Functional imaging of sympathetic activation during mental stress

Area of Science:

• Neuroscience
• Psychophysiology

Background:

• The sympathetic nervous system (SNS) is crucial for adaptation and homeostasis but can maladapt when overactivated.
• Stress-related diseases are linked to SNS maladaptation, yet cortical mechanisms of sympathetic activation during acute mental stress remain unclear.

Purpose of the Study:

• To investigate cerebral activation patterns during acute mental stress using functional magnetic resonance imaging (fMRI).
• To correlate brain activity with physiological stress markers like skin conductance and heart rate.

Main Methods:

• Healthy subjects performed a graded difficulty Stroop task (Colour Word Interference Test, CWT) while undergoing fMRI.
• Skin conductance and heart rate were continuously monitored to assess sympathetic activation.

Main Results:

• Mental stress activated task-specific brain regions including visual, motor, and premotor areas.
• Regions not directly involved in task performance, such as the right insula, superior frontal gyrus, and cerebellum, were also activated.
• These additional regions are implicated in mediating various stress responses.

Conclusions:

• Sympathetic activation during acute mental stress involves both task-related and distinct stress-mediating cortical regions.
• These findings provide a foundation for future research into the neural basis of stress-related disorders.