Episodic memory shows striking improvement during early childhood. However, neural contributions to these behavioral changes are not well understood. The present study examined associations between episodic memory and volume of subregions (head, body, tail) of the hippocampus—a structure known to support episodic memory in school-aged children and adults—during early childhood (n=45). Results revealed significant positive relations between episodic memory and volume of the hippocampal head in both the left and right hemispheres for 6- but not 4-year-old children, suggesting brain-behavior relations vary across development. These findings add new information regarding neural mechanisms of change in memory development during early childhood and suggest developmental differences in hippocampal subregions may contribute to age-related differences in episodic memory ability.

Episodic memory relies on a distributed network of brain regions, with the hippocampus playing a critical and irreplaceable role. Few studies have examined how changes in this network contribute to episodic memory development early in life. The present addressed this gap by examining relations between hippocampal functional connectivity and episodic memory in 4-and 6-year-old children (n=40). Results revealed similar hippocampal functional connectivity between age groups, which included lateral temporal regions, precuneus, and multiple parietal and prefrontal regions, and functional specialization along the longitudinal axis. Despite these similarities, developmental differences were also observed. Specifically, 3 (of 4) regions within the hippocampal memory network were positively associated with episodic memory in 6-year-old children, but negatively associated with episodic memory in 4-year-old children. In contrast, all 3 regions outside the hippocampal memory network were negatively associated with episodic memory in older children, but positively associated with episodic memory in younger children. These interactions are interpreted within an interactive specialization framework and suggest the hippocampus becomes functionally integrated with cortical regions that are part of the hippocampal memory network in adults and functionally segregated from regions unrelated to memory in adults, both of which are associated with age-related improvements in episodic memory ability.

The hippocampus is a medial temporal lobe structure involved in memory, spatial navigation, and regulation of stress responses, making it a structure critical to daily functioning. However, little is known about the functional development of the hippocampus during childhood due to methodological challenges of acquiring neuroimaging data in young participants. This is a critical gap given evidence that hippocampally-mediated behaviors (e.g., episodic memory) undergo rapid and important changes during childhood. To address this gap, the present investigation collected resting-state fMRI scans in 97, 4- to 10-year-old children. Whole brain seed-based analyses of anterior, posterior, and whole hippocampal connectivity were performed to identify regions demonstrating stable (i.e., age-controlled) connectivity profiles as well as age-related differences in connectivity. Results reveal that the hippocampus is a highly connected structure of the brain and that most of the major components of the adult network are evident during childhood, including both unique and overlapping connectivity between anterior and posterior regions. Despite widespread age-controlled connectivity, the strength of hippocampal connectivity with regions of lateral temporal lobes and the anterior cingulate increased throughout the studied age range. These findings have implications for future investigations of the development of hippocampally-mediated behaviors and methodological applications for the appropriateness of whole versus segmented hippocampal seeds in connectivity analyses. Hum Brain Mapp 38:182-201, 2017. © 2016 Wiley Periodicals, Inc.

Although neuroimaging studies in adults demonstrate that cognitive reappraisal effectively down-regulates negative affect and results in increased prefrontal and decreased amygdala activity, very limited empirical data exist on the neural basis of cognitive reappraisal in children. This study aimed to pilot test a developmentally-appropriate guided cognitive reappraisal task in order to examine the effects of cognitive reappraisal on children’s self-reports of affect and brain responses. Study 1 (N =19, 4–10 years-old) found that children successfully employed guided cognitive reappraisal to decrease subjective ratings of negative affect, supporting the effectiveness of the guided cognitive reappraisal task. Study 2 (N =15, ages 6–10 years-old) investigated the neural responses to guided cognitive reappraisal and found that the neural responses showed increased activation in the amygdala and ventromedial prefrontal cortex during the cognitive reappraisal condition compared to the no regulation condition. In addition, amygdala activity was positively correlated with ventromedial prefrontal cortex activation during cognitive reappraisal. Findings suggest that the neural networks supporting cognitive reappraisal in children involve similar brain regions but brain responses deviate from findings in adults. Our findings suggest that the neural networks supporting emotion regulation are still developing during middle childhood, and future research is necessary to delineate age-related development of the neural network involved in cognitive reappraisal.

Rodent models indicate that parenting shapes offspring outcomes by programming the hypothalamic–pituitary–adrenal axis response to stress and, ultimately, altering brain structure and function. The present study tested this hypothesis and explored possible timing‐dependent associations in a longitudinal sample of children (N = 63). At Time 1 (M = 4.23 ± 0.84 years) and Time 2 (M = 7.20 ± 0.89 years), children completed parent–child interaction tasks and a laboratory stressor after which salivary cortisol samples were collected. At Time 2, children also completed a structural MRI. Analyses revealed timing‐ and region‐dependent associations between early and concurrent parenting and cortisol reactivity and hippocampal subregion volumes. Moreover, greater negative parenting during early childhood predicted greater cortisol reactivity three years later, which, in turn, led to reduced left hippocampal tail volume. Findings suggest that the hippocampus is sensitive to environmental influences during early childhood, a result that parallels findings from rodent models.