When meeting other people, some are optimistic and expect to be accepted by others, whereas others are pessimistic and expect mostly rejections. How social feedback is evaluated in situations that meet or do not meet these biases and how people differ in their response to rejection and acceptance depending on the social situation are unknown. In this study, participants experienced rejection and acceptance by peers in two different social contexts, one with high (negative context) and the other with low probability of rejection (positive context). We examined how the neural and behavioral responses to rejection are altered by this context and whether it depends on the individual's sensitivity to rejection. Behavioral results show that, on average, people maintain an optimistic bias even when mostly experiencing rejection. Importantly, personality differences in rejection sensitivity affected both prior expectations to be rejected in the paradigm and the extent to which expectations changed during the paradigm. The context also strongly modulated ERPs and theta responses to rejection and acceptance feedback. Specifically, valence effects on neural responses were enhanced in the negative context, suggesting a greater relevance to monitor social feedback in such a situation. Moreover, midfrontal theta predicted how expectations were changed in response to prediction errors, stressing a role for theta in learning from social feedback. Surprisingly, interindividual differences in rejection sensitivity did not affect neural responses to feedback. Our results stress the importance of considering the interaction between subjective expectations and the social context for behavioral and neural responses to social rejection.

Previous research provided evidence for the critical importance of the PFC and BG for reactive motor inhibition, that is, when actions are cancelled in response to external signals. Less is known about the role of the PFC and BG in proactive motor inhibition, referring to preparation for an upcoming stop signal. In this study, patients with unilateral lesions to the BG or lateral PFC performed in a cued go/no-go task, whereas their EEG was recorded. The paradigm called for cue-based preparation for upcoming, lateralized no-go signals. Based on previous findings, we focused on EEG indices of cognitive control (prefrontal beta), motor preparation (sensorimotor mu/beta, contingent negative variation [CNV]), and preparatory attention (occipital alpha, CNV). On a behavioral level, no differences between patients and controls were found, suggesting an intact ability to proactively prepare for motor inhibition. Patients showed an altered preparatory CNV effect, but no other differences in electrophysiological activity related to proactive and reactive motor inhibition. Our results suggest a context-dependent role of BG and PFC structures in motor inhibition, being critical in reactive, unpredictable contexts, but less so in situations where one can prepare for stopping on a short timescale.

Damage to the ventromedial PFC (VMPFC) can cause maladaptive social behavior, but the cognitive processes underlying these behavioral changes are still uncertain. Here, we tested whether patients with acquired VMPFC lesions show altered approach–avoidance tendencies to emotional facial expressions. Thirteen patients with focal VMPFC lesions and 31 age- and gender-matched healthy controls performed an implicit approach–avoidance task in which they either pushed or pulled a joystick depending on stimulus color. Whereas controls avoided angry faces, VMPFC patients displayed an incongruent response pattern characterized by both increased approach and reduced avoidance of angry facial expressions. The approach bias was stronger in patients with higher self-reported impulsivity and disinhibition and in those with larger lesions. We further used linear ballistic accumulator modeling to investigate latent parameters underlying approach–avoidance decisions. Controls displayed negative drift rates when approaching angry faces, whereas VMPFC lesions abolished this pattern. In addition, VMPFC patients had weaker response drifts than controls during avoidance. Finally, patients showed reduced drift rate variability and shorter nondecision times, indicating impulsive and rigid decision-making. Our findings thus suggest that VMPFC damage alters the pace of evidence accumulation in response to social signals, eliminating a default, protective avoidant bias and facilitating a dysfunctional approach behavior.

Behavioral inhibition and performance monitoring are critical cognitive functions supported by distributed neural networks including the pFC. We examined neurophysiological correlates of motor response inhibition and action monitoring in patients with focal orbitofrontal (OFC) lesions ( n = 12) after resection of a primary intracranial tumor or contusion because of traumatic brain injury. Healthy participants served as controls ( n = 14). Participants performed a visual stop signal task. We analyzed behavioral performance as well as event-related brain potentials and oscillations. Inhibition difficulty was adjusted individually to yield an equal amount of successful inhibitions across participants. RTs of patients and controls did not differ significantly in go trials or in failed stop trials, and no differences were observed in estimated stop signal RT. However, electrophysiological response patterns during task performance distinguished the groups. Patients with OFC lesions had enhanced P3 amplitudes to congruent condition go signals and to stop signals. In stop trials, patients had attenuated N2 and error-related negativity, but enhanced error positivity. Patients also showed enhanced and prolonged post-error beta band increases for stop errors. This effect was particularly evident in patients whose lesion extended to the subgenual cingulate cortex. In summary, although response inhibition was not impaired, the diminished stop N2 and ERN support a critical role of the OFC in action monitoring. Moreover, the increased stop P3, error positivity, and post-error beta response indicate that OFC injury affected action outcome evaluation and support the notion that the OFC is relevant for the processing of abstract reinforcers such as performing correctly in the task.

People are able to adapt their behavior to changing environmental contingencies by rapidly inhibiting or modifying their actions. Response inhibition is often studied in the stop-signal paradigm that requires the suppression of an already prepared motor response. Less is known about situations calling for a change of motor plans such that the prepared response has to be withheld but another has to be executed instead. In the present study, we investigated whether electrophysiological data can provide evidence for distinct inhibitory mechanisms when stopping or changing a response. Participants were instructed to perform in a choice RT task with two classes of embedded critical trials: Stop signals called for the inhibition of any response, whereas change signals required participants to inhibit the prepared response and execute another one instead. Under both conditions, we observed differences in go-stimulus processing, suggesting a faster response preparation in failed compared with successful inhibitions. In contrast to stop-signal trials, changing a response did not elicit the inhibition-related frontal N2 and did not modulate the parietal mu power decrease. The results suggest that compared with changing a response, additional frontal and parietal regions are engaged when having to inhibit a response.

Reactive aggression following provocation is a frequent form of human social behavior. The neural basis of reactive aggression, especially its control, remains poorly understood, however. We conducted an event-related potential (ERP) study using a competitive reaction time task that elicits aggression through provocation. Participants were selected from a larger sample because of extreme scores in trait aggressiveness, yielding high and low trait aggressive groups. As each trial in the task is separated into a decision phase, during which the punishment level for the opponent is set, and an outcome phase, during which the punishment is applied or received, we were able to disentangle provocation-related and evaluation-related modulations of the ERPs during the aggressive interaction. Specifically, we observed an enhanced frontal negativity during the decision phase under high provocation that was positively correlated with the participants' ability to refrain from retaliation. This held true for high trait aggressive participants only, pointing to a higher need for inhibitory and control processes in these people when provoked. During the outcome phase, we detected a mediofrontal negativity in loss compared to win trials, resembling previous ERP findings to negative feedback stimuli, which have been linked to the evaluation of an outcome's valence. This mediofrontal negativity was differentially pronounced in aggressive and nonaggressive participants: Nonaggressive participants showed only a slightly smaller mediofrontal negativity in win than in loss trials, suggesting that for them punishing the opponent had a similar negative valence as being punished.