Cortical preparatory activity indexes learned motor memories.

The brain's remarkable ability to learn and execute various motor behaviours harnesses the capacity of neural populations to generate a variety of activity patterns. Here we explore systematic changes in preparatory activity in motor cortex that accompany motor learning. We trained rhesus monkeys to learn an arm-reaching task1 in a curl force field that elicited new muscle forces for some, but not all, movement directions2,3. We found that in a neural subspace predictive of hand forces, changes in preparatory activity tracked the learned behavioural modifications and reassociated4 existing activity patterns with updated movements. Along a neural population dimension orthogonal to the force-predictive subspace, we discovered that preparatory activity shifted uniformly for all movement directions, including those unaltered by learning. During a washout period when the curl field was removed, preparatory activity gradually reverted in the force-predictive subspace, but the uniform shift persisted. These persistent preparatory activity patterns may retain a motor memory of the learned field5,6 and support accelerated relearning of the same curl field. When a set of distinct curl fields was learned in sequence, we observed a corresponding set of field-specific uniform shifts which separated the associated motor memories in the neural state space7-9. The precise geometry of these uniform shifts in preparatory activity could serve to index motor memories, facilitating the acquisition, retention and retrieval of a broad motor repertoire.

Comparative transcriptome analysis during tuberous stem formation in Kohlrabi (B. oleracea var. gongylodes) at early growth periods (seedling stages).

Tuberous stem of kohlrabi is an important agronomic trait, however, the molecular basis of tuberization is poorly understood. To elucidate the tuberization mechanism, we conducted a comparative transcriptomic analysis between kohlrabi and broccoli at 10 and 20 days after germination (DAG) as tuberous stem initiated between these time points. A total of 5580 and 2866 differentially expressed transcripts (DETs) were identified between genotypes (kohlrabi vs. broccoli) and growth stages (10 DAG vs. 20 DAG), respectively, and most of the DETs were down-regulated in kohlrabi. Gene ontology (GO) and KEGG pathway enrichment analyses showed that the DETs between genotypes are involved in cell wall loosening and expansion, cell cycle and division, carbohydrate metabolism, hormone transport, hormone signal transduction and in several transcription factors. The DETs identified in those categories may directly/indirectly relate to the initiation and development of tuberous stem in kohlrabi. In addition, the expression pattern of the hormone synthesis related DETs coincided with the endogenous IAA, IAAsp, GA, ABA, and tZ profiles in kohlrabi and broccoli seedlings, that were revealed in our phytohormone analysis. This is the first report on comparative transcriptome analysis for tuberous stem formation in kohlrabi at early growth periods. The resulting data could provide significant insights into the molecular mechanism underlying tuberous stem development in kohlrabi as well as in other tuberous organ forming crops.

Inferring single-trial neural population dynamics using sequential auto-encoders.

Neuroscience is experiencing a revolution in which simultaneous recording of thousands of neurons is revealing population dynamics that are not apparent from single-neuron responses. This structure is typically extracted from data averaged across many trials, but deeper understanding requires studying phenomena detected in single trials, which is challenging due to incomplete sampling of the neural population, trial-to-trial variability, and fluctuations in action potential timing. We introduce latent factor analysis via dynamical systems, a deep learning method to infer latent dynamics from single-trial neural spiking data. When applied to a variety of macaque and human motor cortical datasets, latent factor analysis via dynamical systems accurately predicts observed behavioral variables, extracts precise firing rate estimates of neural dynamics on single trials, infers perturbations to those dynamics that correlate with behavioral choices, and combines data from non-overlapping recording sessions spanning months to improve inference of underlying dynamics.

Allele specific DNA marker for fusarium resistance gene FocBo1 in Brassica oleracea.

The fusarium yellows resistance (YR) gene FocBo1 was previously identified and the DNA markers were developed to assist the breeding of YR cultivars in Brassica oleracea. However, the further analysis revealed discrepancies between the phenotypes and the genotypes predicted by those DNA markers in cabbage commercial cultivars. Since this discrepancy seemed to be due to unknown susceptible alleles of focbo1, we sequenced the gene in 19 accessions to determine the sequence variations between alleles and found that there were two resistant FocBo1 alleles and six susceptible alleles in the investigated population. The newly designed PCR markers detected three mutations in the susceptible alleles that generate premature termination codons. These were shown to accurately distinguish resistant and susceptible alleles in more than 200 accessions of B. oleracea inbred lines and cultivars. The study revealed that the locus is represented by 37.2% resistant and 62.8% susceptible alleles within seventy-eight commercial cultivars. Structural analysis of the gene revealed that a part of the allelic variation comes from intragenic recombination between alleles. Our results enable a more precise prediction of the phenotype by marker assisted selection, promoting the production of YR cultivars in B. oleracea.

E-selectin-mediated rolling facilitates pancreatic cancer cell adhesion to hyaluronic acid.

Tumor cell extravasation is a multistep process preceded by cell rolling and arrest on the vessel wall via the formation of specific receptor-ligand bonds. The strength, availability, and number of receptor-ligand bonds regulate the rate by which tumor cells tether, roll, and adhere to vascular walls. Although the mechanics of selectin-mediated rolling have been extensively studied, little is known regarding how tumor cell rolling on selectins facilitates adhesion to a distinct substrate-bound protein with different kinetic properties. By using multicomponent protein patterning and a microfluidic system, we evaluated how E-selectin-dependent rolling modulates hyaluronic acid (HA) adhesion as a function of fluid shear, contact time, and the spacing between E-selectin and HA regions patterned on the substrate. We show that tumor cells rolling on E-selectin were ∼40-fold more likely to bind to HA than nonrolling cells in shear flow. Furthermore, E-selectin-dependent rolling promotes adhesion to HA by both physically slowing cells and enabling them to position proximal to the surface, thereby increasing the on rate of adhesion. A better understanding of tumor cell adhesion under physiologic shear would lead to the development of new diagnostic assays and pave the way to clinical approaches aimed ultimately to halt metastasis.-Shea, D. J., Li, Y. W., Stebe, K. J., Konstantopoulos, K. E-selectin-mediated rolling facilitates pancreatic cancer cell adhesion to hyaluronic acid.

Breeding of lilies and tulips-Interspecific hybridization and genetic background.

Lilies and tulips (Liliaceae family) are economically very important ornamental bulbous plants. Here, we summarize major breeding goals, the role of an integrated method of cut-style pollination and fertilization followed by embryo rescue and mitotic and meiotic polyploidization involved in new assortment development. Both crops have been subjected to extensive interspecific hybridization followed by selection. Additionally, spontaneous polyploidization has played a role in their evolution. In lilies, there is a tendency to replace diploids with polyploid cultivars, whereas in tulip a majority of the cultivars that exist today are still diploid except for triploid Darwin hybrid tulips. The introduction of molecular cytogenetic techniques such as genomic in situ hybridization (GISH) permitted the detailed studies of genome composition in lily and tulip interspecific hybrids and to follow the chromosome inheritance in interspecific crosses. In addition, this review presents the latest information on phylogenetic relationship in lily and tulip and recent developments in molecular mapping using different DNA molecular techniques.

Genome re-sequencing, SNP analysis, and genetic mapping of the parental lines of a commercial F1 hybrid cultivar of Chinese cabbage.

The genome-wide characterization of single nucleotide polymorphism (SNP) between cultivars or between inbred lines contributes to the creation of genetic markers that are important for plant breeding. Functional markers derived from polymorphisms within genes that affect phenotypic variation are especially valuable in plant breeding. Here, we report on the genome re-sequencing and analysis of the two parental inbred lines of the commercial F1 hybrid Chinese cabbage cultivar "W77". Through the genome-wide identification and classification of the SNPs and indels present in each parental line, we identified about 1,500 putative non-functional genes in each parent. We designed cleaved amplified polymorphic sequence (CAPS) markers using specific mutations found at Eco RI restriction sites in the parental lines and confirmed their Mendelian segregation by constructing a linkage map using 96 F2 plants derived from the F1 hybrid cultivar, "W77". Our results and data will be a useful genomic resource for future studies of gene function and metagenomic studies in Chinese cabbage.

The production and characterization of a BoFLC2 introgressed Brassica rapa by repeated backcrossing to an F1.

Flowering time is an important agronomic trait for Brassica rapa crops, and previous breeding work in Brassica has successfully transmitted other important agronomic traits from donor species. However, there has been no previous attempts to produce hybrids replacing the original Brassica FLC alleles with alien FLC alleles. In this paper, we introduce the creation of a chromosome substitution line (CSSL) containing a homozygous introgression of Flowering Locus C from Brassica oleracea (BoFLC2) into a B. rapa genomic background, and characterize the CSSL line with respect to the parental cultivars. The preferential transmission of alien chromosome inheritance and the pattern of transmission observed during the production of the CSSLs are also discussed.

Interplay of the physical microenvironment, contact guidance, and intracellular signaling in cell decision making.

The peritumoral physical microenvironment consists of complex topographies that influence cell migration. Cell decision making, upon encountering anisotropic, physiologically relevant physical cues, has yet to be elucidated. By integrating microfabrication with cell and molecular biology techniques, we provide a quantitative and mechanistic analysis of cell decision making in a variety of well-defined physical microenvironments. We used MDA-MB-231 breast carcinoma and HT1080 fibrosarcoma as cell models. Cell decision making after lateral confinement in 2-dimensional microcontact printed lines is governed by branch width at bifurcations. Cells confined in narrow feeder microchannels prefer to enter wider branches at bifurcations. In contrast, in feeder channels that are wider than the cell body, cells elongate along one side wall of the channel and are guided by contact with the wall to the contiguous branch channel independent of its width. Knockdown of ß1-integrins or inhibition of cellular contractility suppresses contact guidance. Concurrent, but not individual, knockdown of nonmuscle myosin isoforms IIA and IIB also decreases contact guidance, which suggests the existence of a compensatory mechanism between myosin IIA and myosin IIB. Conversely, knockdown or inhibition of cell division control protein 42 homolog promotes contact guidance-mediated decision making. Taken together, the dimensionality, length scales of the physical microenvironment, and intrinsic cell signaling regulate cell decision making at intersections.-Paul, C. D., Shea, D. J., Mahoney, M. R., Chai, A., Laney, V., Hung, W.-C., Konstantopoulos, K. Interplay of the physical microenvironment, contact guidance, and intracellular signaling in cell decision making.

IntroMap: a signal analysis based method for the detection of genomic introgressions.

BACKGROUND: Breeding programs often rely on marker-assisted tests or variant calling of next generation sequence (NGS) data to identify regions of genomic introgression arising from the hybridization of two plant species. In this paper we present IntroMap, a bioinformatics pipeline for the screening of candidate plants through the application of signal processing techniques to NGS data, using alignment to a reference genome sequence (annotation is not required) that shares homology with the recurrent parental cultivar, and without the need for de novo assembly of the read data or variant calling. RESULTS: We show the accurate identification of introgressed genomic regions using both in silico simulated genomes, and a hybridized cultivar data set using our pipeline. Additionally we show, through targeted marker-based assays, validation of the IntroMap predicted regions for the hybrid cultivar. CONCLUSIONS: This approach can be used to automate the screening of large populations, reducing the time and labor required, and can improve the accuracy of the detection of introgressed regions in comparison to a marker-based approach. In contrast to other approaches that generally rely upon a variant calling step, our method achieves accurate identification of introgressed regions without variant calling, relying solely upon alignment.

Neocortical excitation/inhibition balance in information processing and social dysfunction.

Severe behavioural deficits in psychiatric diseases such as autism and schizophrenia have been hypothesized to arise from elevations in the cellular balance of excitation and inhibition (E/I balance) within neural microcircuitry. This hypothesis could unify diverse streams of pathophysiological and genetic evidence, but has not been susceptible to direct testing. Here we design and use several novel optogenetic tools to causally investigate the cellular E/I balance hypothesis in freely moving mammals, and explore the associated circuit physiology. Elevation, but not reduction, of cellular E/I balance within the mouse medial prefrontal cortex was found to elicit a profound impairment in cellular information processing, associated with specific behavioural impairments and increased high-frequency power in the 30-80 Hz range, which have both been observed in clinical conditions in humans. Consistent with the E/I balance hypothesis, compensatory elevation of inhibitory cell excitability partially rescued social deficits caused by E/I balance elevation. These results provide support for the elevated cellular E/I balance hypothesis of severe neuropsychiatric disease-related symptoms.

On the nature of unintentional action: a study of force/moment drifts during multifinger tasks.

We explored the origins of unintentional changes in performance during accurate force production in isometric conditions seen after turning visual feedback off. The idea of control with referent spatial coordinates suggests that these phenomena could result from drifts of the referent coordinate for the effector. Subjects performed accurate force/moment production tasks by pressing with the fingers of a hand on force sensors. Turning the visual feedback off resulted in slow drifts of both total force and total moment to lower magnitudes of these variables; these drifts were more pronounced in the right hand of the right-handed subjects. Drifts in individual finger forces could be in different direction; in particular, fingers that produced moments of force against the required total moment showed an increase in their forces. The force/moment drift was associated with a drop in the index of synergy stabilizing performance under visual feedback. The drifts in directions that changed performance (non-motor equivalent) and in directions that did not (motor equivalent) were of about the same magnitude. The results suggest that control with referent coordinates is associated with drifts of those referent coordinates toward the corresponding actual coordinates of the hand, a reflection of the natural tendency of physical systems to move toward a minimum of potential energy. The interaction between drifts of the hand referent coordinate and referent orientation leads to counterdirectional drifts in individual finger forces. The results also demonstrate that the sensory information used to create multifinger synergies is necessary for their presence over the task duration.

Principles for applying optogenetic tools derived from direct comparative analysis of microbial opsins.

Diverse optogenetic tools have allowed versatile control over neural activity. Many depolarizing and hyperpolarizing tools have now been developed in multiple laboratories and tested across different preparations, presenting opportunities but also making it difficult to draw direct comparisons. This challenge has been compounded by the dependence of performance on parameters such as vector, promoter, expression time, illumination, cell type and many other variables. As a result, it has become increasingly complicated for end users to select the optimal reagents for their experimental needs. For a rapidly growing field, critical figures of merit should be formalized both to establish a framework for further development and so that end users can readily understand how these standardized parameters translate into performance. Here we systematically compared microbial opsins under matched experimental conditions to extract essential principles and identify key parameters for the conduct, design and interpretation of experiments involving optogenetic techniques.

Large-scale high-density brain-wide neural recording in nonhuman primates.

High-density, integrated silicon electrodes have begun to transform systems neuroscience, by enabling large-scale neural population recordings with single cell resolution. Existing technologies, however, have provided limited functionality in nonhuman primate species such as macaques, which offer close models of human cognition and behavior. Here, we report the design, fabrication, and performance of Neuropixels 1.0-NHP, a high channel count linear electrode array designed to enable large-scale simultaneous recording in superficial and deep structures within the macaque or other large animal brain. These devices were fabricated in two versions: 4416 electrodes along a 45 mm shank, and 2496 along a 25 mm shank. For both versions, users can programmatically select 384 channels, enabling simultaneous multi-area recording with a single probe. We demonstrate recording from over 3000 single neurons within a session, and simultaneous recordings from over 1000 neurons using multiple probes. This technology represents a significant increase in recording access and scalability relative to existing technologies, and enables new classes of experiments involving fine-grained electrophysiological characterization of brain areas, functional connectivity between cells, and simultaneous brain-wide recording at scale.

Giant obscurin regulates migration and metastasis via RhoA-dependent cytoskeletal remodeling in pancreatic cancer.

Obscurins, encoded by the OBSCN gene, are giant cytoskeletal proteins with structural and regulatory roles. Large scale omics analyses reveal that OBSCN is highly mutated across different types of cancer, exhibiting a 5-8% mutation frequency in pancreatic cancer. Yet, the functional role of OBSCN in pancreatic cancer progression and metastasis has to be delineated. We herein show that giant obscurins are highly expressed in normal pancreatic tissues, but their levels are markedly reduced in pancreatic ductal adenocarcinomas. Silencing of giant obscurins in non-tumorigenic Human Pancreatic Ductal Epithelial (HPDE) cells and obscurin-expressing Panc5.04 pancreatic cancer cells induces an elongated, spindle-like morphology and faster cell migration via cytoskeletal remodeling. Specifically, depletion of giant obscurins downregulates RhoA activity, which in turn results in reduced focal adhesion density, increased microtubule growth rate and faster actin dynamics. Although OBSCN knockdown is not sufficient to induce de novo tumorigenesis, it potentiates tumor growth in a subcutaneous implantation model and exacerbates metastasis in a hemispleen murine model of pancreatic cancer metastasis, thereby shortening survival. Collectively, these findings reveal a critical role of giant obscurins as tumor suppressors in normal pancreatic epithelium whose loss of function induces RhoA-dependent cytoskeletal remodeling, and promotes cell migration, tumor growth and metastasis.

High-performance pipeline for MutMap and QTL-seq.

Summary: Bulked segregant analysis implemented in MutMap and QTL-seq is a powerful and efficient method to identify loci contributing to important phenotypic traits. However, the previous pipelines were not user-friendly to install and run. Here, we describe new pipelines for MutMap and QTL-seq. These updated pipelines are approximately 5-8 times faster than the previous pipeline, are easier for novice users to use, and can be easily installed through bioconda with all dependencies. Availability: The new pipelines of MutMap and QTL-seq are written in Python and can be installed via bioconda. The source code and manuals are available online (MutMap: https://github.com/YuSugihara/MutMap, QTL-seq: https://github.com/YuSugihara/QTL-seq).

Genome-wide analysis of long noncoding RNAs, 24-nt siRNAs, DNA methylation and H3K27me3 marks in Brassica rapa.

Long noncoding RNAs (lncRNAs) are RNA fragments that generally do not code for a protein but are involved in epigenetic gene regulation. In this study, lncRNAs of Brassica rapa were classified into long intergenic noncoding RNAs, natural antisense RNAs, and intronic noncoding RNAs and their expression analyzed in relation to genome-wide 24-nt small interfering RNAs (siRNAs), DNA methylation, and histone H3 lysine 27 trimethylation marks (H3K27me3). More than 65% of the lncRNAs analyzed consisted of one exon, and more than 55% overlapped with inverted repeat regions (IRRs). Overlap of lncRNAs with IRRs or genomic regions encoding for 24-nt siRNAs resulted in increased DNA methylation levels when both were present. LncRNA did not overlap greatly with H3K27me3 marks, but the expression level of intronic noncoding RNAs that did coincide with H3K27me3 marks was higher than without H3K27me3 marks. The Brassica genus comprises important vegetables and oil seed crops grown across the world. B. rapa is a diploid (AA genome) thought to be one of the ancestral species of both B. juncea (AABB genome) and B. napus (AACC) through genome merging (allotetrapolyploidization). Complex genome restructuring and epigenetic alterations are thought to be involved in these allotetrapolyploidization events. Comparison of lncRNAs between B. rapa and B. nigra, B. oleracea, B. juncea, and B. napus showed the highest conservation with B. oleracea. This study presents a comprehensive analysis of the epigenome structure of B. rapa at multi-epigenetic levels (siRNAs, DNA methylation, H3K27me3, and lncRNAs) and identified a suite of candidate lncRNAs that may be epigenetically regulated in the Brassica genus.

Dendritic calcium signals in rhesus macaque motor cortex drive an optical brain-computer interface.

Calcium imaging is a powerful tool for recording from large populations of neurons in vivo. Imaging in rhesus macaque motor cortex can enable the discovery of fundamental principles of motor cortical function and can inform the design of next generation brain-computer interfaces (BCIs). Surface two-photon imaging, however, cannot presently access somatic calcium signals of neurons from all layers of macaque motor cortex due to photon scattering. Here, we demonstrate an implant and imaging system capable of chronic, motion-stabilized two-photon imaging of neuronal calcium signals from macaques engaged in a motor task. By imaging apical dendrites, we achieved optical access to large populations of deep and superficial cortical neurons across dorsal premotor (PMd) and gyral primary motor (M1) cortices. Dendritic signals from individual neurons displayed tuning for different directions of arm movement. Combining several technical advances, we developed an optical BCI (oBCI) driven by these dendritic signalswhich successfully decoded movement direction online. By fusing two-photon functional imaging with CLARITY volumetric imaging, we verified that many imaged dendrites which contributed to oBCI decoding originated from layer 5 output neurons, including a putative Betz cell. This approach establishes new opportunities for studying motor control and designing BCIs via two photon imaging.

Genetics of Clubroot and Fusarium Wilt Disease Resistance in Brassica Vegetables: The Application of Marker Assisted Breeding for Disease Resistance.

The genus Brassica contains important vegetable crops, which serve as a source of oil seed, condiments, and forages. However, their production is hampered by various diseases such as clubroot and Fusarium wilt, especially in Brassica vegetables. Soil-borne diseases are difficult to manage by traditional methods. Host resistance is an important tool for minimizing disease and many types of resistance (R) genes have been identified. More than 20 major clubroot (CR) disease-related loci have been identified in Brassica vegetables and several CR-resistant genes have been isolated by map-based cloning. Fusarium wilt resistant genes in Brassica vegetables have also been isolated. These isolated R genes encode the toll-interleukin-1 receptor/nucleotide-binding site/leucine-rice-repeat (TIR-NBS-LRR) protein. DNA markers that are linked with disease resistance allele have been successfully applied to improve disease resistance through marker-assisted selection (MAS). In this review, we focused on the recent status of identifying clubroot and Fusarium wilt R genes and the feasibility of using MAS for developing disease resistance cultivars in Brassica vegetables.