Correlates Of Recollection Research Articles

Effects of emotional study context on immediate and delayed recognition memory: Evidence from event-related potentials

Whilst research has largely focused on the recognition of emotional items, emotion may be a more subtle part of our surroundings and conveyed by context rather than by items. Using ERPs, we investigated which effects an arousing context during encoding may have for item-context binding and subsequent familiarity-based and recollection-based item-memory. It has been suggested that arousal could facilitate item-context bindings and by this enhance the contribution of recollection to subsequent memory judgements. Alternatively, arousal could shift attention onto central features of a scene and by this foster unitisation during encoding. This could boost the contribution of familiarity to remembering. Participants learnt neutral objects paired with ecologically highly valid emotional faces whose names later served as neutral cues during an immediate and delayed test phase. Participants identified objects faster when they had originally been studied together with emotional context faces. Items with both neutral and emotional context elicited an early frontal ERP old/new difference (200-400 ms). Neither the neurophysiological correlate for familiarity nor recollection were specific to emotionality. For the ERP correlate of recollection, we found an interaction between stimulus type and day, suggesting that this measure decreased to a larger extend on Day 2 compared with Day 1. However, we did not find direct evidence for delayed forgetting of items encoded in emotional contexts at Day 2. Emotion at encoding might make retrieval of items with emotional context more readily accessible, but we found no significant evidence that emotional context either facilitated familiarity-based or recollection-based item-memory after a delay of 24 h.

Recognition memory for pictures in children with ADHD: An event-related potential study

Objective: Children with ADHD are reported to accompany by various degrees of recognition memory cognitive deficits. We aimed to investigate age-related changes of the amplitude in event-related potential recordings on recognition memory in Chinese children with ADHD and to provide theoretical basis of neuro-electrophysiology for the cognition development of children. Method: ERP and behavioral data of 6-to-10-year-old children with ADHD (n = 94) and typically developing controls (TD, n = 96) were collected while the children performed a classical visual study-test paradigm task. Results: Children with ADHD have defects in pictures recognition and showed a significantly smaller P2 component than that of TD children. The development of P2 and P3 component were different between the two groups. Moreover, the TD children showed the frontal old/new effect (N2) taken as a correlate of familiarity at 6 years old, and a parietal old/new effect (P3) taken as a correlate of recollection at 9 years old, while children with ADHD showed a parietal old/new effect (P3) only at 6 years old. Conclusion: Our study provided the novel evidence that recognition memory follow different developmental trajectories at the age of 6-10 between TD and ADHD.

ERP evidence for the control of emotional memories during strategic retrieval

Neural evidence for the strategic retrieval of task-relevant ‘target’ memories at the expense of less relevant ‘nontarget’ memories has been demonstrated across a wide variety of studies. In ERP studies, this evidence consists of the ERP correlate of recollection (i.e. the ‘left parietal old/new effect’) being evident for targets and attenuated for nontargets. It is not yet known, however, whether this degree of strategic control can be extended to emotionally valenced words, or whether these items instead reactivate associated memories. The present study used a paradigm previously employed to demonstrate the strategic retrieval of neutral words (Herron & Rugg, Psychonomic Bulletin and & Review, 10(3), 703-–710, 2003b) to assess the effects of stimulus valence on behavioural and event-related potential (ERP) measures of strategic retrieval. While response accuracy and reaction times associated with targets were unaffected by valence, negative nontargets and new items were both associated with an elevated false alarm rate and longer RTs than their neutral equivalents. Both neutral and negative targets and nontargets elicited early old/new effects between 300 and 500 ms. Critically, whereas neutral and negative targets elicited robust and statistically equivalent left parietal old/new effects between 500 and 800 ms, these were absent for neutral and negative nontargets. A right frontal positivity associated with postretrieval monitoring was evident for neutral targets versus nontargets, for negative versus neutral nontargets, and for targets versus new items. It can therefore be concluded that the recollection of negatively valenced words is subject to strategic control during retrieval, and that postretrieval monitoring processes are influenced by emotional valence.

Commentary on: Recollection reduces unitised familiarity effect.

Commentary on: Recollection reduces unitised familiarity effect.

Modifications of recognition memory processes in preterm children: an event-related potential study.

Prematurity may cause hippocampal compromise. Therefore, hippocampus-dependent memory processes (recollection-based retrieval) may be more impaired than hippocampus-independent processes (familiarity-based retrieval). The memory of 18 children born preterm with reduced hippocampal volumes, without neonatal complications (weeks of gestation < 34, weight < 1,600 g), and 15 controls (8-10 years) was tested using an item recognition task. While groups were equal in memory performance, dissociation was found: The event-related potential (ERP) correlate of familiarity was intact in the preterm group, whereas the correlate of recollection was attenuated. A follow-up experiment ruled out that this was due to general cognitive deficits. Furthermore, gestational age correlated with the ERP index of recollection. Thus, recognition memory in preterm children may be characterized by a compensation of attenuated recollection by familiarity.

Electrophysiological evidence for late maturation of strategic episodic retrieval processes

Improvement in source memory performance throughout development is thought to be mediated by strategic processes that facilitate the retrieval of task-relevant information. Using event-related potentials (ERPs), we examined developmental changes in these processes during adolescence. Adolescents (13-14 years) and adults (19-29 years) completed a memory exclusion task which required the discrimination between words studied in one color ('targets') and words studied in the alternative color ('non-targets') under two conditions that put different demands on strategic control. Memory accuracy improved with age and also increased with decreasing control demands in both age groups. The parietal old/new effect, an ERP correlate of recollection, was reliable for targets across conditions in both age groups. By contrast, ERP correlates of non-target recollection were present in adolescents across conditions but not in adults. This suggests that adults implemented a strategy to prioritize recollection of target information with greater success than adolescents regardless of control demands, presumably reflecting maturational differences in cognitive control. In support of this view, the ERP amplitude difference between targets and non-targets was positively correlated with a measure of working memory capacity (WMC) in adults but not in adolescents. A further age-related difference was that ERP correlates of post-retrieval processing, including late right-frontal old/new effects and late posterior negativities, were observed in adults only. Together, our data suggest protracted maturation in the strategic processes that underlie selective recollection and post-retrieval control.

Electrophysiological insights into control over recollection

Electrophysiological correlates of successful episodic retrieval were measured in an experiment where participants switched frequently between two different episodic retrieval conditions. They completed three trials of each condition before switching to the other condition. The key contrasts were between neural indices of successful retrieval that were separated according to the number of successive trials of the same condition that had been completed. An electrophysiological correlate of recollection––the left-parietal event-related potential (ERP) old/new effect––was smaller on the first and second trial than on the third successive trial that participants completed for each condition. This ERP old/new effect is assumed to index the extent to which recollection has occurred, and this outcome suggests that control over recovery of task-relevant episodic content is compromised when additional cognitive demands are imposed around the time of retrieval.

Intentional suppression can lead to a reduction of memory strength: behavioral and electrophysiological findings.

Previous research has shown that the intentional suppression of unwanted memories can lead to forgetting in later memory tests. However, the mechanisms underlying this effect remain unclear. This study employed recognition memory testing and event-related potentials (ERPs) to investigate whether intentional suppression leads to the inhibition of memory representations at an item level. In a think/no-think experiment, participants were cued to either suppress (no-think condition) or retrieve (think condition) previously learned words, 18 or 0 times. Performance in a final recognition test was significantly reduced for repeatedly suppressed no-think items when compared to the baseline, zero-repetition condition. ERPs recorded during the suppression of no-think items were significantly more negative-going in a time window around 300 ms when compared to ERPs in the think condition. This reduction correlated with later recognition memory impairment. Furthermore, ERPs to no-think items from 225 to 450 ms were more negative-going in later phases of the experiment, suggesting a gradual reduction of memory strength with repeated suppression attempts. These effects were dissociable from correlates of recollection (500–600 ms) and inhibitory control (450–500 ms) that did not vary over the time-course of the experiment and appeared to be under strategic control. Our results give strong evidence that the no-think manipulation involves inhibition of memory representations at an item level.

ERP correlates of recognition memory: Effects of retention interval and false alarms

Within the framework of the dual process model of recognition memory, prior work with event-related potentials (ERPs) has suggested that an early component, the FN400, is a correlate of familiarity while a later component, the Late Positive Complex (LPC), is a correlate of recollection. However, other work has questioned the validity of these correlations, suggesting that the FN400 effect is too short-lived to reflect an explicit memory phenomenon and that the LPC may be influenced by decision-related factors. Using a Remember/Know paradigm we addressed these issues by (1) examining the effect of study-test delay on correctly recognized items associated with familiarity (‘Know’ responses) and recollection (‘Remember’ responses) and by (2) examining FN400 and LPC modulation associated with false alarms. Supporting the relationship of the FN400 with familiarity, attenuation of this component was present for ‘Know’ responses relative to correct rejections after both the short (39 min) and long (24 h) delay conditions. Attenuation of the FN400 also occurred for false alarms (responses largely driven by familiarity) relative to correct rejections. Although an increased LPC amplitude was found associated with ‘Remember’ responses at both delays, a decreased LPC amplitude was observed with false alarms relative to correct rejections. This latter result is discussed with regard to the possibility of an overlapping posterior negativity.

Dissociable neural correlates for familiarity and recollection during the encoding and retrieval of pictures

Results from behavioral studies have supported the idea that recognition memory can be supported by at least two different processes, recollection and familiarity. However, it remains unclear whether these two forms of memory reflect neurally distinct processes. Furthermore, it is unclear whether recollection and familiarity can be best conceived as differing primarily in terms of retrieval processing, or whether they additionally differ at encoding. To address these issues, we used event-related brain potentials (ERPs) to monitor neural correlates of familiarity and recollection at both encoding and retrieval. Participants studied pictures of objects in two types of study blocks and subsequently made remember–know and source memory judgments during retrieval. Results showed that, during encoding, neural correlates of subsequent familiarity and recollection onsetted in parallel, but exhibited differences in scalp topography and time course. Subsequent familiarity-based recognition was associated with a left-lateralized enhanced positivity and observed at anterior scalp sites from 300 to 450 ms, whereas subsequent recollection was associated with a topographically distinct right-lateralized positivity at anterior scalp sites from 300 to 450 ms and bilateral activity from 450 to 600 ms. During retrieval, neural correlates of familiarity emerged earlier than correlates of recollection. Familiarity was associated with an enhanced positivity at frontopolar scalp sites from 150 to 450 ms, whereas recollection was associated with positive ERP modulations over bilateral frontal (300–600 ms) and parietal (450–800 ms) sites. These results demonstrate that familiarity and recollection reflect the outcome of neurally distinct memory processes at both encoding and retrieval.