title: Two Independent Frontal Midline Theta Oscillations during Conflict Detection and Adaptation in a Simon-Type Manual Reaching Task.
abstract: One of the most firmly established factors determining the speed of human behavioral responses toward action-critical stimuli is the spatial correspondence between the stimulus and response locations. If both locations match, the time taken for response production is markedly reduced relative to when they mismatch, a phenomenon called the Simon effect. While there is a consensus that this stimulus-response (S-R) conflict is associated with brief (4-7 Hz) frontal midline theta (fmθ) complexes generated in medial frontal cortex, it remains controversial (1) whether there are multiple, simultaneously active theta generator areas in the medial frontal cortex that commonly give rise to conflict-related fmθ complexes; and if so, (2) whether they are all related to the resolution of conflicting task information. Here, we combined mental chronometry with high-density electroencephalographic measures during a Simon-type manual reaching task and used independent component analysis and time-frequency domain statistics on source-level activities to model fmθ sources. During target processing, our results revealed two independent fmθ generators simultaneously active in or near anterior cingulate cortex, only one of them reflecting the correspondence between current and previous S-R locations. However, this fmθ response is not exclusively linked to conflict but also to other, conflict-independent processes associated with response slowing. These results paint a detailed picture regarding the oscillatory correlates of conflict processing in Simon tasks, and challenge the prevalent notion that fmθ complexes induced by conflicting task information represent a unitary phenomenon related to cognitive control, which governs conflict processing across various types of response-override tasks.SIGNIFICANCE STATEMENTHumans constantly monitor their environment for and adjust their cognitive control settings in response to conflicts, an ability that arguably paves the way for survival in ever-changing situations. Anterior cingulate-generated frontal midline theta (fmθ) complexes have been hypothesized to play a role in this conflict-monitoring function. However, it remains a point of contention whether fmθ complexes govern conflict processing in a unitary, paradigm-nonspecific manner. Here, we identified two independent fmθ oscillations triggered during a Simon-type task, only one of them reflecting current and previous conflicts. Importantly, this signal differed in various respects (cortical origin, intertrial history) from fmθ phenomena in other response-override tasks, challenging the prevalent notion of conflict-induced fmθ as a unitary phenomenon associated with the resolution of conflict.
authors.affiliation: Department of Experimental Psychology and thomas.toellner@psy.lmu.de.|Graduate School of Systemic Neurosciences, LMU Munich, D-80802 Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Töllner
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego, La Jolla, California 92093.
authors.forename: Scott
authors.identifier: 0000-0002-9048-8438
authors.initials: S
authors.lastname: Makeig
authors.affiliation: Department of Experimental Psychology and.|Department of Psychological Sciences, Birkbeck College, University of London, London, WC1E 7HX, United Kingdom, and.
authors.forename: Hermann J
authors.initials: HJ
authors.lastname: Müller
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego, La Jolla, California 92093.
authors.forename: Tzyy-Ping
authors.identifier: 0000-0002-8377-2166
authors.initials: TP
authors.lastname: Jung
authors.affiliation: Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California, San Diego, La Jolla, California 92093.|Department of Biological Psychology and Neuroergonomics, TU Berlin, D-10587 Berlin, Germany.
authors.forename: Klaus
authors.identifier: 0000-0003-2673-1832
authors.initials: K
authors.lastname: Gramann
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D001931:Brain Mapping; D003220:Conflict, Psychological; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation; D025341:Principal Component Analysis; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D017603:Signal Detection, Psychological / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology*; D014796:Visual Perception; D055815:Young Adult
keywords: cognitive control; conflict processing; independent component analysis