Affective face biases in visual and prefrontal cortex measured with visual entrainment

Area of Science:

• Cognitive Neuroscience
• Social Neuroscience
• Neuroimaging

Background:

• Affective facial expressions are potent social cues that capture attention, often at the expense of other visual information.
• Functional neuroimaging implicates the prefrontal cortex in regulating responses to emotional distractors, but measuring unique neural signals from competing stimuli is challenging.
• Existing methods limit understanding of how the brain generates attentional biases towards affective stimuli.

Purpose of the Study:

• To investigate the neural mechanisms underlying attentional biases towards concurrent and spatially overlapping visual stimuli, specifically faces and Gabor patches.
• To track unique neural signals elicited by task-relevant and distractor stimuli using a novel frequency tagging approach.
• To determine how facial expressions (angry, neutral, happy) modulate neural responses and attentional biases in different cortical regions.

Main Methods:

• Employed a novel frequency tagging approach with visual entrainment during magnetoencephalography (MEG).
• Tracked unique neural signals from a task-relevant Gabor patch and a spatially overlapping face with varying expressions.
• Utilized beamforming to project entrainment responses to the cortex and calculated a competition index to assess stimulus bias.

Main Results:

• Found stronger neural bias towards the Gabor patch (task-relevant stimulus) in the prefrontal cortex for neutral faces compared to angry or happy faces.
• Observed a stronger neural bias towards the face stimulus in the calcarine cortex for angry expressions compared to neutral or happy expressions.
• Identified sensitivity to facial expression in brain regions associated with face processing, social cognition, and attention.

Conclusions:

• The prefrontal cortex plays a role in regulating responses to emotional distractors, showing a bias towards non-emotional stimuli when competing.
• The calcarine cortex exhibits enhanced processing for angry facial expressions, consistent with electroencephalography findings.
• Frequency tagging paradigms are effective for isolating neural responses to concurrent, overlapping stimuli, advancing the study of social and emotional processing.