Science posts

See science posts on page 4 below.

    • 2009
    • Althaus M et al.
    • Differential effects of 5-HTTLPR and DRD2/ANKK1 polymorphisms on electrocortical measures of error and feedback processing in children.
    • OBJECTIVE: Applying a probabilistic learning task we examined the influence of functional polymorphisms of the serotonin transporter gene (5-HTTLPR) and the D2 dopamine receptor gene (DRD2/ANKK1) on error and feedback processing by measuring electrocortical event-related potentials (ERPs) in 10- to 12-year-old children. METHODS: Three pairwise group comparisons were conducted on four distinguishable ERP components, two of which were response-related, the other two feedback-related. RESULTS: Our ERP data revealed that children carrying the short (S) variant of the 5-HTTLPR gene process their errors more intensively while exhibiting less habituation to negative feedback with task progression compared to children who are homozygous for the 5-HTTLPR long (L) variant. Children possessing the Taq1 A variant of the DRD2 gene showed greater sensitivity to negative feedback and, as opposed to Taq1 A non-carriers, a diminishing sensitivity to positive feedback with task progression...
    • 2008
    • Diego A. Pizzagalli et al.
    • Single dose of a dopamine agonist impairs reinforcement learning in humans: Behavioral evidence from a laboratory-based measure of reward responsiveness
    • Rationale The dopaminergic system, particularly D2-like dopamine receptors, has been strongly implicated in reward processing. Animal studies have emphasized the role of phasic dopamine (DA) signaling in reward-related learning, but these processes remain largely unexplored in humans. Objectives To evaluate the effect of a single, low dose of a D2/D3 agonist—pramipexole—on reinforcement learning in healthy adults. Based on prior evidence indicating that low doses of DA agonists decrease phasic DA release through autoreceptor stimulation, we hypothesized that 0.5 mg of pramipexole would impair reward learning due to presynaptic mechanisms. Materials and methods Using a double-blind design, a single 0.5-mg dose of pramipexole or placebo was administered to 32 healthy volunteers, who performed a probabilistic reward task involving a differential reinforcement schedule as well as various control tasks. Results As hypothesized, response bias towa..
    • 2004
    • Ellen R. A. de Bruijn et al.
    • Drug-induced stimulation and suppression of action monitoring in healthy volunteers
    • Rationale Action monitoring has been studied extensively by means of measuring the error-related negativity (ERN). The ERN is an event-related potential (ERP) elicited immediately after an erroneous response and is thought to originate in the anterior cingulate cortex (ACC). Although the ACC has a central role in the brain, only a few studies have been performed to investigate directly the effects of drugs on action monitoring. A recent theory argues that the mesencephalic dopamine system carries an error signal to the ACC, where it generates the ERN. Methods ERPs and behavioral measurements were obtained from 12 healthy volunteers performing an Eriksen Flankers task. On each of the 4 test days, the stimulant d-amphetamine, the sedative lorazepam, the antidepressant mirtazapine, or a placebo was orally administered in a double-blind, four-way crossover design. Results The indirect dopamine agonist amphetamine led to a strong enlargement of ERN amplitudes without affecting ..
    • 2012
    • A. Meyer et al.
    • Additive effects of the dopamine D2 receptor and dopamine transporter genes on the error-related negativity in young children
    • The error-related negativity (ERN) is a negative deflection in the event-related potential that occurs approximately 50ms following the commission of an error at fronto-central electrode sites. Previous models suggest dopamine plays a role in the generation of the ERN. We recorded event-related potentials (ERPs) while 279 children aged 5–7 years completed a simple Go/No-Go task; the ERN was examined in relation to the dopamine D2 receptor (DRD2) and dopamine transporter (DAT1) genes. Results suggest an additive effect of the DRD2 and DAT1 genotype on ERN magnitude such that children with at least one DRD2 A1 allele and children with at least one DAT1 9 allele have an increased (i.e. more negative) ERN. These results provide further support for the involvement of dopamine in the generation of the ERN.
    • 2004
    • Yasuda, Asako et al.
    • Error-related negativity reflects detection of negative reward prediction error
    • Error-related negativity (ERN) is a negative deflection in the event-related potential elicited in error trials. To examine the function of ERN, we performed an experiment in which two within-participants factors were manipulated: outcome uncertainty and content of feedback. The ERN was largest when participants expected correct feedback but received error feedback. There were significant positive correlations between the ERN amplitude and the rate of response switching in the subsequent trial, and between the ERN amplitude and the trait version score on negative affect scale. These results suggest that ERN reflects detection of a negative reward prediction error and promotes subsequent response switching, and that individuals with high negative affect are hypersensitive to a negative reward prediction error.
    • 2004
    • Yeung, Nick et al.
    • The Neural Basis of Error Detection: Conflict Monitoring and the Error-Related Negativity
    • According to a recent theory, anterior cingulate cortex is sensitive to response conflict, the coactivation of mutually incompatible responses. The present research develops this theory to provide a new account of the error-related negativity (ERN), a scalp potential observed following errors. Connectionist simulations of response conflict in an attentional task demonstrated that the ERN-its timing and sensitivity to task parameters-can be explained in terms of the conflict theory. A new experiment confirmed predictions of this theory regarding the ERN and a second scalp potential, the N2, that is proposed to reflect conflict monitoring on correct response trials. Further analysis of the simulation data indicated that errors can be detected reliably on the basis of post-error conflict. It is concluded that the ERN can be explained in terms of response conflict and that monitoring for conflict may provide a simple mechanism for detecting errors.
    • 2002
    • Holroyd, Clay B et al.
    • The neural basis of human error processing: Reinforcement learning, dopamine, and the error-related negativity
    • The authors present a unified account of 2 neural systems concerned with the development and expression of adaptive behaviors: a mesencephalic dopamine system for reinforcement learning and a "generic" error-processing system associated with the anterior cingulate cortex. The existence of the error-processing system has been inferred from the error-related negativity (ERN), a component of the event-related brain potential elicited when human participants commit errors in reaction-time tasks. The authors propose that the ERN is generated when a negative reinforcement learning signal is conveyed to the anterior cingulate cortex via the mesencephalic dopamine system and that this signal is used by the anterior cingulate cortex to modify performance on the task at hand. They provide support for this proposal using both computational modeling and psychophysiological experimentation
    • 2014
    • Kevin Alastair M. Tan
    • Endogenous and exogenous attention in theory of mind: role of the default - mode network
    • The neural correlates of social cognition strongly overlap with the default-mode network (DMN). Theory of mind involves reasoning about others mental states. Neural activity from theory of mind has been shown to be distinct from similar types of social cognition. In this experiment, we dissociate the effect of exogenously-directed attention on theory of mind functional anatomy. Our results suggest that differences in functional anatomy between theory of mind and other types of social cognition are attributable to the use of exogenously-directed attention. The exclusive use of internal representations during theory of mind activates most of the DMN with a bias towards midline regions. The inclusion of exogenously-directed attention during theory of mind preferentially activates lateral DMN regions and adjacent structures of the task-positive network (TPN). Exogenously-directed attention was also found to activate the temporoparietal junction(TPJ) as a whole, w..
    • 2013
    • Hikaru Takeuchi et al.
    • Resting state functional connectivity associated with trait emotional intelligence
    • Previous neuroimaging studies have suggested that trait emotional intelligence (TEI) is associated with components of the neural network involved in social cognition (SCN) and somatic marker circuitry (SMC). Our study is the first to investigate the association of TEI with resting-state functional connectivity (RSFC) between the key nodes of SCN and SMC [medial prefromtal cortex (mPFC) and bilateral anterior insula (AI), respectively] and other brain regions. We found that (a) the intrapersonal factor of TEI was negatively correlated with RSFC between mPFC and the anterior part of the right dorsolateral prefrontal cortex (DLPFC), (b) the TEI interpersonal factor score was positively correlated with RSFC between mPFC and the lingual gyrus, and (c) total TEI was positively correlated with RSFC between mPFC and the precuneus as well as (d) between the left AI and the middle part of the right DLPFC. Taken together with previous study findings, our findings can be comprehensively understo..
    • 2012
    • Adam E. Green et al.
    • A Gene–Brain–Cognition Pathway: Prefrontal Activity Mediates the Effect of COMT on Cognitive Control and IQ
    • A core thesis of cognitive neurogenetic research is that genetic effects on cognitive ability are mediated by specific neural functions, however, demonstrating neural mediation has proved elusive. Pairwise relationships between genetic variation and brain function have yielded heterogeneous findings to date. This heterogeneity indicates that a multiple mediator modeling approach may be useful to account for complex relationships involving function at multiple brain regions. This is relevant not only for characterizing healthy cognition but for modeling the complex neural pathways by which disease-related genetic effects are transmitted to disordered cognitive phenotypes in psychiatric illness. Here, in 160 genotyped functional magnetic resonance imaging participants, we used a multiple mediator model to test a gene–brain–cognition pathway by which activity in 4 prefrontal brain regions mediates the effects of catechol-O-methyltransferase (COMT) gene on cognitive c..

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