Enhancing Anger Perception With Transcranial Alternating Current Stimulation Induced Gamma Oscillations.

BACKGROUND: In recent years a variety of neuroimaging studies have highlighted a role of neural oscillations in perception and cognition. However, surprisingly little is known about oscillatory activity underlying facial emotion perception. The limited number of studies that have addressed this question indicate that gamma oscillations are one mechanism underlying this process. OBJECTIVE: The present study aimed to further elucidate the role of neural oscillations within the gamma range in facial emotion perception in healthy adults by using transcranial alternating current stimulation (tACS). METHODS: To that effect we carried out three experiments with separate groups of participants using tACS to modulate occipital oscillations while participants completed facial anger and facial identity tasks. RESULTS: The results of these experiments indicated that modulating occipital gamma with 40 Hz tACS enhances facial anger perception. CONCLUSION: This finding implicates an important role of occipital gamma oscillations in facial emotion perception.

Synesthesia for color is linked to improved color perception but reduced motion perception.

Synesthesia is a rare condition in which one property of a stimulus (e.g., shape) triggers a secondary percept (e.g., color) not typically associated with the first. Work on synesthesia has predominantly focused on confirming the authenticity of synesthetic experience, but much less research has been conducted to examine the extent to which synesthesia is linked to broader perceptual differences. In the research reported here, we examined whether synesthesia is associated with differences in color and motion processing by comparing these abilities in synesthetes who experience color as their evoked sensation with nonsynesthetic participants. We show that synesthesia for color is linked to facilitated color sensitivity but decreased motion sensitivity. These findings are discussed in relation to the neurocognitive mechanisms of synesthesia and interactions between color and motion processing in typical adults.