Automatic approach and avoidance tendencies toward rewards and threats are fundamental for survival but may conflict with long-term goals or situational demands. Effective regulation of these responses is essential for adaptive behavior, with dysregulation implicated in disorders such as anxiety and addiction. Although prior research highlights the inferior frontal gyrus in response inhibition and the anterior prefrontal cortex in affective control, the neural mechanisms underlying inhibition during affective-motivational conflict remain unclear. This dissertation characterizes the behavioral, physiological, and neural substrates of suppressing automatic approach-avoidance tendencies and examines the modulatory role of competing incentives. Using a novel free versus forced approach-avoidance conflict paradigm, participants first learned conditioned stimulus-outcome associations and then executed joystick-based approach and avoidance responses. Behavioral, psychophysiological (eye tracking, heart rate, pupil dilation), and fMRI data were integrated to elucidate multi-level dynamics of motivational conflict resolution. We found robust evidence that responses counteracting automatic approach-avoidance tendencies (e.g., approaching aversive stimuli) incurred cognitive costs, reflected in slower responses than concordant responses (e.g., avoiding aversive stimuli). Conflict amplified individual differences in avoidance propensity and threat vigilance. Neural findings revealed that overcoming threat-driven avoidance specifically recruited the left inferior frontal gyrus, whereas suppressing reward-driven approach lacked distinct neural signatures. Heart rate deceleration preceding action suggests a general preparation of behavioral responses. Single-valence stimuli elicited respective valence-specific gaze biases during anticipation of reward and threat. Moreover, anticipation of threat and conflict activated a salience-control network (anterior/middle cingulate cortex, anterior insula, inferior frontal gyrus, ventral striatum) with heightened pupil dilation relative to reward processing. Ventral striatum activity patterns and connectivity with the right temporoparietal junction predicted individual differences in behavioral divergence under conflict relative to threat. Introducing competing outcomes dynamically reshaped emotional appraisal, reoriented attention, and modulated autonomic responses, enabling adaptive goal-switching behaviors despite asymmetry in subjective valence. Collectively, these findings indicate that approach-avoidance regulation is mediated by salience-driven neural mechanisms influenced by individual motivational biases and can be adaptively modulated by competing incentives. This work advances the understanding of motivational conflict resolution and informs potential interventions for anxiety and addiction.
Menghuan Chen (Thu,) studied this question.