A revised computational neuroanatomy for motor control

We discuss a new framework for understanding the structure of motor control. Our approach integrates existing models of motor control with the reality of hierarchical cortical processing and the parallel segregated loops that characterize cortical-subcortical connections. We also incorporate the recent claim that cortex functions via predictive representation and optimal information utilization. Our framework assumes each cortical area engaged in motor control generates a predictive model of a different aspect of motor behavior. In maintaining these predictive models, each area interacts with a different part of the cerebellum and basal ganglia. These subcortical areas are thus engaged in domain appropriate system identification and optimization. This refocuses the question of division of function among different cortical areas. What are the different aspects of motor behavior that are predictively modelled? We suggest that one fundamental division is between modelling of task and body while another is the model of state and action. Thus, we propose that the posterior parietal cortex, somatosensory cortex, premotor cortex, and motor cortex represent task state, body state, task action, and body action, respectively. In the second part of this review, we demonstrate how this division of labor can better account for many recent findings of movement encoding, especially in the premotor and posterior parietal cortices

Translation initiation factor eIF3 promotes programmed stop codon readthrough.

Programmed stop codon readthrough is a post-transcription regulatory mechanism specifically increasing proteome diversity by creating a pool of C-terminally extended proteins. During this process, the stop codon is decoded as a sense codon by a near-cognate tRNA, which programs the ribosome to continue elongation. The efficiency of competition for the stop codon between release factors (eRFs) and near-cognate tRNAs is largely dependent on its nucleotide context; however, the molecular mechanism underlying this process is unknown. Here, we show that it is the translation initiation (not termination) factor, namely eIF3, which critically promotes programmed readthrough on all three stop codons. In order to do so, eIF3 must associate with pre-termination complexes where it interferes with the eRF1 decoding of the third/wobble position of the stop codon set in the unfavorable termination context, thus allowing incorporation of near-cognate tRNAs with a mismatch at the same position. We clearly demonstrate that efficient readthrough is enabled by near-cognate tRNAs with a mismatch only at the third/wobble position. Importantly, the eIF3 role in programmed readthrough is conserved between yeast and humans

Bill-EVR: an embodied virtual reality framework for reward-and-error-based motor rehab-learning

VR rehabilitation is an established field by now, however, it often refers to computer screen-based interactive rehabilitation activities. In recent years, there was an increased use of VR-headsets, which can provide an immersive virtual environment for real-world tasks, but they are lacking any physical interaction with the task objects and any proprioceptive feedback. Here, we focus on Embodied Virtual Reality (EVR), an emerging field where not only the visual input via VR-headset but also the haptic feedback is physically correct. This happens because subjects interact with physical objects that are veridically aligned in Virtual Reality. This technology lets us manipulate motor performance and motor learning through visual feedback perturbations. Bill-EVR is a framework that allows interventions in the performance of real-world tasks, such as playing pool billiard, engaging end-users in motivating life-like situations to trigger motor (re)learning - subjects see in VR and handle the real-world cue stick, the pool table and shoot physical balls. Specifically, we developed our platform to isolate and evaluate different mechanisms of motor learning to investigate its two main components, error-based and reward-based motor adaptation. This understanding can provide insights for improvements in neurorehabilitation: indeed, reward-based mechanisms are putatively impaired by degradation of the dopaminergic system, such as in Parkinson's disease, while error-based mechanisms are essential for recovering from stroke-induced movement errors. Due to its fully customisable features, our EVR framework can be used to facilitate the improvement of several conditions, providing a valid extension of VR-based implementations and constituting a motor learning tool that can be completely tailored to the individual needs of patients

Individual movement variability magnitudes are predicted by cortical neural variability

Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior–parietal cortex of individual subjects explained their movement–extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities

Welzijn (opfok) vleeskuikenouderdieren

Praktijkcentrum 'Het Spelderholt' heeft in samenwerking met ID-Lelystad onderzocht of tweemaal in plaats van eenmaal per dag voeren in de opfokperiode het welzijn van vleeskuikenouderdieren verbetert. Hiermee werd niet het verwachte effect op het gedrag verkregen

Atlas of radiation budget measurements from satellites (1962-1970)

December 1974.Includes bibliographical references

Study of tropical cyclone structural evolution, A

Includes bibliographical references.The destructive potential of a tropical cyclone is highly dependent on both the intensity and size of the storm. There has been extensive research done on intensity and intensity change, but far less work has focused on tropical cyclone structure and structural changes. The recent highly active Atlantic tropical seasons reemphasize the need for a better understanding of tropical cyclone structural evolution. This is particularly true of the 2005 season which produced a number of storms, such as Katrina, Rita, and Wilma, that not only became extremely intense, but also grew substantially in size during intensification. In contrast to these giants are the storms such as Hurricanes Charley (2004) and Emily (2005), which reached equal intensity, but remained fairly small in size. The goal of this study is to gain a better understanding of what causes these different structural evolutions in tropical cyclones. The inner core (0-200 km) wind-fields of Atlantic and Eastern Pacific tropical cyclones from 1995-2005 from aircraft reconnaissance flight-level data is used to calculate the low-level inner core kinetic energy. An inner core kinetic energy-intensity relationship is defined which describes the general trend of tropical cyclone inner core kinetic energy (KE) with respect to intensity. However, this mean KE/intensity relationship does not define the evolution of an individual storm. The KE deviations from the mean relationship for each storm are used to determine the cases where a storm is experiencing significant structural changes. The evolution of the KE deviations from the mean with respect to intensity indicates that hurricanes generally either grow and weaken or maintain their intensity, or strengthen but do not grow at the same time. The data is sorted by the state of intensification (intensifying, weakening, or maintaining intensity) and structure change (growing or non-growing), defining six sub-groups. The dynamic, thermodynamic, and internal conditions for the storm sub-groups are analyzed with the aid of statistical testing in order to determine what conditions are significantly different for growing versus non-growing storms in each intensification regime. These results reveal that there are two primary types of growth processes. The first is through eyewall replacement cycles, an internally dominated process, and the second via external forcing from the synoptic environment. As a supplement to this study, a new tropical cyclone classification system based on inner core KE is presented as a complement to the Saffir-Simpson hurricane scale.Funding for this research was sponsored by CIRA activities and participation in the GOES Improved Measurement Product Assurance Plan (GIMPAP) under NOAA cooperative agreement NA17RJ1