined with a remember (R)/know (K)/guess (G) procedure. Recall and recognition of targets (studied words), critical lures (associated words) and unrelated distractors were measured. Between-group comparisons were made using t-tests and mixed ANOVAs. Independent estimates for recollection and familiarity were also calculated.

Results. True memory was impaired in patients. Similar rates of false memory for critical lures were found in both groups. False memory for unrelated distractors was increased in patients. Contrary to controls, who attributed more R and K responses to targets than lures, patients attributed similar proportions of R and K responses to targets and lures. Furthermore, patients attributed more K responses than controls to all distractors.

Conclusions. These findings suggest a deficit in recollection- and familiarity-based memory in psychotic adolescents as well as reliance on preserved gist or meaning-based memory to support poor item-specific memory.     

Effects of multiple study–test repetition on the neural correlates of recognition memory: ERPs dissociate remembering and knowing

Event-related potential (ERP) frontal (300–500 ms) and parietal (500–700 ms) episodic memory (EM) effects are thought to reflect, respectively, familiarity and recollection. However, as most ERP studies use preexperimentally familiar items, an alternative idea is that the frontal EM effect reflects conceptual priming. Repetition of unnameable symbols was used to assess modulations of the putative ERP indices of familiarity and recollection. The same symbols were viewed in each of 4 study/test blocks. Increases in familiarity and conceptual processing of symbols did not modulate the frontal EM effect, suggesting that it reflects neither familiarity nor conceptual priming. The magnitude of the parietal EM effect increased and its onset latency decreased across tests for items given remember (R) but not know (K) judgments. R and K old–new topographies differed. These findings support dual-process proposals that familiarity- and recollection-based processes are distinct.     

Age‐related changes in ERP correlates of visuospatial and motor processes

Although previous ERP studies have demonstrated slowing of visuospatial and motor processes with age, such studies frequently included only young and elderly participants, and lacked information about age‐related changes across the adult lifespan. The present research used a Simon task with two irrelevant dimensions (position and direction of an arrow) to study visuospatial (N2 posterior contralateral, N2pc) and motor (response‐locked lateralized readiness potential, LRP‐r) processes in young, middle‐aged, and elderly adults. The reaction time and motor execution stage (LRP‐r) increased gradually with age, while visuospatial processes (N2pc latency) were similarly delayed in the older groups. No age‐related increase in interference was observed, probably related to a delay in processing the symbolic meaning of the direction in older groups, which was consistent with age‐related differences in distributional analyses and N2pc amplitude modulations.     

Interfacing mind and brain: a neurocognitive model of recognition memory

A variety of processes contribute to successful recognition memory, some of which can be associated with spatiotemporally distinct event-related potential old/new effects. An early frontal and a subsequent parietal old/new effect are correlated with the familiarity and recollection subcomponents of recognition memory, respectively, whereas a late, postretrieval old/new effect seems to reflect an ensemble of evaluation processes that are set by the task context in which retrieval occurs. Both the early frontal and the parietal old/new effects are differentially modulated by the informational content (e.g., object forms and spatial locations) of recognition and seem to rely on brain systems damaged in amnesia. The late frontal effect appears to reflect prefrontal cortex activation. A neurophysiologically based model of recognition memory retrieval is presented and it is shown that coupling recognition memory subprocesses with distinct old/new effects allow examination of the time course of the processes that contribute to correct and to illusory memories. In conjunction with event-related functional magnetic resonance imaging activation patterns the brain systems recruited by various aspects of episodic memory retrieval can be identified.     

Neural correlates of visual recognition in 3-month-old infants: the role of experience

Early experiences contribute powerfully to the development of neural systems that underlie various perceptual and cognitive abilities in humans. In one of the first studies to systematically control infants' exposure to a familiar object, we examined the effects of controlled experience on the neural correlates of visual recognition in two groups of infants. One group received 1 month of in‐home familiarization to a 3D model of a female face. Another group received 1.5 min of in‐lab familiarization to the 3D model of a female face, creating two conditions that differed in the amount and, importantly, the context of exposure to a familiar stimulus. Following familiarization, event‐related potentials (ERPs) were recorded at 3 months of age while infants viewed pictures of the familiar face and an unfamiliar face. Results demonstrated that while both groups of infants discriminated between the familiar and unfamiliar faces, the pattern of neural processing was reversed for the two groups. Thus, the amount and context of visual exposure altered the neural correlates of recognition processes in young infants. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 53:416–424, 2011.     

Age-related differences in neural correlates of face recognition during the toddler and preschool years

Research on the development of face recognition in infancy has shown that infants respond to faces as if they are special and recognize familiar faces early in development. Infants also show recognition and differential attachment to familiar people very early in development. We tested the hypothesis that infants' responses to familiar and unfamiliar faces differ at different ages. Specifically, we present data showing age-related changes in infants' brain responses to mother's face versus a stranger's face in children between 18 and 54 months of age. We propose that these changes are based on age-related differences in the perceived salience of the face of the primary caregiver versus strangers.     

Neural correlates of successful and partial inhibitions in children: An ERP study

This experiment used event‐related potentials (ERPs) to investigate the neural processes underlying the development of response inhibition in a modified version of the go/no‐go paradigm [Cragg and Nation [2008] Developmental Science 11(6): 819–827]. N2 and P3 ERP components on correct go trials and partial and successful inhibitions were compared in 7‐ and 9‐year‐old children. A larger N2 effect on successful inhibitions was found in 9‐year‐olds compared to 7‐year‐olds at fronto‐central electrodes. N2 amplitude was positively related to behavioral performance in the 7‐year‐olds suggesting it may reflect inhibitory processes; however, this relationship was not present in the 9‐year‐olds. Age differences were also apparent in the go P3, perhaps indicating differences in stimulus processing. The no‐go P3 component was larger on successful than partial inhibitions. In contrast, there was no difference in N2 amplitude between partial and successful inhibitions. A significant difference was found in N2 latency however. This suggests that inhibitory processes are similar in both cases but initiated earlier on successful inhibitions. N2 latency was also shorter in 9‐year‐olds than 7‐year‐olds supporting an increase in the efficiency of response inhibition with age. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 533–543, 2009.     

Development and topography of auditory event-related potentials (ERPs): Mismatch and processing negativity in individuals 8–22 years of age

How do event related potentials (ERPs) reflecting auditory processing develop across adolescence? Such development was described for five ERP components in four groups of 11 healthy participants with mean ages of 10, 14, 17, and 21 years. Data from 19 sites during diffuse (passive) and focused (discrimination) attention in a three-tone oddball were analyzed to see how ERP loci varied with age for tone type attention condition, and for four types of difference waves reflecting nontarget and target comparison. Age interacted with site for most components. P1 loci sensitive to rare tones moved postoriorly and N1 loci lost their right bias in early puberty. The P2 loci did not move anterior to Council adulthood N2 amplitude, sensative to attention condition, developed a frontal focus by 17 years. Right biased P3 loci moved lo the midline with focused attention similarly in all age groups. Difference waves developed in three stages; In 10-years-old participants early deflection (<150 ms) were diffusely distributed; in mid adolescent participants, the main frontal negative component (150-300 ms) became well formed and lost an earlier right bias: and for participants 17 years old and older, the late positive complex developed a right bias in target-derived waves. Latency decreases for early frontal components were marked in participants 10–14 years old and for later posterior components m participants 14–17 years old. Major developments appeared at the onset of adolescence in early stimulus selection processes and during adolescence in the in the differential use of this information (N2- and P3-like latencies).     

Cognitive control after distraction: event-related brain potentials (ERPs) dissociate between different processes of attentional allocation

Attentional reallocation after a distracting event is an important function of cognitive control. This process is tapped by the reorienting negativity (RON) event-related brain potential. It was argued that the RON reflects orientation of attention to relevant information in working memory. To test this hypothesis participants performed an auditory duration discrimination task. The stimuli were presented in a frequent standard or a rare deviant pitch with deviants resulting in behavioral distraction. Participants accomplished this task under two conditions: In the refocus condition participants were asked to respond to every stimulus; in the reorient condition participants were instructed to ignore deviant stimuli and omit a reaction. The results suggest that different functions of attentional allocation are reflected by two RON subcomponents: the fast orientation of the focus of attention in working memory and a subsequent poststimulus evaluation process.     

Visual novel stimuli in an ERP novelty oddball paradigm: effects of familiarity on repetition and recognition memory

The orienting response, the brain's reaction to novel and/or out of context familiar events, is reflected by the novelty P3 of the ERP. Contextually novel events also engender high rates of recognition memory. We examined, under incidental and intentional conditions, the effects of visual symbol familiarity on the novelty P3 recorded during an oddball task and on the parietal episodic memory (EM) effect, an index of recollection. Repetition of familiar, but not unfamiliar, symbols elicited a reduction in the novelty P3. Better recognition performance for the familiar symbols was associated with a robust parietal EM effect, which was absent for the unfamiliar symbols in the incidental task. These data demonstrate that processing of novel events depends on expectation and whether stimuli have preexisting representations in long-term semantic memory.     

Decomposition of the ERP late posterior negativity: effects of retrieval and response fluency

Negativity elicited by recognized items over posterior sites--the late posterior negativity (LPN)--has been linked to action monitoring, task "uncertainty," and contextual retrieval. Four recognition tests required retrieval of encoding operations. Task fluency was assumed to increase with each block. The responses assigned to the episodic sources were reversed in Block 3 to reduce response fluency. Dissociable LPNs were identified; the 1200-1900-ms LPN was insensitive to task and response fluency and may reflect the maintenance of a retrieved episode. The 600-1200-ms LPN was sensitive to task fluency and may index the search for episodic information. A response-related LPN was sensitive to response fluency and was consistent with an action monitoring role. The findings confirm that the LPN is functionally heterogeneous, and comprises subcomponents sensitive to retrieval fluency, action monitoring, and postretrieval processing respectively.     

On separating processes of event categorization, task preparation, and mental rotation proper in a handedness recognition task.

We investigated the nature of event-related potential (ERP) effects in a handedness recognition task requiring mental rotation. Thirty subjects were tested with rotated and sometimes reflected alphanumeric characters while ERPs were recorded from 18 electrodes. On each trial, a cue provided valid information about the angular displacement of the following probe. This design allowed a distinction between three processing episodes: evaluation of the difficulty of the forthcoming task, preparation for the task, and the mental rotation task itself. The three episodes were accompanied by distinct ERP effects having distinct polarities, a different rank order of amplitudes for different probe orientations, and a different topography. These data confirm previous findings showing that mental rotation is accompanied by a parietal negativity. However, they also suggest that the rotation-related negativity found after tilted stimuli in standard mental rotation tasks is most likely overlapping with another, simultaneously triggered ERP effect functionally related to an evaluation of task difficulty.     

ERP correlates of pre-attentive processing of Cantonese lexical tones: The effects of pitch contour and pitch height

The pre-attentive processing of Cantonese tones was studied with an auditory passive oddball paradigm. Event-related potentials to standard and deviant auditory stimuli were recorded as participants watched a silent movie attentively. The standards and deviants differed in either pitch level or pitch contour. Mismatch negativity (MMN) and P3a were elicited by all types of deviant tones, suggesting that lexical tone was processed pre-attentively. In addition, the size and latency of MMN were sensitive to the size of pitch level change, while the latency of P3a captured the presence of pitch contour change. These results indicate that pitch contour and pitch height are two important dimensions in sensory processing of lexical tones.     

Object‐substitution masking modulates spatial attention deployment and the encoding of information in visual short‐term memory: Insights from occipito‐parietal ERP components

If object‐substitution masking (OSM) arises from mask representations replacing target representations, OSM should impede the formation of representations in visual short‐term memory (VSTM). We utilized event‐related potentials to examine the effect of OSM on target processing. An N2pc was observed on trials with delayed‐offset masks, indicating that focused attention was directed to the target. The sustained posterior contralateral negativity (SPCN), an index of VSTM storage, was observed in delayed‐offset trials only on trials with correct responses. This supports the hypothesis that inaccurate performance on delayed‐offset trials arises from a failure to encode the target in VSTM. On co‐termination trials, accuracy was high and neither the N2pc nor SPCN was observed. This indicates that, in the absence of masking, the task was accomplished by maintaining a diffuse attentional state that enabled the joint encoding of the potential target items.     

Residue iteration decomposition (RIDE): A new method to separate ERP components on the basis of latency variability in single trials

Event-related brain potentials (ERPs) are important research tools because they provide insights into mental processing at high temporal resolution. Their usefulness, however, is limited by the need to average over a large number of trials, sacrificing information about the trial-by-trial variability of latencies or amplitudes of specific ERP components. Here we propose a novel method based on an iteration strategy of the residues of averaged ERPs (RIDE) to separate latency-variable component clusters. The separated component clusters can then serve as templates to estimate latencies in single trials with high precision. By applying RIDE to data from a face-priming experiment, we separate priming effects and show that they are robust against latency shifts and within-condition variability. RIDE is useful for a variety of data sets that show different degrees of variability and temporal overlap between ERP components.     

Development of neural processes mediating rhyme judgments: Phonological and orthographic interactions

Development of neural processes underlying integration of phonological and orthographic information were assessed by measuring event-related brain potentials (ERPs), judgment accuracies and reaction times (RTs) in 20 children (9-10 years) and 20 adults performing visual rhyme judgments. Half the trials were phonologically and orthographically congruent across the prime-target pairs (e.g., thrown-own, cake-own), and half were incongruent (e.g., gown-own, cone-own). For both children and adults, behavioral performance was most affected when different phonological representations had to be encoded from similar orthographic representations (e.g., gown-own), and the amplitudes of the N350 reflected effects of both rhyme and phonological/orthographic congruency. Latencies of the N350 were shorter over the left hemisphere only in adults, and phonological/orthographic incongruence produced greater delays in children's processing. Therefore, it appears that neural systems mediating rhyming judgments develop early; however, adults exhibit increased efficiency for left-hemisphere processing and are less affected by interference from incongruent phonological and orthographic codes.     

The time course of orthography and phonology: ERP correlates of masked priming effects in Spanish

One key issue for computational models of visual-word recognition is the time course of orthographic and phonological information during reading. Previous research, using both behavioral and event related brain potential (ERP) measures, has shown that orthographic codes are activated very early but that phonological activation starts to occur immediately afterward. Here we report an ERP masked priming experiment in Spanish that investigates this issue further by using very strict control conditions. The critical phonological comparison was between two pairs of primes having the same orthographic similarity to the target words but differing in phonological similarity (e.g., conal - CANAL vs. cinal - CANAL vis à vis ponel - PANEL vs. pinel - PANEL ), whereas the critical orthographic contrast was between pairs of primes that had the same phonological similarity to the target but differing in orthographic similarity (e.g., conal - CANAL vs. konal - CANAL ). Orthographic priming was mainly observed in the 150–250-ms time window whereas phonological priming occurred in the 350–550-ms window.     

Rhythm perception: Speeding up or slowing down affects different subcomponents of the ERP P3 complex

The aim of this study was to investigate, by measuring the event related potential (ERP) P3 complex, whether the perception of small accelerations differs from that of small decelerations. Participants had to decide whether the last beat of a short sequence was presented 'too early' or 'too late'. Target beats were accelerated or decelerated with 0%, 2%, 5%, or 10%. Individuals differed in their capability to detect small tempo changes. We found that good responders were able to identify all tempo changes whereas poor responders were only able to identify large (10%) tempo changes. In addition, we found that tempo changes affected two subcomponents of the ERP P3 in good performers. Accelerations increased a late-P3 amplitude whereas decelerations increased an early-P3 amplitude. These results imply the principle possibility to measure differential P3 effects within one task. This is important for acquiring more refined knowledge concerning different subcomponents of the ERP P3 complex and the cognitive processes by which they are elicited.     

Following the time course of face gender and expression processing: A task-dependent ERP study

The effects of task demands and the interaction between gender and expression in face perception were studied using event-related potentials (ERPs). Participants performed three different tasks with male and female faces that were emotionally inexpressive or that showed happy or angry expressions. In two of the tasks (gender and expression categorization) facial properties were task-relevant while in a third task (symbol discrimination) facial information was irrelevant. Effects of expression were observed on the visual P100 component under all task conditions, suggesting the operation of an automatic process that is not influenced by task demands. The earliest interaction between expression and gender was observed later in the face-sensitive N170 component. This component showed differential modulations by specific combinations of gender and expression (e.g., angry male vs. angry female faces). Main effects of expression and task were observed in a later occipito-temporal component peaking around 230 ms post-stimulus onset (EPN or early posterior negativity). Less positive amplitudes in the presence of angry faces and during performance of the gender and expression tasks were observed. Finally, task demands also modulated a positive component peaking around 400 ms (LPC, or late positive complex) that showed enhanced amplitude for the gender task. The pattern of results obtained here adds new evidence about the sequence of operations involved in face processing and the interaction of facial properties (gender and expression) in response to different task demands.