Deficits in Emotional Perception-Related Motor Cortical Excitability in Individuals with Trait Anxiety: A Transcranial Magnetic Stimulation Study

Abnormal emotional perception may contribute to emotional dysfunction in individuals with anxiety. This study explored the progression of impaired emotional perception with the deepening of anxiety in individuals with nonclinical trait anxiety, by measuring the motor cortical excitability associated with emotional perception. In total, 87 participants were assigned to a high trait anxiety (n = 27), moderate trait anxiety (n = 30), or low trait anxiety (n = 30) group. Transcranial magnetic stimulation was applied to the right primary motor cortex at 150 ms or 300 ms after the onset of positive, negative, or neutral images, while participants performed an emotion recognition task, and motor-evoked potentials (MEPs) were collected. For participants with low trait anxiety, MEP amplitudes were significantly higher for both negative and positive stimuli than for neutral stimuli. Participants with moderate trait anxiety showed significantly higher MEP amplitudes only for negative stimuli. Participants with high trait anxiety showed no significant difference in MEP amplitudes for positive, negative, and neutral stimuli. Trait anxiety score was negatively correlated with MEP amplitude: For higher trait anxiety scores, MEP amplitudes were correlated with lower emotional perception of positive and negative stimuli. Findings suggest that anxiety impairs emotional perception-related motor cortical excitability, starting with decreased motor cortical excitability responses to positive information and progressing to negative information as anxiety levels increase.