The role of the striatum in effort-based decision-making in the absence of reward

Decision-making involves weighing costs against benefits, for instance, in terms of the effort it takes to obtain a reward of a given magnitude. This evaluation process has been linked to the dorsal anterior cingulate cortex (dACC) and the striatum, with activation in these brain structures reflecting the discounting effect of effort on reward. Here, we investigate how cognitive effort influences neural choice processes in the absence of an extrinsic reward. Using functional magnetic resonance imaging in humans, we used an effort-based decision-making task in which participants were required to choose between two options for a subsequent flanker task that differed in the amount of cognitive effort. Cognitive effort was manipulated by varying the proportion of incongruent trials associated with each choice option. Choice-locked activation in the striatum was higher when participants chose voluntarily for the more effortful alternative but displayed the opposite trend on forced-choice trials. The dACC revealed a similar, yet only trend-level significant, activation pattern. Our results imply that activation levels in the striatum reflect a cost-benefit analysis, in which a balance is made between effort discounting and the intrinsic motivation to choose a cognitively challenging task. Moreover, our findings indicate that it matters whether this challenge is voluntarily chosen or externally imposed. As such, the present findings contrast with classical findings on effort discounting that found reductions in striatum activation for higher effort by finding enhancements of the same neural circuits when a cognitively challenging task is voluntarily selected and does not entail the danger of losing reward

Ganciclovir/valganciclovir prophylaxis decreases cytomegalovirus-related events and bronchiolitis obliterans syndrome after lung transplantation

BACKGROUND: Until recently, cytomegalovirus (CMV) infection represented a major threat to lung transplant recipients. Preliminary studies have shown that antiviral prophylaxis might improve the outcome for these patients. METHODS: We extended our initial pilot trial of prolonged prophylaxis with either oral ganciclovir (1 g 3 times per day) or valganciclovir (450 mg twice per day). The trial included 96 patients who were at risk for CMV-related events. RESULTS: CMV prophylaxis resulted in a significant decrease in CMV-related events (i.e., active infection and disease), from 75% in a control group and for 274 cases from the literature who did not receive prophylaxis to a cumulative incidence of 27% (P < .001). Only 11% of the prophylaxis recipients experienced CMV disease (P = .002). Moreover, at 5 years, there was a significant decrease in the rate of bronchiolitis obliterans syndrome, from 60% to 43% (P = .002), and an improved rate of survival, from 47% to 73% (P= .036), irrespective of the immunosuppressive regimen received. CMV strains with UL97 mutations were recovered from 7 of 12 analyzed cases, but the presence of this mutation had no impact on the severity of CMV disease. CONCLUSIONS: A regimen of prolonged ganciclovir or valganciclovir prophylaxis decreased the rate of active CMV infection and disease, reduced the incidence of bronchiolitis obliterans syndrome, and improved the survival rate. Drug-resistant CMV strains may occur, but such strains appeared to have no impact on the outcome of CMV-related events

Melting of tantalum at high pressure determined by angle dispersive x-ray diffraction in a double-sided laser-heated diamond-anvil cell

The high pressure and high temperature phase diagram of Ta has been studied in a laser-heated diamond-anvil cell (DAC) using x-ray diffraction measurements up to 52 GPa and 3800 K. The melting was observed at nine different pressures, being the melting temperature in good agreement with previous laser-heated DAC experiments, but in contradiction with several theoretical calculations and previous piston-cylinder apparatus experiments. A small slope for the melting curve of Ta is estimated (dTm/dP = 24 K/GPa at 1 bar) and a possible explanation for this behaviour is given. Finally, a P-V-T equation of states is obtained, being the temperature dependence of the thermal expansion coefficient and the bulk modulus estimated.Comment: 31 pages, 8 figures, to appear in J.Phys.:Cond.Matte

"Medikamente sind Bomben" - zum Metapherngebrauch von Lungentransplantations-Patienten mit guter oder ungenügender Compliance

Fragestellung: Nach einer Organtransplantation finden komplexe psychologische Verarbeitungsprozesse statt. In der vorliegenden Studie wurde untersucht, welche Metaphern im Zusammenhang mit Transplantationserfahrungen verwendet werden, und ob Unterschiede zwischen Patienten mit guter bzw. ungenügender Compliance im Gebrauch dieser Metaphern bestehen. Methode: 14 lungentransplantierte Patienten wurden in einem halbstrukturierten Interview zu ihren Transplantationserfahrungen befragt. Ihre Compliance wurde von den behandelnden Ärzten eingeschätzt. Die Auswertung der Interviews erfolgte anhand einer Metaphernanalyse, welche Hinweise auf vor- und unbewusste Vorstellungen der Patienten liefert. Die Interraterreliabilität über die Metapherngruppen war Cohen’s Kappa K = 0.8. Ergebnisse: Die Patienten konzeptualisierten ihren Körper, aber auch ihr Selbst als ein “Gefäß”, dass sowohl materielle (z.B. die Lunge) wie immaterielle Objekte (z.B. Gedanken an den Spender, Affekte) enthält. Der wichtigste Unterschied zwischen den Compliance-Gruppen bestand darin, dass Patienten mit ungenügender Compliance eine grössere Distanz zur transplantierten Lunge erlebten. Auch konzeptualisierten sie ihren Körper bzw. ihr Selbst nicht als ein Gefäß, das die Lunge enthält. Diskussion: Die Ergebnisse zeigen, dass gute Compliance mit einer erfolgreichen Organintegration assoziiert ist, welche die Zugehörigkeit der Lunge in einem als Gefäß konzeptualisierten Körper bzw. Selbst umfasst. Patienten mit ungenügender Compliance nehmen die Lunge eher als Fremdkörper wahr. Diese Verarbeitungsprozesse sind teils bewusster, teils vor- und unbewusster Natur

X-ray diffraction measurements of Mo melting to 119 GPa and the high pressure phase diagram

In this paper, we report angle-dispersive X-ray diffraction data of molybdenum melting, measured in a double-sided laser-heated diamond-anvil cell up to a pressure of 119 GPa and temperatures up to 3400 K. The new melting temperatures are in excellent agreement with earlier measurements up to 90 GPa that relied on optical observations of melting and in strong contrast to most theoretical estimates. The X-ray measurements show that the solid melts from the bcc structure throughout the reported pressure range and provide no evidence for a high temperature transition from bcc to a close-packed structure, or to any other crystalline structure. This observation contradicts earlier interpretations of shock data arguing for such a transition. Instead, the values for the Poisson ratios of shock compressed Mo, obtained from the sound speed measurements, and the present X-ray evidence of loss of long-range order suggest that the 210 GPa ( ∼ 4100 K) transition in the shock experiment is from the bcc structure to a new, highly viscous, structured [email protected]

The Interplay of “Big Five ” Personality Factors and Metaphorical Schemas: A Pilot Study with 20 Lung Transplant Recipients

The Qualitative Report Volume 12 Number 3 September 2007 397-413 http://www.nova.edu/ssss/QR/QR12-3/goetzmann.pdf The Interplay of “Big Five ” Personality Factors and Metaphorical Schemas: A Pilot Study with 20 Lung Transplant Recipients Lutz Goetzmann University Hospital Zurich, Zurich, Switzerland Karin S. Moser Roehampton University, London Esther Vetsch, Erhard Grieder, Richard Klaghofer, Rahel Naef, Erich W. Russi, Annette Boehler, and Claus Buddeberg University Hospital Zurich, Zurich, Switzerland The aim of the present study was to investigate the interplay between personality factors and metaphorical schemas. The “Big Five” personality factors of 20 patients after lung transplantation were examined with the NEO-FFI. Patients were questioned about their social network , and self- and body-image. The interviews were assessed with metaphor analysis. Significant positive correlations were found between “extraversion” and metaphors for acoustics, play/sport and economy, furthermore between “openness to experience” and metaphors for acoustics, container, battle, illness. A positive correlation was also found between “openness to experience” and metaphor frequency. Significant negative correlations were found between “conscientiousness” and metaphors for illness. The results indicate that personality factors may correspond with certain implicit metaphorical schemas

Structure and Dynamics of Liquid Iron under Earth's Core Conditions

First-principles molecular dynamics simulations based on density-functional theory and the projector augmented wave (PAW) technique have been used to study the structural and dynamical properties of liquid iron under Earth's core conditions. As evidence for the accuracy of the techniques, we present PAW results for a range of solid-state properties of low- and high-pressure iron, and compare them with experimental values and the results of other first-principles calculations. In the liquid-state simulations, we address particular effort to the study of finite-size effects, Brillouin-zone sampling and other sources of technical error. Results for the radial distribution function, the diffusion coefficient and the shear viscosity are presented for a wide range of thermodynamic states relevant to the Earth's core. Throughout this range, liquid iron is a close-packed simple liquid with a diffusion coefficient and viscosity similar to those of typical simple liquids under ambient conditions.Comment: 13 pages, 8 figure

Recent evolution of an ice‐cored moraine at the Gentianes Pass, Valais Alps, Switzerland

International audienceLateral moraines located in permafrost environments often preserve large amounts of both glacier and periglacial ice. To understand how ice‐cored moraines located in high alpine environments evolve in a context of both glacier retreat and permafrost degradation, we performed 11 terrestrial laser‐scanning measurement campaigns between 2007 and 2014 on a highly anthropogenic overprinted moraine prone to instability. Resulting comparison of the subsequent 3D models allowed to qualitatively and quantitatively analyze the morphological evolution of the moraine. The comparisons indicate a very high geomorphic activity of the moraine including large areas affected by downslope movements of blocks and 10 landslides with a volume between 24 ± 1 and 1,138 ± 47 m3. Data also indicated a very strong ice melt with a loss of ice thickness locally reaching 17.7 m at the foot of the moraine. These results, compared with resistivity and thermal measurements of the ground, suggest the combined role of ice loss at the foot of the moraine and the permafrost activity/warming in triggering these processes