2,048 research outputs found
Decision and Reward in Intertemporal Choice: The Roles of Brain Development, Inter-individual Differences and Pharmacological Influences
Human decision making is closely related to reward processing because many decisions rely to a certain degree on the evaluation of different outcome values. Reward-based decisions can be health-related, for example if someone has to compare the outcome value of the instant reward of smoking a cigarette to that of the long term goal of keeping well and fit. Such comparisons do not only rely on the nominal value of the alternatives but also on devaluation of rewards over time. The value of being healthy at older age might outweigh the value of smoking a cigarette but since the payoff of the health-outcome will be delayed, humans tend to decrease the value of this option. Therefore in this example one might choose the immediate reward of smoking a cigarette. The proclivity to devaluate the value of rewards over time has been widely investigated with experimental intertemporal choice tasks, in which subjects have to choose between smaller sooner rewards and larger later rewards. A stronger individual devaluation proclivity (i.e. discounting rate) has been reported to be related to addiction. Research in neuroeconomics has suggested the competing neurobehavioural decision systems (CNDS) theory, proposing that an imbalance between an executive (cortical prefrontal brain areas) and an impulsive (i.e. subcortical areas, such as ventral striatum (VS), amygdala) system in the brain leads to steeper discounting and a higher risk for addiction. Additionally, temporal discounting has been proposed as a transdisease process, i.e., “a process that occurs across a range of disorders, making findings from one disorder relevant to other disorders” (Bickel, Jarmolowicz, Mueller, Koffarnus, & Gatchalian, 2012, Abstract). Thus, the CNDS theory and temporal discounting might also have implications for other health-related behaviour than substance use.
So far many factors have been shown to be associated with higher discount rates: for instance, adolescent age, lower intelligence and nicotine dependence. Further, it has been shown that adolescents are at highest risk to start smoking. On the other hand a higher education level has been shown to be associated to lower rates of smoking. Thus, it seems likely that a higher discount rate might be one reason why adolescents experiment with smoking, why lower education is associated to nicotine addiction and why dependent smokers are not successful in smoking cessation. But relatively little is known about the neural processes behind these variables, which could be also seen as exemplary risk- and protective factors regarding addiction. The 3 studies of the thesis at hand were conducted to extend the knowledge about neural processes associated to age, intelligence and smoking in their relation to intertemporal choice. The task was chosen because of its relevance for addiction and a variety of health-related behaviour.
The first study was conducted to explore the neural correlates of age related differences between adolescents at age 14 and young adults during intertemporal choices. Additionally, the roles of discounting and choice consistency were investigated. Although adoles-cents discounted delayed rewards more steeply than adults, neural processing of reward value did not differ between groups, when controlling reward values for the individual discount rates. However, a higher discount rate was related to a lower responsivity in the ventral striatum to delayed rewards, independent of age. Concerning decision making, adolescents exhib-ited a lower consistency of choices and less brain activity in a parietal network than adults (i.e. posterior and inferior parietal regions). Thus, reward value processing might be more sensitive to the discount rate than to chronological age. Lower consistency of intertemporal choices might indicate ongoing maturation of parietal brain areas from adolescence to young adulthood.
The second study was conducted to reveal the associations between neural processes of decision making and intelligence in adolescents. The results of study 2 revealed networks in the adolescent brain where brain activity was related to crystallised intelligence as well as to intertemporal choice behaviour. Specifically, during decision processing higher crystallised intelligence as well as more consistent decisions were associated with higher brain activity in the posterior parietal cortex. Processing of delayed rewards was also related to crystallised intelligence, i.e. more intelligent adolescents showed higher brain activation in the anterior cingulate cortex (ACC) and the inferior frontal gyrus (IFG), which was in turn related to a lower discount rate. Additionally, associations between the parental education level and crys-tallised intelligence of the adolescent participants of the study and their discount rate were found, indicating that parental education as an environmental factor could be related to a low-er risk for addiction. This protective effect might be mediated by the offspring’s crystallised intelligence and discount rate which are both related to brain activity in parts of the same brain networks (i.e. the IFG).
The third study was done to investigate neural processes of intertemporal decisions in smokers and non-smokers. To test whether the effects of smoking on the discount rate are due to chronic or acute nicotine intake, non-smokers were additionally assessed under acute nico-tine administration. Study 3 revealed that the effects of nicotine on intertemporal choice behaviour were related to chronic intake of nicotine in smokers rather than to acute nicotine ad-ministration in non-smokers. Regarding the neural processes, smokers compared to non-smokers showed lower brain activity in the posterior parietal cortex. Comparable but weaker effects were found under acute nicotine in non-smokers. Although acute nicotine administra-tion altered neural processes, behavioural changes might only occur after repeated nicotine intake. However, the study did not preclude that the differences are predrug characteristics.
Altogether the studies revealed overlapping neural correlates of intertemporal choices which are related to the individual age, the discount rate, the choice consistency, the individual intelligence as well as acute and chronic nicotine intake. This might provide an integrative view on how inter-individual differences and behaviour during intertemporal choices are based on common neural correlates which in turn might have implications for the development and the maintenance of addiction. Specifically, hyposensitivity towards delayed rewards in the adolescent ventral striatum, which has also been found in smokers compared to non-smokers, is associated with higher discount rates and higher risk for smoking initiation. In contrast, higher activation in the IFG and the ACC in more intelligent individuals during reward value processing might enhance behavioural inhibition and control and, hence, might prevent nicotine addiction. In line with the CNDS theory responsivity in subcortical brain areas (i.e. impulsive system), such as the VS was related to the risk factor of adolescent age, whereas activity in cortical areas (IFG and ACC) was related to the protective factors of high-er crystallised intelligence.
Since there was only one study beside the studies of the current thesis reporting results regarding consistency, one can only speculate about implications for health-related behaviour, such as addiction. Consistency might play a role, especially for cessation success. Thus, the findings that adolescents as well as less intelligent individuals were less consistent might point to a higher risk for maintenance of nicotine addiction. The higher brain activity in a fronto-parietal network, which has been shown in studies 1 and 2 in adults as well as in more intelligent adolescents, was related to higher consistency of choices in both studies. Thus, the finding might be a possible neural correlate for the association between the risk factor of ado-lescent age, the protective factor of higher crystallised intelligence, and more consistent deci-sion making.
In conclusion the findings of the current thesis contribute to a better understanding of how inter-individual differences and environmental factors might be accompanied by neural processes which in turn might be related to individual development of addiction. Further the results might extend the CNDS theory regarding neural correlates of exemplary risk and pro-tective factors regarding adolescents’ health behaviour and smoking in adults
Diagnosis of brain damage through the use of three visual tests: retinal rivalry spiral after-imaage and stereoscopic figure tracings
International comparative study of systems for the government advancement of research and development
The reorganization, structure and instruments of government advancement of research in three countries was compared: France, Sweden and the USA. In France the powers are centralized; in Sweden and the USA, decentralized. Assistance to projects is provided with grants and contracts in all three countries. France and Sweden also give loans with conditional waiving of reimbursement in case of failure. In all three countries indirect assistance is provided only with small tax breaks
Meta-analysis of GWAS of over 16,000 individuals with autism spectrum disorder highlights a novel locus at 10q24.32 and a significant overlap with schizophrenia
Background:
Over the past decade genome-wide association studies (GWAS) have been applied to aid in the understanding of the biology of traits. The success of this approach is governed by the underlying effect sizes carried by the true risk variants and the corresponding statistical power to observe such effects given the study design and sample size under investigation. Previous ASD GWAS have identified genome-wide significant (GWS) risk loci; however, these studies were of only of low statistical power to identify GWS loci at the lower effect sizes (odds ratio (OR) <1.15).
Methods:
We conducted a large-scale coordinated international collaboration to combine independent genotyping data to improve the statistical power and aid in robust discovery of GWS loci. This study uses genome-wide genotyping data from a discovery sample (7387 ASD cases and 8567 controls) followed by meta-analysis of summary statistics from two replication sets (7783 ASD cases and 11359 controls; and 1369 ASD cases and 137308 controls).
Results:
We observe a GWS locus at 10q24.32 that overlaps several genes including PITX3, which encodes a transcription factor identified as playing a role in neuronal differentiation and CUEDC2 previously reported to be associated with social skills in an independent population cohort. We also observe overlap with regions previously implicated in schizophrenia which was further supported by a strong genetic correlation between these disorders (Rg = 0.23; P = 9 × 10−6). We further combined these Psychiatric Genomics Consortium (PGC) ASD GWAS data with the recent PGC schizophrenia GWAS to identify additional regions which may be important in a common neurodevelopmental phenotype and identified 12 novel GWS loci. These include loci previously implicated in ASD such as FOXP1 at 3p13, ATP2B2 at 3p25.3, and a ‘neurodevelopmental hub’ on chromosome 8p11.23.
Conclusions:
This study is an important step in the ongoing endeavour to identify the loci which underpin the common variant signal in ASD. In addition to novel GWS loci, we have identified a significant genetic correlation with schizophrenia and association of ASD with several neurodevelopmental-related genes such as EXT1, ASTN2, MACROD2, and HDAC4
Hybrid concurrency control and recovery for multi-level transactions
Multi-level transaction schedulers adapt confiict-serializability on different levels. They exploit the fact that many low-level conflicts (e.g. on the level of pages) become irrelevant, if higher-level application semantics is taken into account. Multi-level transactions may lead to an increase in concurrency.
It is easy to generalize locking protocols to the case of multi-level transactions. In this, however, the possibility of deadlocks may diminish the increase in concurrency. This stimulates the investigation of optimistic or hybrid approaches to concurrency control.
Until now no hybrid concurrency control protocol for multi-level transactions has been published. The new FoPL protocol (Forward oriented Concurrency Control with Preordered Locking) is such a protocol. It employs access lists on the database objects and forward oriented commit validation. The basic test on all levels is based on the reordering of the access lists. When combined with queueing and deadlock detection, the protocol is not only sound, but also complete for multi-level serializable schedules. This is definitely an advantage of FoPL compared with locking protocols. The complexity of deadlock detection is not crucial, since waiting transactions do not hold locks on database objects. Furthermore, the basic FoPL protocol can be optimized in various ways.
Since the concurrency control protocol may force transactions to be aborted, it is necessary to support operation logging. It is shown that as well as multi-level locking protocols can be easily coupled with the ARIES algorithms. This also solves the problem of rollback during normal processing and crash recovery
HySenS data exploitation for urban land cover analysis
This paper addresses the use of HySenS airborne hyperspectral data for environmental urban monitoring. It is known that hyperspectral data can help to characterize some of the relations between soil composition, vegetation characteristics, and natural/artificial materials in urbanized areas. During the project we collected DAIS and ROSIS data over the urban test area of Pavia, Northern Italy, though due to a late delivery of ROSIS data only DAIS data was used in this work. Here we show results referring to an accurate characterization and classification of land cover/use, using different supervised approaches, exploiting spectral as well as spatial information. We demonstrate the possibility to extract from the hyperspectral data information which is very useful for environmental characterization of urban areas
Book review: Os Quartetos de Cordas de Villa-Lobos: Forma e Função
SALLES, Paulo de Tarso. Os quartetos de cordas de Villa-Lobos: Forma e Função. São Paulo: Editora da Universidade de São Paulo, 2018.SALLES, Paulo de Tarso. Os quartetos de cordas de Villa-Lobos: Forma e Função. São Paulo: Editora da Universidade de São Paulo, 2018
Villa-Lobos and Tom Jobim: an analysis of influences
A influência de Heitor Villa-Lobos (1887-1959) em compositores de música popular brasileira, especialmente Antonio Carlos Jobim (1927-1994), é algo já bastante comentado, tornando-se praticamente um senso-comum. Apesar disso não encontramos, ainda, trabalhos de análise voltados de forma aprofundada para esta comparação entre obras dos dois compositores, além de outros aspectos. Desta forma, abordaremos alguns diferentes aspectos a respeito de possíveis análises sobre a influência de um sobre o outro, e vice-versa. A primeira parte deste artigo pretende discutir, então, a respeito das conexões entre Villa-Lobos e Tom Jobim a partir do conceito de influência, sob dois aspectos diferentes. O primeiro é a partir de reflexões sobre a influência que Tom Jobim sofreu de Villa-Lobos, seja mediante depoimentos feitos pelo próprio Jobim – ou por amigos e colegas músicos que possuíram alguma ligação com o compositor–, seja por meio de estudos analíticos feitos por estudiosos acadêmicos de Villa-Lobos e Tom Jobim. O segundo consiste em comentar de que modo a obra de Villa-Lobos tem sido lida nas últimas décadas como tendo um viés de música popular (com uma influência diacrônica de Jobim sobre Villa-Lobos), mudando a forma de recepção e de apropriação da obra (e mesmo da imagem) de Villa-Lobos. A segunda parte do artigo traz algumas análises comparativas entre trechos de determinadas obras dos dois compositores, empregando ferramentas analíticas como a teoria dos conjuntos e a teoria neoriemanniana.The influence of Heitor Villa-Lobos (1887-1959) on Brazilian popular music composers, especially Antonio Carlos Jobim (1927-1994), is something that has already been commented on, becoming practically a common sense. Nevertheless, we cannot find analytical works focused on this comparison between the works of both composers, in addition to other aspects. In this way, we will approach some different aspects regarding possible analyses on the influence of one over the other, and vice-versa. The first part of this article intends to discuss the connections between Villa-Lobos and Tom Jobim from the concept of influence, in two different aspects. The first is based on reflections about the influence of Villa-Lobos on Tom Jobin, whether through testimonials made by Jobim himself (or by friends and fellow musicians who had some connection with the composer), or even through analytical studies made by academic students of Villa-Lobos and Tom Jobim. The second is demonstrating how Villa-Lobos’s work has been approached in recent decades through popular music (with a diachronic influence of Jobim over him), changing the forms of reception and appropriation of his work (and even of his image). The second part of the article develops a few comparative analyses between parts of works by both composers, using analytical tools such as musical set theory and neo riemannian theory
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