How behavior shapes the brain and the brain shapes behavior: Insights from memory development

• In Event: Functional development of episodic memory in the hippocampus

Abstract

Source memory improves substantially during childhood (e.g., Riggins, 2014). This improvement is thought to be closely related to hippocampal maturation, as evidenced by age- and memory-related differences in hippocampal structure and function across development (e.g., Ghetti and Bunge, 2012; Riggins et al., 2020). As previous studies have mainly used cross-sectional designs to assess relations between source memory and hippocampal function, it remains unknown whether changes in the brain precede improvements in memory or vice versa. To address this gap, the current study followed 4- and 6-year-old children for 3 years, which allowed us to explore developmental changes in intrinsic hippocampal functional connectivity and to assess differences between the 4- and 6-year-old cohorts in the predictive relations between source memory and functional connectivity. Specifically, we hypothesized that early source memory gains would predict later intrinsic hippocampal functional connectivity and earlier intrinsic hippocampal functional connectivity would predict later gains in source memory abilities.
Children were participants in a large study investigating memory and brain development that used an accelerated longitudinal design (N=200, 100 males; REFERENCES BLINDED FOR REVIEW). The first wave (W1) included 4- to 8-year-old children. The 4- and 6-year-old children were invited back for two subsequent waves of testing (W2 and W3). Each wave included young and old cohorts (Young cohort: W1= 4 years, W2 = 5 years, W3 = 6 years; Old cohort: W1 = 6 years, W2 = 7 years, W3 = 8 years). We measured children’s source memory in each wave. Additionally, participants completed a task-free fMRI scan and a T1-wighted structural MRI scan. We calculated intrinsic functional connectivity between hippocampus and other cortical regions that were found to be activated during the formation of source memories (Geng et al., 2019). A series of fixed effects models were run to examine whether earlier changes in source memory predicted later intrinsic hippocampal functional connectivity and whether earlier hippocampal functional connectivity predicted later changes in source memory.
Consistent with previous studies, we found that there were age-related increases in source memory and intrinsic functional connectivity between the hippocampus and other cortical regions. Novel findings showed that changes in memory ability early in life predicted later intrinsic connectivity between hippocampus and cortical regions and that earlier intrinsic hippocampal functional connectivity predicted later changes in source memory (Figure 1).

Authors

• Fengji Geng, Zhejiang University College of Education
  Presenting Author

• Morgan Botdorf, University of Maryland - College Park
  Non-Presenting Author

• Tracy Riggins, University of Maryland - College Park
  Non-Presenting Author