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Published August 15, 2017 | Supplemental Material + Accepted Version
Journal Article Open

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


People 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 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.

Additional Information

© 2017 Elsevier Inc. Received 1 January 2017, Revised 5 May 2017, Accepted 1 June 2017, Available online 9 June 2017. We thank Xiaojing Wu and Min Pu for collecting some of the data. This research was supported by the National Natural Science Foundation of China (No. 31371128) and MOE Tier 1 (R-581-000-191-112) to R.Y., the Scientific Research Foundation of Graduate School of South China Normal University (2015wkxm02) and China Scholarship Council (201506750027) to S. Sun, and an NIMH Conte Center (P50MH094258) to R.A. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Author Contributions: S.Sun, R.A., R.Y., and S.W. designed experiments. S.Sun, S.Z., and S.W. performed research. S.Sun, S.Z., Z.F., D.W., R.Y. and S.W. analyzed data. S.Sun, S.Shimojo, R.A., R.Y., and S.W. wrote the paper. All authors discussed the results and contributed toward the manuscript. The authors declare no conflict of interest.

Attached Files

Accepted Version - nihms-1060066.pdf

Supplemental Material - mmc1.pdf


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