Functional connectivity between cortical memory networks and the hippocampus across development
Lena J. Skalaban1 (email@example.com), Steven A. Martinez1, Ashley D. Hawk1, J. Benjamin Hutchison2, Vishnu P. Murty1; 1Temple University, 2University of Oregon
Decades of research has focused on the role of the hippocampus in the development of memory. However, recent work in adults uncovered a set of cortical memory networks functionally connected to the hippocampus including a Medial Temporal Network (MTN), and a Default Mode Network (DMN) –– comprised of the Medial Prefrontal (MP), Posterior Medial (PM), and Anterior Temporal (AT) sub-networks (Barnett et al., 2021). We sought to test the existence of these networks in the developing brain using a publicly available fMRI movie-watching dataset collected in 3-12 year-olds and adults (Richardson et al., 2017). We generated two dueling hypotheses: a) given the general posterior to anterior developmental gradient, it could be that posterior-reliant subnetworks like the MTN and PM develop earlier than the AT and MP networks; b) conversely, in a memory-centric hypothesis, the PM sub-network might develop later than the AT sub-network, given its proposed role in slower-developing episodic memory. We find significant evidence of the existence of these cortical networks in all age groups except the 3-4 year-olds. We find significant age-related changes in the PM and MP sub-networks and the MTN, but no changes with age in the AT sub-network. While 8-12 year-olds show adult-like connectivity from all of the cortical networks to the hippocampus, children aged 3-4 and 5-7 show significantly lower connectivity to the hippocampus than the older age groups. These results coincide with our memory centric hypothesis and will be evaluated further using inter-subject correlation approaches within and across age groups.
Topic Area: LONG-TERM MEMORY: Development & aging
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