Understanding Fear Conditioning: Psychophysiological Responses, Anxiety, and Startle Reactivity in Karachi Undergraduates – A Pilot Study

Background: Fear conditioning, a cornerstone in the exploration of fear learning, provides insights into the intricate mechanisms shaping adaptive and maladaptive fear responses. This pilot study delves into fear conditioning among undergraduate students in Karachi, Pakistan, aiming to understand the nuanced interplay between anxiety, startle reactivity, and physiological measures. Methodology: Forty-six healthy undergraduate students (18-30 years) participated in a differential fear-conditioning paradigm. Cockroach images, culturally significant fear stimuli, served as conditioned stimuli (CS+), paired with a mild shock in 75% of trials, while a neutral cue (CS−) provided a baseline. Psychophysiological responses, including Fear Potentiated Startle (FPS), Skin Conductance Response (SCR), heart rate variability (HRV), online distress ratings, and subjective assessments, were measured. Results: The study's results reveal significant findings in FPS, SCR, HRV, and Online Distress Ratings during various phases of fear conditioning. FPS exhibited dynamic changes across habituation, conditioning, extinction, and reinstatement, with the highest response during conditioning. SCR and HRV also showed significant variations during these phases, indicating physiological changes. Distress ratings increased significantly during conditioning. Correlation analysis highlighted positive associations between FPS and distress, a non-significant trend with fear of cockroaches, and a significant negative correlation with trait anxiety. Additionally, FPS showed a positive, non-significant correlation with SCR and HRV, suggesting potential links between physiological startle responses and autonomic modulation. Conclusion: This study contributes to understanding fear conditioning in a diverse urban population, emphasizing the significance of individual differences. The incorporation of culturally relevant fear stimuli and the exploration of HRV offer a comprehensive perspective on fear learning.