Functional connectivity of the hippocampus and its subfields in resting-state networks
Date
2021Author
Ezama, Laura
Hernández-Cabrera, Juan A.
Seoane, Sara
Pereda, Ernesto
Janssen, Niels
Metadata
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Ezama, L, Hernández-Cabrera, JA, Seoane, S, Pereda, E, Janssen, N. Functional connectivity of the hippocampus and its subfields in resting-state networks. Eur J Neurosci. 2021; 53: 3378– 3393. https://doi.org/10.1111/ejn.15213
Abstract
Many neuroimaging studies have shown that the hippocampus participates in a
resting-state
network called the default mode network. However, how the hippocampus
connects to the default mode network, whether the hippocampus connects
to other resting-state
networks and how the different hippocampal subfields
take part in resting-state
networks remains poorly understood. Here, we examined
these issues using the high spatial-resolution
7T resting-state
fMRI dataset from the
Human Connectome Project. We used data-driven
techniques that relied on spatially-restricted
Independent Component Analysis, Dual Regression and linear mixed-effect
group-analyses
based on participant-specific
brain morphology. The results
revealed two main activity hotspots inside the hippocampus. The first hotspot was
located in an anterior location and was correlated with the somatomotor network.
This network was subserved by co-activity
in the CA1, CA3, CA4 and Dentate Gyrus
fields. In addition, there was an activity hotspot that extended from middle to posterior
locations along the hippocampal long-axis
and correlated with the default mode
network. This network reflected activity in the Subiculum, CA4 and Dentate Gyrus
fields. These results show how different sections of the hippocampus participate in
two known resting-state
networks and how these two resting-state
networks depend
on different configurations of hippocampal subfield co-activity.