Emotion-perception interplay in the visual cortex: "the eyes follow the heart"

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Emotive stimuli modulate perceptual thresholds and activate limbic and sensory cortical regions.
• The influence of stimulus characteristics on emotional activation in sensory cortex remains unclear.
• Functional Magnetic Resonance Imaging (fMRI) adaptation reveals brain response dynamics.

Purpose of the Study:

• To investigate how emotional valence affects sensory cortex activation using fMRI adaptation.
• To explore if traumatic experiences, specifically in Posttraumatic Stress Disorder (PTSD), alter visual cortex responses to trauma-related stimuli.

Main Methods:

• Utilized Expressional Transfiguration (ET) of faces to manipulate emotional valence while controlling visual features.
• Employed fMRI adaptation by comparing repeated vs. different stimulus presentations to assess brain response dynamics.
• Compared brain activation patterns in PTSD veterans and non-PTSD veterans exposed to combat-related stimuli.

Main Results:

• Emotional valence significantly altered fMRI adaptation in the lateral occipital complex (LOC), but not overall activation levels.
• PTSD veterans showed reduced fMRI adaptation (less signal decrease with repeated stimuli) to combat-related images compared to non-PTSD veterans.
• Differences between PTSD and non-PTSD groups were specific to repeated presentations of trauma-related stimuli in visual cortical regions.

Conclusions:

• Emotional valence modulates sensory cortex processing, detectable via fMRI adaptation.
• Traumatic experiences may lead to altered sensory cortex function in individuals with PTSD.
• Findings suggest that trauma can impact brain activity at the sensory processing level itself.