Search

The human brain undergoes rapid development during the first years of life. Beginning in utero, a wide array of biological, social, and environmental factors can have lasting impacts on brain structure and function. To understand how prenatal and early life experiences alter neurodevelopmental trajectories and shape health outcomes, several NIH Institutes, Centers, and Offices collaborated to support and launch the HEALthy Brain and Child Development (HBCD) Study. The HBCD Study is a multi-site prospective longitudinal cohort study, that will examine human brain, cognitive, behavioral, social, and emotional development beginning prenatally and planned through early childhood. Influenced by the success of the ongoing Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®) and in partnership with the NIH Helping to End Addiction Long-term® Initiative, or NIH HEAL Initiative®, the HBCD Study aims to establish a diverse cohort of over 7000 pregnant participants to understand how early life experiences, including prenatal exposure to addictive substances and adverse social environments as well as their interactions with an individuals genes, can affect neurodevelopmental trajectories and outcomes. Knowledge gained from the HBCD Study will help identify targets for early interventions and inform policies that promote resilience and mitigate the neurodevelopmental effects of adverse childhood experiences and environments.

Nonhuman research has implicated developmental processes within the hippocampus in the emergence and early development of episodic memory, but research in humans has been constrained by the difficulty of examining hippocampal function during early development. In the present study, we assessed 48 2-year-olds with a novel paradigm in which participants completed two games on a tablet that required remembering associations between unique characters, the places they visited, and the temporal order with which they did so. At the completion of each game, a unique, novel song played. Toddlers remembered spatial locations better than temporal order during an immediate test, after a 20-minute delay, and after a week delay. After the last behavioral session, toddlers underwent an fMRI task during natural nocturnal sleep evaluating hippocampal activation in response to learned and novel songs. We found that the extent of hippocampal activation for learned songs compared to novel songs during sleep was correlated with memory for temproal order across all time delays, but not with memory for spatial locations. The results confirm that that the functional contribution of the hippocampus to early memory can be assessed during sleep and suggest that assessment of temporal aspects of memory in the current task best capture this contribution.

Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory emerges during infancy and improves during early childhood and beyond. Developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence and persistence of episodic memory in late infancy and early childhood. However, these hypotheses are based on non-human models. In-vivo investigations in early human development of hippocampal processes have been significantly limited by methodological challenges in acquiring neuroimaging data, particularly task-related functional neuroimaging data, from infants and toddlers. Recent studies in adults have shown neural activity in the brain regions supporting episodic memory during slow-wave sleep using functional magnetic resonance imaging (fMRI), and fMRI has been increasingly utilized in infancy and early childhood to address other research questions. We review initial evidence and present preliminary data showing the promise of this approach for examining hippocampal contribution to how infants and toddlers remember individual events, and their association with information about the context in which the event occurred. Overall, our review, integrated with the presentation of some preliminary data provides insight on leveraging sleep to gain new perspectives on early memory functioning.

Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory emerges during infancy and improves during early childhood and beyond. Developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence and persistence of episodic memory in late infancy and early childhood. However, these hypotheses are based on non-human models. In-vivo investigations in early human development of hippocampal processes have been significantly limited by methodological challenges in acquiring neuroimaging data, particularly task-related functional neuroimaging data, from infants and toddlers. Recent studies in adults have shown neural activity in the brain regions supporting episodic memory during slow-wave sleep using functional magnetic resonance imaging (fMRI), and fMRI has been increasingly utilized in infancy and early childhood to address other research questions. We review initial evidence and present preliminary data showing the promise of this approach for examining hippocampal contribution to how infants and toddlers remember individual events, and their association with information about the context in which the event occurred. Overall, our review, integrated with the presentation of some preliminary data provides insight on leveraging sleep to gain new perspectives on early memory functioning.

Nonhuman research has implicated developmental processes within the hippocampus in the emergence and early development of episodic memory, but methodological challenges have hindered assessments of this possibility in humans. Here, we delivered a previously learned song and a novel song to 2-year-old toddlers during natural nocturnal sleep and, using functional magnetic resonance imaging, found that hippocampal activation was stronger for the learned song compared with the novel song. This was true regardless of whether the song was presented intact or backwards. Toddlers who remembered where and in the presence of which toy character they heard the song exhibited stronger hippocampal activation for the song. The results establish that hippocampal activation in toddlers reflects past experiences, persists despite some alteration of the stimulus, and is associated with behavior. This research sheds light on early hippocampal and memory functioning and offers an approach to interrogate the neural substrates of early memory.

Episodic prospection is the ability to mentally simulate personal future events that are rich in contextual detail and plausible for the individual. It therefore incorporates episodic information (who, what, where, and when of a particular event), as well as details about one's self (e.g., knowledge, goals, motivations and desires). The ability to mentally simulate personal future events is thought to serve an adaptive purpose as it allows the individual to plan actions that align with his or her future goals and challenges. This review seeks to integrate research exploring how changes in episodic memory and self-concept, and their associated neural mechanisms, contribute to the development of episodic prospection between childhood and adolescence. Elucidating the mechanisms contributing to this development is critical for understanding its potential influence on learning, goal achievement, and pedagogy between childhood and adolescence.

Preschoolers have limited capacity to use past experiences to prepare for the future. Two experiments sought to further understand these limitations. Experiment 1 (N = 42) showed that 3- to 4-year olds' difficulty performing anticipated future actions was constrained by their memory for relevant past actions, especially those including temporal information. Experiment 2 (N = 94) sought to determine whether preschoolers fail to see that past experiences can inform future-oriented actions. When the connection between the past and future was experimentally heightened, future thinking accuracy improved, but only if preschoolers remembered past experiences. The results indicate that past recall is a prerequisite for future thinking but failure to bridge past and future further accounts for observed limitations in future thinking in early childhood. [ABSTRACT FROM AUTHOR]

Studies comparing memory and future event simulation find that future events are more positive, and more often depend on life script events (e.g., culturally normative landmark events) than past events. Previous research does not address the link between this positivity bias and the life stage of college-age participants or their reliance on these scripted events. To examine this positivity bias, narratives of past and anticipated future events were elicited from participants aged 18–74 years, and were examined for reliance on the life script and valence ratings. Results showed that, across age groups, future events were rated as more positive than past events, and that life script events were common in the distant future. Notably, whereas younger adult age groups wrote primarily about their own life script events, older participants more commonly wrote about attending the life script events of significant others, such as children and grandchildren. These findings suggest that simulated future events play a valuable role in self-enhancement across the lifespan. Furthermore, the life script can be viewed as a useful search mechanism when one is missing the episodic details that are more available in memories; however, it is not the source of positivity bias for future events. [ABSTRACT FROM PUBLISHER]