Lateral prefrontal anodal transcranial direct current stimulation augments resolution of auditory...

Successful action control requires the ability to attend to relevant sensory signals in the environment. This, however, can be complicated when different sensory inputs compete for the brain's limited resources. Under such conditions, sensory processes interact with top-down attention to selectively process goal-relevant stimuli, while inhibiting irrelevant or distracting sensory signals. In the current study, we set out to provide causal mechanistic insights for whether and how prefrontal regions are involved in resolving attentional-perceptual conflicts. To this end, we applied atDCS and examined neurophysiological processes of selective auditory perception. To evaluate whether atDCS differentially affects intermingled neurophysiological subprocesses involved during conflict resolution, we decomposed the EEG data using residue iteration decomposition (RIDE). We show that the right prefrontal regions are causally involved in resolving attentional-perceptual conflicts and that atDCS increases the efficacy to do so. The data show that dissociable neurophysiological signals are specifically affected by atDCS. Conflict resolution processes that involve inhibition of competing stimuli and response evaluation and are associated with right middle frontal gyrus (BA46) seem to become intensified by atDCS during the resolution of attentional-perceptual conflicts. After stimulation the early stimulus processing level was also less prone to sensory conflicts, but this alone could not explain the increased behavioral efficacy associated with atDCS. These observed effects likely reflect changes in neuronal gain control mechanisms. Taken together, results of this study may have implications for treating attentional hyperactivity disorder, for which pharmacological intervention is currently the common therapeutic approach.