Task characteristics are critical for the use of familiarity: An ERP study on episodic memory development in middle childhood

Adolescent-specific memory effects: evidence from working memory, immediate and long-term recognition memory performance in 8-30 yr olds

Working memory and recognition memory develop across adolescence, but the relationship between them is not fully understood. We investigated associations between n-back task performance and subsequent recognition memory in a community sample (8-30 yr, n = 150) using tasks from the Adolescent Brain Cognitive Development Study (ABCD Study) to cross-sectionally assess memory in an age range that will be sampled longitudinally. We added a 24-h delay condition to assess long-term recognition. Overall working memory, immediate and long-term recognition performance peaked in adolescence. Age effects in recognition memory varied by items (old targets, old distractors, and new items) and delay (0 and 24 h). For immediate recognition, accuracy was higher for targets and new items than for distractors, with accuracy for targets peaking in adulthood and accuracy for new items peaking during adolescence. For long-term recognition, adolescents' accuracy was higher for targets than distractors, while adults showed similarly high accuracy for targets and distractors and children showed low accuracy for both. This pattern appeared to be specific to recognition of items from the high working memory load condition. The results suggest that working memory may facilitate long-term recognition of task-relevant over irrelevant items and may benefit the detection of new information during adolescence.

Using temporo-spatial principal component analysis as tool to dissociate latent ERP components of episodic memory retrieval: Objectifying time-window selection for overlapping ERP components

This report details how principal component analysis (PCA) can be used as a valuable tool to dissociate latent ERP components, even when considerable temporal and spatial overlap makes it difficult to discern ERP effects in standard time windows. We illustrate our methodological approach in a data set from a recognition memory paradigm, in which event-related potential (ERP) correlates of familiarity, recollection and the late parietal negativity (LPN) were partially overlapping. By adapting standard time windows based on the results of a temporo-spatial PCA, small yet reliable ERP correlates reflecting familiarity and recollection for identical items and late recollection for changed items were identified, complementing the result pattern observed in behavioral performance. Due to similar temporo-spatial characteristics and opposing polarities in late parietal ERP correlates associated with memory retrieval, component overlap is often observed in this field of research. Hence, the complex interplay of several processes underlying higher cognitive functions such as memory retrieval may interfere with standard ERP assessment. In such instances, PCA can provide promising ways to objectively assess time window selection for subsequent ERP analyses.

Adapting event-related potential research paradigms for children: Considerations from research on the development of recognition memory

Most developmental event-related potential (ERP) research uses experimental paradigms modified from research with adults. One major challenge is identifying how to adapt these paradigms effectively for use with younger individuals. This paper provides guidance for developmental adaptations by considering research on the development of recognition memory. We provide a brief overview of recognition memory tasks and ERP components associated with recognition memory in children and adults. Then, we provide some general recommendations, discuss common differences between ERP studies of recognition memory in adults and children (e.g., the type of stimuli presented, response modalities), and provide suggestions for assessing the effect of task modifications on ERP components of interest. Specifically, we recommend (a) testing both children and adults on the modified paradigm to allow for a continuity of findings across development, (b) comparing children of different ages on the modified paradigm based on expectations regarding when developmental change occurs for the cognitive process of interest, and (c) empirically assessing the effect of methodological differences between paradigms. To illustrate the latter, we analyzed data from our lab comparing memory-related ERP components when children experienced a 1-day, 2-day, or 1-week delay between encoding and retrieval.

Memory specificity is linked to repetition effects in event-related potentials across the lifespan

The specificity with which past experiences can be remembered varies across the lifespan, possibly due to differences in how precisely information is encoded. Memory formation can be investigated through repetition effects, the common finding that neural activity is altered when stimuli are repeated. However, whether differences in this indirect measure of memory formation relate to lifespan differences in memory specificity has not yet been established. In the present study, we examined repetition effects in event-related potentials and their relation to recognition. During incidental encoding, children (aged 7-9 years), young adults (18-30 years), and older adults (65-76 years) viewed repeated object images from different categories. During subsequent recognition, we distinguished memory for the specific items versus the general categories. We identified repetition suppression in all age groups, and repetition enhancement for adults. Furthermore, individual item recognition performance comprising lure discrimination was positively associated with the magnitude of the neural repetition effects, which did not differ between groups, indicating common neural mechanisms of memory formation. Our findings demonstrate that neural repetition effects reflect the formation of highly specific memory representations and highlight their significance as a neural indicator of individual differences in episodic memory encoding across the lifespan.

Examining the development of memory for temporal context and its underlying neural processes using event-related potentials

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Memory for temporal context, vital for episodic memory, shows prolonged development.

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Cognitive processes and neural mechanisms driving age-related improvements unclear.

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Event-related potentials (ERP) used with 7−9-year-olds, 10−12-year-olds, and adults.

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We found age-related improvements, ERP effects, and brain-behavior relations.

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Implications for temporal memory and episodic memory development discussed.

Time is a critical feature of episodic memory—memory for events from a specific time and place (Tulving, 1972). Previous research indicates that temporal memory (memory for ‘when’) is slower to develop than memory for other details (e.g., ‘what’ and ‘where’), with improvements observed across middle and late childhood. The factors that drive these changes are not yet clear. We used an event-related potential (ERP) recognition memory paradigm to investigate the underlying processes of memory for temporal context in middle to late childhood (7−9-year-olds; 10−12-year-olds) and young adulthood. Behaviorally, we observed age-related improvements in the ability to place events in temporal context. ERP analyses showed old/new effects for children and adults. We also found brain-behavior relations for 1) episodic memory (ERP mean amplitude difference between source hits and correctly identified new trials was correlated to behavioral accuracy), and 2) temporal memory (ERP mean amplitude difference between source hits and source error trials was correlated to accuracy of temporal memory judgments). This work furthers our understanding of the cognitive processes and neural signatures supporting temporal memory development in middle to late childhood, and has implications for episodic memory development more broadly.

Age- and performance-related differences in source memory retrieval during early childhood: Insights from event-related potentials

Across early childhood, children's ability to remember individual items and the details that accompany these items (i.e., episodic memory) improves greatly. Given that these behavioral improvements coincide with increases in age, effects of age and performance are often confounded. This study used event-related potentials (ERPs) to investigate age- and performance-related differences in the neural processes underlying the development of memory for details during early childhood. Using a source memory paradigm, ERP components related to episodic memory, the negative component (Nc), and late slow wave (LSW) were examined in 4- to 8-year-old children. Analyses focused on trials for which children correctly remembered the source related to an item versus trials where the item was remembered but the source was forgotten. Results revealed LSW, but not Nc, differed as a function of age and performance. Specifically, LSW effects were similar across source correct and source incorrect trials in all high-performing children and in low-performing older children; however, LSW effects differed across conditions in low-performing younger children. Results show developmental differences in retrieval processes across early childhood and highlight the importance of considering age and performance when examining electrophysiological correlates of episodic memory during development.

Neuronal oscillations reveal the processes underlying intentional compared to incidental learning in children and young adults

This EEG study investigated the neuronal processes during intentional compared to incidental learning in young adults and two groups of children aged 10 and 7 years. Theta (3–8 Hz) and alpha (10–16 Hz) neuronal oscillations were analyzed to compare encoding processes during an intentional and an incidental encoding task. In all three age groups, both encoding conditions were associated with an increase in event-related theta activity. Encoding-related alpha suppression increased with age. Memory performance was higher in the intentional compared to the incidental task in all age groups. Furthermore, intentional learning was associated with an improved encoding of perceptual features, which were relevant for the retrieval phase. Theta activity increased from incidental to intentional encoding. Specifically, frontal theta increased in all age groups, while parietal theta increased only in adults and older children. In younger children, parietal theta was similarly high in both encoding phases. While alpha suppression may reflect semantic processes during encoding, increased theta activity during intentional encoding may indicate perceptual binding processes, in accordance with the demands of the encoding task. Higher encoding-related alpha suppression in the older age groups, together with age differences in parietal theta activity during incidental learning in young children, is in line with recent theoretical accounts, emphasizing the role of perceptual processes in mnemonic processing in young children, whereas semantic encoding processes continue to mature throughout middle childhood.