Brain systems for baroreflex suppression during stress in humans

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Psychophysiology

Background:

• The arterial baroreflex regulates blood pressure homeostasis.
• Psychological stressors impair baroreflex sensitivity (BRS) in humans and animals.
• Human brain mechanisms linking stress to BRS suppression remain unclear.

Purpose of the Study:

• To investigate the human brain systems involved in stress-induced suppression of baroreflex sensitivity.
• To correlate brain activity and functional connectivity with changes in BRS during a psychological stressor.

Main Methods:

• 97 adults underwent beat-to-beat blood pressure and heart rate monitoring during a cognitive stress task.
• Spontaneous baroreflex sensitivity (BRS) was quantified using a validated sequence method.
• Functional magnetic resonance imaging (fMRI) measured brain activity and functional connectivity during the task.

Main Results:

• Task performance increased blood pressure and heart rate, and reduced BRS.
• Reduced BRS correlated with increased activity in central autonomic and cardiovascular control regions (cingulate cortex, insula, amygdala, PAG).
• Task performance enhanced functional connectivity between the anterior insula and the cingulate cortex, amygdala, midbrain PAG, and pons.

Conclusions:

• This study provides human evidence for brain systems suppressing baroreflex function during psychological stress.
• Findings elucidate neurobiological mechanisms of stressor-related cardiovascular reactivity.
• These insights are relevant for understanding essential hypertension and atherosclerotic heart disease risk.