Dopaminergic drug effects during reversal learning depend on anatomical connections between the orbitofrontal cortex and the amygdala

Contains fulltext : 123589.pdf (publisher's version ) (Open Access)Dopamine in the striatum is known to be important for reversal learning. However, the striatum does not act in isolation and reversal learning is also well accepted to depend on the orbitofrontal cortex (OFC) and the amygdala. Here we assessed whether dopaminergic drug effects on human striatal BOLD signalling during reversal learning is associated with anatomical connectivity in an orbitofrontal-limbic-striatal network, as measured with diffusion tensor imaging. By using a fibre-based approach, we demonstrate that dopaminergic drug effects on striatal BOLD signal varied as a function of fractional anisotropy (FA) in a pathway connecting the OFC with the amygdala. Moreover, our experimental design allowed us to establish that these white-matter dependent drug effects were mediated via D2 receptors. Thus, white matter dependent effects of the D2 receptor agonist bromocriptine on striatal BOLD signal were abolished by co-administration with the D2 receptor antagonist sulpiride. These data provide fundamental insight into the mechanism of action of dopaminergic drug effects during reversal learning. In addition, they may have important clinical implications by suggesting that white matter integrity can help predict dopaminergic drug effects on brain function, ultimately contributing to individual tailoring of dopaminergic drug treatment strategies in psychiatry

Nuclear Education and Training: From Concern to Capability

The OECD Nuclear Energy Agency (NEA) first published in 2000 Nuclear Education and Training: Cause for Concern?, which highlighted significant issues in the availability of human resources for the nuclear industry. Ten years on, Nuclear Education and Training: From Concern to Capability considers what has changed in that time and finds that, while some countries have taken positive actions, in a number of others human resources could soon be facing serious challenges in coping with existing and potential new nuclear facilities. This is exacerbated by the increasing rate of retirement as the workforce ages. This report provides a qualitative characterisation of human resource needs and appraises instruments and programmes in nuclear education and training initiated by various stakeholders in different countries. In this context, it also examines the current and future uses of nuclear research facilities for education and training purposes. Regarding the nuclear training component of workforce competence, it outlines a job taxonomy which could be a basis for addressing the needs of workers across this sector. It presents the taxonomy as a way of enhancing mutual recognition and increasing consistency of education and training for both developed and developing countries.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen

Anatomical connection strength predicts dopaminergic drug effects on fronto-striatal function

Item does not contain fulltextRATIONALE: The neurotransmitter dopamine plays a key role in cognitive functions that are associated with fronto-striatal circuitry and has been implicated in many neuropsychiatric disorders. However, there is a large variability in the direction and extent of dopaminergic drug effects across individuals. OBJECTIVES: We investigated whether individual differences in dopaminergic drug effects on human fronto-striatal functioning are associated with individual differences in white matter tracts. METHODS: The effects of the dopamine receptor agonist bromocriptine were assessed using functional magnetic resonance imaging in 22 healthy volunteers in a placebo-controlled, double-blind, within-subject design. Human psychopharmacology and functional neuroimaging were combined with functional connectivity analyses and structural connectivity analyses to establish a link between dopaminergic drug effects on fronto-striatal function and fronto-striatal anatomy. RESULTS: We demonstrate that bromocriptine alters functional signals associated with attention switching in the basal ganglia. Crucially, individual differences in the drug's effect on these signals could be predicted from individual differences in fronto-striato-thalamic white matter tracts, as indexed by diffusion tensor imaging. Anatomical fronto-striatal connectivity also predicted drug effects on switch-related functional connectivity between the basal ganglia and the prefrontal cortex. CONCLUSIONS: These data reinforce the link between dopamine, cognition and the basal ganglia and have implications for the individual tailoring of dopaminergic drug therapy based on anatomical fronto-striatal connection strength