Heart Rate Variability Biofeedback Alleviates Subthreshold Depression by Reconstructing the Brain-Heart Axis via...

Area of Science:

• Neuroscience
• Cardiology
• Psychiatry

Background:

• Subthreshold depression (StD) is associated with cardiac autonomic dysfunction.
• The habenula (Hb)-centered brain network's role in StD and its regulation of the cardiac autonomic nervous system (ANS) is not fully understood.
• Heart rate variability biofeedback (HRV-BF) is a potential non-pharmacological intervention for depression.

Purpose of the Study:

• To investigate the habenula (Hb)-centered brain network's role in regulating the cardiac autonomic nervous system (ANS) in subthreshold depression (StD).
• To explore the brain-heart axis mechanisms underlying the antidepressant effects of heart rate variability biofeedback (HRV-BF).

Main Methods:

• Thirty-four StD participants and 32 healthy controls (HC) underwent scale assessments and cardiovascular measurements.
• StD participants received a 4-week HRV-BF intervention, with resting-state functional magnetic resonance imaging (rs-fMRI) performed pre- and post-intervention.
• Region of interest (ROI)-wise and voxel-wise functional connectivity (FC) analyses were conducted using the bilateral Hb as the seed.

Main Results:

• StD participants showed elevated heart rate and altered HRV indices compared to controls.
• Aberrant functional connectivity (FC) was observed between the Hb and regions including the nucleus accumbens (NAc) and ventral pallidum (VeP) in StD.
• The 4-week HRV-BF intervention improved HRV indices, partially restored Hb-centered network FC, and reduced depressive symptoms and improved sleep quality.

Conclusions:

• Aberrant Hb-centered functional connectivity contributes to cardiac autonomic dysfunction in StD.
• Hb-NAc and Hb-VeP functional connectivity may serve as neuroimaging biomarkers for StD.
• HRV-BF enhances vagal tone, rebalances cardiac ANS function, and restores Hb-centered network connectivity, offering a promising intervention target.