It's the Other Way Around! Early Modulation of Sensory Distractor Processing Induced by Late Response Conflict

Understanding the neural processes that maintain goal-directed behavior is a major challenge for the study of attentional control. Although much of the previous work on the issue has focused on prefrontal brain areas, little is known about the contribution of sensory brain processes to the regulation of attentional control. The present EEG study examined brain oscillatory activities invoked in the processing of response conflict in a lateralized Eriksen single-flanker task, in which target letters were presented at fixation and single distractor letters were presented either left or right to the targets. Distractors were response compatible, response incompatible, or neutral in relation to the responses associated with the targets. The behavioral results showed that responses to targets in incompatible trials were slower and more error prone than responses in compatible trials. The electrophysiological results revealed an early sensory lateralization effect in (both evoked and induced) theta power (3-6 Hz) that was more pronounced in incompatible than compatible trials. The sensory lateralization effect preceded in time a midfrontal conflict effect that was indexed by an increase of (induced) theta power (6-9 Hz) in incompatible compared with compatible trials. The findings indicate an early modulation of sensory distractor processing induced by response conflict. Theoretical implications of the findings, in particular with respect to the theory of event coding and theories relating to stimulus-response binding [Henson, R. N., Eckstein, D., Waszak, F., Frings, C., & Horner, A. Stimulus-response bindings in priming. Trends in Cognitive Sciences, 18, 376-384, 2014; Hommel, B., Musseler, J., Aschersleben, G., & Prinz, W. The theory of event coding (TEC): A framework for perception and action planning. Behavioral and Brain Sciences, 24, 849-878, 2001], are discussed.