Interindividual variability in the dimensions of goaldirected behaviour and their neural correlates

Goal-directed behaviour is an instrumental action performed to control our environment in order to provide a satisfactory outcome. It has been shown that these actions do not solely depend on action-outcome contingencies, but are also strongly influenced by personality traits or psychiatric disorders. Personality aspects such as sensitivity to rewards and impulsivity, as well as schizophrenia, have been identified as prominent factors, though the exact relation still remains unclear. Therefore, the goal of this dissertation is to provide an additional specification of interindividual differences in goal-directed behaviour on a neural level. Using functional imaging, we employed 2 different paradigms to probe reward-related as well as inhibition-related neural activation in healthy subjects and patients with schizophrenia. Study I investigated the neural response during a monetary incentive delay task in 23 healthy subjects, relating the observed activations with psychometric assessed traits of behavioural approach/inhibition. We found that the tendency to approach reward-related situations leads to an elevated neural response to positive outcomes, and an attenuated response to omissions. Additionally, a high behavioural inhibition tendency led to an attenuated response to rewards. Study II applied the monetary incentive delay task on a group of 15 patients with schizophrenia, demonstrating a negative relation between striatal activation during the expectation of reward and the symptom of apathy, as well as negative relation between orbitofrontal activation during the receipt of a reward and the symptom of depression. Study III investigated the relation between the personality trait of impulsivity and brain activation during the inhibition of inappropriate responses. Results showed that impulsivity is positively related to activations of bilateral ventroprefrontal regions. The results illustrate the importance of frontal-subcortical networks in goal-directed behaviour in clinical and non-clinical populations. An orbitofrontal/striatal network is specifically related to behavioural approach and inhibition tendencies, whereas impairments in the ventral striatum can lead to symptoms of apathy and depression in patients with schizophrenia. Additionally, activity in ventrolateral prefrontal regions is related to motor inhibition during successful inhibition of unwanted responses. Providing exact definitions of the specific functions and dependencies of frontal-subcortical circuits can inform our understanding of cognitive and emotional functions, and support research dealing with psychiatric disorders

The neural correlates of reinforcement sensitivity theory: a systematic review of the (f)MRI literature

Objectives: Reinforcement Sensitivity Theory (RST) is a theory of motivation, emotion and learning, that has been translated into an account of personality. RST proposes neural structures that form the basis of systems responsible for reward (BAS), punishment (FFFS) and conflict processing (BIS). This systematic review collated studies examining psychometric measures of RST alongside structural and function MRI data to (i) examine how psychometric RST is associated with the proposed neural topologies of RST, (ii) identify any common associations between psychometric RST and other brain regions, and (iii) provide recommendations for advancing the current literature base. Methods: Initial search terms identified 10952 papers. After processing, 39 papers that investigated the association between RST scales and neural functioning in healthy adult samples were included in this review. Results: There was general support for associations between the BAS and the structure/activity of the pre-frontal cortex and ventral striatum with some additional findings for the ventral pallidum and ventral tegmental area. There was also some support for associations between BIS/FFFS and structure/activity of frontal regions, cingulate cortices and the amygdala. Conclusions: Overall, psychometric correlates of RST were associated with activity in proposed neural circuitry, with the most consistent support being found for the BAS; however, psychometric and experimental limitations still hamper the differentiation of the BIS and FFFS systems in their activation of deeper brain networks. Future studies need to include revised RST scales that separate the BIS and FFFS and implement more rigorous tasks that allow for the examination of each system both independently and codependently

Reward, learning and games

The link between reward and learning has chiefly been studied scientifically in the context of reinforcement learning. This type of learning, which relies upon midbrain dopaminergic response, differs greatly from the learning valued by educators, which typically involves declarative memory formation. However, with recent insights regarding the modulation of hippocampal function by midbrain dopamine, scientific understanding of the midbrain response to reward may be becoming more relevant to education. Here, we consider the potential for our current understanding of reward to inform educational learning, and consider its implications for game-like interventions in the classroom

Consolidation power of extrinsic rewards: reward cues enhance long-term memory for irrelevant past events

Recent research suggests that extrinsic rewards promote memory consolidation through dopaminergic modulation processes. However, no conclusive behavioral evidence exists given that the influence of extrinsic reward on attention and motivation during encoding and consolidation processes are inherently confounded. The present study provides behavioral evidence that extrinsic rewards (i.e., monetary incentives) enhance human memory consolidation independently of attention and motivation. Participants saw neutral pictures, followed by a reward or control cue in an unrelated context. Our results (and a direct replication study) demonstrated that the reward cue predicted a retrograde enhancement of memory for the preceding neutral pictures. This retrograde effect was observed only after a delay, not immediately upon testing. An additional experiment showed that emotional arousal or unconscious resource mobilization cannot explain the retrograde enhancement effect. These results provide support for the notion that the dopaminergic memory consolidation effect can result from extrinsic reward. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract

The Relationship between Arousal, Personality, and Perception of Control in a Gambling Task

The somatic marker hypothesis posits that physiological arousal is partially responsible for decision-making behavior. Arousal, measured by skin conductance responses (SCR), increases before deck choice in the Iowa Gambling Task (IGT). These markers co-vary with performance -- pathological gamblers lack these markers and perform poorly. Personality also modulates IGT behavior – high-novelty-seeking (NS) individuals tend to perform worse. In the IGT, participants decide which deck to select, creating a potential confound between personality, performance, and arousal. For example, high-NS individuals select the bad decks more often, potentially causing habituation and a muted SCR. The first goal of this research was to replicate the finding that personality modulates arousal in a task which removes these confounds. Participants selected a series of cards from two decks. Each card was either a win or loss. Real money was used. To remove the potential confound between choice and outcome, all participants experienced the same outcomes regardless of choice. SCR was measured during the task. Personality characteristics previously shown to modulate gambling behavior, such as sensation seeking (SS), were measured. Arousal may also occur during other phases of gambling, for example, before or after the outcome is revealed. To date, few studies have examined the relationship between arousal in these different phases. The second goal was to determine this relationship. The phases of gambling (pre-choice, anticipation, and outcome) were temporally separated to allow for precise SCR measurement in each phase. The final goal was to determine the relationship between perceived control and physiological arousal. An \u27illusion of control\u27, e.g., pulling the lever on a slot machine, promotes gambling, especially in pathological gamblers. Little work has addressed the relationship between personality, control, and arousal. In different sessions, participants either selected the next card or the next card was selected for them. SS decreased arousal during all three gambling phases. The perception of control decreased arousal during the pre-choice phase only. This latter effect was strongest for low-SS individuals. The ramifications of this study are clear: identifying how physiological responses vary with personality opens up avenues for potential treatment of problem gambling

Factorization in Denjoy-Carleman classes associated to representations of (R^d,+)

For two types of moderate growth representations of (R^d, +) on sequen- tially complete locally convex Hausdorff spaces (including F-representations [14]), we introduce Denjoy-Carleman classes of ultradifferentiable vectors and show a strong factorization theorem of Dixmier-Malliavin type for them. In particular, our fac- torization theorem solves [14, Conjecture 6.4] for analytic vectors of representations of G = (R^d,+). As an application, we show that various convolution algebras and modules of ultradifferentiable functions satisfy the strong factorization property

Conscience Sensitive Psychiatric Diagnosis of Maltreated Children and Adolescents

The sequelae of maltreatment are conceptualized according to the DSM IV multiaxial system expanded for heuristic purposes. Axis I and Axis IV are expanded to take into account important variables of maltreatment. Differential Axis I diagnoses are identified with special emphasis placed on PTSD, Dissociation, Depression and Disruptive Behavior Disorders. Axes II and III are heuristically expanded to call attention to developmental psychopathology, particularly in the domains of conscience, and associated putative neurobiological sequelae of maltreatment, indicating a pathway to the psychobiology of conscience. Conscience sensitive assessment of maltreated children is illustrated with two case vignettes and selected conscience drawings. A ‘transaxial,’ conscience sensitive approach to DSM nosology is recommended as a corrective. There will likely be additional implications for the psychobiology of conscience as neuroimaging and assessment of conscience functions in health and psychopathology become more refined.Support for this and other work by the I.U. Conscience Project conducted in collaboration with Pleasant Run Inc. has been generously provided by Mr. and Mrs. Jim Irsay and The Indianapolis Colts, The Moore Foundation and other individual anonymous donors

Structural brain change in Attention Deficit Hyperactivity Disorder identified by meta-analysis.

BACKGROUND: The authors sought to map gray matter changes in Attention Deficit Hyperactivity Disorder (ADHD) using a novel technique incorporating neuro-imaging and genetic meta-analysis methods. METHODS: A systematic search was conducted for voxel-based structural magnetic resonance imaging studies of patients with ADHD (or with related disorders) in relation to comparison groups. The authors carried out meta-analyses of the co-ordinates of gray matter differences. For the meta-analyses they hybridised the standard method of Activation Likelihood Estimation (ALE) with the rank approach used in Genome Scan Meta-Analysis (GSMA). This system detects three-dimensional conjunctions of co-ordinates from multiple studies and permits the weighting of studies in relation to sample size. RESULTS: For gray matter decreases, there were 7 studies including a total of 114 patients with ADHD (or related disorders) and 143 comparison subjects. Meta-analysis of these studies identified a significant regional gray matter reduction in ADHD in the right putamen/globus pallidus region. Four studies reported gray matter increases in ADHD but no regional increase was identified by meta-analysis. CONCLUSION: In ADHD there is gray matter reduction in the right putamen/globus pallidus region. This may be an anatomical marker for dysfunction in frontostriatal circuits mediating cognitive control. Right putamen lesions have been specifically associated with ADHD symptoms after closed head injuries in children.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are