3,817 research outputs found
Decoding the future from past experience: learning shapes predictions in early visual cortex.
Learning the structure of the environment is critical for interpreting the current scene and predicting upcoming events. However, the brain mechanisms that support our ability to translate knowledge about scene statistics to sensory predictions remain largely unknown. Here we provide evidence that learning of temporal regularities shapes representations in early visual cortex that relate to our ability to predict sensory events. We tested the participants' ability to predict the orientation of a test stimulus after exposure to sequences of leftward- or rightward-oriented gratings. Using fMRI decoding, we identified brain patterns related to the observers' visual predictions rather than stimulus-driven activity. Decoding of predicted orientations following structured sequences was enhanced after training, while decoding of cued orientations following exposure to random sequences did not change. These predictive representations appear to be driven by the same large-scale neural populations that encode actual stimulus orientation and to be specific to the learned sequence structure. Thus our findings provide evidence that learning temporal structures supports our ability to predict future events by reactivating selective sensory representations as early as in primary visual cortex.This work was supported by a Wellcome Trust Senior Research Fellowship to AEW
(095183/Z/10/Z) and grants to ZK from the Biotechnology and Biological Sciences Research
Council [H012508], a Leverhulme Trust Research Fellowship (RF-2011-378) and the People
Programme (Marie Curie Actions) of the European Union's Seventh
Framework Programme FP7/2007-2013/ under REA grant agreement no. PITN-GA-2011-290011.This is the published version. It first appeared at http://jn.physiology.org/content/early/2015/02/27/jn.00753.2014
Targeting kidney mesangium by nanoparticles of defined size
Nanoparticles are being investigated for numerous medical applications and are showing potential as an emerging class of carriers for drug delivery. Investigations on how the physicochemical properties (e.g., size, surface charge, shape, and density of targeting ligands) of nanoparticles enable their ability to overcome biological barriers and reach designated cellular destinations in sufficient amounts to elicit biological efficacy are of interest. Despite proven success in nanoparticle accumulation at cellular locations and occurrence of downstream therapeutic effects (e.g., target gene inhibition) in a selected few organs such as tumor and liver, reports on effective delivery of engineered nanoparticles to other organs still remain scarce. Here, we show that nanoparticles of ~75 ± 25-nm diameters target the mesangium of the kidney. These data show the effects of particle diameter on targeting the mesangium of the kidney. Because many diseases originate from this area of the kidney, our findings establish design criteria for constructing nanoparticle-based therapeutics for targeting diseases that involve the mesangium of the kidney
Measurement of dynamic kc from the drop weight tear test, August 1968 (Luft\u27s M.S. thesis)
Processing graded feedback: Electrophysiological correlates of learning from small and large errors
Feedback processing is important for learning and therefore may affect the consolidation of skills. Considerable research demonstrates electrophysiological differences between correct and incorrect feedback, but how we learn from small versus large errors is usually overlooked. This study investigated electrophysiological differences when processing small or large error feedback during a time estimation task. Data from high-learners and low-learners were analyzed separately. In both high- and low-learners, large error feedback was associated with higher feedback-related negativity (FRN) and small error feedback was associated with a larger P300 and increased amplitude over the motor related areas of the left hemisphere. In addition, small error feedback induced larger desynchronization in the alpha and beta bands with distinctly different topographies between the two learning groups: The high-learners showed a more localized decrease in beta power over the left frontocentral areas, and the low-learners showed a widespread reduction in the alpha power following small error feedback. Furthermore, only the high-learners showed an increase in phase synchronization between the midfrontal and left central areas. Importantly, this synchronization was correlated to how well the participants consolidated the estimation of the time interval. Thus, although large errors were associated with higher FRN, small errors were associated with larger oscillatory responses, which was more evident in the high-learners. Altogether, our results suggest an important role of the motor areas in the processing of error feedback for skill consolidation
Handlungsorientierungen von Hochschullehrenden im Umgang mit der Entwicklung lernergebnisbasierter Curricula
Die Entwicklung hochschulischer Curricula ist mit dem Anspruch verbunden, lernergebnisorientiert zu erfolgen. Wie genau Lernergebnisse in der Praxis der Curriculumentwicklung entstehen, ist in der prozessbezogenen Curriculumforschung jedoch noch wenig bekannt. Dieser Beitrag widmet sich daher den impliziten Handlungsorientierungen, die die Bearbeitung curricularer Aufgaben durch Hochschullehrende leiten. Die Befunde weisen auf deutliche Unterschiede zwischen einer geschlossenen und einer offenen Orientierung hin. Diese führen zu sehr unterschiedlichen Formen des Umgangs u. a. mit dem Perspektivenwechsel von der Input- zur Outcome-Steuerung und zu sehr unterschiedlichen Ergebnissen
Light-chain-induced renal tubular acidosis: effect of sodium bicarbonate on sodium-proton exchange
We measured sodium-proton (Na+/H+) exchange in lymphocytes and platelets of a 46-year-old woman with the adult Fanconi syndrome before, during, and after treatment with NaHCO3. Kappa light chains in her urine and unique but rarely observed crystalline structures confirmed the presence of light-chain nephropathy. Her glomerular filtration rate was only moderately impaired at 72 ml/min. NaHCO3 at 1, 3, and 5 mmol/kg/day for 5 days increased her serum HCO3 and pH from 17 to 21 mmol/l and 7.28 to 7.39 respectively. Plasma renin and aldosterone values were decreased by NaHCO3. Na+/H+ exchange (δHi/min) was measured with the fluorescent marker BCECF after acidification of lymphocytes and platelets with sodium propionate at five (10-50mM) doses. Na+/H+ exchange was accelerated in this patient compared to normal controls. NaHCO3 treatment significantly decreased Na+/H+ exchange in lymphocytes, but not in platelets. These findings suggest that Na+/H+ exchange can be influenced by NaHCO3 ingestion at doses that only modestly affect systemic pH. Since Na+/H+ exchange is involved in stimulus response coupling, cell growth regulation, cell differentiation, and perhaps the progression of nephrosclerosis, these observations may have clinical relevanc
How to return to subjectivity? Natorp, Husserl, and Lacan on the limits of reflection
This article discusses the recent call within contemporary phenomenology to return to subjectivity in response to certain limitations of naturalistic explanations of the mind. The meaning and feasibility of this call is elaborated by connecting it to a classical issue within the phenomenological tradition concerning the possibility of investigating the first-person perspective through reflection. We will discuss how this methodological question is respectively treated and reconfigured in the works of Natorp, Husserl, and Lacan. Finally, we will lay out some possible consequences of such a cross-reading for the conception of subjectivity and the concomitant effort to account for this dimension of first-person experience in response and in addition to its omission within the standard third-person perspective of psychological research
Monitoring and Pay: An Experiment on Employee Performance under Endogenous Supervision
We present an experimental test of a shirking model where monitoring intensity is endogenous and effort a continuous variable. Wage level, monitoring intensity and consequently the desired enforceable effort level are jointly determined by the maximization problem of the firm. As a result, monitoring and pay should be complements. In our experiment, between and within treatment variation is qualitatively in line with the normative predictions of
the model under standard assumptions. Yet, we also find evidence for reciprocal behavior. Our data analysis shows, however, that it does not pay for the employer to solely rely on the reciprocity of employees
Wide Distribution of a High-Virulence Borrelia burgdorferi Clone in Europe and North America
We found substantial population differentiation and recent trans-Atlantic dispersal of a high-virulence B. burgdorferi clone
On the need for an international effort to capture, share and use crystallization screening data
Development of an ontology for the description of crystallization experiments and results is proposed
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