Facial expressions and complex IAPS pictures: common and differential networks

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Affective Science

Background:

• Emotion research often uses distinct visual stimuli: facial expressions and evocative scenes.
• It's unclear if these stimuli engage identical neural processes.
• Facial expressions may prime emotion recognition, while scenes might evoke direct emotional experiences.

Purpose of the Study:

• To compare brain activation patterns using functional magnetic resonance imaging (fMRI) between facial emotion stimuli and complex emotional pictures.
• To determine if these different visual formats activate similar or distinct neural regions in healthy volunteers.

Main Methods:

• fMRI was used to measure Blood-Oxygen-Level-Dependent (BOLD) activation.
• Participants passively viewed blocks of emotional faces and International Affective Picture System (IAPS) images, balanced for emotion type (happy, sad, anger, fear, neutral).
• Eye movements, reaction times, and subjective ratings of emotion, valence, and arousal were recorded.

Main Results:

• Both stimulus types activated shared brain structures: amygdala, posterior hippocampus, ventromedial prefrontal cortex, and visual cortex.
• Expressive faces, despite lower arousal ratings, uniquely activated the superior temporal gyrus, insula, and anterior cingulate cortex compared to IAPS pictures.
• Most activated regions responded across various emotions, though some showed emotion-specific responses.

Conclusions:

• Facial expressions and complex emotional pictures recruit overlapping neural networks involved in emotion processing.
• Distinct brain regions are uniquely engaged by facial stimuli, potentially reflecting differences in emotion perception versus direct emotional experience.
• These findings highlight nuanced neural responses to different types of emotional visual stimuli.