title: N270 sensitivity to conflict strength and working memory: A combined ERP and sLORETA study.
abstract: The event-related potential N270 component is known to be an electrophysiological marker of the supramodal conflict processing. However little is know about the factors that may modulate its amplitude. In particular, among all studies that have investigated the N270, little or no control of the conflict strength and of the load in working memory have been done leaving a lack in the understanding of this component. We designed a spatial audiovisual conflict task with simultaneous target and cross-modal distractor to evaluate the N270 sensitivity to the conflict strength (i.e., visual target with auditory distractor or auditory target with visual distractor) and the load in working memory (goal task maintenance with frequent change in the target modality). In a first session, participants had to focus on one modality for the target position to be considered (left-hand or right-hand) while the distractor could be at the same side (compatible) or at opposite side (incompatible). In a second session, we used the same set of stimuli as in the first session with an additional distinct auditory signal that clued the participants to frequently switch between the auditory and the visual targets. We found that (1) reaction times and N270 amplitudes for conflicting situations were larger within the auditory target condition compared to the visual one, (2) the increase in target maintenance effort led to equivalent increase of both reaction times and N270 amplitudes within all conditions and (3) the right dorsolateral prefrontal cortex current density was higher for both conflicting and active maintenance of the target situations. These results provide new evidence that the N270 component is an electrophysiological marker of the supramodal conflict processing that is sensitive to the conflict strength and that conflict processing and active maintenance of the task goal are two functions of a common executive attention system.
authors.affiliation: DCAS, ISAE, Université de Toulouse, 10 Avenue E. Belin, 31055 Toulouse cedex 4, France; INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France. Electronic address: s.scannella@isae.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Scannella
authors.affiliation: INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Pariente
authors.affiliation: INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: De Boissezon
authors.affiliation: INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Castel-Lacanal
authors.affiliation: INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chauveau
authors.affiliation: DCAS, ISAE, Université de Toulouse, 10 Avenue E. Belin, 31055 Toulouse cedex 4, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Causse
authors.affiliation: DCAS, ISAE, Université de Toulouse, 10 Avenue E. Belin, 31055 Toulouse cedex 4, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Dehais
authors.affiliation: INSERM, UMRS 825, Université de Toulouse, CHU Purpan, Pavillon Baudot, 31024 Toulouse cedex 3, France.
authors.forename: Josette
authors.initials: J
authors.lastname: Pastor
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003220:Conflict, Psychological; D003463:Cues; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time; D012984:Software; D014796:Visual Perception / Q000502:physiology*
keywords: Dorsolateral prefrontal cortex; Executive attention; N270; Supramodal conflict processing; Working memory; sLORETA