As a major regulator of dopamine (DA), DA autoreceptors (DAARs) exert substantial influence over DA-mediated behaviors. This paper reviews the physiological and behavioral impact of DAARs. Individual ...differences in DAAR functioning influences temperamental traits such as novelty responsivity and impulsivity, both of which are associated with vulnerability to addictive behavior in animal models and a broad array of externalizing behaviors in humans. DAARs additionally impact the response to psychostimulants and other drugs of abuse. Human PET studies of D2-like receptors in the midbrain provide evidence for parallels to the animal literature. These data lead to the proposal that weak DAAR regulation is a risk factor for addiction and externalizing problems. The review highlights the potential to build translational models of the functional role of DAARs in behavior. It also draws attention to key limitations in the current literature that would need to be addressed to further advance a weak DAAR regulation model of addiction and externalizing risk.
•Dopamine autoreceptors regulate the firing, synthesis and the magnitude and precision of dopamine release.•Weak autoreceptor control is associated with greater novelty responsivity/seeking and impulsivity in rodents and humans.•Both autoreceptor levels and impulsivity/novelty responsive traits predict responses to psychostimulants and addiction risk.•Weak dopamine autoreceptor regulation is proposed as a risk factor for addiction and externalizing traits.
Of the putative psychopathological endophenotypes in major depressive disorder (MDD), the anhedonic subtype is particularly well supported. Anhedonia is generally assumed to reflect aberrant ...motivation and reward responsivity. However, research has been limited by a lack of objective measures of reward motivation. We present the Effort-Expenditure for Rewards Task (EEfRT or "effort"), a novel behavioral paradigm as a means of exploring effort-based decision-making in humans. Using the EEfRT, we test the hypothesis that effort-based decision-making is related to trait anhedonia.
61 undergraduate students participated in the experiment. Subjects completed self-report measures of mood and trait anhedonia, and completed the EEfRT. Across multiple analyses, we found a significant inverse relationship between anhedonia and willingness to expend effort for rewards.
These findings suggest that anhedonia is specifically associated with decreased motivation for rewards, and provide initial validation for the EEfRT as a laboratory-based behavioral measure of reward motivation and effort-based decision-making in humans.
▶ Anhedonia includes motivational and consummatory aspects of reward processing. ▶ Current research often fails to discriminate between these two aspects. ▶ Preclinical data suggest that these two ...aspects are neurobiologically dissociable. ▶ Consequently, we propose motivational and consummatory anhedonia. ▶ We also introduce “decisional anhedonia” to address anhedonic effects on decisions.
Anhedonia is a core symptom of major depressive disorder (MDD), the neurobiological mechanisms of which remain poorly understood. Despite decades of speculation regarding the role of dopamine (DA) in anhedonic symptoms, empirical evidence has remained elusive, with frequent reports of contradictory findings. In the present review, we argue that this has resulted from an underspecified definition of anhedonia, which has failed to dissociate between consummatory and motivational aspects of reward behavior. Given substantial preclinical evidence that DA is involved primarily in motivational aspects of reward, we suggest that a refined definition of anhedonia that distinguishes between deficits in pleasure and motivation is essential for the purposes of identifying its neurobiological substrates. Moreover, bridging the gap between preclinical and clinical models of anhedonia may require moving away from the conceptualization of anhedonia as a steady-state, mood-like phenomena. Consequently, we introduce the term “decisional anhedonia” to address the influence of anhedonia on reward decision-making. These proposed modifications to the theoretical definition of anhedonia have implications for research, assessment and treatment of MDD.
Highlights • Dopamine release in mesolimbic reward circuits leads to reinforcement tied to predictions and outcomes. • Musical pleasure involves complex interactions between dopamine systems and ...cortical areas. • Individual variability in superior temporal cortex may explain varied musical preferences. • Cognitive, auditory, affective, and reward circuits interact to make music pleasurable.
Psychological research increasingly indicates that emotional processes interact with other aspects of cognition. Studies have demonstrated both the ability of emotional stimuli to influence a broad ...range of cognitive operations, and the ability of humans to use top-down cognitive control mechanisms to regulate emotional responses. Portions of the prefrontal cortex appear to play a significant role in these interactions. However, the manner in which these interactions are implemented remains only partially elucidated. In the present review we describe the anatomical connections between ventral and dorsal prefrontal areas as well as their connections with limbic regions. Only a subset of prefrontal areas are likely to directly influence amygdalar processing, and as such models of prefrontal control of emotions and models of emotional regulation should be constrained to plausible pathways of influence. We also focus on how the specific pattern of feedforward and feedback connections between these regions may dictate the nature of information flow between ventral and dorsal prefrontal areas and the amygdala. These patterns of connections are inconsistent with several commonly expressed assumptions about the nature of communications between emotion and cognition.
Abnormal reward processing is a prominent transdiagnostic feature of psychopathology. The present review provides a framework for considering the different aspects of reward processing and their ...assessment, and highlights recent insights from the field of neuroeconomics that may aid in understanding these processes. Although altered reward processing in psychopathology has often been treated as a general hypo- or hyperresponsivity to reward, increasing data indicate that a comprehensive understanding of reward dysfunction requires characterization within more specific reward-processing domains, including subjective valuation, discounting, hedonics, reward anticipation and facilitation, and reinforcement learning. As such, more nuanced models of the nature of these abnormalities are needed. We describe several processing abnormalities capable of producing the types of selective alterations in reward-related behavior observed in different forms of psychopathology, including (mal)adaptive scaling and anchoring, dysfunctional weighting of reward and cost variables, competition between valuation systems, and reward prediction error signaling.
We propose a taxonomy of psychopathology based on patterns of shared causal influences identified in a review of multivariate behavior genetic studies that distinguish genetic and environmental ...influences that are either common to multiple dimensions of psychopathology or unique to each dimension. At the phenotypic level, first-order dimensions are defined by correlations among symptoms; correlations among first-order dimensions similarly define higher-order domains (e.g., internalizing or externalizing psychopathology). We hypothesize that the robust phenotypic correlations among first-order dimensions reflect a hierarchy of increasingly specific etiologic influences. Some nonspecific etiologic factors increase risk for all first-order dimensions of psychopathology to varying degrees through a general factor of psychopathology. Other nonspecific etiologic factors increase risk only for all first-order dimensions within a more specific higher-order domain. Furthermore, each first-order dimension has its own unique causal influences. Genetic and environmental influences common to family members tend to be nonspecific, whereas environmental influences unique to each individual are more dimension-specific. We posit that these causal influences on psychopathology are moderated by sex and developmental processes. This causal taxonomy also provides a novel framework for understanding the heterogeneity of each first-order dimension: Different persons exhibiting similar symptoms may be influenced by different combinations of etiologic influences from each of the 3 levels of the etiologic hierarchy. Furthermore, we relate the proposed causal taxonomy to transdimensional psychobiological processes, which also impact the heterogeneity of each psychopathology dimension. This causal taxonomy implies the need for changes in strategies for studying the etiology, psychobiology, prevention, and treatment of psychopathology.
▶ Traditional clinical batteries are insufficient for assessing orbitomedial functions. ▶ Several experimental tasks are sensitive to orbital and ventromedial damage. ▶ The range of deficits have ...critical implications for models of orbitomedial function.
Assessment of the functions of the orbitofrontal cortex and ventromedial prefrontal cortex has proven to be a unique challenge for neuropsychologists. Orbitomedial damage occurs in a range of disorders including traumatic brain injury, ruptured aneurysms, surgical resection, and frontotemporal dementia. We review the effects of orbitomedial damage on a range of neuropsychological tasks, including tasks measuring object alternation and reversal learning, decision-making (gambling), facial emotion recognition, theory of mind, olfactory recognition, autobiographical memory and behavioral rating measures. At present, there is no singular gold standard measure of orbitomedial dysfunction, and assessment requires an integrative approach that reflects the heterogeneity of the region. The heterogeneous neuropsychological deficits arising from orbitomedial damage are difficult to ascribe to a unitary function or process, but appear to reflect a set of processes necessary for monitoring and adapting to changing reinforcement contingencies.
Rapid evaluation of ecologically relevant stimuli may lead to their preferential access to awareness. Continuous flash suppression allows assessment of affective processing under conditions in which ...stimuli have been rendered invisible due to the strongly suppressive nature of dynamic noise relative to static images. The authors investigated whether fearful expressions emerge from suppression into awareness more quickly than images of neutral or happy expressions. Fearful faces were consistently detected faster than neutral or happy faces. Responses to inverted faces were slower than those to upright faces but showed the same effect of emotional expression, suggesting that some key feature or features in the inverted faces remained salient. When using stimuli solely representing the eyes, a similar bias for detecting fear emerged, implicating the importance of information from the eyes in the preconscious processing of fear expressions.
There is an ongoing revolution in psychology and psychiatry that will likely change how we conceptualize, study and treat psychological problems. Many theorists now support viewing psychopathology ...as consisting of continuous dimensions rather than discrete diagnostic categories. Indeed, recent papers have proposed comprehensive taxonomies of psychopathology dimensions to replace the DSM and ICD taxonomies of categories. The proposed dimensional taxonomies, which portray psychopathology as hierarchically organized correlated dimensions, are now well supported at phenotypic levels. Multiple studies show that both a general factor of psychopathology at the top of the hierarchy and specific factors at lower levels predict different functional outcomes. Our analyses of data on a large representative sample of child and adolescent twins suggested the causal hypothesis that phenotypic correlations among dimensions of psychopathology are the result of many familial influences being pleiotropic. That is, most genetic variants and shared environmental factors are hypothesized to non‐specifically influence risk for multiple rather than individual dimensions of psychopathology. In contrast, person‐specific experiences tend to be related to individual dimensions. This hierarchical causal hypothesis has been supported by both large‐scale family and molecular genetic studies. Current research focuses on three issues. First, the field has not settled on a preferred statistical model for studying the hierarchy of causes and phenotypes. Second, in spite of encouraging progress, the neurobiological correlates of the hierarchy of dimensions of psychopathology are only partially described. Third, although there are potentially important clinical implications of the hierarchical model, insufficient research has been conducted to date to recommend evidence‐based clinical practices.
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