Date of Award
4-28-2022
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
The hippocampus is critically important for a diverse range of neural processes, such as episodic memory, prospective memory, affective processing, and spatial navigation. Using both individual-specific precision functional mapping and large-sample group-averaged approaches of characterizing large-scale functional network organization in the human hippocampus, we uncovered general principles of and behaviorally-associated individual differences in hippocampal organization across development in children and adults. We found the hippocampus to be modularly organized along the anterior-posterior axis with the anterior hippocampus being preferentially connected to the default mode network (DMN), as expected. However, the posterior hippocampus was strongly connected to the parietal memory network (PMN). Although these general principles of anterior-posterior organization generalized to other datasets, precision functional mapping also elucidated differences related to an individual with an unusual cognitive ability, i.e., superior memorization. Namely, the memory champion exhibited a greater degree of heterogeneity in network partition and contextual association network (CAN) connectivity in the posterior hippocampus that had only before been seen in the anterior—which may be associated with the intense memory training utilizing the Method of Loci undergone by memory athletes. The memory champion’s unique hippocampal network organization is one of the first pieces of evidence suggesting that environment and life experiences may be at play in the development of network variants. Lastly, some of these foundational features of hippocampal network organization were also present by middle childhood, where the differentiation between anterior and posterior hippocampus was already stark. Although PMN connectivity in the posterior hippocampus is already evident in middle childhood, the developmental changes occurring within the DMN and CAN are still at play in the anterior hippocampus, such that there is greater preferential connectivity to the CAN as opposed to the DMN. The reproducibility of these network parcellations in the hippocampus serves as the baseline for truer estimates of hippocampal network development to adult levels.
Language
English (en)
Chair and Committee
Nico Dosenbach
Recommended Citation
Zheng, Annie, "Characterization of Large-Scale Functional Network Organization in the Human Hippocampus" (2022). Arts & Sciences Electronic Theses and Dissertations. 3251.
https://openscholarship.wustl.edu/art_sci_etds/3251