Brain activity of professional investors signals future stock performance

A major aspiration of investors is to better forecast stock performance. Interestingly, emerging "neuroforecasting" research suggests that brain activity associated with anticipatory reward relates to market behavior and population-wide preferences, including stock price dynamics. In this study, we extend these findings to professional investors processing comprehensive real-world information on stock investment options while making predictions of long-term stock performance. Using functional MRI, we sampled investors' neural responses to investment cases and assessed whether these responses relate to future performance on the stock market. We found that our sample of investors could not successfully predict future market performance of the investment cases, confirming that stated preferences do not predict the market. Stock metrics of the investment cases were not predictive of future stock performance either. However, as investors processed case information, nucleus accumbens (NAcc) activity was higher for investment cases that ended up overperforming in the market. These findings remained robust, even when controlling for stock metrics and investors' predictions made in the scanner. Cross-validated prediction analysis indicated that NAcc activity could significantly predict future stock performance out-of-sample above chance. Our findings resonate with recent neuroforecasting studies and suggest that brain activity of professional investors may help in forecasting future stock performance.

The acute effects of stress on dishonesty are moderated by individual differences in moral default

In daily life we regularly must decide whether to act dishonestly for personal gain or to be honest and maintain a positive image of ourselves. While evidence suggests that acute stress influences moral decisions, it is unclear whether stress increases or decreases immoral behavior. Here, we hypothesize that stress, through its effects on cognitive control, has different effects on moral decision making for different individuals, depending on their moral default. We test this hypothesis by combining a task which allows for inconspicuously measuring spontaneous cheating with a well-established stress induction task. Our findings confirm our hypothesis, revealing that effects of stress on dishonesty are not uniform, but instead depend on the individual: for those who are relatively dishonest, stress increases dishonesty, whereas for participants who are relatively honest stress makes them more honest. These findings go a long way in resolving the conflicting findings in the literature on the effects of stress on moral decisions, suggesting that stress affects dishonesty differently for different individuals, depending on their moral default.

A multivariate brain signature for reward

The processing of reinforcers and punishers is crucial to adapt to an ever changing environment and its dysregulation is prevalent in mental health and substance use disorders. While many human brain measures related to reward have been based on activity in individual brain regions, recent studies indicate that many affective and motivational processes are encoded in distributed systems that span multiple regions. Consequently, decoding these processes using individual regions yields small effect sizes and limited reliability, whereas predictive models based on distributed patterns yield larger effect sizes and excellent reliability. To create such a predictive model for the processes of rewards and losses, termed the Brain Reward Signature (BRS), we trained a model to predict the signed magnitude of monetary rewards on the Monetary Incentive Delay task (MID; N = 39) and achieved a highly significant decoding performance (92% for decoding rewards versus losses). We subsequently demonstrate the generalizability of our signature on another version of the MID in a different sample (92% decoding accuracy; N = 12) and on a gambling task from a large sample (73% decoding accuracy, N = 1084). We further provided preliminary data to characterize the specificity of the signature by illustrating that the signature map generates estimates that significantly differ between rewarding and negative feedback (92% decoding accuracy) but do not differ for conditions that differ in disgust rather than reward in a novel Disgust-Delay Task (N = 39). Finally, we show that passively viewing positive and negatively valenced facial expressions loads positively on our signature, in line with previous studies on morbid curiosity. We thus created a BRS that can accurately predict brain responses to rewards and losses in active decision making tasks, and that possibly relates to information seeking in passive observational tasks.

Resting-state BOLD signal variability is associated with individual differences in metacontrol

Numerous studies demonstrate that moment-to-moment neural variability is behaviorally relevant and beneficial for tasks and behaviors requiring cognitive flexibility. However, it remains unclear whether the positive effect of neural variability also holds for cognitive persistence. Moreover, different brain variability measures have been used in previous studies, yet comparisons between them are lacking. In the current study, we examined the association between resting-state BOLD signal variability and two metacontrol policies (i.e., persistence vs. flexibility). Brain variability was estimated from resting-state fMRI (rsfMRI) data using two different approaches (i.e., Standard Deviation (SD), and Mean Square Successive Difference (MSSD)) and metacontrol biases were assessed by three metacontrol-sensitive tasks. Results showed that brain variability measured by SD and MSSD was highly positively related. Critically, higher variability measured by MSSD in the attention network, parietal and frontal network, frontal and ACC network, parietal and motor network, and higher variability measured by SD in the parietal and motor network, parietal and frontal network were associated with reduced persistence (or greater flexibility) of metacontrol (i.e., larger Stroop effect or worse RAT performance). These results show that the beneficial effect of brain signal variability on cognitive control depends on the metacontrol states involved. Our study highlights the importance of temporal variability of rsfMRI activity in understanding the neural underpinnings of cognitive control.

Cognitive control and dishonesty

Dishonesty is ubiquitous and imposes substantial financial and social burdens on society. Intuitively, dishonesty results from a failure of willpower to control selfish behavior. However, recent research suggests that the role of cognitive control in dishonesty is more complex. We review evidence that cognitive control is not needed to be honest or dishonest per se, but that it depends on individual differences in what we call one's 'moral default': for those who are prone to dishonesty, cognitive control indeed aids in being honest, but for those who are already generally honest, cognitive control may help them cheat to occasionally profit from small acts of dishonesty. Thus, the role of cognitive control in (dis)honesty is to override the moral default.

Different Neural Mechanisms Underlie Non-habitual Honesty and Non-habitual Cheating

There is a long-standing debate regarding the cognitive nature of (dis)honesty: Is honesty an automatic response or does it require willpower in the form of cognitive control in order to override an automatic dishonest response. In a recent study (Speer et al., 2020), we proposed a reconciliation of these opposing views by showing that activity in areas associated with cognitive control, particularly the inferior frontal gyrus (IFG), helped dishonest participants to be honest, whereas it enabled cheating for honest participants. These findings suggest that cognitive control is not needed to be honest or dishonest per se but that it depends on an individual's moral default. However, while our findings provided insights into the role of cognitive control in overriding a moral default, they did not reveal whether overriding honest default behavior (non-habitual dishonesty) is the same as overriding dishonest default behavior (non-habitual honesty) at the neural level. This speaks to the question as to whether cognitive control mechanisms are domain-general or may be context specific. To address this, we applied multivariate pattern analysis to compare neural patterns of non-habitual honesty to non-habitual dishonesty. We found that these choices are differently encoded in the IFG, suggesting that engaging cognitive control to follow the norm (that cheating is wrong) fundamentally differs from applying control to violate this norm.

Measuring Neural Arousal for Advertisements and Its Relationship With Advertising Success

Abundant research has established the important role of ad-evoked feelings on consumers' reaction to advertising. However, measurement of feelings through explicit self-report is not without its limitations. The current study adds to previous work by showing a sophisticated way of first estimating how arousal is represented in the brain via an independent task (using EEG), and thereafter using this representation to measure arousal in response to advertisements. We then estimate the relationship between the identified process (arousal) and external measures of ad effectiveness (as measured by notability and attitude toward the ad). The results show that the neural measure of arousal is positively associated with notability of ads in the population at large, but may be negatively associated with attitude toward these ads. The implications for the application of EEG in ad testing and for understanding the relationship between arousal and effective advertising are discussed.

Decoding fairness motivations from multivariate brain activity patterns

A preference for fairness may originate from prosocial or strategic motivations: we may wish to improve others’ well-being or avoid the repercussions of selfish behavior. Here, we used functional magnetic resonance imaging to identify neural patterns that dissociate these two motivations. Participants played both the ultimatum and dictator game (UG–DG) as proposers. Because responders can reject the offer in the UG, but not the DG, offers and neural patterns between the games should differ for strategic players but not prosocial players. Using multivariate pattern analysis, we found that the decoding accuracy of neural patterns associated with UG and DG decisions correlated significantly with differences in offers between games in regions associated with theory of mind (ToM), such as the temporoparietal junction, and cognitive control, such as the dorsolateral prefrontal cortex and inferior frontal cortex. We conclude that individual differences in prosocial behavior may be driven by variations in the degree to which self-control and ToM processes are engaged during decision-making such that the extent to which these processes are engaged is indicative of either selfish or prosocial motivations.

Neural Mechanisms of Choice Diversification

When asked to select several options at once, people tend to choose a greater diversity of items than when they are asked to make these selections one at a time. Using functional magnetic resonance imaging (fMRI), we provide novel insight into the neural mechanisms underlying diversification in portfolio choices. We found that, as participants made multiple selections from a menu of different options, the current state of their choice portfolio (i.e., the previously selected options) dynamically modulates activity in the neural valuation system in response to the options under evaluation. More specifically, we found that activity in the ventral striatum (VS) decreases when the option has already been selected ("satiation"), while activity in the ventromedial prefrontal cortex increases when other options have previously been selected ("novelty-seeking"). Our findings reveal two processes that drive diversification in portfolio choices, and suggest that the context of previous selections strongly impacts how the brain evaluates current choice options.

Decoding dynamic affective responses to naturalistic videos with shared neural patterns

This study explored the feasibility of using shared neural patterns from brief affective episodes (viewing affective pictures) to decode extended, dynamic affective sequences in a naturalistic experience (watching movie-trailers). Twenty-eight participants viewed pictures from the International Affective Picture System (IAPS) and, in a separate session, watched various movie-trailers. We first located voxels at bilateral occipital cortex (LOC) responsive to affective picture categories by GLM analysis, then performed between-subject hyperalignment on the LOC voxels based on their responses during movie-trailer watching. After hyperalignment, we trained between-subject machine learning classifiers on the affective pictures, and used the classifiers to decode affective states of an out-of-sample participant both during picture viewing and during movie-trailer watching. Within participants, neural classifiers identified valence and arousal categories of pictures, and tracked self-reported valence and arousal during video watching. In aggregate, neural classifiers produced valence and arousal time series that tracked the dynamic ratings of the movie-trailers obtained from a separate sample. Our findings provide further support for the possibility of using pre-trained neural representations to decode dynamic affective responses during a naturalistic experience.

Neural similarity at temporal lobe and cerebellum predicts out-of-sample preference and recall for video stimuli

The extent to which brains respond similarly to a specific stimulus, across a small group of individuals, has been previously found to predict out-of-sample aggregate preference for that stimulus. However, the location in the brain where neural similarity predicts out-of-sample preference remains unclear. In this article, we attempt to identify the neural substrates in three functional magnetic resonance imaging (fMRI) studies. Two fMRI studies (N = 40 and 20), using previously broadcasted TV commercials, show that spatiotemporal neural similarity at temporal lobe and cerebellum predict out-of-sample preference and recall. A follow-up fMRI study (N = 28) with previously unseen movie-trailers replicated the predictive effect of neural similarity. Moreover, neural similarity provided unique information on out-of-sample preference above and beyond in-sample preference. Overall, the findings suggest that neural similarity at temporal lobe and cerebellum - traditionally associated with sensory integration and emotional processing - may reflect the level of engagement with video stimuli.

Implicit measurement of emotional experience and its dynamics

Although many studies revealed that emotions and their dynamics have a profound impact on cognition and behavior, it has proven difficult to unobtrusively measure emotions. In the current study, our objective was to distinguish different experiences elicited by audiovisual stimuli designed to evoke particularly happy, sad, fear and disgust emotions, using electroencephalography (EEG) and a multivariate approach. We show that we were able to classify these emotional experiences well above chance level. Importantly, we retained all the information (frequency and topography) present in the data. This allowed us to interpret the differences between emotional experiences in terms of component psychological processes such as attention and arousal that are known to be associated with the observed activation patterns. In addition, we illustrate how this method of classifying emotional experiences can be applied on a moment-by-moment basis in order to track dynamic changes in the emotional response over time. The application of our approach may be of value in many contexts in which the experience of a given stimulus or situation changes over time, ranging from clinical to consumption settings.

Internally directed cognition and mindfulness: an integrative perspective derived from predictive and reactive control systems theory

In the present paper, we will apply the predictive and reactive control systems (PARCS) theory as a framework that integrates competing theories of neural substrates of awareness by describing the "default mode network" (DMN) and anterior insula (AI) as parts of two different behavioral and homeostatic control systems. The DMN, a network that becomes active at rest when there is no external stimulation or task to perform, has been implicated in self-reflective awareness and prospection. By contrast, the AI is associated with awareness and task-related attention. This has led to competing theories stressing the role of the DMN in self-awareness vs. the role of interoceptive and emotional information integration in the AI in awareness of the emotional moment. In PARCS, the respective functions of the DMN and AI in a specific control system explains their association with different qualities of awareness, and how mental states can shift from one state (e.g., prospective self-reflection) to the other (e.g., awareness of the emotional moment) depending on the relative dominance of control systems. These shifts between reactive and predictive control are part of processes that enable the intake of novel information, integration of this novel information within existing knowledge structures, and the creation of a continuous personal context in which novel information can be integrated and understood. As such, PARCS can explain key characteristics of mental states, such as their temporal and spatial focus (e.g., a focus on the here and now vs. the future; a first person vs. a third person perspective). PARCS further relates mental states to brain states and functions, such as activation of the DMN or hemispheric asymmetry in frontal cortical functions. Together, PARCS deepens the understanding of a broad range of mental states, including mindfulness, mind wandering, rumination, autobiographical memory, imagery, and the experience of self.

Oxytocin effects on complex brain networks are moderated by experiences of maternal love withdrawal

The neuropeptide oxytocin has been implicated in a variety of social processes. However, recent studies indicate that oxytocin does not enhance prosocial behavior in all people in all circumstances. Here, we investigate effects of intranasal oxytocin administration on intrinsic functional brain connectivity with resting state functional magnetic resonance imaging. Participants were 42 women who received a nasal spray containing either 16 IU of oxytocin or a placebo and reported how often their mother used love withdrawal as a disciplinary strategy involving withholding love and affection after a failure or misbehavior. We found that oxytocin changes functional connectivity between the posterior cingulate cortex (PCC) and the brainstem. In the oxytocin group there was a positive connectivity between these regions, whereas the placebo group showed negative connectivity. In addition, oxytocin induced functional connectivity changes between the PCC, the cerebellum and the postcentral gyrus, but only for those participants who experienced low levels of maternal love withdrawal. We speculate that oxytocin enhances prosocial behavior by influencing complex brain networks involved in self-referential processing and affectionate touch, most prominently in individuals with supportive family backgrounds.

Testosterone Inhibits Trust but Promotes Reciprocity

The steroid hormone testosterone has been associated with behavior intended to obtain or maintain high social status. Although such behavior is typically characterized as aggressive and competitive, it is clear that high social status is achieved and maintained not only through antisocial behavior but also through prosocial behavior. In the present experiment, we investigated the impact of testosterone administration on trust and reciprocity using a double-blind randomized control design. We found that a single dose of 0.5 mg of testosterone decreased trust but increased generosity when repaying trust. These findings suggest that testosterone may mediate different types of status-seeking behavior. It may increase competitive, potentially aggressive, and antisocial behavior when social challenges and threats (i.e., abuse of trust and betrayal) need to be considered; however, it may promote prosocial behavior in the absence of these threats, when high status and good reputation may be best served by prosocial behavior.

Medial frontal negativity reflects learning from positive feedback

The ability to learn from the consequences of our actions is crucial for adaptive goal-directed behavior. We learn to avoid actions that lead to unfavorable outcomes and pursue actions that lead to desirable results. By recording event-related potentials (ERPs), we show that neural reinforcement learning signals associated with positive outcomes are predictive of subsequent learning of a sequence of motor actions: Positive feedback to a response that was later correctly repeated was associated with a larger medial frontal negativity (MFN) compared to when it was not correctly repeated on a subsequent encounter. This finding adds to recent evidence suggesting that the function of the anterior cingulate cortex is to establish associations between actions and their outcomes, both positive and negative.

"What's that?" "What Went Wrong?" Positive and Negative Surprise and the Rostral-Ventral to Caudal-Dorsal Functional Gradient in the Brain

Medial prefrontal cortical (mPFC) functions may be aspects of ventral or dorsal control pathways, depending on the position along a rostral–ventral to caudal–dorsal gradient within medial cortex that may mirror the pattern of interconnections between cortex and striatum. Rostral–ventral mPFC is connected to ventral striatum and posterior cingulate cortex/precuneus are connected with dorsal striatum. Reentrant ventral (limbic), central (associative), and dorsal (motor) corticostriatal loops pass information from ventral-to-dorsal striatum, shifting hedonic processing toward habitual action. Splitting up unexpected occurrences (positive surprise) from non-occurrences (negative surprise) instead of splitting according to valence mirrors the importance of negative surprise in dorsal habitual control which is insensitive to the valence of outcomes. The importance of positive surprise and valence increases toward the rostral–ventral end of the gradient in mPFC and ventrolateral prefrontal cortex. We discuss paradigms that may help to disentangle positive from negative surprise. Moreover, we think that the framework of the functional gradient may help giving various functions in mPFC their place in a larger scheme.

Cortisol-induced increases of plasma oxytocin levels predict decreased immediate free recall of unpleasant words

Cortisol and oxytocin have been shown to interact in both the regulation of stress responses and in memory function. In the present study we administered cortisol to 35 healthy female subjects in a within-subject double-blind placebo-controlled design, while measuring oxytocin levels, adrenocorticotropic hormone (ACTH) levels, and free recall of pleasant and of unpleasant words. We found that cortisol administration suppressed ACTH levels and (1) induced a decrease in oxytocin associated with ACTH suppression and (2) an increase in oxytocin that was independent from ACTH suppression. This cortisol-induced increase in plasma oxytocin was associated with a selective decrease in immediate free recall of unpleasant words from primacy positions. The present results add to evidence that cortisol-induced increases in oxytocin could mediate some of the effects of stress and cortisol on memory, and possibly play a role in the regulation of the hypothalamo-pituitary-adrenal stress response. This mechanism could significantly impact affective and social behaviors, in particular during times of stress.

Individual Differences in Asymmetric Resting-State Frontal Cortical Activity Modulate ERPs and Performance in a Global-Local Attention Task

Recent research has demonstrated that individual differences in approach motivation modulate attentional scope. In turn, approach and inhibition have been related to different neural systems that are associated with asymmetries in relative frontal activity (RFA). Here, we investigated whether such individual differences in asymmetric hemispheric activity during rest, and self-report measures of approach motivation (as measured by the behavioral inhibition system, BIS/behavioral activation system, BAS scales) would be predictive of the efficiency of attentional processing of global and local visual information, as indexed by event-related potentials (ERPs) and performance measures. In the reported experiment, participants performed a visual attention task in which they were required to either attend to the global shape or the local components of presented stimuli. Electroencephalogram was recorded during task performance and during an initial “resting state” measurement. The results showed that only the BAS-Reward Responsiveness subscale was associated with left RFA during rest, while BIS, BAS-Drive, and BAS-Fun Seeking were associated with more right-lateralized RFA. Importantly, left RFA during the “resting state” measurement was associated with increased P3 (right-lateralized) amplitudes and decreased P3 latencies on trials requiring a global focus. In turn, these ERPs were associated with enhanced performance on trials requiring a global focus. These results provide the first evidence for a positive association between left RFA during rest and increased efficiency of right-lateralized brain mechanisms that are involved in processing global information.

A potential role of the inferior frontal gyrus and anterior insula in cognitive control, brain rhythms, and event-related potentials

In the present paper, we review evidence for of a model in which the inferior frontal gyrus/anterior insula (IFG/AI) area is involved in elaborate attentional and working memory processing and we present the hypothesis that this processing may take different forms and may have different effects, depending on the task at hand: (1) it may facilitate fast and accurate responding, or (2) it may cause slow responding when prolonged elaborate processing is required to increase accuracy of responding, or (3) it may interfere with accuracy and speed of next-trial (for instance, post-error) performance when prolonged elaborate processing interferes with processing of the next stimulus. We present our viewpoint that ventrolateral corticolimbic control pathways, including the IFG/AI, and mediodorsal corticolimbic control pathways, including dorsal anterior cingulate cortex areas, play partly separable, but interacting roles in adaptive behavior in environmental conditions that differ in the level of predictability: compared to dorsal feed-forward control, the ventral corticolimbic control pathways implement control over actions through higher responsiveness to momentary environmental stimuli. This latter control mode is associated with an attentional focus on stimuli that are urgent or close in time and space, while the former control mode is associated with a broader, more global focus in time and space. Both control pathways have developed extensively through evolution, and both developed their own “cognitive controls,” such that neither one can be properly described as purely “cognitive” or “emotional.” We discuss literature that suggests that the role of IFG/AI in top-down control is reflected in cortical rhythms and event-related potentials. Together, the literature suggests that the IFG/AI is an important node in brain networks that control cognitive and emotional processing and behavior.

Oxytocin modulates amygdala, insula, and inferior frontal gyrus responses to infant crying: a randomized controlled trial

BACKGROUND

Oxytocin facilitates parental caregiving and mother-infant bonding and might be involved in responses to infant crying. Infant crying provides information about the physical status and mood of the infant and elicits parental proximity and caregiving. Oxytocin might modulate the activation of brain structures involved in the perception of cry sounds-specifically the insula, the amygdala, and the thalamocingulate circuit-and thereby affect responsiveness to infant crying.

METHOD

In a randomized controlled trial we investigated the influence of intranasally administered oxytocin on neural responses to infant crying with functional magnetic resonance imaging. Blood oxygenation level-dependent responses to infant crying were measured in 21 women who were administered oxytocin and 21 women who were administered a placebo.

RESULTS

Induced oxytocin levels reduced, experimentally, activation in the amygdala and increased activation in the insula and inferior frontal gyrus pars triangularis.

CONCLUSIONS

Our findings suggest that oxytocin promotes responsiveness to infant crying by reducing activation in the neural circuitry for anxiety and aversion and increasing activation in regions involved in empathy.

Social status determines how we monitor and evaluate our performance

Since people with low status are more likely to experience social evaluative threat and are therefore more inclined to monitor for these threats and inhibit approach behaviour, we expected that low-status subjects would be more engaged in evaluating their own performance, compared with high-status subjects. We created a highly salient social hierarchy based on the performance of a simple time estimation task. Subjects could achieve high, middle or low status while performing this task simultaneously with other two players who were either higher or lower in status. Subjects received feedback on their own performance, as well as on the performance of the other two players simultaneously. Electroencephalography (EEG) was recorded from all three participants. The results showed that medial frontal negativity (an event-related potential reflecting performance evaluation) was significantly enhanced for low-status subjects. Implications for status-related differences in goal-directed behaviour are discussed.

Oxytocin receptor gene associated with the efficiency of social auditory processing

Oxytocin has been shown to facilitate social aspects of sensory processing, thereby enhancing social communicative behaviors and empathy. Here we report that compared to the AA/AG genotypes, the presumably more efficient GG genotype of an oxytocin receptor gene polymorphism (OXTR rs53576) that has previously been associated with increased sensitivity of social processing is related to less self-reported difficulty in hearing and understanding people when there is background noise. The present result extends associations between oxytocin and social processing to the auditory and vocal domain. We discuss the relevance of our findings for autistic spectrum disorders (ASD), as ASD seems related to specific impairments in the orienting to, and selection of speech sounds from background noise, and some social processing impairments in patients with ASD have been found responsive to oxytocin treatment.

Failing where others have succeeded: Medial Frontal Negativity tracks failure in a social context

Most of us can appreciate that it feels worse to fail when people around you are successful than when others are also failing. Indeed, comparison with other individuals is of central importance within social groups. Despite the importance of relative success or failure for human decision making and even well-being, the underlying neurobiological substrate of this social comparison process is not well understood. In the present study, ERPs were recorded while two participants received feedback on both their own, and the other participant's performance on each trial. The results showed that medial frontal negativity, an ERP component associated with deviations from the desired outcome, is particularly enhanced when an individual's own outcomes are worse than those of others. These results indicate that the way the brain evaluates the success of our actions is crucially dependent on the success or failure of others.

Cortisol involvement in mechanisms of behavioral inhibition

We studied whether baseline cortisol is associated with post-error slowing, a measure that depends upon brain areas involved in behavioral inhibition. Moreover, we studied whether this association holds after controlling for positive associations with behavioral inhibition scores and error-related negativity (ERN) amplitudes that cortisol and post-error slowing may share. Healthy female volunteers performed a flanker task. Cortisol was independently positively associated with post-error slowing and the ERN, supporting hypotheses that cortisol is involved in behavioral inhibition. Additionally, cortisol mediated an association between ERN and more post-error slowing, which suppressed a direct association between ERN and less post-error slowing. The results are relevant, not only for researchers of behavioral inhibition, but also for researchers of the basic mechanisms of the ERN and post-error slowing, and may bring those literatures together.

Brain substrates of behavioral programs associated with self-regulation

The present paper proposes that four neuromodulator systems underpin highly generalized behavioral sets, but each targets either dorsomedial or ventrolateral cortical systems, where it produces its effects in either a proactive or reactive orientation to the environment. This way systems are discriminated that control reactive approach (dopaminergic), reactive avoidance (cholinergic), proactive behavior (noradrenergic), and withdrawal (serotonergic). This model is compared with models of temperament, affect, personality, and so-called two-system models from psychology. Although the present model converges with previous models that point to a basic scheme underlying temperamental and affective space, at the same time it suggest that specific additional discriminations are necessary to improve descriptive fit to data and solve inconsistencies and confusions. We demonstrate how proactive and reactive actions and controls can be confused, and that this has many potential implications for psychology and neurobiology. We uncover conceptual problems regarding constructs such as effortful control, positive affect, approach-avoidance, extraversion, impulsivity, impulse-control, and goal-directedness of behavior. By delineating those problems, our approach also opens up ways to tackle them.

Fairness concerns predict medial frontal negativity amplitude in ultimatum bargaining

Despite evidence that anterior cingulate cortex (ACC) activity is related to social exclusion, rejection and unfairness, evidence that medial frontal negativity (MFN), which has its source in the ACC, reflects these constructs remains unforthcoming. In the present study, subjects participated as recipients in an ultimatum game, while we recorded their electro-encephalogram (EEG). Participants responded to fair and unfair offers from different human proposers. In addition, participants rated themselves on a measure evaluating their concern for fairness. Results showed that MFN amplitude was more pronounced for unfair offers compared to fair offers. Moreover, this effect was shown to be most pronounced for subjects with high concerns for fairness. Our findings suggest that the MFN not only reflects whether outcomes match expectations, but also reflects whether the process by which these outcomes came about matches a social or even a moral norm. In addition, the present results suggest that people in bargaining situations are not only concerned with their own outcomes, but are also concerned with the fairness of the process that resulted in these outcomes.

The importance of failure: feedback-related negativity predicts motor learning efficiency

Learning from past mistakes is of prominent importance for successful future behavior. In the present study, we tested whether reinforcement learning signals in the brain are predictive of adequate learning of a sequence of motor actions. We recorded event-related potentials (ERPs) while subjects engaged in a sequence learning task. The results showed that brain responses to feedback (the feedback-related negativity [FRN]) predicted whether subjects learned to avoid an erroneous response the next time this action had to be performed. Our findings add to a growing literature on feedback-based performance adjustment, by showing that FRN amplitudes may reflect the acquisition of motor skill and the consolidation of contingencies between stimuli or cues and their associated responses, providing evidence that learning efficiency and future performance can be predicted by the neural response to current feedback: FRN amplitude associated with a mistake is predictive of whether this mistake will be repeated, or learned from.

Social power and approach-related neural activity

It has been argued that power activates a general tendency to approach whereas powerlessness activates a tendency to inhibit. The assumption is that elevated power involves reward-rich environments, freedom and, as a consequence, triggers an approach-related motivational orientation and attention to rewards. In contrast, reduced power is associated with increased threat, punishment and social constraint and thereby activates inhibition-related motivation. Moreover, approach motivation has been found to be associated with increased relative left-sided frontal brain activity, while withdrawal motivation has been associated with increased right sided activations. We measured EEG activity while subjects engaged in a task priming either high or low social power. Results show that high social power is indeed associated with greater left-frontal brain activity compared to low social power, providing the first neural evidence for the theory that high power is associated with approach-related motivation. We propose a framework accounting for differences in both approach motivation and goal-directed behaviour associated with different levels of power.

Mental fatigue: costs and benefits

A framework for mental fatigue is proposed, that involves an integrated evaluation of both expected rewards and energetical costs associated with continued performance. Adequate evaluation of predicted rewards and potential risks of actions is essential for successful adaptive behaviour. However, while both rewards and punishments can motivate to engage in activities, both types of motivated behaviour are associated with energetical costs. We will review findings that suggest that the nucleus accumbens, orbitofrontal cortex, amygdala, insula and anterior cingulate cortex are involved evaluating both the potential rewards associated with performing a task, as well as assessing the energetical demands involved in task performance. Behaviour will only proceed if this evaluation turns out favourably towards spending (additional) energy. We propose that this evaluation of predicted rewards and energetical costs is central to the phenomenon of mental fatigue: people will no longer be motivated to engage in task performance when energetical costs are perceived to outweigh predicted rewards.

The psychobiology of burnout: are there two different syndromes?

BACKGROUND

Plasma prolactin levels are sensitive to dopamine and serotonin function, and fatigue. Low cortisol, dopamine and/or serotonin may be involved in burnout and detachment.

METHODS

In this double-blind within-subject study, we treated 9 female burnout subjects and 9 controls with 35 mg cortisol and placebo orally. We measured state affect and plasma prolactin, oxytocin, cortisol and adrenocorticotropic hormone levels, and administered an attachment questionnaire.

RESULTS

The burnout subjects displayed an extreme distribution of basal prolactin levels, displaying higher or lower levels compared to the controls. The low prolactin burnouts had profoundly low attachment scores and tended to have low oxytocin levels. The high prolactin burnout subjects tended to show cortisol-induced decreased prolactin and fatigue, and increased vigor.

CONCLUSION

Results are consistent with the hypothesis that burnout subjects are either characterized by low serotonergic function or by low dopaminergic function, and that the latter group benefits from cortisol replacement. These preliminary results suggest that differentiating between two syndromes may resolve inconsistencies in research on burnout, and be necessary for selecting the right treatment strategy.

Task engagement and the relationships between the error-related negativity, agreeableness, behavioral shame proneness and cortisol

Previous results suggest that both cortisol mobilization and the error-related negativity (ERN/Ne) reflect goal engagement, i.e. the mobilization and allocation of attentional and physiological resources. Personality measures of negative affectivity have been associated both to high cortisol levels and large ERN/Ne amplitudes. However, measures of positive social adaptation and agreeableness have also been related to high cortisol levels and large ERN/Ne amplitudes. We hypothesized that, as long as they relate to concerns over social evaluation and mistakes, both personality measures reflecting positive affectivity (e.g. agreeableness) and those reflecting negative affectivity (e.g. behavioral shame proneness) would be associated with an increased likelihood of high task engagement, and hence to increased cortisol mobilization and ERN/Ne amplitudes. We had female subjects perform a flanker task while EEG was recorded. Additionally, the subjects filled out questionnaires measuring mood and personality, and salivary cortisol immediately before and after task performance was measured. The overall pattern of relationships between our measures supports the hypothesis that cortisol mobilization and ERN/Ne amplitude reflect task engagement, and both relate positively to each other and to the personality traits agreeableness and behavioral shame proneness. We discuss the potential importance of engagement-disengagement and of concerns over social evaluation for research on psychopathology, stress and the ERN/Ne.

Error-related ERP components and individual differences in punishment and reward sensitivity

Although the focus of the discussion regarding the significance of the error related negatively (ERN/Ne) has been on the cognitive factors reflected in this component, there is now a growing body of research that describes influences of motivation, affective style and other factors of personality on ERN/Ne amplitude. The present study was conducted to further evaluate the relationship between affective style, error related ERP components and their neural basis. Therefore, we had our subjects fill out the Behavioral Activation System/Behavioral Inhibition System (BIS/BAS) scales, which are based on Gray's (1987, 1989) biopsychological theory of personality. We found that subjects scoring high on the BIS scale displayed larger ERN/Ne amplitudes, while subjects scoring high on the BAS scale displayed larger error positivity (Pe) amplitudes. No correlations were found between BIS and Pe amplitude or between BAS and ERN/Ne amplitude. Results are discussed in terms of individual differences in reward and punishment sensitivity that are reflected in error related ERP components.

Effects of mental fatigue on attention: an ERP study

The effects of mental fatigue on attention were assessed. Subjects performed a visual attention task for 3 h without rest. Subjective levels of fatigue, performance measures and EEG were recorded. Subjective fatigue ratings, as well as theta and lower-alpha EEG band power increased, suggesting that the 3 h of task performance resulted in an increase in fatigue. Reaction times, misses and false alarms increased with time on task, indicating decreased performance efficiency in fatigued subjects. Subjects were unable to inhibit automatic shifting of attention to irrelevant stimuli, reflected by a larger negativity in the N1 latency range for irrelevant, compared to relevant stimuli. This difference in negativity was unaffected by time on task. However, N1 and N2b amplitude did change with time on task: N1 amplitude decreased, and the difference in N2b amplitude between relevant and irrelevant stimuli (larger N2b amplitude evoked by relevant stimuli) decreased with time on task. The results indicate a dissociation in the effects of mental fatigue on goal-directed (top-down) and stimulus-driven (bottom-up) attention: mental fatigue results in a reduction in goal-directed attention, leaving subjects performing in a more stimulus-driven fashion.

Mental fatigue, motivation and action monitoring

In this study we examined whether the effects of mental fatigue on behaviour are due to reduced action monitoring as indexed by the error related negativity (Ne/ERN), N2 and contingent negative variation (CNV) event-related potential (ERP) components. Therefore, we had subjects perform a task, which required a high degree of action monitoring, continuously for 2h. In addition we tried to relate the observed behavioural and electrophysiological changes to motivational processes and individual differences. Changes in task performance due to fatigue were accompanied by a decrease in Ne/ERN and N2 amplitude, reflecting impaired action monitoring, as well as a decrease in CNV amplitude which reflects reduced response preparation with increasing fatigue. Increasing the motivational level of our subjects resulted in changes in behaviour and brain activity that were different for individual subjects. Subjects that increased their performance accuracy displayed an increase in Ne/ERN amplitude, while subjects that increased their response speed displayed an increase in CNV amplitude. We will discuss the effects prolonged task performance on the behavioural and physiological indices of action monitoring, as well as the relationship between fatigue, motivation and individual differences.

Impaired cognitive control and reduced cingulate activity during mental fatigue

Neurocognitive mechanisms underlying the effects of mental fatigue are poorly understood. Here, we examined whether error-related brain activity, indexing performance monitoring by the anterior cingulate cortex (ACC), and strategic behavioural adjustments were modulated by mental fatigue, as induced by 2 h of continuous demanding cognitive task performance. Findings that (1) mental fatigue is associated with compromised performance monitoring and inadequate performance adjustments after errors, (2) monitoring functions of ACC and striatum rely on dopaminergic inputs from the midbrain, and (3) patients with striatal dopamine deficiencies show symptomatic mental fatigue, suggest that mental fatigue results from a failure to maintain adequate levels of dopaminergic transmission to the striatum and the ACC, resulting in impaired cognitive control.