Dissociating action inhibition, conflict monitoring and sensory mismatch into independent components of event related potentials in GO/NOGO task Juri D. Kropotov a, b, ⁎, Valery A. Ponomarev a , Stig Hollup b , Andreas Mueller c a Institute of the Human Brain of Russian Academy of Sciences, 12 a, ul. Academica Pavlova, St. Petersburg 197376, Russia b Institute of Psychology, Norwegian University of Science and Technology, Dragvoll, Bld.12, 7491 Trondheim, Norway c Brain and Trauma Foundation, Grison, Switzerland; Praxis für Kind, Organisation und Entwicklung, Untere Gasse 17, 7000 Chur, Switzerland abstract article info Article history: Received 23 January 2011 Revised 21 April 2011 Accepted 26 April 2011 Available online 3 May 2011 Keywords: Event-related potentials (ERPs) Independent component analysis (ICA) GO/NOGO paradigm N2 and P3 waves sLORETA Independent component (IC) The anterior N2 and P3 waves of event related potentials (ERPs) in the GO/NOGO paradigm in trials related to preparatory set violations in previous studies were inconsistently associated either with action inhibition or conflict monitoring operations. In the present study a paired stimulus GO/NOGO design was used in order to experimentally control the preparatory sets. Three variants of the same stimulus task manipulated sensory mismatch, action inhibition and conflict monitoring operations by varying stimulus-response associations. The anterior N2 and P3 waves were decomposed into components by means of independent component analysis (ICA). The ICA was performed on collection of 114 individual ERPs in the three experimental conditions. Three of the independent components were selectively affected by the task manipulations indicating association of these components with sensory mismatch, action inhibition and conflict monitoring operations. According to sLORETA the sensory mismatch component was generated in the left and right temporal areas, the action suppression component was generated in the supplementary motor cortex, and the conflict monitoring component was generated in the anterior cingulate cortex. © 2011 Elsevier Inc. All rights reserved. Introduction Humans show a high extent of flexibility facing events that do not fit a prepotent model of behavior. This flexibility is associated with several psychological operations united under a general concept of cognitive control (Folstein and Van Petten, 2008). The cognitive control includes at least two operations: 1) operation of inhibition of an ongoing response pattern in order to avoid interference from irrelevant actions (Barkley, 1997; Aron, 2007) and 2) conflict monitoring operation detecting conflict when response tendencies are interfering with each other (van Veen and Carter, 2002; Botvinick, 2007). In experimental conditions for studying cognitive control a GO/ NOGO paradigm has been used. In the conventional GO/NOGO paradigm two stimuli (for example of green and red color) are sequentially and randomly presented with relatively long (more than 1 s) inter-stimulus intervals (Gemba and Sasaki, 1989). The subject is preparing to make an action as fast and as precise as possible in response to the GO cues (for example green color) and has to withhold from the action in response to the NOGO cues (red color). Event related potentials (ERPs) recorded in the GO/NOGO paradigm exhibit two waveforms obtained in the difference NOGO– GO potentials and labeled correspondingly N2 NOGO (referred in this paper as N2 wave) and P3 NOGO (referred in this paper as P3 wave). The N2 wave is distributed over frontal–central electrodes and peaks between 250 and 350 ms (Pfefferbaum et al., 1985; Kok, 1986; Jodo and Kayama, 1992). The P3 wave follows the N2 wave and has a similar scalp distribution (Pfefferbaum et al., 1985; Kok, 1986; Jodo and Kayama, 1992). In the early research the N2 and P3 waves were considered as a single complex N2/P3 (Simson et al., 1977). However recent research considers these waves as separate categories (Huster et al., 2010). The hypothesis that the N2 wave is associated with inhibition of action is supported by the following findings: 1) the N2 is larger in overt response inhibition tasks in comparison to silent counting tasks (Pfefferbaum et al., 1985; Bruin and Wijers, 2002), 2) The N2 is increased by pressure to respond quickly (Jodo and Kayama, 1992), 3) the N2 is larger in participants with low rather than high false alarm rates (Falkenstein et al., 1999), and 4) the N2 is larger when NOGO stimuli share some features with GO stimuli and thus initiate preparation to respond that must be suppressed (Azizian et al., 2006). However, in a study by Nieuwenhuis et al. (2003) the N2 was evoked in GO trials when the frequency of presentations of NOGO trials was quite high. This observation indicated that the N2 might reflect conflict arising from competition between the execution and the inhibition of a response. This suggestion was recently supported NeuroImage 57 (2011) 565–575 ⁎ Corresponding author at: Institute of the Human Brain of Russian Academy of Sciences, 12 a, ul. Academica Pavlova, St. Petersburg 197376, Russia. Fax: +7 812 234 32 47. E-mail address: jdkropotov@yahoo.com (J.D. Kropotov). 1053-8119/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.neuroimage.2011.04.060 Contents lists available at ScienceDirect NeuroImage journal homepage: www.elsevier.com/locate/ynimg