Short-Term Effects of Aerobic Exercise on Brain Connectivity in Individuals With Subthreshold Depression

Area of Science:

• Neuroscience
• Clinical Psychology
• Exercise Science

Background:

• Subthreshold depression (StD) is a key risk factor for major depressive disorder (MDD).
• Aerobic exercise is known to alleviate depressive symptoms and potentially prevent MDD.
• The neurobiological mechanisms underlying aerobic exercise's effects on StD are not well understood.

Purpose of the Study:

• To investigate the short-term effects of aerobic exercise on brain connectivity in individuals with StD.
• To explore the neural mechanisms through which aerobic exercise impacts depressive and anxiety symptoms in StD.
• To determine if baseline brain differences can distinguish StD from healthy controls (HCs).

Main Methods:

• An 8-week aerobic exercise intervention was conducted with 44 individuals with StD and 34 HCs.
• Granger causality analysis (GCA) and frequency-dependent functional connectivity (FC) were used to assess brain activity.
• Support vector machine (SVM) analysis was employed to differentiate between StD and HCs based on baseline brain data.

Main Results:

• Individuals with StD exhibited altered GCA and FC in cognitive control and visual processing regions prior to exercise.
• The SVM classifier achieved 80.77% accuracy in distinguishing StD from HCs.
• Aerobic exercise significantly reduced depression and anxiety levels, restoring abnormal GCA and FC patterns.

Conclusions:

• Aerobic exercise demonstrates short-term efficacy in improving depression and anxiety symptoms in individuals with StD.
• The intervention effectively restores aberrant brain connectivity patterns, suggesting a neurobiological basis for its therapeutic effects.
• These findings highlight aerobic exercise as a potential strategy for managing StD and preventing MDD progression.