Subject’s State Modulates Oscillatory Responses to Emotional Facial Expressions

Subject’s state during the experiment and his or her perception of the experimental procedure are usually ignored, although they may potentially considerably change the pattern of results. In this study, the effect of subject’s state on cortical oscillatory responses to emotional facial expressions was investigated in a sample of 40 subjects aged 17–32 years. The strength of oscillatory responses in all frequency bands was lower in subjects who felt tenseness, experienced negative emotions, and did not like the experimental procedure. Moreover, in these subjects, personality-related differences in cortical oscillatory responses were not found, though they were found in subjects who reported being relaxed and liked the procedure. The observed individual differences in subject’s state partly depended on personality and partly on other factors that preexisted before the experiment. These data show that subject’s state is an important contributor to observed oscillatory dynamics and should be taken into account.