I want it now! Neural correlates of hypersensitivity to immediate reward in hypomania

The Impact of Immediate and Delayed Rewards on Task-Switching Performance

BACKGROUND/OBJECTIVES

Switching between different tasks incurs switch costs. Previous research has demonstrated that rewards can enhance performance in cognitive tasks. However, prior studies have primarily focused on the overall improvement in cognitive task performance, with limited research on how different types of rewards function under various task conditions. This study aims to investigate the distinct effects of immediate and delayed rewards on cognitive task performance in different task conditions (repeated trials and task-switching trials) and to explore the underlying neural mechanisms, particularly focusing on how rewards influence attention allocation during the concurrent processing of multiple cues.

METHODS

This study recruited 27 college students (average age 19 years old, 10 males and 17 females). A cue-based task-switching paradigm incorporating immediate and delayed rewards was employed. The study examined the effects of immediate and delayed rewards on cognitive task performance in repeated trials and task-switching trials. Event-related potentials (ERPs) were recorded to investigate the neural mechanisms underlying reward effects on attention allocation.

RESULTS

Behavioral results indicated that immediate rewards significantly enhanced performance in repeated trials compared to delayed rewards. In contrast, no significant difference between immediate and delayed rewards was observed in task-switching trials. ERP results showed that immediate rewards induced a larger P300 amplitude than delayed rewards under the task repetition condition. No P300 difference was found between immediate and delayed rewards under the task-switching condition.

CONCLUSIONS

The findings suggest that rewards enhance task performance by optimizing the allocation of attention to the ongoing task when multiple cues are processed concurrently. When additional resources are required to process task-related cues, there may be insufficient remaining capacity to effectively process reward cues, which could be essential for the optimal completion of the task. These results support the Expected Value of Control (EVC) theory in task-switching scenarios.

Characterizing within-person variance in, and menstrual cycle associations with, event-related potentials associated with positive and negative valence systems: The reward positivity and the error-related negativity

Event-related potentials (ERPs) are widely employed as measures of transdiagnostic cognitive processes that are thought to underlie various clinical disorders (Hajcak et al., 2019). Despite their prevalent use as individual difference measures, the effects of within-person processes, such as the human menstrual cycle, on a broad range of ERPs are poorly understood. The present study leveraged a within-subject design to characterize between- and within-person variance in ERPs as well as effects of the menstrual cycle in two frequently studied ERPs associated with positive and negative valence systems underlying psychopathology-the Reward Positivity (RewP) and the Error- Related Negativity (ERN). Seventy-one naturally-cycling participants completed repeated EEG and ecological momentary assessments of positive and negative affect in the menstrual cycle's early follicular, periovulatory, and mid-luteal phases. We examined the mean degree of change between cycle phases in both ERPs, the between-person variability in the degree of change in both ERPs, and whether an individual's degree of cyclical change in these ERPs show coherence with their degree of cyclical change in positive and negative affect recorded across the cycle. Results revealed no significant changes in positive and negative affect across the cycle and rather small changes in ERP amplitudes. Significant random slopes in our model revealed larger individual differences in trajectories of change in ERP amplitudes and affect, in agreement with prior evidence of heterogeneity in dimensional hormone sensitivity. Additionally, state-variance in these ERPs correlated with positive and negative affect changes across the cycle, suggesting that cycle-mediated ERP changes may have relevance for affect and behavior. Finally, exploratory latent class growth mixture modeling revealed subgroups of individuals that display disparate patterns of change in ERPs that should be further investigated.

Neural abnormalities of reward processing in adolescents with bipolar disorders: An ERP study

Adolescent onset is common in bipolar disorders (BDs) and is associated with a worse illness course in adulthood. A model of BDs suggests that a dysregulated behavioral approach system (BAS), a neural system that mobilizes reward-seeking behavior, is at the root of BDs. Normative adolescence is often accompanied by dynamic changes to neural structures underlying the BAS and related cognitive processes. It is possible that adolescent-onset BDs is associated with abnormal BAS neurodevelopment. Consistently, the present study is the first to compare specific BAS-relevant anticipatory and consummatory reward processes as indexed by event-related potentials (ERPs) in adolescents with BDs and typically developing peers. Using a sample of 43 adolescents with BDs and 56 without psychopathology, we analyzed N1 and P3 responses to anticipatory cues and feedback-related negativity (FRN) and P3 responses to feedback stimuli during a monetary incentive delay (MID) task. Hierarchical linear models examined relationships between ERP amplitudes and diagnostic group, MID condition, sex, and age. During anticipation phase, adolescent boys with BDs exhibited significantly larger N1 amplitudes in loss than even or gain trials. During feedback phase, compared to their healthy peers, adolescents with BDs had smaller FRN amplitudes across all conditions. Additional effects involving age, sex and trial type were observed. The findings indicate subtle, non-ubiquitous BAS-relevant neural abnormalities involving early attentional processes during reward anticipation and reward learning following feedback in adolescents with BDs. Adolescents with BDs did not show overall hypersensitive neural responses to monetary reward anticipation or feedback observed in adults with BDs.

Contextual valence influences the neural dynamics of time and magnitude representation during feedback evaluation

Contextual valence is an important dimension during value-based decision-making. Previous research has revealed behavioral and neural asymmetries between the gain context and the loss context. The present event-related potential study investigated the effects of contextual valence on neural dynamics underlying magnitude and time, two important reward dimensions, during feedback evaluation. Forty-two participants performed a simple guessing task in which they experienced both a gain context wherein high or low rewards were delivered immediately or six months later, and a loss context wherein high or low losses were delivered in the same way. Results showed that in the gain context, time and magnitude information were processed in a parallel way during the time windows of the reward positivity (RewP) and the P3. In the loss context, however, time and magnitude information were processed in a serial way such that time information was encoded during the RewP and P3 periods, whereas magnitude information was not tracked until the time window of the late positive potential. Our findings suggest that the neural dynamics underlying time and magnitude information are distinct between the gain and loss contexts, thus providing a novel perspective for the well-known gain-loss asymmetry.

Explaining reversal learning deficits in anxiety with electrophysiological evidence

Reversal learning is a crucial aspect of behavioral flexibility that plays a significant role in environmental adaptation and development. While previous studies have established a link between anxiety and impaired reversal learning ability, the underlying mechanisms behind this association remain unclear. This study employed a probabilistic reversal learning task with electroencephalographic recording to investigate these mechanisms. Participants were divided into two groups based on their scores on Spielberger's State-Trait Anxiety Inventory: high trait-anxiety (HTA) and low trait-anxiety (LTA), consisting of 50 individuals in each group. The results showed that the HTA group had poorer reversal learning performance than the LTA group, including a lower tendency to shift to the new optimal option after rule reversals (reversal-shift). The study also examined event-related potentials elicited by reversals and found that although the N1 (related to attention allocation), feedback-related negativity (FRN: related to belief updating), and P3 (related to response inhibition) were all sensitive to the grouping factor, only the FRN elicited by reversal-shift mediated the relationship between anxiety and the number/reaction time of reversal-shift. From these findings, we suggest that abnormalities in belief updating may contribute to the impaired reversal learning performance observed in anxious individuals. In our opinion, this study sheds light on potential targets for interventions aimed at improving behavioral flexibility in anxious individuals.

Neural dynamics underlying self-control in the primate subthalamic nucleus

The subthalamic nucleus (STN) is hypothesized to play a central role in neural processes that regulate self-control. Still uncertain, however, is how that brain structure participates in the dynamically evolving estimation of value that underlies the ability to delay gratification and wait patiently for a gain. To address that gap in knowledge, we studied the spiking activity of neurons in the STN of monkeys during a task in which animals were required to remain motionless for varying periods of time in order to obtain food reward. At the single-neuron and population levels, we found a cost-benefit integration between the desirability of the expected reward and the imposed delay to reward delivery, with STN signals that dynamically combined both attributes of the reward to form a single integrated estimate of value. This neural encoding of subjective value evolved dynamically across the waiting period that intervened after instruction cue. Moreover, this encoding was distributed inhomogeneously along the antero-posterior axis of the STN such that the most dorso-posterior-placed neurons represented the temporal discounted value most strongly. These findings highlight the selective involvement of the dorso-posterior STN in the representation of temporally discounted rewards. The combination of rewards and time delays into an integrated representation is essential for self-control, the promotion of goal pursuit, and the willingness to bear the costs of time delays.

Pharmacological Modulation of Temporal Discounting: A Systematic Review

Temporal discounting is a phenomenon where a reward loses its value as a function of time (e.g., a reward is more valuable immediately than when it delays in time). This is a type of intertemporal decision-making that has an association with impulsivity and self-control. Many pathologies exhibit higher discounting rates, meaning they discount more the values of rewards, such as addictive behaviors, bipolar disorder, attention-deficit/hyperactivity disorders, social anxiety disorders, and major depressive disorder, among others; thus, many studies look for the mechanism and neuromodulators of these decisions. This systematic review aims to investigate the association between pharmacological administration and changes in temporal discounting. A search was conducted in PubMed, Scopus, Web of Science, Science Direct and Cochrane. We used the PICO strategy: healthy humans (P-Participants) that received a pharmacological administration (I-Intervention) and the absence of a pharmacological administration or placebo (C-Comparison) to analyze the relationship between the pharmacological administration and the temporal discounting (O-outcome). Nineteen studies fulfilled the inclusion criteria. The most important findings were the involvement of dopamine modulation in a U-shape for choosing the delayed outcome (metoclopradime, haloperidol, and amisulpride). Furthermore, administration of tolcapone and high doses of d-amphetamine produced a preference for the delayed option. There was a time-dependent hydrocortisone effect in the preference for the immediate reward. Thus, it can be concluded that dopamine is a crucial modulator for temporal discounting, especially the D2 receptor, and cortisol also has an important time-dependent role in this type of decision. One of the limitations of this systematic review is the heterogeneity of the drugs used to assess the effect of temporal discounting.

Neural correlates of impulsivity in bipolar disorder: A systematic review and clinical implications

Impulsivity is a common feature of bipolar disorder (BD) with ramifications for functional impairment and premature mortality. This PRISMA-guided systematic review aims to integrate findings on the neurocircuitry associated with impulsivity in BD. We searched for functional neuroimaging studies that examined rapid-response impulsivity and choice impulsivity using the Go/No-Go Task, Stop-Signal Task, and Delay Discounting Task. Findings from 33 studies were synthesized with an emphasis on the effect of mood state of the sample and affective salience of the task. Results suggest trait-like brain activation abnormalities in regions implicated in impulsivity that persist across mood states. During rapid-response inhibition, BD exhibit under-activation of key frontal, insular, parietal, cingulate, and thalamic regions, but over-activation of these regions when the task involves emotional stimuli. Delay discounting tasks with functional neuroimaging in BD are lacking, but hyperactivity of orbitofrontal and striatal regions associated with reward hypersensitivity may be related to difficulty delaying gratification. We propose a working model of neurocircuitry dysfunction underlying behavioral impulsivity in BD. Clinical implications and future directions are discussed.

Scarcity Enhances Outcome Evaluation in the Present: Electroencephalography Evidence

Scarcity goods have generally been perceived as high in value in real-world and empirical studies. However, few studies have investigated this value over time, such as performance in intertemporal decision making. This study’s chief objective was to determine how scarcity evaluation changes temporally. We used the electroencephalogram technique and an outcome evaluation task with the valuation of scarcity and ordinary rewards delivered at different times to explore the effect of scarcity on delay discounting. The feedback-related negativity (FRN) results show that ordinary goods were associated with a more negative amplitude than scarcity goods, and that rewards delivered in the future evoked more negative deflection compared to those delivered immediately. The prominent FRN effect was derived mainly from ordinary trials rather than scarcity trials in the immediate condition and in the future rather than only in the immediate condition. The Frontal Asymmetry Index (FAI) results show that the scarcity condition was associated with greater relative left frontal cortical activity than the ordinary condition when delivered immediately. The frontal asymmetry indicated greater approach motivation. Our electrophysiology data indicate that scarcity goods have a perceived high value, particularly when delivered immediately.

Decision value signals in the ventromedial prefrontal cortex and motivational and hedonic symptoms across mood and psychotic disorders

Deficits in motivation and pleasure are common across many psychiatric disorders, and manifest as symptoms of amotivation and anhedonia, which are prominent features of both mood and psychotic disorders. Here we provide evidence for an association between neural value signals and symptoms of amotivation and anhedonia across adults with major depression, bipolar disorder, schizophrenia, or no psychiatric diagnosis. We found that value signals in the ventromedial prefrontal cortex (vmPFC) during intertemporal decision-making were dampened in individuals with greater motivational and hedonic deficits, after accounting for primary diagnosis. This relationship remained significant while controlling for diagnosis-specific symptoms of mood and psychosis, such as depression as well as positive and negative symptoms. Our results demonstrate that dysfunction in the vmPFC during value-based decision-making is specifically linked to motivational and hedonic impairments. These findings provide a quantitative neural target for the potential development of novel treatments for amotivation and anhedonia.

Expectations of immediate and delayed reward differentially affect cognitive task performance

The current study used a modified Monetary Incentive Delay task to examine the neural mechanisms underlying anticipating and receiving an immediate or delayed reward and examined the influence of pursuing these rewards on cognitive task performance. A pre-cue indicating the potential of gaining a monetary reward (immediate-, delayed-, vs. no-reward) was followed by a target stimulus requiring a fast and accurate response. Then, response-contingent feedback was presented indicating whether or not the participant would receive the corresponding reward. Linear mixed-effect models revealed the fastest behavioural responses and the strongest neural activity, as reflected in event-related-potentials and event-related-spectral-perturbation responses, for immediate reward, followed by delayed reward, with the slowest behavioural responses and the weakest neural activities observed in the no-reward condition. Expectations related to the cue-P3 component and the cue-delta activities predicted behavioural performance, especially in the immediate reward condition. Moreover, exploratory analyses revealed that depression moderated the relationship between target-locked neural activity and behavioural performance in the delayed reward condition, with lower neural activity being related to worse behavioural performance amongst participants scoring high on depression. These results indicate that differential value representations formed through delay discounting directly affect neural responses in reward processing and directly influence the effort invested in the current task, which is reflected by behavioural responses and is in agreement with the expected value of control theory.

Exploring psychopathy traits on intertemporal decision-making, neurophysiological correlates, and emotions on time estimation in community adults

There are certain characteristics of psychopathy that may be related to changes in intertemporal choices. Specifically, traits such as impulsivity or lack of inhibitory control may be associated with a more pronounced discounting function in intertemporal choices (IC) and, in turn, this function may be based on changes in the basic mechanisms of time estimation (TE). Therefore, this study aimed to examine potential differences in neurophysiological correlates, specifically through N1, P3, and LPP measurements, which may be related to TE and IC, examining their modulation according to psychopathic traits, different emotional conditions, and different decision-making conditions. This experimental study included 67 adult participants (48 women) from the northern region of Portugal, who performed an intertemporal decision-making task and, of those, 19 participants (16 women), with a mean age of 25 years (SD = 5.41) and a mean of 16 years of schooling (SD = 3.37) performed the time estimation task. The instruments/measures applied were MoCA, used as a neurocognitive screening tool; the Triarchic Psychopathy Measure (TriPM), a self-report instrument with 58 items that map the core features of psychopathy along three facets – boldness, meanness, and disinhibition – and considers them continuously distributed among the general population; intertemporal decision-making and time estimation tasks – for the time estimation task, the stimuli consisted of 45 color images extracted from the Nencki Affective Picture System (NAPS). In the TE task, there was an almost significant effect of disinhibition on the values of θ, with higher values on this variable associated with greater values of θ in the unpleasant emotional condition. In the IC task, there were no significant effects of any psychopathy measure on the values of the gains and losses ratios. In addition, the analysis of the neurophysiological correlates of the IC task did not reveal a main effect of the decision-making condition, nor effects of any psychopathy measure on the N1 and P3 amplitudes. The analysis of the neurophysiological correlates of the TE task revealed that higher meanness values are associated with smaller N1 amplitude in the pleasant emotional condition, whereas higher disinhibition values are associated with greater N1 amplitude in the pleasant emotional condition. Still in this task, higher disinhibition values were associated with a smaller LPP amplitude in the unpleasant emotional condition. The increase in the distribution of attention resources towards time and/or the increase in activation states, including those originated by responses to emotional stimuli, may be the main factor that alters the way impulsive individuals and, presumably, individuals with high psychopathy, consider time when making decisions.

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There are certain characteristics of psychopathy that may be related to changes in IC.

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Higher meanness values are associated with smaller N1 amplitude in the pleasant emotional condition (TE task).

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Higher disinhibition values are associated with greater N1 amplitude in the pleasant emotional condition (TE task).

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Higher disinhibition values were associated with a smaller LPP amplitude in the unpleasant emotional condition (TE task).

Intersection between social inequality and emotion regulation on emerging adult cannabis use

Emerging adulthood (EA; ages 18-25) is characterized by socioemotional and neurodevelopmental challenges. Cannabis is a widely used substance among EAs, and hazardous use may increase risk for sustained use patterns and related health consequences. Research shows differential increases in hazardous use by objective as well as subjective measures of social inequality, with more concerning trajectories for youth with greater experiences of social inequality. Learning how to flexibly monitor and modify emotions in proactive ways (i.e., emotion regulation) is a central developmental task navigated during the EA window. Challenges to and with emotion regulation processes can contribute to the emergence of mental health symptoms during EA, including hazardous cannabis use. In this perspective, we highlight emotion dysregulation and social inequality as two critical factors that interact to either buffer against or exacerbate cannabis use during the EA period, noting critical gaps in the literature that merit additional research. We recommend novel methods and longitudinal designs to help clarify how dynamic cognition-emotion interplay predicts trajectories of negative emotional experiences and cannabis use in EA.

The effects of reward and frustration in patients with bipolar disorder: Evidence from a computerized task with non-contingent feedback

BACKGROUND

Bipolar disorder (BD) is characterized by mood changes that implies alterations in reward sensitivity and frustration tolerance. This study examined the effects of monetary reward and frustration on attentional performance and on affective experience across mood states in BD.

METHODS

An Affective Posner Task in which the nature of contingencies are divided in the three successive blocks (baseline condition, monetary reward and non-contingent feedback) was applied to BD individuals in their different episodes: mania (n = 30), depression (n = 30), and euthymia (n =  30) as well as to a group of healthy controls (n = 30).

RESULTS

Monetary reward improved performance (in terms of faster response times) in the euthymic group and the control group, whereas it impaired performance in the manic group and has not significant effect in the depressed group. In addition, an increased interference of frustration on response accuracy was exhibited in the three groups of BD patients (including euthymia) compared with healthy controls.

LIMITATIONS

Participants' affective experience was self-informed by a Likert scale, so the reliability of this measure can be undermined in symptomatic patients in terms of stability and objectivity. Although it was statistically controlled, at the time of testing, all BD patients were medicated.

CONCLUSIONS

A dissociated effect of reward and frustration was found between symptomatic and euthymic states in BD: whereas the benefit from monetary reward is affected only during symptomatic episodes (i.e., a state), the notably increased interference of frustration is exhibited also during euthymia (i.e., a trait).

Trait sensation seeking is associated with heightened beta-band oscillatory dynamics over left ventrolateral prefrontal cortex during reward expectancy

BACKGROUND

Sensation Seeking, the proclivity toward novel and stimulating experiences, is associated with greater left ventrolateral prefrontal cortex (vlPFC) activity during uncertain reward expectancy. Here, we examined relationships between sensation seeking and vlPFC oscillatory dynamics using electroencephalography (EEG).

METHODS

In 26 adolescents/young adults (16 female; 22.3 ± 1.7yrs), EEG was measured during uncertain reward expectancy. Event-related spectral perturbations (ERSP) from 15-80 Hz (beta/gamma bands) were compared as a function of uncertain reward expected value and assessed for relationships with feedback-related negativity (FRN) response to outcome feedback and response tendency measures of risk for BD.

RESULTS

Event-related synchronization (ERS) between 15-25 Hz (beta) over left vlPFC was sensitive to the expected value of uncertain reward (rho=0.46; p = 0.048), and correlated with sensation seeking (r = 0.49, p < 0.01) and feedback-related negativity (FRN), where greater beta ERS was related to larger FRN (r = -0.39, p = 0.047). FRN was also related to behavioral inhibition (r = 0.49, p < 0.01).

LIMITATIONS

It is unknown whether results may extrapolate to clinical populations, given the healthy sample used here. Further, although we have confidence that the beta-band signal we measure in this study arises from left prefrontal cortex, we largely infer a left vlPFC source.

CONCLUSIONS

These findings highlight the role of left vlPFC in evaluation of immediate rewards. We now provide a link between reward expectancy-related left vlPFC activity and the well-characterized FRN, with a known role in attentive processing. These findings can guide treatment development for mania/hypomania at-risk individuals, including transcranial alternating current stimulation.

Reward mechanism of depressive episodes in bipolar disorder: Enhanced theta power in feedback-related negativity

INTRODUCTION

This study aimed to explore the reward-related neural mechanism in patients with depressive mood in bipolar disorder (BD) using event-related potentials. It remains unknown whether or not different neurobiological markers underlying depression symptoms in BD depression and major depression disorder (MDD).

METHODS

24 patients with BD depression and 20 healthy controls were included. Participants underwent evaluation with the Temporal Experience of Pleasure Scale (TEPS), followed by the classical gambling paradigm, while undergoing 64-channel electroencephalography. The waveform of feedback-related negativity (FRN) was extracted from the 250-350 ms time-window after participants received feedback regarding loss or gain. Event-related potential datasets were obtained using time-frequency analysis.

RESULTS

(1) The TEPS scores of the patients were significantly lower than those of the controls [t₍₄₂₎ = 5.16, p < 0.01]. (2) The event of loss elicited a deeper FRN in patients than that in controls [t₍₄₂₎ = 2.19, p < 0.05], while no difference was observed in the event of gains (t₍₄₂₎ = 1.12, p > 0.05). (3) Theta power rooted in FRN in patients was significantly higher in loss than in gain [F_(1,42) = 30.32, p < 0.01]. (4) Analysis of Variance (ANOVA) illustrated the interaction effect of theta power in gain/loss between two groups [F_(1,42) = 3.59, p = 0.06].

LIMITATION

Our study did not analyze the effect of different drugs which might affect our results.

CONCLUSION

The enhanced reflection of negative feedback was consistent with the negative bias, impulse control impairment, and emotional dysregulation observed in the bipolar disorder spectrum. We suggested that the extreme theta power generated from the anterior cingulate gyrus (ACC) might be the main component of abnormal FRN.

A Systematic Review of the Balloon Analogue Risk Task (BART) in Alcohol Research

Risk-taking propensity has been crucial to the investigation of alcohol use and consequences. One measure, the balloon analogue risk task (BART), has been used consistently over the past two decades. However, it is unclear how this measure is related to alcohol outcomes. This paper systematically reviews the literature on the BART and alcohol outcomes. First, direct associations between the BART and alcohol use are reviewed including correlations, group comparisons, the BART's prediction of alcohol outcomes and BART performance after consuming alcohol. Then, potential moderators that explain when and for whom the BART is related to alcohol outcomes are reviewed. Finally, potential mechanisms that explain how the BART and alcohol outcomes are related are reviewed. This review reveals patterns in the BART suggesting risk-taking propensity may be related to changes in alcohol use over time; however, there is little evidence to suggest BART scores increase after consuming alcohol. Yet, additional research suggests adjusted average pump scores may be too simplistic for the amount of information the BART captures and understanding individual's patterns of responses on the BART is important for investigating its relation to alcohol outcomes. Finally, this review opens up several future directions for research to understand how risk-taking propensity is related to alcohol outcomes.

Mapping Disease Course Across the Mood Disorder Spectrum Through a Research Domain Criteria Framework

BACKGROUND

The National Institute of Mental Health Research Domain Criteria (RDoC) initiative aims to establish a neurobiologically valid framework for classifying mental illness. Here, we examined whether the RDoC construct of reward learning and three aspects of its underlying neurocircuitry predicted symptom trajectories in individuals with mood pathology.

METHODS

Aligning with the RDoC approach, we recruited individuals (n = 80 with mood disorders [58 unipolar and 22 bipolar] and n = 32 control subjects; 63.4% female) based on their performance on a laboratory-based reward learning task rather than clinical diagnosis. We then assessed 1) anterior cingulate cortex prediction errors using electroencephalography, 2) striatal reward prediction errors using functional magnetic resonance imaging, and 3) medial prefrontal cortex glutamatergic function (mPFC Gln/Glu) using ¹H magnetic resonance spectroscopy. Severity of anhedonia, (hypo)mania, and impulsivity were measured at baseline, 3 months, and 6 months.

RESULTS

Greater homogeneity in aspects of brain function (mPFC Gln/Glu) was observed when individuals were classified according to reward learning ability rather than diagnosis. Furthermore, mPFC Gln/Glu levels predicted more severe (hypo)manic symptoms cross-sectionally, predicted worsening (hypo)manic symptoms longitudinally, and explained greater variance in future (hypo)manic symptoms than diagnostic information. However, rather than being transdiagnostic, this effect was specific to individuals with bipolar disorder. Prediction error indices were unrelated to symptom severity.

CONCLUSIONS

Although findings are preliminary and require replication, they suggest that heightened mPFC Gln/Glu warrants further consideration as a predictor of future (hypo)mania. Importantly, this work highlights the value of an RDoC approach that works in tandem with, rather than independent of, traditional diagnostic frameworks.

Clinical Correlates of False Positive Assignment in Bipolar Screening Measures Across Psychiatric Diagnoses among Patients without Bipolar Disorder

OBJECTIVE

In this study, we aimed to determine clinical correlates of false positive assignment (FPA) on commonly used bipolar screening questionnaires.

METHODS

A retrospective chart review was conducted to a total of 3885 psychiatric outpatients. After excluding patients who have bipolar spectrum illnesses, patients who were assigned as having hypomania on the mood disorder questionnaire (MDQ) or the hypomania checklist-32 (HCL-32) were identified as patients who had FPA. Psychiatric diagnoses and severity of emotional symptoms were compared between patients with and without FPA.

RESULTS

Patients with FPA on the MDQ showed significant associations with presence of major depressive disorder, generalized anxiety disorder, and alcohol-use disorder, while patients with FPA on the HCL-32 showed associations with presence of panic disorder and agoraphobia. FPA on the MDQ was also associated with greater emotional symptoms and lifetime history of suicide attempts. Logistic regression analysis showed that male sex, younger age, presence of alcohol-use disorder, and severity of depression and obsessive-compulsive symptoms were significantly associated with FPA on the MDQ.

CONCLUSION

The FPA for the MDQ was associated with clinical factors linked to trait impulsivity, and the FPA for both the MDQ and the HCL-32 could be related to increased anxiety.

Creativity and Bipolar Disorder: A Shared Genetic Vulnerability

Bipolar disorder is a lifelong mood disorder characterized by extreme mood swings between mania and depression. Despite fitness costs associated with increased mortality and significant impairment, bipolar disorder has persisted in the population with a high heritability and a stable prevalence. Creativity and other positive traits have repeatedly been associated with the bipolar spectrum, particularly among unaffected first-degree relatives and those with milder expressions of bipolar traits. This suggests a model in which large doses of risk variants cause illness, but mild to moderate doses confer advantages, which serve to maintain bipolar disorder in the population. Bipolar disorder may thus be better conceptualized as a dimensional trait existing at the extreme of normal population variation in positive temperament, personality, and cognitive traits, aspects of which may reflect a shared vulnerability with creativity. Investigations of this shared vulnerability may provide insight into the genetic mechanisms underlying illness and suggest novel treatments.

Intrinsic prefrontal organization underlies associations between achievement motivation and delay discounting

Achievement motivation is a core component of human decision making. However, neural mechanisms that link achievement motivation and intertemporal choice have not yet been elucidated. Here, we examined neural pathways underlying the relationship between achievement motivation and intertemporal choice using a delay discounting task and resting-state functional magnetic resonance imaging on 86 healthy subjects. Behaviorally, delay discounting rate was positively correlated with achievement motivation. Functional coupling of the dorsolateral prefrontal cortex (dlPFC) with the medial prefrontal cortex (mPFC), medial orbitofrontal cortex and ventral striatum was positively correlated with achievement motivation. Notably, the mediation analysis showed that the impact of achievement motivation on delay discounting was mediated by intrinsic connectivity between the dlPFC and mPFC. Our findings suggest that intrinsic organization within the prefrontal cortex plays a key role in linking achievement motivation and intertemporal choice.

Alterations in Task-Related Brain Activation in Children, Adolescents and Young Adults at Familial High-Risk for Schizophrenia or Bipolar Disorder - A Systematic Review

Children, adolescents, and young adults with at least one first-degree relative [familial high-risk (FHR)] with either schizophrenia (SZ) or bipolar disorder (BD) have a one-in-two risk of developing a psychiatric disorder. Here, we review functional magnetic resonance imaging (fMRI) studies which examined task-related brain activity in young individuals with FHR-SZ and FHR-BD. A systematic search identified all published task-related fMRI studies in children, adolescents, and young adults below an age of 27 years with a first-degree relative with SZ or BD, but without manifest psychotic or affective spectrum disorder themselves. The search identified 19 cross-sectional fMRI studies covering four main cognitive domains: 1) working memory (n = 3), 2) cognitive control (n = 4), 3) reward processing (n = 3), and 4) emotion processing (n = 9). Thirteen studies included FHR-BD, five studies included FHR-SZ, and one study included a pooled FHR group. In general, task performance did not differ between the respective FHR groups and healthy controls, but 18 out of the 19 fMRI studies revealed regional alterations in task-related activation. Brain regions showing group differences in peak activation were regions associated with the respective task domain and showed little overlap between FHR-SZ and FHR-BD. The low number of studies, together with the low number of subjects, and the substantial heterogeneity of employed methodological approaches within the domain of working memory, cognitive control, and reward processing impedes finite conclusions. Emotion processing was the most investigated task domain in FHR-BD. Four studies reported differences in activation of the amygdala, and two studies reported differences in activation of inferior frontal/middle gyrus. Together, these studies provide evidence for altered brain processing of emotions in children, adolescents, and young adults at FHR-BD. More studies of higher homogeneity, larger sample sizes and with a longitudinal study design are warranted to prove a shared or specific FHR-related endophenotypic brain activation in young first-degree relatives of individuals with SZ or BD, as well as to pinpoint specific alterations in brain activation during cognitive-, emotional-, and reward-related tasks.

Cooperation moderates the impact of effort on reward valuation

Effort is valuable, but researchers have different opinions on whether effort can reduce or increase the valuation of rewards. The effect of cooperation on reward valuation also remains unclear. In this study, we conducted two experiments to examine the effect of effort on reward valuation (Experiment 1) and whether this effect can be influenced by cooperation (Experiment 2), using electroencephalogram (EEG) technology. We found that when participants worked alone, they generated a larger feedback-related negativity (FRN) amplitude for losing rewards than for gaining rewards, with more effort resulting in larger FRN amplitudes for losing rewards. However, when participants worked together with a partner, there was no significant difference between the amplitude for gaining rewards and that for losing rewards during low-effort tasks. Nevertheless, for high-effort tasks, the FRN amplitude for losing rewards was significantly larger than that for gaining rewards. Moreover, in both experiments, we found larger N1 amplitudes for gaining rewards than for losing rewards. Our ERP results suggest that in the early stage of processing, people pay extra attention to rewards, after that the effort level influences their reward valuation. In addition, cooperation regulates the reduced valuation of losing rewards only when people invest low effort.

Objective cognitive functioning in self-reported habitual short sleepers not reporting daytime dysfunction: examination of impulsivity via delay discounting

Study Objectives

(1) Examine performance on an objective measure of reward-related cognitive impulsivity (delay discounting) among self-reported habitual short sleepers and medium (i.e. recommended 7-9 hours) length sleepers either reporting or not reporting daytime dysfunction; (2) Inform the debate regarding what type and duration of short sleep (e.g. 21 to 24 hours of total sleep deprivation, self-reported habitual short sleep duration) meaningfully influences cognitive impulsivity; (3) Compare the predictive utility of sleep duration and perceived dysfunction to other factors previously shown to influence cognitive impulsivity via delay discounting performance (age, income, education, and fluid intelligence).

Methods

We analyzed data from 1190 adults from the Human Connectome Project database. Participants were grouped on whether they reported habitual short (≤6 hours) vs. medium length (7-9 hours) sleep duration and whether they perceived daytime dysfunction using the Pittsburgh Sleep Quality Index.

Results

All short sleepers exhibited increased delay discounting compared to all medium length sleepers, regardless of perceived dysfunction. Of the variables examined, self-reported sleep duration was the strongest predictor of delay discounting behavior between groups and across all 1190 participants.

Conclusions

Individuals who report habitual short sleep are likely to exhibit increased reward-related cognitive impulsivity regardless of perceived sleep-related daytime impairment. Therefore, there is a reason to suspect that these individuals exhibit more daytime dysfunction, in the form of reward-related cognitive impulsivity, than they may assume. Current findings suggest that assessment of sleep duration over the prior month has meaningful predictive utility for human reward-related impulsivity.

The paraventricular thalamus is a critical mediator of top-down control of cue-motivated behavior in rats

Cues in the environment can elicit complex emotional states, and thereby maladaptive behavior, as a function of their ascribed value. Here we capture individual variation in the propensity to attribute motivational value to reward-cues using the sign-tracker/goal-tracker animal model. Goal-trackers attribute predictive value to reward-cues, and sign-trackers attribute both predictive and incentive value. Using chemogenetics and microdialysis, we show that, in sign-trackers, stimulation of the neuronal pathway from the prelimbic cortex (PrL) to the paraventricular nucleus of the thalamus (PVT) decreases the incentive value of a reward-cue. In contrast, in goal-trackers, inhibition of the PrL-PVT pathway increases both the incentive value and dopamine levels in the nucleus accumbens shell. The PrL-PVT pathway, therefore, exerts top-down control over the dopamine-dependent process of incentive salience attribution. These results highlight PrL-PVT pathway as a potential target for treating psychopathologies associated with the attribution of excessive incentive value to reward-cues, including addiction.

Delay discounting and reward sensitivity in a 2 × 2 study of bipolar disorder and alcohol dependence

BACKGROUND AND AIMS

Separate studies have shown increased delay discounting in people with bipolar disorder (BD) and people with alcohol dependence (AD) relative to people without mental health problems. Delay discounting was compared in people with no mental health problems, AD, BD and AD plus BD. Associations of delay discounting with self-reported impulsivity and reward sensitivity were also assessed.

DESIGN

The study was a two-by-two factorial comparative observational design.

SETTING

Data were collected at baseline diagnostic visits as part of a neuroimaging study at a medical university in South Carolina, USA.

PARTICIPANTS

Twenty-two BD + AD, 33 BD, 28 AD and 27 people without mental health problems participated.

MEASUREMENTS

Diagnostic and clinician-rated symptom measures, self-report questionnaires and a computerized delay discounting task were administered. Two-by-two general linear univariate models were tested to examine between-group differences on discounting rates, and bivariate correlations and hierarchical regression analyses were performed to examine associations between discounting rates and self-reported reward sensitivity and impulsivity.

FINDINGS

There was a significant main effect of AD (P = 0.006, η2  = 0.068). The main effect of BD and the BD × AD interaction terms were non-significant (P ≥ 0.293, η2  ≤ 0.010). Reward sensitivity and impulsivity were not significantly associated with discounting rates after adjustment for the other (P ≥ 0.089).

CONCLUSIONS

People with alcohol dependence appear to have higher delay discounting, while previously found associations between bipolar disorder and delay discounting may be secondary to alcohol use disorder.

Overlapping and distinct neural metabolic patterns related to impulsivity and hypomania in Parkinson's disease

Impulsivity and hypomania are common non-motor features in Parkinson's disease (PD). The aim of this study was to find the overlapping and distinct neural correlates of these symptoms in PD. Symptoms of impulsivity and hypomania were assessed in 24 PD patients using the Barratt Impulsiveness Scale (BIS-11) and Self-Report Manic Inventory (SRMI), respectively. In addition, fluorodeoxyglucose positron emission tomography (FDG-PET) imaging for each individual was performed. We conducted two separate multiple regression analyses for BIS-11 and SRMI scores with FDG-PET data to identify the brain regions that are associated with both impulsivity and hypomania scores, as well as those exclusive to each symptom. Then, seed-based functional connectivity analyses on healthy subjects identified the areas connected to each of the exclusive regions and the overlapping region, used as seeds. We observed a positive association between BIS-11 and SRMI scores and neural metabolism only in the prefrontal areas. Conjunction analysis revealed an overlapping region in the middle frontal gyrus. Regions exclusive to impulsivity were found in the medial part of the right superior frontal gyrus and regions exclusive to hypomania were in the right superior frontal gyrus, right precentral gyrus and right paracentral lobule. Connectivity patterns of seeds exclusively related to impulsivity were different from those for hypomania in healthy brains. These results provide evidence of both overlapping and distinct regions linked with impulsivity and hypomania scores in PD. The exclusive regions for each characteristic are connected to specific intrinsic functional networks.

[Predictors of suicidal behaviour in adolescents with depressive disorders]

A review of recent publications is devoted to risk factors for suicidal behavior in adolescents with depressive disorders. The authors summarized Russian and international studies on the clinical course of affective disorders, in particular bipolar disorders, their clinical heterogeneity and incompleteness in adolescence. Particular attention is given to the complexity of early identification of predictors of suicidal behavior in depressive disorders due to comprehensiveness of exogenous and endogenous effects characteristic of adolescence. The role of genetic loading for affective disorders, problems of children having parents with affective disorders, social and psychological factors (violence in families, school bullying etc.) and risks of suicidal behavior are described. It is of great significance to investigate premorbid adjustment, subaffective manifestations of disorders in adolescence to predict the trajectory of the disease, its complications in the form of suicidal behavior and opportunities for early intervention.

Baseline impulsivity may moderate L-DOPA effects on value-based decision-making

Research has indicated a major role of dopamine in decision-making processes, but the underlying mechanisms remain largely unknown due to inconsistency in effects of dopaminergic drugs. To clarify the impact of dopamine on impulsive choice, we administered 150 mg L-DOPA to 87 healthy adults in a randomized, placebo-controlled, double-blind, crossover study, evaluating performance in four value-based decision-making tasks. We predicted that baseline impulsivity would moderate L-DOPA effects. In support of our hypothesis, L-DOPA had no main effect on impulsive choice, but reduced risk-seeking for gains in more-impulsive subjects. Because L-DOPA effects may be influenced by body weight, we repeated our analyses on data from half of the sample (n = 44) with lower weight, anticipating a stronger effect. In addition to the effect on risk-seeking for gains, low-weight participants also exhibited baseline-dependent effects of L-DOPA on loss aversion and delay discounting. Our results are consistent with the hypothesis of an inverted U-shaped dopamine function in which both low and high extremes of dopamine signaling are associated with high-impulsive choice. Consideration of differential baseline impulsivity and body weight may resolve previous seemingly paradoxical pharmacological results and might deepen our understanding of dopaminergic mechanisms underlying impulsivity.

A test of dopamine hyper- and hyposensitivity in alcohol use

Biases in outcome processing, mediated by the mesocortical dopaminergic (DA) system, may predict individual differences in the frequency and quantity of alcohol use. We tested the hypothesis that genetic markers associated with increased DA neurotransmission contribute to reduced neural sensitivity to costs and increased alcohol use in an undergraduate sample. We created a DA transmission score using five genetic markers related to DA transmission and assessed neural sensitivity to cost using the feedback-related negativity (FRN), an event-related potential implicated in neural outcome evaluation, on both passive evaluative and active decision-making tasks. Self-reported alcohol use was assessed using the Daily Drinking Questionnaire-Revised. Participants with a higher DA transmission score reported increased alcohol consumption and exhibited a more blunted FRN on both the passive and active tasks. While dopamine hyposensitivity is common among chronic alcohol users, these data provide preliminary evidence that hypersensitivity of the dopamine system may underlie increased alcohol use in those who have not yet developed a chronic alcohol use disorder.

Can delay discounting deliver on the promise of RDoC?

The National Institute of Mental Health launched the Research Domain Criteria (RDoC) initiative to better understand dimensions of behavior and identify targets for treatment. Examining dimensions across psychiatric illnesses has proven challenging, as reliable behavioral paradigms that are known to engage specific neural circuits and translate across diagnostic populations are scarce. Delay discounting paradigms seem to be an exception: they are useful for understanding links between neural systems and behavior in healthy individuals, with potential for assessing how these mechanisms go awry in psychiatric illnesses. This article reviews relevant literature on delay discounting (or the rate at which the value of a reward decreases as the delay to receipt increases) in humans, including methods for examining it, its putative neural mechanisms, and its application in psychiatric research. There exist rigorous and reproducible paradigms to evaluate delay discounting, standard methods for calculating discount rate, and known neural systems probed by these paradigms. Abnormalities in discounting have been associated with psychopathology ranging from addiction (with steep discount rates indicating relative preference for immediate rewards) to anorexia nervosa (with shallow discount rates indicating preference for future rewards). The latest research suggests that delay discounting can be manipulated in the laboratory. Extensively studied in cognitive neuroscience, delay discounting assesses a dimension of behavior that is important for decision-making and is linked to neural substrates and to psychopathology. The question now is whether manipulating delay discounting can yield clinically significant changes in behavior that promote health. If so, then delay discounting could deliver on the RDoC promise.

Linking Cognitive Measures of Response Inhibition and Reward Sensitivity to Trait Impulsivity

Impulsivity is regarded as a multifaceted construct that comprises two dimensions: rapid-response impulsivity and reward-delay impulsivity. It is unclear, however, which aspects of trait impulsivity, as assessed by self-report measures are related to rapid-response impulsivity and/or to reward-delay impulsivity, as different results have been reported in studies using both self-report and cognitive measures. This study aimed to directly relate self-report measures of impulsivity to cognitive measures of impulsivity in individuals at low- or high-levels on two impulsivity dimensions, specifically rapid-response impulsivity and reward-delay impulsivity. Participants were classified into high- or low-impulsivity groups based on (1) level of rapid-response impulsivity (determined by BIS-11 Motor subscale scores); (2) level of reward-delay impulsivity (determined by BIS/BAS subscale scores); and (3) a combination of rapid-response impulsivity and reward-delay impulsivity levels. Impulsivity was assessed using Go/No-Go, Stop-Signal and Delay-Discounting tasks and self-report measures. The high rapid-response impulsivity group showed significantly higher reward-delay impulsivity on both, the Delay-Discounting tasks and on self-report measures assessing reward-delay impulsivity, than the low-risk group. Based on the level of reward-delay impulsivity, the high reward-delay impulsivity group scored significantly higher on task-based (cognitive) and self-report measures assessing rapid-response inhibition than the low reward-delay impulsivity group. Combining both dimensions of impulsivity showed that the high-impulsivity group performed significantly worse in rapid-response paradigms and temporally discounted significantly more impulsively than the low-impulsivity group. Thus, combined impulsivity factors provide better assessment of impulsivity than each dimension alone. In conclusion, robust differences in impulsivity can be identified in non-clinical young adults.

Hypomania and depression associated with distinct neural activity for immediate and future rewards

Bipolar spectrum and unipolar depressive disorders have been associated with distinct and opposite profiles of reward-related neural activity. These opposite profiles may reflect a differential preexisting vulnerability for both types of disorders. In support, recent ERP studies find that, following reward feedback, a larger reward positivity (RewP) is associated with greater vulnerability for bipolar spectrum disorders, whereas a smaller RewP is associated with greater vulnerability for depression. However, prior studies have investigated only immediate rewards and have not examined dimensions of both bipolar disorder and unipolar depression within the same sample. The present study is the first to investigate feedback-related ERP correlates of proneness to hypomania and unipolar depressive tendencies within the same sample and to expand our scope to include future rewards. Participants completed a modified time estimation task where the same monetary reward was available immediately or at one of five different future dates. Results revealed proneness to hypomania and unipolar depressive tendencies were related to an elevated and blunted RewP, respectively, but only following immediate rewards (i.e., today). Following rewards in the distant future (e.g., 8 months), proneness to hypomania and depressive tendencies were associated with elevated and blunted amplitudes for the P3, respectively, a subsequent ERP component reflecting motivational salience during extended feedback processing. Furthermore, these opposing profiles were independent of, and significantly different from, one another. These results suggest that feedback-related ERPs following immediate and future rewards are candidate biomarkers that can physiologically separate vulnerability for bipolar spectrum from unipolar depressive disorders.

The neural encoding of information prediction errors during non-instrumental information seeking

In a dynamic world, accurate beliefs about the environment are vital for survival, and individuals should therefore regularly seek out new information with which to update their beliefs. This aspect of behaviour is not well captured by standard theories of decision making, and the neural mechanisms of information seeking remain unclear. One recent theory posits that valuation of information results from representation of informative stimuli within canonical neural reward-processing circuits, even if that information lacks instrumental use. We investigated this question by recording EEG from twenty-three human participants performing a non-instrumental information-seeking task. In this task, participants could pay a monetary cost to receive advance information about the likelihood of receiving reward in a lottery at the end of each trial. Behavioural results showed that participants were willing to incur considerable monetary costs to acquire early but non-instrumental information. Analysis of the event-related potential elicited by informative cues revealed that the feedback-related negativity independently encoded both an information prediction error and a reward prediction error. These findings are consistent with the hypothesis that information seeking results from processing of information within neural reward circuits, and suggests that information may represent a distinct dimension of valuation in decision making under uncertainty.

Mood congruent tuning of reward expectation in positive mood: evidence from FRN and theta modulations

Positive mood broadens attention and builds additional mental resources. However, its effect on performance monitoring and reward prediction errors remain unclear. To examine this issue, we used a standard mood induction procedure (based on guided imagery) and asked 45 participants to complete a gambling task suited to study reward prediction errors by means of the feedback-related negativity (FRN) and mid-frontal theta band power. Results showed a larger FRN for negative feedback as well as a lack of reward expectation modulation for positive feedback at the theta level with positive mood, relative to a neutral mood condition. A control analysis showed that this latter result could not be explained by the mere superposition of the event-related brain potential component on the theta oscillations. Moreover, these neurophysiological effects were evidenced in the absence of impairments at the behavioral level or increase in autonomic arousal with positive mood, suggesting that this mood state reliably altered brain mechanisms of reward prediction errors during performance monitoring. We interpret these new results as reflecting a genuine mood congruency effect, whereby reward is anticipated as the default outcome with positive mood and therefore processed as unsurprising (even when it is unlikely), while negative feedback is perceived as unexpected.

Elevated outcome-anticipation and outcome-evaluation ERPs associated with a greater preference for larger-but-delayed rewards

Although waiting for a reward reduces or discounts its value, some people have a stronger tendency to wait for larger rewards and forgo smaller-but-immediate rewards. This ability to delay gratification is captured by individual differences in so-called intertemporal choices in which individuals are asked to choose between larger-but-delayed versus smaller-but-immediate rewards. The current study used event-related potentials (ERPs) to examine whether enhancement in two neurocognitive processes, outcome anticipation and outcome evaluation, modulate individual variability in intertemporal responses. After completing a behavioral intertemporal choice task, 34 participants performed an ERP gambling task. From this ERP task, we separately examined individual differences in outcome anticipation (stimulus-preceding negativity; SPN), early outcome valuation (feedback-related negativity; FRN), and late outcome evaluation (P3). We observed that both elevated outcome-anticipation (SPN) and late outcome-evaluation (P3) neural processes predicted a stronger preference toward larger-but-delayed rewards. No relationship was observed between intertemporal responses and early outcome evaluation (FRN), indicating that the relationship between outcome evaluation and intertemporal responses was specific to the late outcome-evaluation processing stream. Moreover, multiple regression analyses indicated that the SPN and P3 independently modulate individual differences in intertemporal responses, suggesting separate mechanisms underlie the relationship between these two neurocognitive processes and intertemporal responses. Accordingly, we identify two potential neurocognitive modulators of individual variability in intertemporal responses. We discuss the mechanisms underlying these modulators in terms of anticipation-related processing (SPN) and a saliency bias toward gain (compared to loss) outcomes (P3).

Increased reward-oriented impulsivity in older bipolar patients: A preliminary study

OBJECTIVE

Impulsivity is a well-established trait of bipolar disorder (BD) that persists across mood phases. It is, however, still unknown whether, in BD, impulsivity remains stable or varies in intensity over the lifespan. This cross-sectional study compared impulsive behavior in older euthymic BD patients and healthy individuals using a range of self-rating and behavioral measures of impulsivity.

METHODS

28 BD patients (56.07 ± 4.08 years, 16 women) and 15 healthy controls (HC; 55.1 ± 3.95 years, 6 women) were administered the Barratt Impulsivity Scale (BIS) and selected tasks of the Cambridge Neuropsychological Test Automated Batter (CANTAB) reflecting impulsivity. Multivariate analysis of variance controlled for age compared impulsivity measures across BD and HC.

RESULTS

BD patients displayed poor decision making, risk taking, and increased delay aversion. Other measures of impulsivity such as response inhibition, sustained cognitive control, and BIS scores were, overall, comparable between BD and HC.

CONCLUSIONS

These preliminary findings suggest that, in BD, aspects of impulsivity related to reward-based decision making persist into late adulthood. Large scale, longitudinal studies are needed to evaluate the relationship of age to impulsivity over time, and explore the link between impulsivity and illness progression in elderly individuals with BD.

Sensory profiles as potential mediators of the association between hypomania and hopelessness in 488 major affective outpatients

INTRODUCTION

Extreme sensory processing patterns may contribute to the pathophysiology of major affective disorders. We aimed to examine whether significant correlations exist between sensory profiles, hypomania, self-reported depression, and hopelessness and whether sensory profiles may be potential mediators of the association between hypomania and depression/hopelessness.

METHODS

The sample consisted of 488 euthymic affective disorder patients of which 283 diagnosed with unipolar and 162 with bipolar disorder with an age ranging from 18 to 65 years (mean = 47.82 ± 11.67).

RESULTS

Lower registration of sensory input and sensory sensitivity significantly correlated with elevated self-reported depression, hopelessness, and irritable/risk-taking hypomania while sensation seeking and avoiding significantly correlated with elevated depression and hopelessness but not with irritable/risk-taking hypomania. Moreover, individuals with lower ability to register sensory input and higher hypomania showed higher self-reported depression than those with good registration of sensory information. According to SEM analyses, there was both a direct/indirect effect of irritable/risk-taking on depression-hopelessness with the mediation model explaining 48% of the variance in depression-hopelessness.

LIMITATIONS

The relatively small sample size and the cross-sectional nature of the study design do not allow the generalization of the main findings.

CONCLUSION

Low registration was associated with enhanced depressed mood and hopelessness while sensory seeking may be considered a resilient factor.

Structural characteristics of the brain reward circuit regions in patients with bipolar I disorder: A voxel-based morphometric study

Bipolar I disorder (BD-I) is often misdiagnosed, leading to inadequate treatment and significant disability along with reduced quality of life. Recent neural models suggest that the reward circuitry is affected in bipolar disorder. The purpose of the present study was to identify structural abnormalities in the brain reward-processing neural circuitry among patients with BD-I. 21 patients with BD-I and 21 healthy controls (HC) participated in this study. Structural magnetic resonance imaging was performed. Region-of-interest (ROI) voxel-based morphometry analysis was applied to assess the presence of structural changes between the BD-I patient group and the control group. The results of the reward circuitry ROI analysis revealed lower gray matter volumes in the left ventromedial prefrontal cortex (VMPFC), left dorsomedial prefrontal cortex (DMPFC), and left ventrolateral prefrontal cortex (VLPFC) in patients with BD-I compared to HC. Our results suggest that abnormalities in the brain reward-processing neural circuitry, especially those in the left VMPFC, left DMPFC, and left VLPFC, may play an important role in the pathophysiology of BD-I.

The clinical trajectory of emerging bipolar disorder among the high-risk offspring of bipolar parents: current understanding and future considerations

BACKGROUND

Relatively little is known about the onset of bipolar disorder, yet the early illness course is already associated with significant morbidity and mortality. Therefore, characterizing the bipolar illness trajectory is key to risk prediction and early intervention advancement.

MAIN BODY

In this narrative review, we discuss key findings from prospective longitudinal studies of the high-risk offspring of bipolar parents and related meta-analyses that inform us about the clinical trajectory of emerging bipolar disorder. Challenges such as phenotypic and etiologic heterogeneity and the non-specificity of early symptoms and syndromes are highlighted. Implications of the findings for both research and clinical practice are discussed.

CONCLUSION

Bipolar disorder in young people at familial risk does not typically onset with a hypomanic or manic episode. Rather the first activated episode is often preceded by years of impairing psychopathological states that vary over development and across emerging bipolar subtype. Taking heterogeneity into account and adopting a more comprehensive approach to diagnosis seems necessary to advance earlier identification and our understanding of the onset of bipolar disorder.

Reward Dysfunction in the Manic Spectrum: Unable to Win? The Use of Biographical Information to Refine Neurobiological Modeling

OBJECTIVE

The manic spectrum is thought to be characterized by a hypersensitive biobehavioral reward system, the behavioral activation system. Evidence for this framework comes from questionnaire-based, self-report data collected in cross-sectional and prospective studies of mania, mania in remission, and proneness to hypomania, and from functional neuroimaging investigations of brain reward circuit activity during incentivized choice protocols. Although heightened reward anticipation is consistently documented, the status of later goal attainment activity, hedonic responses, and satiety reactions is less clear. This report examines the status of such reward receipt processes as they operate in the manic spectrum.

METHODS

A case report of a typical subject with bipolar II disorder with a hyperthymic temperament is presented using longitudinal, biographical data.

RESULTS

Diminished reward receipt, pleasure, and satiety were demonstrated indicating impaired hedonic processing in hyperthymic temperament. This impairment indicates a dissociation between early, intensified reward pursuit processes and later, blunted, reward attainment activity.

CONCLUSIONS

The experience and neural correlates of hedonic processing may be impaired in the manic spectrum. Possible mechanisms for this impairment and its dissociation from the earlier stage of reward processing characterized by hyperactive reward pursuit are considered. Clinical reports and longitudinal, life-based follow-up can provide important data to supplement more experimentally based neurobiological models of reward dysfunction in bipolar disorders.

Reward Dysfunction in the Manic Spectrum: Unable to Win? The Use of Biographical Information to Refine Neurobiological Modeling

OBJECTIVE

The manic spectrum is thought to be characterized by a hypersensitive biobehavioral reward system, the behavioral activation system. Evidence for this framework comes from questionnaire-based, self-report data collected in cross-sectional and prospective studies of mania, mania in remission, and proneness to hypomania, and from functional neuroimaging investigations of brain reward circuit activity during incentivized choice protocols. Although heightened reward anticipation is consistently documented, the status of later goal attainment activity, hedonic responses, and satiety reactions is less clear. This report examines the status of such reward receipt processes as they operate in the manic spectrum.

METHODS

A case report of a typical subject with bipolar II disorder with a hyperthymic temperament is presented using longitudinal, biographical data.

RESULTS

Diminished reward receipt, pleasure, and satiety were demonstrated indicating impaired hedonic processing in hyperthymic temperament. This impairment indicates a dissociation between early, intensified reward pursuit processes and later, blunted, reward attainment activity.

CONCLUSIONS

The experience and neural correlates of hedonic processing may be impaired in the manic spectrum. Possible mechanisms for this impairment and its dissociation from the earlier stage of reward processing characterized by hyperactive reward pursuit are considered. Clinical reports and longitudinal, life-based follow-up can provide important data to supplement more experimentally based neurobiological models of reward dysfunction in bipolar disorders.

The roles of valuation and reward processing in cognitive function and psychiatric disorders

In neuroeconomics, valuation refers to the process of assigning values to states and actions on the basis of the animal's current representation of the environment, while reward processing corresponds to processing the feedback received from the environment to update the values of states and actions. In this article, we review the brain circuits associated with valuation and reward processing and argue that these are fundamental processes critical to many cognitive functions. Specifically, we focus on the role of valuation and reward processing in attention, memory, decision making, and learning. Next, the extant neuroimaging literature on a number of psychiatric disorders is reviewed (i.e., addiction, pathological gambling, schizophrenia, and mood disorders), and an argument is made that associated deficits in cognitive functions can be explained in terms of abnormal valuation and reward processing. The review concludes with the impact of this framework in clinical settings and prescriptions for future research, in particular with regard to the conversions of qualitatively different valuation systems into a system of common currency.

Positive Traits in the Bipolar Spectrum: The Space between Madness and Genius

Bipolar disorder is a severe, lifelong mood disorder for which little is currently understood of the genetic mechanisms underlying risk. By examining related dimensional phenotypes, we may further our understanding of the disorder. Creativity has a historical connection with the bipolar spectrum and is particularly enhanced among unaffected first-degree relatives and those with bipolar spectrum traits. This suggests that some aspects of the bipolar spectrum may confer advantages, while more severe expressions of symptoms negatively influence creative accomplishment. Creativity is a complex, multidimensional construct with both cognitive and affective components, many of which appear to reflect a shared genetic vulnerability with bipolar disorder. It is suggested that a subset of bipolar risk variants confer advantages as positive traits according to an inverted-U-shaped curve with clinically unaffected allele carriers benefitting from the positive traits and serving to maintain the risk alleles in the population. The association of risk genes with creativity in healthy individuals (e.g., NRG1), as well as an overall sharing of common genetic variation between bipolar patients and creative individuals, provides support for this model. Current findings are summarized from a multidisciplinary perspective to demonstrate the feasibility of research in this area to reveal the mechanisms underlying illness.

Anxious Individuals Are Impulsive Decision-Makers in the Delay Discounting Task: An ERP Study

Impulsivity, which is linked to a wide range of psychiatric disorders, is often characterized by a preference for immediate but smaller rewards over delayed but larger rewards. However, debate exists on the relationship between anxiety and impulsivity. Here we use event-related potential (ERP) components as biomarkers in the temporal discounting task to examine the effect of anxiety on inter-temporal decision-making. Our behavioral results indicated that the high trait anxiety (HTA) group made significantly more immediate choices than the low trait anxiety (LTA) group. Compared with the LTA group, shorter response time was associated with immediate rewards in the HTA group. Furthermore, previous studies have demonstrated three ERP components that are associated with impulsivity and/or delay discounting. First, the N1 is an early sensory component involved in selective attention and attention processing for goal-directed actions. Second, the reward positivity (RewP) reflects reward-related dopaminergic activity and encodes reward values. Third, the P3 is regarded as a measure of motivational significance in the decision-making literature. Accordingly, this study found in the immediate-option-evoked ERPs that the HTA group had a larger N1 than the LTA group did. For the delayed-option-evoked ERPs, the HTA group had larger N1 and RewP for the immediate choice than the LTA group did, while the LTA group had a larger P3 for the delayed choice than the HTA group did. These results support the notion that anxiety individuals are impulsive decision-makers in the Delay Discounting Task.

Transdiagnostic Psychiatric Symptoms and Event-Related Potentials following Rewarding and Aversive Outcomes

There is a need for a better understanding of transdiagnostic psychiatric symptoms that relate to neurophysiological abnormalities following rewarding and aversive feedback in order to inform development of novel targeted treatments. To address this need, we examined a transdiagnostic sample of 44 adults (mean age: 35.52; 57% female), which consisted of individuals with broadly-defined schizophrenia-spectrum disorders (n = 16), bipolar disorders (n = 10), other mood and anxiety disorders (n = 5), and no history of a psychiatric disorder (n = 13). Participants completed a Pavlovian monetary reward prediction task during 32-channel electroencephalogram recording. We assessed the event-related potentials (ERPs) of feedback-related negativity (FRN), feedback-related positivity (FRP), and the late positive potential (LPP), following better and worse than expected outcomes. Examination of symptom relationships using stepwise regressions across the entire sample revealed that an increase in the clinician-rated Negative Symptoms factor score from the Positive and Negative Syndrome Scale, was related to a decreased LPP amplitude during better than expected (i.e., rewarding) outcomes. We also found that increased self-reported scores on the Schizotypal Personality Questionnaire (Brief-Revised) Disorganized factor related to an increased FRN amplitude during worse than expected (i.e., aversive) outcomes. Across the entire sample, the FRP component amplitudes did not show significant relationships to any of the symptoms examined. Analyses of the three diagnostic groups of schizophrenia-spectrum disorders, bipolar disorders, and nonpsychiatric controls did not reveal any statistically significant differences across the ERP amplitudes and conditions. These findings suggest relationships between specific neurophysiological abnormalities following rewarding and aversive outcomes and particular transdiagnostic psychiatric symptoms.

When your pain signifies my gain: neural activity while evaluating outcomes based on another person's pain

The overlap between pain and reward processing pathways leds researchers to hypothesize that there are interactions between them in the human brain. Two hypotheses have been proposed. The "competition hypothesis" posits that reward can reduce pain-related neural activity and vice versa. The "salience hypothesis" suggests that the motivational salience of pain and reward can be mutually reinforced. However, no study has tested these two hypotheses from temporal perspective as we know. In the present study, pictures depicted other people in painful or non-painful situations were used to indicate the valence of outcomes in a gambling task. The event-related potential results revealed an interaction between another person's pain and outcome valence in multiple time stages. Specifically, the amplitudes of the N1 and P3 were enhanced in the win condition compared with the loss condition when the outcome was indicated by painful picture. This interactions between pain and reward support the salience hypothesis but not the competition hypothesis. The present results provide evidence from human subjects that support the salience hypothesis, which claims that observing other people's pain can enhance the salience of reward.

Attentional Bias Predicts Increased Reward Salience and Risk Taking in Bipolar Disorder

BACKGROUND

There is amassing evidence that risky decision-making in bipolar disorder is related to reward-based differences in frontostriatal regions. However, the roles of early attentional and later cognitive processes remain unclear, limiting theoretical understanding and development of targeted interventions.

METHODS

Twenty euthymic bipolar disorder and 19 matched control participants played a Roulette task in which they won and lost money. Event-related potentials and source analysis were used to quantify predominantly sensory-attentional (N1), motivational salience (feedback-related negativities [FRN]), and cognitive appraisal (P300) stages of processing. We predicted that the bipolar disorder group would show increased N1, consistent with increased attentional orienting, and reduced FRN, consistent with a bias to perceive outcomes more favorably.

RESULTS

As predicted, the bipolar disorder group showed increased N1 and reduced FRN but no differences in P300. N1 amplitude was additionally associated with real-life risk taking, and N1 source activity was reduced in visual cortex but increased activity in precuneus, frontopolar, and premotor cortex, compared to those of controls.

CONCLUSIONS

These findings demonstrate an early attentional bias to reward that potentially drives risk taking by priming approach behavior and elevating reward salience in the frontostriatal pathway. Although later cognitive appraisals of these inputs may be relatively intact in remission, interventions targeting attention orienting may also be effective in long-term reduction of relapse.

Associations of age with reward delay discounting and response inhibition in adolescents with bipolar disorders

OBJECTIVES

Bipolar disorders' (BD) onset before age 18 is a potential marker for a more severe illness course. Adolescence is also a period of significant normative maturation of inhibitory control and reward-relevant decision-making processes, such as decreased delay discounting (i.e., decreased preference for smaller, immediate versus larger, delayed rewards). Adults with BD exhibit elevated delay discounting rates. Very little is known about developmental changes in delay discounting in adolescents with BD, or about associations between inhibitory control and delay discounting in BD. The present study addresses these questions.

METHODS

The sample included 78 participants, ages 13 to 23, with BD or without history of mental illness. Group differences and group by age interaction effects on delay discounting (32 BD, 32 controls with valid responses), probability discounting (34 BD, 37 controls) and inhibitory control indices (34 BD, 38 controls) were assessed.

RESULTS

Among healthy controls, less discounting of delayed rewards was associated with older age, whereas adolescents with BD did not show age-related associations. There were no group differences in probability discounting or inhibitory control.

LIMITATIONS

The cross-sectional nature of the study cannot fully rule out the less likely interpretation of group differences in cohort effects.

CONCLUSIONS

The lack of age-related improvement in delay tolerance in BD suggests disrupted development of executive control processes within reward contexts, which in turn may contribute to understanding more severe course of pediatric onset BD. Longitudinal studies are needed to examine delay discounting in relation to maturation of neural reward systems among adolescents with BD.