Ube3a is required for experience-dependent maturation of the neocortex

Experience-dependent maturation of neocortical circuits is required for normal sensory and cognitive abilities, which are distorted in neurodevelopmental disorders. We have tested whether experience-dependent neocortical modifications require Ube3a, an E3 ubiquitin ligase whose dysregulation has been implicated in autism and Angelman syndrome (AS). Using visual cortex as a model, we demonstrate that experience-dependent maturation of excitatory cortical circuits is severely impaired in AS mice deficient in Ube3a. This developmental defect is associated with profound impairments in neocortical plasticity. Remarkably, normal plasticity is preserved under conditions of sensory deprivation, but rapidly lost by sensory experiences. The loss of neocortical plasticity is reversible, as late-onset visual deprivation restores normal synaptic plasticity. Further, Ube3a-deficient mice lack ocular dominance plasticity in vivo when challenged with monocular deprivation. These results show that Ube3a is necessary to maintain plasticity during experience-dependent neocortical development, and suggest that loss of neocortical plasticity contributes to deficits associated with AS

NrCAM Deletion Causes Topographic Mistargeting of Thalamocortical Axons to the Visual Cortex and Disrupts Visual Acuity

NrCAM is a neural cell adhesion molecule of the L1 family that has been linked to autism spectrum disorders (ASDs), a disease spectrum in which abnormal thalamocortical connectivity may contribute to visual processing defects. Here we show that NrCAM interaction with Neuropilin-2 (Npn-2) is critical for Semaphorin3F (Sema3F)-induced guidance of thalamocortical axon subpopulations at the ventral telencephalon (VTe), an intermediate target for thalamic axon sorting. Genetic deletion of NrCAM or Npn-2 caused contingents of embryonic thalamic axons to misproject caudally in the VTe, away from a caudal-high Sema3F gradient. The resultant thalamocortical map of NrCAM null mutants showed striking mistargeting of motor and somatosensory thalamic axon contingents to the primary visual cortex, but retino-geniculate targeting and segregation were normal. NrCAM formed a molecular complex with Npn-2 in brain and neural cells, and was required for Sema3F-induced growth cone collapse in thalamic neuron cultures, consistent with a vital function for NrCAM in Sema3F-induced axon repulsion. NrCAM null mice displayed reduced responses to visual evoked potentials (VEPs) recorded from layer IV in the binocular zone of primary visual cortex (V1), particularly when evoked from the ipsilateral eye, indicating abnormal visual acuity and ocularity. These results demonstrate that NrCAM is required for normal maturation of cortical visual acuity, and suggest that the aberrant projection of thalamic motor and somatosensory axons to the visual cortex in NrCAM null mutant mice impairs cortical functions

Monaural Source Separation Using a Random Forest Classifier

We address the problem of separating two audio sources from a single channel mixture recording. A novel method called Multi Layered Random Forest (MLRF) that learns a binary mask for both the sources is presented. Random Forest (RF) classifiers are trained for each frequency band of a source spectrogram. A specialized set of linear transformations are applied to a local time-frequency (T-F) neighborhood of the mixture that captures relevant local statistics. A sampling method is presented that efficiently samples T-F training bins in each frequency band. We draw equal numbers of dominant (more power) training samples from the two sources for RF classifiers that estimate the Ideal Binary Mask (IBM). An estimated IBM in a given layer is used to train a RF classifier in the next higher layer of the MLRF hierarchy. On average, MLRF performs better than deep Recurrent Neural Networks (RNNs) and Non-Negative Sparse Coding (NNSC) in signal-to-noise ratio (SNR) of reconstructed audio, overall T-F bin classification accuracy, as well as PESQ and STOI scores. Additionally, we demonstrate the ability of the MLRF to correctly reconstruct T-F bins of the target even when the latter has lower power in that frequency band

Trait characterization of genetic resources reveals useful variation for the improvement of cultivated Nordic red clover

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Seed Dormancy in Hairy Vetch (Vicia villosa Roth) Is Influenced by Genotype and Environment

Seed dormancy complicates the agricultural use of many legume species. Understanding the genetic and environmental drivers of seed dormancy is necessary for advancing crop improvement for legumes, such as Vicia villosa. In this study, we quantify the magnitude of genetic and environmental effects on physical dormancy among 1488 maternal V. villosa plants from 18 diverse environments. Furthermore, we explore the relationship between physical dormancy and environmental conditions during seed development. Additive genetic variance (h2) accounted for 40% of the variance, while the growing environment explained 28% of the variance in physical dormancy. Maternal lines showed complete variance in physical dormancy, as one line was 100% dormant, and 56 lines were 0% dormant. Distributions of physical dormancy varied widely among seed production environments, with some site-years strongly skewed toward physically dormant seed, while other site-years exhibited little dormant seed. Twenty-three weather variables were associated with environmental and error effects of physical dormancy. High mean and minimum relative humidity, low mean and maximum temperature, and high precipitation weakly grouped with low physical dormancy. Weather variables calculated from fixed time windows approximating seed maturity to seed harvest at each site-year tended to be less predictive than biological seed drying windows calculated based on seed maturity of each maternal line. Overall, individual and cumulative effects of weather variables were poor predictors of physical dormancy. Moderate heritability indicates that breeding programs can select against physical dormancy and improve V. villosa for agricultural use. Marker-based approaches would maximize selection for physical dormancy by reducing the influence of unpredictable environmental effects

Ube3a is required for experience-dependent maturation of the neocortex

Photograph of a scene at the reconstructed Choctaw Chief's House

Potential of some neglected european annual legume crops for forage production

There is a general trend of re-introducing currently neglected and underutilised crops into diverse farming systems and providing them with novel roles in contemporary agriculture, which is faced with numerous challenges. One such novel role could be the use of traditional grain legume crops for forage production. One of the essential traits needed for improving the potential of quality forage production in faba bean is a decreased proportion of lignin in forage dry matter, providing more slender stems with a higher nutritional value for feeding ruminants. Hairy vetch demonstrates a wide variability of agronomic traits and may be regarded as having great potential for utilisation in breeding and developing new cultivars for forage production and green manure. The future breeding efforts will emphasize chemical composition, especially crude and digestible protein and fibre content. Despite its relatively short stem length, bitter vetch may serve as one of the best ideotypes in breeding annual forage legumes because of its large number of photosynthetically active leaves and its extremely good utilisation of growing space. The indeterminate stem growth is one of the main obstacles in developing the grass pea cultivars with both high forage yield and reliable seed yield. This trait is equally important in hairy vetch, and needs to be efficiently solved for both forage and grain production