Electrophysiological indices of memory for temporal order in early childhood: Implications for the development of recollection

The ability to recall contextual details associated with an event begins to develop in the first year of life, yet adult levels of recall are not reached until early adolescence. Dual-process models of memory suggest that the distinct retrieval process that supports the recall of such contextual information is recollection. In the present investigation, we used both behavioral and electrophysiological measures to assess the development of memory for contextual details, as indexed by memory for temporal order, in early childhood. Results revealed age-related improvements in memory for temporal order despite similar levels of memory for the individual items themselves. Furthermore, this pattern of recall was associated with specific components in the electrophysiological response. Consistent with electrophysiological research in adults, distributed, positive going activity late in the waveform was associated with increases in recall of contextual details and the development of recollective processes.This research was supported by grants from NIH to Charles A. Nelson (NS34458) and Michael K. Georgieff (HD29421), a grant from the NICHD to Patricia J. Bauer (HD28425), and a grant from the NIH National Center for Research Resources (RR00400)

Developmental differences in relations between parent-reported executive function and unitized and non-unitized memory representations during childhood

Funding for Open Access provided by the UMD Libraries Open Access Publishing Fund.Previous research has documented an association between executive functioning (EF) and memory for bound details. However, it is unknown if this relation varies as a function of the type of bound information (i.e., unitized versus non-unitized) and whether this association changes as a function of age during childhood, when both EF and memory undergo rapid development. The current study sought to address these gaps by examining whether relations between parent-reported EF differed for unitized versus non-unitized memory representations and if these relations differed between children who were 4, 6, or 8 years of age. Results revealed that EF was selectively associated with non-unitized associative memory in 8-year-old children; no significant relations between EF and either memory condition were evident in 4- or 6-year-olds. These results suggest relations between EF and memory may be specific to non-unitized representations and that this association may emerge across childhood as both EF and memory abilities develop

Exploring Hippocampal Structural Differences in Habitual vs Non-habitual Nappers During Early Childhood

During sleep, memories become less vulnerable to interference, both during overnight sleep and naps. Previous research in adults suggests this effect is partially due to a “transfer” of memories from hippocampus to cortex, but there is little research investigating this process in children. Existing literature suggests habitually napping children need naps more than non-habitually napping children because their hippocampus is less mature. This study examines the relation between habitual versus non-habitual nappers and the hippocampus in early childhood. The participants are part of a larger ongoing study, from which we had 21 participants (Mage= 4.49 years, SD=0.51, 9 female). Of the 21 participants, 8 were nappers (napped 5+ days/week) and 13 were non-nappers (napped <5 days/week). Hippocampal volumes were extracted from T1 weighted MRI scans via FreeSurfer 6.0.0 and refined with a Segmentation Adapter Tool (Morey et al., 2009). Subregions of hippocampal head, body, and tail were identified via standard anatomical landmarks (Watson et al., 1992; Weiss et al., 2005). Preliminary analyses examined possible confounding differences between groups (age, sex, and intercranial volume). There were no differences, thus these measures were not controlled for. Results showed significant differences in hippocampal tail volumes. In the left hemisphere, nappers had larger volumes than non-nappers. Although these are preliminary results, the findings support that variation in hippocampal development may relate to nap status in developing children. Future research will focus on increased sample sizes and investigate other brain regions to determine the specificity of these effects.National Institute of Health (NIH), National Science Foundation (NSF

Relations between amygdala:hippocampus ratios and depressive symptoms in typically developing 4- to 8-year-old children

Previous literature suggests that the coordination between the amygdala and hippocampus, regions critical for encoding of complex memory and emotion, are associated with depression and risk factors for depression, such as negative memory bias, during adulthood (Yavas et al., 2019; Gerritsen et al., 2012). Research on adolescents ages 8-17 suggests that increased amygdala:hippocampus ratios are related to the severity of anxiety in pediatric major depression (MacMillan et al., 2003). Although associations between amygdala:hippocampus ratios and depression are well-documented in older samples, these associations are not well-explored in early childhood (i.e., <8 years). Given this is a developmental period during which both the amygdala and the hippocampus undergo structural and functional changes (Riggins et al., 2018; Stern et al., 2019), it may be especially important to understand how these developmental changes relate to depressive symptoms in early childhood. The present research aims to address this gap in the literature. Specifically, we examined depressive symptoms and amygdala:hippocampus ratios in typically developing 4- to 8-year-old children drawn from a larger, longitudinal study on brain development in early childhood (N=200, 100 female; Riggins et al., 2018). Depression scores were assessed using the Children’s Depression Inventory (CDI; Kovacs, 1985). Brain region volumes were collected using a standard resolution (.9mm3), T1-weighted whole brain structural magnetic resonance imaging (MRI) scan and processed using FreeSurfer (v5.1). In addition to amygdala and hippocampal volumes, intracranial volume (ICV) was collected as a control for participant head size. Analysis using partial correlations revealed a significant association between total amygdala:hippocampus ratios and depressive symptoms, r(50) = -.234, p = .048. The association between right amygdala:hippocampus ratios and depressive symptoms approached significance, r(50) = -.218, p = .060, and the association between left amygdala:hippocampus ratios and depressive symptoms were not significant. Contrary to previous research, smaller amygdala:hippocampus ratios predicted increased depressive symptoms. Implications for this research are discussed further

Empathic responding and hippocampal volume in young children

©American Psychological Association, 2019. This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. The final article is available, upon publication, at: https://doi.org/10.1037/dev0000684Empathic responding—the capacity to understand, resonate with, and respond sensitively to others’ emotional experiences—is a complex human faculty that calls upon multiple social, emotional, and cognitive capacities and their underlying neural systems. Emerging evidence in adults has suggested that the hippocampus and its associated network may play an important role in empathic responding, possibly via processes such as memory of emotional events, but the contribution of this structure in early childhood is unknown. We examined concurrent associations between empathic responding and hippocampal volume in a sample of 78 children (ages 4–8 years). Larger bilateral hippocampal volume (adjusted for intracranial volume) predicted greater observed empathic responses toward an experimenter in distress, but only for boys. The association was not driven by a specific subregion of the hippocampus (head, body, tail), nor did it vary with age. Empathic responding was not significantly related to amygdala volume, suggesting specificity of relations with the hippocampus. Results support the proposal that hippocampal structure contributes to individual differences in children’s empathic responding, consistent with research in adults. Findings shed light on an understudied structure in the complex neural systems supporting empathic responding and raise new questions regarding sex differences in the neurodevelopment of empathy in early childhood. (PsycInfo Database Record (c) 2020 APA, all rights reserved)https://doi.org/10.1037/dev000068

Elicited Imitation Performance at 20 Months Predicts Memory Abilities in School-Aged Children

Over the first decade of life there are marked improvements in mnemonic abilities. An important question from both a theoretical and applied perspective is the extent of continuity in the nature of memory over this period. The present longitudinal investigation examined declarative memory during the transition from toddlerhood to school-age using both experimental and standardized assessments. Results indicate significant associations between immediate nonverbal recall at 20 months (measured by elicited imitation) and immediate verbal and nonverbal memory (measured by standardized and laboratory-based tasks) at 6 years in typically developing children. Regression models revealed this association was specific, as measures of language abilities and temperament were not predictive of later memory performance. These findings suggest both continuity and specificity within the declarative memory system over the first years of life. Theoretical and applied implications of these findings are discussed

Children With Chromosome 22q11.2 Deletion Syndrome Exhibit Impaired Spatial Working Memory

Abstract Individuals with chromosome 22q11.2 deletion syndrome (22q11.2DS) have been shown to have impairments in processing spatiotemporal information. The authors examined whether children with 22q11.2DS exhibit impairments in spatial working memory performance due to these weaknesses, even when controlling for maintenance of attention. Children with 22q11.2DS (n 5 47) and typically developing controls (n 5 49) ages 6-15 years saw images within a grid and after a delay, then indicated the positions of the images in the correct temporal order. Children with 22q11.2DS made more spatial and temporal errors than controls. Females with 22q11.2DS made more spatial and temporal errors than males. These results extend findings of impaired spatiotemporal processing into the memory domain in 22q11.2DS by documenting their influence on working memory performance

Personal Familiarity Influences the Processing of Upright and Inverted Faces in Infants

Infant face processing becomes more selective during the first year of life as a function of varying experience with distinct face categories defined by species, race, and age. Given that any individual face belongs to many such categories (e.g. A young Caucasian man's face) we asked how the neural selectivity for one aspect of facial appearance was affected by category membership along another dimension of variability. 6-month-old infants were shown upright and inverted pictures of either their own mother or a stranger while event-related potentials (ERPs) were recorded. We found that the amplitude of the P400 (a face-sensitive ERP component) was only sensitive to the orientation of the mother's face, suggesting that “tuning” of the neural response to faces is realized jointly across multiple dimensions of face appearance

Effects of Prenatal Drug Exposure on Adolescent Brain Activation During a Visuospatial Working Memory Task

Background: Previous research examining effects of prenatal drug exposure (PDE) has yielded mixed results regarding cognitive performance during school age years. Associations between PDE and tests of global functioning (IQ and academic achievement) tend to be minimal and are typically attenuated by environmental variables (e.g., caregiving environment). On the other hand, significant negative associations have been reported in tests of executive functioning (sustained attention, inhibitory control, and behavioral regulation), even with covariate control. These findings are consistent with animal models of PDE that report developmental abnormalities in brain regions associated with strong dopaminergic innervation including the striatum, anterior cingulate cortex, and prefrontal cortex. In humans, these regions are putatively involved in executive functions that coordinate the basic cognitive processes required for goal-directed action (e.g., attention inhibitory control, planning, working memory). The objective of the present study was to assess the effects of PDE on brain functioning during adolescence. Methods: fMRI was used to examine visuospatial working memory (VSWM) in 35 adolescents (mean: 14.3 years); 20 with intrauterine exposure to cocaine, heroin, or both and 15 unexposed children from the same community. All participants performed a 2-back VSWM paradigm that required dynamic storage and manipulation of spatial information. Whole-brain functional EPI scans were acquired using a 3T Siemens Scanner with standard parameters. Participants completed one 6-minute block-design run that alternated between a 30 second control condition (which required observation of visual stimuli, sustained attention, and a motor response) and 30 seconds of the VSWM condition. Brain responses were analyzed using the AFNI software package with appropriate contrasts and p < 0.05 corrected for multiple comparisons. Results: Across all participants, the VSWM task activated the frontal-parietal attention network including bilateral superior parietal lobules, precuneus, middle frontal gyri, superior frontal gyri, and insular cortex. Significant deactivations were observed in regions of the “default network,” including the left anterior cingulate gyrus, medial frontal gyrus, posterior cingulate, and bilateral parahippocampal cortices. Whole-brain between group comparisons with both age and gender entered as covariates revealed 3 regions that were differentially activated in the drug-exposed compared to the non-exposed group. These regions included right inferior parietal lobe, right precentral gryus, and left cuneus. The drug-exposed group showed deactivation of the right inferior parietal lobule compared to no change in the non-exposed group. The non-exposed group showed activations in both the right precentral gyrus and left cuneus compared to no change in the drug-exposed group. These differences in activations were detected despite equivalent behavioral performance on the task (i.e., accuracy and response time) and after statistically controlling environmental variables that differed between the groups, including placement in nonmaternal care, maternal age at time of birth and prenatal exposure to cigarettes. Discussion: Despite similar task performance, adolescents with a history of PDE showed different neural activations than the comparison group. Regions that were differentially activated are implicated in sequencing task information (i.e., right parietal lobe), working memory performance in healthy control children (i.e., right precentral gyrus), and visual attention (i.e., left cuneus). These results suggest regions and components of working memory processing that may be differentially affected by PDE in adolescence.This study was supported by the National Institute on Drug Abuse (NIDA) – Intramural Research Program and NIDA grants R01-DA07432 and R01-DA021059