title: Auditory conflict resolution correlates with medial-lateral frontal theta/alpha phase synchrony.
abstract: When multiple persons speak simultaneously, it may be difficult for the listener to direct attention to correct sound objects among conflicting ones. This could occur, for example, in an emergency situation in which one hears conflicting instructions and the loudest, instead of the wisest, voice prevails. Here, we used cortically-constrained oscillatory MEG/EEG estimates to examine how different brain regions, including caudal anterior cingulate (cACC) and dorsolateral prefrontal cortices (DLPFC), work together to resolve these kinds of auditory conflicts. During an auditory flanker interference task, subjects were presented with sound patterns consisting of three different voices, from three different directions (45° left, straight ahead, 45° right), sounding out either the letters "A" or "O". They were asked to discriminate which sound was presented centrally and ignore the flanking distracters that were phonetically either congruent (50%) or incongruent (50%) with the target. Our cortical MEG/EEG oscillatory estimates demonstrated a direct relationship between performance and brain activity, showing that efficient conflict resolution, as measured with reduced conflict-induced RT lags, is predicted by theta/alpha phase coupling between cACC and right lateral frontal cortex regions intersecting the right frontal eye fields (FEF) and DLPFC, as well as by increased pre-stimulus gamma (60-110 Hz) power in the left inferior fontal cortex. Notably, cACC connectivity patterns that correlated with behavioral conflict-resolution measures were found during both the pre-stimulus and the pre-response periods. Our data provide evidence that, instead of being only transiently activated upon conflict detection, cACC is involved in sustained engagement of attentional resources required for effective sound object selection performance.
authors.affiliation: Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
authors.forename: Samantha
authors.initials: S
authors.lastname: Huang
authors.affiliation: Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America; Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Matti
authors.initials: M
authors.lastname: Hämäläinen
authors.affiliation: Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
authors.forename: Jyrki
authors.initials: J
authors.lastname: Ahveninen
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001519:Behavior; D001931:Brain Mapping; D003220:Conflict, Psychological; D003344:Cortical Synchronization / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology; D013647:Task Performance and Analysis; D013826:Theta Rhythm / Q000502:physiology*; D055815:Young Adult