The human amygdala is a key structure for processing emotional facial expressions, but it remains unclear what aspects of emotion are processed. We investigated this question with three different approaches: behavioural analysis of 3 amygdala lesion patients, neuroimaging of 19 healthy adults, and single-neuron recordings in 9 neurosurgical patients. The lesion patients showed a shift in behavioural sensitivity to fear, and amygdala BOLD responses were modulated by both fear and emotion ambiguity (the uncertainty that a facial expression is categorized as fearful or happy). We found two populations of neurons, one whose response correlated with increasing degree of fear, or happiness, and a second whose response primarily decreased as a linear function of emotion ambiguity. Together, our results indicate that the human amygdala processes both the degree of emotion in facial expressions and the categorical ambiguity of the emotion shown and that these two aspects of amygdala processing can be most clearly distinguished at the level of single neurons.

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.

E-mail: steffen.herff[at]epfl.ch.We thank Lauren Fairley, Jon Prince, and Estefanía Cano for constructive comments on an earlier draft, and Arihant Singhai, Ren Jie Tay, and Jing Wen Chai for their support during data collection. We thank Feng Lei for advice on the choice of cognitive assessment tests and 2 organising training on administering the tests. The study was supported by the Singapore Ministry of Education (MOE2016-T2-1-015) awarded to Prof Yu. Steffen A. Herff developed the paradigm, and designed, coded, as well as prepared the experiment. Kat R. Agres helped develop the experimental design and paradigm. Data collection was performed or supervised by Steffen A. Herff and Shanshan Zhen. Data was analyzed and interpreted by Steffen A. Herff. The manuscript was written by Steffen A. Herff with Shanshan Zhen, Rongjun Yu, and Kat R. Agres providing comments. The project and collaboration were initiated by Kat R. Agres, and Rongjun Yu provided lab space and equipment. All authors approved the final version of this manuscript. We have no known conflict of interest to disclose.We archived a preprint of the present work which can be accessed through: https://psyarxiv.com/kuy6p.

People often anticipate certain benefits when making dishonest decisions. In this article, we aim to dissociate the neural-cognitive processes of (1) dishonest decisions that focus on overall benefits of being dishonest (regardless of whether the benefits are self-serving or prosocial) from (2) those that distinguish between self-serving and prosocial benefits. Thirty-one participants had the opportunity to maximize their monetary benefits by voluntarily making dishonest decisions while undergoing functional magnetic resonance imaging (fMRI). In each trial, the monetary benefit of being dishonest was either self-serving or prosocial. Behaviorally, we found dissociable patterns of dishonest decisions: some participants were dishonest for overall benefits, while others were primarily dishonest for self-serving (compared with prosocial) benefits. When provided an opportunity to be dishonest for either self-serving or prosocial benefits, participants with a stronger overall tendency to be dishonest had stronger vmPFC activity, as well as stronger functional connectivity between the vmPFC and dlPFC. Furthermore, vmPFC activity was associated with decisions to be dishonest both when the benefits of being dishonest were self-serving and prosocial. Conversely, high self-serving-biased participants had stronger striatum activity and stronger functional connectivity between the striatum and middle-mPFC when they had a chance to be dishonest for self-serving (compared with prosocial) benefits. Altogether, we showed that activity in (and functional connectivity between) regions in the valuation (e.g., vmPFC and Str) and executive control (e.g., dlPFC and mmPFC) systems play a key role in registering the social-related goal of dishonest decisions.