Effect of Attention on Processing Emotional Chinese Words: An Event-Related fMRI Study

Whether attention can modulate amygdala response to emotional materials has been hotly debated, and most evidence comes from emotional facial expressions which have much ecological significance. In contrast, little is known about the influence of attention on processing of emotional words as revealed by brain activation. We adopted an event-related fMRI paradigm to investigate whether brain responses to emotional words are affected by spatial attention using Chinese two-character words as stimuli. During the scan, the participant’s attention was directed to the horizontal or vertical locations which contain pairs of Chinese words or line-drawing houses, and he/she was required to indicate whether the pair of stimuli at the pre-specified locations were the same or different while ignoring the other irrelevant pair of stimuli. Reaction time, accuracy, and eye movements were recorded, and functional imaging data were acquired. Results showed that while neutral words at attended locations versus unattended locations produced brain activation patterns consistent with the reports of previous studies with Chinese words as visual stimuli, pleasant words showed no differential activation and unpleasant words evoked higher activation only in inferior frontal gyrus. Conversely, unpleasant words at unattended locations versus attended locations elicited activities in brain regions including amygdala, indicating possible attentional suppression to amygdala’s response to unpleasant words.