有无反馈对欺骗过程的神经机制的调控作用

欺骗行为会导致欺骗结果的产生,欺骗结果又会直接影响欺骗行为的发生及其内在机制.虽然有研究表明,欺骗结果会对相应的欺骗过程产生调控作用,但对这一调控作用的机制并不清楚.本研究采用功能核磁共振技术,对两组被试分别使用有、无反馈(欺骗结果)的GKT范式并记录两组被试在进行诚实反应和欺骗反应时的大脑激活模式.结果发现,有反馈组与无反馈组相比,有反馈组的诚实反应和欺骗反应都导致了左侧顶叶皮层、左背部前扣带皮层、左侧脑岛、双侧视皮层和右侧小脑的更大激活;对两组而言,欺骗反应和诚实反应都导致了右腹外侧前额区域、双侧缘上回、左侧脑岛、右后内侧额叶、右侧颞中回和右侧纹状体的更大激活;此外,与无反馈组相比,有反馈组的欺骗反应与诚实反应在双侧纹状体和左侧脑岛上的激活差异更加明显.这些结果表明,有无欺骗结果对欺骗过程的神经机制具有调控作用,当需要面临欺骗结果时,欺骗过程将更大程度地涉及到奖赏预期和风险厌恶过程的参与.     

Phenotypic Variability: Its Components, Measurement and Underlying Developmental Processes

Variability contrasts with variation in that variability describes the potential for variation, not simply the expressed variation. The power of studying variability lies in creating a conceptual framework around which the relationship between the genotype and phenotype can be understood. Here, we attempt to demonstrate the importance of phenotypic variability, how it structures variation, and how fundamental developmental processes structure variability. Given the broad scope of this topic, we focus on three widely studied properties of variability: canalization, developmental stability and morphological integration. We have organized the paper to emphasize the importance of differentiating between the theory surrounding these components of phenotypic variability, their measurement and the biological factors surrounding their expression. First, we define these properties of variability, how they relate to each other and to variability as a whole. Second, we summarize the common methods of measurement for canalization, developmental stability and morphological integration and the reasoning behind these methods. Finally, we focus on jaw development as an example of how the basic processes of development affect variability and the resultant variation, with emphasis on how processes at all levels of the organismal hierarchy interact with one another and contribute to phenotypic variability.     

Proteolytic Processes Underlying Molt-Induced Claw Muscle Atrophy in Decapod Crustaceans

The claw muscles of large-clawed decapod crustaceans undergoa programmed atrophy in preparation for molting, or ecdysis.This is mediated by five cytosolic proteinases organized intotwo proteolytic pathways: calcium-dependent and ubiquitin/proteasome-dependent.The calcium-dependent system consists of four calcium-dependentcysteine proteinases (CDPs I, IIa, IIb, and III; native masses310, 125, 195, and 59 kDa, respectively) that completely degrademyofibrillar proteins and are activated in atrophic muscles.Immunological analysis shows that the active-site sequence inCDP IIa (60-kDa subunit mass) is similar to that in mammalianCDPs (calpains), and that CDP IIb is homologous to a calpain-likegene isolated from Drosophila cDNA libraries. Increased intracellullarCa²⁺ stimulates proteolysis in situ, indicating CDPs play animportant role in muscle protein catabolism. The ubiquitin/proteasome-dependentsystem involves the ATP-dependent conjugation of multi-ubiquitinchains to protein by ubiquitin-conjugating enzymes. This actsas a signal for substrate degradation by the 26S proteasome,a multi-subunit complex consisting of a 20S proteasome catalytic"core" and two PA700 (19S) regulatory complexes. PolyubiquitinmRNA, ubiquitin-protein conjugates, and 20S proteasome are elevatedabout 5-, 8-, and 2-fold, respectively, during atrophy. A heat-inducedform of the 20S proteasome hydrolyzes myosin, troponin, andtropomyosin to large fragments in vitro. Biochemical studiesidentified the branched-chain amino acid-preferring (BrAAP)activity, one of six distinct catalytic components in the complex,as the activity that carries out these initial cleavages. Theseresults indicate that the ubiquitin/proteasome pathway is involved,but its precise role remains to be resolved.     

Diffusion Modelling Reveals the Decision Making Processes Underlying Negative Judgement Bias in Rats

Human decision making is modified by emotional state. Rodents exhibit similar biases during interpretation of ambiguous cues that can be altered by affective state manipulations. In this study, the impact of negative affective state on judgement bias in rats was measured using an ambiguous-cue interpretation task. Acute treatment with an anxiogenic drug (FG7142), and chronic restraint stress and social isolation both induced a bias towards more negative interpretation of the ambiguous cue. The diffusion model was fit to behavioural data to allow further analysis of the underlying decision making processes. To uncover the way in which parameters vary together in relation to affective state manipulations, independent component analysis was conducted on rate of information accumulation and distances to decision threshold parameters for control data. Results from this analysis were applied to parameters from negative affective state manipulations. These projected components were compared to control components to reveal the changes in decision making processes that are due to affective state manipulations. Negative affective bias in rodents induced by either FG7142 or chronic stress is due to a combination of more negative interpretation of the ambiguous cue, reduced anticipation of the high reward and increased anticipation of the low reward.     

Processes Underlying the Nutritional Programming of Embryonic Development by Iron Deficiency in the Rat

Poor iron status is a global health issue, affecting two thirds of the world population to some degree. It is a particular problem among pregnant women, in both developed and developing countries. Feeding pregnant rats a diet deficient in iron is associated with both hypertension and reduced nephron endowment in adult male offspring. However, the mechanistic pathway leading from iron deficiency to fetal kidney development remains elusive. This study aimed to establish the underlying processes associated with iron deficiency by assessing gene and protein expression changes in the rat embryo, focussing on the responses occurring at the time of the nutritional insult. Analysis of microarray data showed that iron deficiency in utero resulted in the significant up-regulation of 979 genes and down-regulation of 1545 genes in male rat embryos (d13). Affected processes associated with these genes included the initiation of mitosis, BAD-mediated apoptosis, the assembly of RNA polymerase II preinitiation complexes and WNT signalling. Proteomic analyses highlighted 7 proteins demonstrating significant up-regulation with iron deficiency and the down-regulation of 11 proteins. The main functions of these key proteins included cell proliferation, protein transport and folding, cytoskeletal remodelling and the proteasome complex. In line with our recent work, which identified the perturbation of the proteasome complex as a generalised response to in utero malnutrition, we propose that iron deficiency alone leads to a more specific failure in correct protein folding and transport. Such an imbalance in this delicate quality-control system can lead to cellular dysfunction and apoptosis. Therefore these findings offer an insight into the underlying mechanisms associated with the development of the embryo during conditions of poor iron status, and its health in adult life.     

Setting Goals and Measuring Success: Linking Patterns and Processes in Stream Restoration

The influences of productivity, vegetation coverage, and benthivorous fish abundance on macroinvertebrate abundance and mean size were examined in Midwestern USA impoundments. While impoundment productivity was not strongly related to total abundance and mean size of macroinvertebrates, it was related to specific taxa. As productivity increased, Ephemeroptera and Odonata abundance decreased and Diptera abundance increased. Despite the shift in taxonomic composition, mean individual size of the macroinvertebrate community varied little with changes in impoundment productivity. Relationships between macroinvertebrates and benthivorous fish were mixed. Macroinvertebrate abundance, especially Diptera, increased with increases in bluegill Lepomis macrochirus Rafinesque abundance and decreased with increases in channel catfish Ictalurus punctatus (Rafinesque) (which are stocked annually) abundance. Fish were not related to the mean size of macroinvertebrates. Macrophyte coverage was not related to macroinvertebrate abundance or mean size. Overall, macroinvertebrate abundance was mostly related to productivity and benthivorous fish in these impoundments. Mean size of macroinvertebrates did not differ with productivity, fish abundance, or macrophyte coverage.     

Catching bird flu in a droplet

It is assumed that a timely mass administration of antiviral drugs, backed by quarantines and social distancing, could contain a nascent influenza epidemic at its source, provided that the first clusters of cases were localized within a short time. However, effective routine surveillance may be impossible in countries lacking basic public health resources. For a global containment strategy to be successful, low-cost, easy-to-use handheld units that permit decentralized testing would be vital. Here we present a microfluidic platform that can detect the highly pathogenic avian influenza virus H5N1 in a throat swab sample by using magnetic forces to manipulate a free droplet containing superparamagnetic particles. In a sequential process, the viral RNA is isolated, purified, preconcentrated by 50,000% and subjected to ultrafast real-time RT-PCR. Compared to commercially available tests, the bioassay is equally sensitive and is 440% faster and 2,000-5,000% cheaper.     

Catching the pulse: money and circulation in a Sri Lankan marketplace

This article traces the movement, management, and generation of money in a Sri Lankan wholesale vegetable market, pulling into focus certain local economic and moral logics. What traders do with cash is revealing. I argue that how traders use money – the way it is handled, risked, spent, and lent – exhibits skill, implies hierarchy, and cultivates social connections. Exploring idioms of economic activity such as ‘catching the pulse’ and ‘rolling the money’, the article examines relations between different kinds of trader. Moving money through businesses permits participation in the complex communication network of the market. This is central to existing in the social world of the trader. I argue that following money notes – rather than commodities – as they travel around the marketplace and between the hands of transactors renders ethnographically observable the formations of personhood and long‐term relations that take place in the market.     

Catching a red herring: autumn colours and aphids

The purpose of this note is not to support any particular hypothesis explaining the evolution of red coloured autumn leaves, but to present evidence that shows existing knowledge does not support one such hypothesis – that red coloured leaves evolved as a signal to protect trees from aphids feeding and laying eggs on them in autumn. An alternative hypothesis is that autumn-feeding aphids are senescence-feeders, evolved to feed only on senescing leaves. These aphids are programmed to detect and feed on such leaves when they are still green and yellow and actively exporting their nutrients. Aphids reject or ignore red leaves because they are no longer good food, not because they are protecting the trees from the aphids.     

Oscillations in a Simple Neuromechanical System: Underlying Mechanisms

A half-center neural oscillator was coupled to a simple mechanical system to study the closed-loop interactions between a central pattern generator and its effector muscles. After a review of the open-loop mechanisms that were previously introduced by Skinner et al. (1994), we extend their geometric approach and introduce four additional closed-loop mechanisms by the inclusion of an antagonistic muscle pair acting on a mass and connected to the half-center neural oscillator ipsilaterally. Two of the closed-loop mechanisms, mechanical release mechanisms, have close resemblance to open-loop release mechanisms whereas the latter two, afferent mechanisms, have a strong dependence on the mechanical properties of the system. The results also show that stable oscillations can emerge in the presence of sensory feedback even if the neural system is not oscillatory. Finally, the feasibility of the closed-loop mechanisms was shown by weakening the idealized assumptions of the synaptic and the feedback connections as well as the rapidity of the oscillations.     

Parasites and sex: Catching the red queen

One version of the Red Queen hypothesis suggests that sexual reproduction may be an advantage in a coevolutionary arms race. Antagonistic biotic interactions, especially those between parasite and host, are thought to represent a sufficient evolutionary force to counterbalance the supposed inefficiency of sexual reproduction. Recent experimental studies demonstrate negative frequency-dependent selection, increased parasite load in parthenogenetic races relative to sympatric sexual conspecifics and correlations between recombination rate and frequency of parasitic chromosomes. These studies provide strong empirical evidence that there is an important role for parasites in maintaining sex.