Representational organization of novel task sets during proactive encoding

Recent multivariate analyses of brain data have boosted our understanding of the organizational principles that shape neural coding. However, most of this progress has focused on perceptual visual regions (Connolly et al., 2012), whereas far less is known about the organization of more abstract, action-oriented representations. In this study, we focused on humans{\textquoteright} remarkable ability to turn novel instructions into actions. While previous research shows that instruction encoding is tightly linked to proactive activations in fronto-parietal brain regions, little is known about the structure that orchestrates such anticipatory representation. We collected fMRI data while participants (both males and females) followed novel complex verbal rules that varied across control-related variables (integrating within/across stimuli dimensions, response complexity, target category) and reward expectations. Using Representational Similarity Analysis (Kriegeskorte et al., 2008) we explored where in the brain these variables explained the organization of novel task encoding, and whether motivation modulated these representational spaces. Instruction representations in the lateral prefrontal cortex were structured by the three control-related variables, while intraparietal sulcus encoded response complexity and the fusiform gyrus and precuneus organized its activity according to the relevant stimulus category. Reward exerted a general effect, increasing the representational similarity among different instructions, which was robustly correlated with behavioral improvements. Overall, our results highlight the flexibility of proactive task encoding, governed by distinct representational organizations in specific brain regions. They also stress the variability of motivation-control interactions, which appear to be highly dependent on task attributes such as complexity or novelty.SIGNIFICANCE STATEMENTIn comparison with other primates, humans display a remarkable success in novel task contexts thanks to our ability to transform instructions into effective actions. This skill is associated with proactive task-set reconfigurations in fronto-parietal cortices. It remains yet unknown, however, how the brain encodes in anticipation the flexible, rich repertoire of novel tasks that we can achieve. Here we explored cognitive control and motivation-related variables that might orchestrate the representational space for novel instructions. Our results showed that different dimensions become relevant for task prospective encoding depending on the brain region, and that the lateral prefrontal cortex simultaneously organized task representations following different control-related variables. Motivation exerted a general modulation upon this process, diminishing rather than increasing distances among instruction representations

The Film Philadelphia As A Case Study Of Ethical Dilemmas In The Workplace

In this paper we present the film Philadelphia as an exemplary text for teaching business ethics.  For this purpose, we show students three scenes from the film and guide them as they engage in ethical reasoning. Through the exercise, students should: understand the nature of ethical dilemmas; understand a model for ethical decision-making and apply it to shed light on selected situations presented in the film; and lastly, understand ethical dimensions of discrimination. After engaging with the exercise, students should also develop a clear understanding of the difficulty of reaching ethical decisions in their professional careers. In addition, the exercise serves as an opportunity to discuss issues of HIV and AIDS in contemporary organizations

Analysis of the geological control on the Arroyo Las Lajas, Cordoba, flashiness through an hydrological modeling

Se analiza la incidencia de factores litológicos, estructurales y bióticos en la respuesta hidrológica (torrencialidad) de una cuenca hídrica serrana aplicando el modelo matemático ARHymo. La cuenca alta del arroyo Las Lajas se encuentra en las sierras de Comechingones, entre 1.200 y 750 m s.n.m., con una superficie de 41 km2 y una red de drenaje de orden de Horton 6. La morfología de la cuenca está fuertemente controlada por la traza de la falla Las Lajas, una estructura de actividad reciente que separa un sustrato granítico de otro metamórfico. Para el modelado, la cuenca alta fue subdividida en 42 subcuencas. Para cada una de ellas se obtuvieron valores de curva número (CN). La torrencialidad de cada subcuenca fue estimada en base a los tiempos al pico (Tp) y a la distribución temporal de la onda de creciente reflejada en los hidrogramas. Se confrontaron las formas de los hidrogramas de subcuencas representativas y la distribución de las frecuencias de los tiempos al pico, con las características geológicas de la cuenca. Las subcuencas desarrolladas en metamorfitas con fuerte control estructural mostraron mayor torrencialidad que las ubicadas en el sustrato granítico.The impact of lithological, structural and biotic factors in the hydrological response of a mountain drainage basin is analyzed using the mathematical model ARHymo. The upstream reach of the Las Lajas creek is located in the Comechingones Ranges, between 1,200 to 750 m a.s.l.; it has an area of 41 km2 and a drainage network of Horton order 6. The morphology of the basin is strongly controlled by the Las Lajas fault, a recently active structure that separates granitic from metamorphic substrates. The basin was subdivided into 42 subbasins and curve numbers were computed for each subbasin. The flashiness of the flood wave was estimated from time-to-peak data and from the shapes of hydrographs. Comparison of the shapes of the hydrographs of representative subbasins and the distribution of time-to-peak frequencies, with the geological features of the basin, suggests that the subbasins developed on metamorphic substrate show greater flashiness than those located on granitic substrate.Fil: Doffo, Nelso. Universidad Nacional de Rio Cuarto; ArgentinaFil: Eric, Carlos F.. Universidad Nacional de Rio Cuarto; ArgentinaFil: Gonzalez Bonorino, Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Binding dynamics of a monomeric SSB protein to DNA : a single-molecule multi-process approach

People Programme of the European Union’s Seventh Framework Programme [REA 334496 to B.E.B.]; Leonardo da Vinci European Union Programme (to M.F.G.); Wellcome Trust [099149/Z/12/Z, 091825/Z/10/Z]. Funding for open access charge: Wellcome Trust; University of St Andrews.Single-stranded DNA binding proteins (SSBs) are ubiquitous across all organisms and are characterized by the presence of an OB (oligonucleotide/oligosaccharide/oligopeptide) binding motif to recognize single-stranded DNA (ssDNA). Despite their critical role in genome maintenance, our knowledge about SSB function is limited to proteins containing multiple OB-domains and little is known about single OB-folds interacting with ssDNA. Sulfolobus solfataricus SSB (SsoSSB) contains a single OB-fold and being the simplest representative of the SSB-family may serve as a model to understand fundamental aspects of SSB:DNA interactions. Here, we introduce a novel approach based on the competition between Förster resonance energy transfer (FRET), protein-induced fluorescence enhancement (PIFE) and quenching to dissect SsoSSB binding dynamics at single monomer resolution. We demonstrate that SsoSSB follows a monomer-by-monomer binding mechanism that involves a positive-cooperativity component between adjacent monomers. We found that SsoSSB dynamic behaviour is closer to that of Replication Protein A than to Escherichia coli SSB; a feature that might be inherited from the structural analogies of their DNA-binding domains. We hypothesize that SsoSSB has developed a balance between highdensity binding and a highly dynamic interaction with ssDNA to ensure efficient protection of the genome but still allow access to ssDNA during vital cellular processes.Publisher PDFPeer reviewe

Flavored Non-Minimal Left-Right Symmetric Model Fermion Masses and Mixings

A complete study on the fermion masses and flavor mixing is presented in a non-minimal left-right symmetric model (NMLRMS) where the ${\bf S}_{3}\otimes {\bf Z}_{2}\otimes {\bf Z}^{e}_{2}$ flavor symmetry drives the Yukawa couplings. In the quark sector, the mass matrices possess a kind of the generalized Fritzsch textures that allow us to fit the CKM mixing matrix in good agreement to the last experimental data. In the lepton sector, on the other hand, a soft breaking of the $\mu\leftrightarrow \tau$ symmetry provides a non zero and non maximal reactor and atmospheric angles, respectively. The inverted and degenerate hierarchy are favored in the model where a set of free parameters is found to be consistent with the current neutrino data.Comment: 23 pages, 9 figures. references added, typos corrected, JCGI added his current institution;conclusions rewrote and unchanged results. Version published in European Physical Journal