Individual differences in behavioral activation and cardiac vagal control influence affective startle modification

Area of Science:

• Psychophysiology
• Neuroscience
• Behavioral Science

Background:

• Startle response (SR) and its modification (SRM) are linked to stress responses and disorders like PTSD.
• Behavioral Inhibition and Activation Systems (BIS/BAS) framework relates to motivational processes influencing affective SRM and stress reactivity.
• Vagally-mediated cardiac activity (HRV) is associated with SRM and stress regulation.

Purpose of the Study:

• To investigate the influence of individual differences in BIS/BAS and resting HRV on affective SRM.
• To examine how BAS and HRV interact to affect stress reactivity and SRM.

Main Methods:

• Eighty-six subjects viewed affective pictures with acoustic SR stimuli.
• SR magnitude assessed via eyeblink electromyography.
• BIS/BAS measured using scales; resting HRV derived from electrocardiography.

Main Results:

• Startle inhibition and potentiation were associated with BAS and HRV, but not BIS.
• An interaction between BAS and HRV was observed: the HRV-SRM link strengthened as BAS scores decreased.
• BAS may influence both withdrawal and approach behaviors.

Conclusions:

• Trait stress reactivity is influenced by BAS and cardiac vagal activity.
• BAS moderates the relationship between cardiac vagal activity and SRM.
• Findings offer theoretical and practical implications for SRM, stress disorders, and health.