Abstract
Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults’ volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: 1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); 2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults’ hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition x time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.
Competing Interest Statement
The authors have declared no competing interest.
Clinical Trial
NCT03458910
Funding Statement
This study was supported by NIH R01AG057184 (PI Mather).
Author Declarations
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Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
The University of Southern California Institutional Review Board gave ethical approval for this work.
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Footnotes
We changed analysis model and added ASL results. We also modified the introduction and discussions.
Data Availability
All data produced are available online at OpenNeuro (https://openneuro.org/datasets/ds003823).