Decision ambiguity is mediated by a late positive potential originating from cingulate cortex

Abstract

Decision ambiguity is mediated by a late positive potential originating from cingulate cortex, NeuroImage, http://dx.doi.org/10.1016/j.neuroimage. 2017.06.003 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractPeople often make decisions in the face of ambiguous information, but it remains unclear how ambiguity is represented in the brain. We used three types of ambiguous stimuli and combined EEG and fMRI to examine the neural representation of perceptual decisions under ambiguity.We identified a late positive potential, the LPP, which differentiated levels of ambiguity, and which was specifically associated with behavioral judgments about choices that were ambiguous, rather than passive perception of ambiguous stimuli. Mediation analyses together with two further control experiments confirmed that the LPP was generated only when decisions are made (not during mere perception of ambiguous stimuli), and only when those decisions involved 2 choices on a dimension that is ambiguous. A further control experiment showed that a stronger LPP arose in the presence of ambiguous stimuli compared to when only unambiguous stimuli were present. Source modeling suggested that the LPP originated from multiple loci in cingulate cortex, a finding we further confirmed using fMRI and fMRI-guided ERP source prediction.Taken together, our findings argue for a role of an LPP originating from cingulate cortex in encoding decisions based on task-relevant perceptual ambiguity, a process that may in turn influence confidence judgment, response conflict, and error correction.

Ambiguous at the second sight: Mixed facial expressions trigger late electrophysiological responses linked to lower social impressions

“…Understanding the role of ambiguity in processing facial expressions is important given that in the real world, faces are "inherently ambiguous" and often contain features of multiple emotions (Aviezer et al, 2008;Hassin, Aviezer, & Bentin, 2013). This investigation also helps us to extend our understanding of the mechanisms underlying ambiguity processing more generally, as similar behavioral effects in evaluation have been obtained with a variety of facial and nonfacial stimuli (Carr et al, 2017a;Carr et al, 2017b;Sun et al, 2017;Winkielman, Halberstadt, Fazendeiro, & Catty, 2006). Before we describe the current study, we offer more background on the concept of processing fluency and the EEG measures of face processing in the brain.…”

“…At the later stages, the perceiver must resolve a conflict between the perceived mix of facial features and the activated emotion categories, especially when the current task requires the perceiver to do so. Resolution of this conflict takes cognitive effort, recruiting cognitive, motivational, and affective resources (Sun et al, 2017;Willadsen-Jensen & Ito, 2006). The resolution of the conflict then allows the perceiver to assign the faces into some emotion category that can then support social judgment.…”

“…To better understand the dynamics of face perception, categorization, and evaluation, researchers have often relied on EEG measures, especially event-related brain potentials (ERPs). Such measures allow for precise assessment of temporal dynamics (Eimer & Holmes, 2007) and provide information about the mental effort involved in such processing (Sun et al, 2017). Accordingly, we use ERP measures to explore early and late effects, as a function of the physical features of the faces and the impact of the categorization task.…”

“…The late positive potential ERP component, the LPP, appears 400-800 ms poststimulus onset and reflects more complex processes associated with memory, categorization, and evaluation of the affective and motivational significance of the stimulus for the perceiver (Friedman & Johnson, 2000;Frenkel & Bar-Haim, 2011;Schacht & Sommer, 2009;Sun et al, 2017). Critically, previous work has distinguished the timing and presumed brain sources of different psychological processes generating distinct types of LPP response.…”

“…Specifically, more frontal LPPs differentiate levels of ambiguity and depend on the choice requirements, rather than passive perception of ambiguous stimuli (Calvo, Marrero, Beltran, 2013;O'Connell et al, 2012;Kelly and O'Connell, 2013;Murphy et al, 2015). Recently Sun et al (2017) have shown greater LPP responses to ambiguous stimuli, including mixed facial expressions, but only when participants had to make a categorization choice. In their study, which used a similar paradigm to our investigation, stimuli varied on two dimensions, and participants made classification decisions that were either related or unrelated to the dimensions on which the stimuli were ambiguous.…”