Cerebellar Modules and Their Role as Operational Cerebellar Processing Units

The compartmentalization of the cerebellum into modules is often used to discuss its function. What, exactly, can be considered a module, how do they operate, can they be subdivided and do they act individually or in concert are only some of the key questions discussed in this consensus paper. Experts studying cerebellar compartmentalization give their insights on the structure and function of cerebellar modules, with the aim of providing an up-to-date review of the extensive literature on this subject. Starting with an historical perspective indicating that the basis of the modular organization is formed by matching olivocorticonuclear connectivity, this is followed by consideration of anatomical and chemical modular boundaries, revealing a relation between anatomical, chemical, and physiological borders. In addition, the question is asked what the smallest operational unit of the cerebellum might be. Furthermore, it has become clear that chemical diversity of Purkinje cells also results in diversity of information processing between cerebellar modules. An additional important consideration is the relation between modular compartmentalization and the organization of the mossy fiber system, resulting in the concept of modular plasticity. Finally, examination of cerebellar output patterns suggesting cooperation between modules and recent work on modular aspects of emotional behavior are discussed. Despite the general consensus that the cerebellum has a modular organization, many questions remain. The authors hope that this joint review will inspire future cerebellar research so that we are better able to understand how this brain structure makes its vital contribution to behavior in its most general form

Grain Surface Models and Data for Astrochemistry

AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions

Enhancing studies of the connectome in autism using the autism brain imaging data exchange II

The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neural correlates of co-occurring psychopathology; 284 diffusion imaging datasets are also included. It is anticipated that these enhancements will contribute to unraveling key sources of ASD heterogeneity

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Solubilities of CO₂, CH₄, C₂H₆, CO, H₂, N₂, N₂O, and H₂S in commercial physical solvents from Monte Carlo simulations

The removal of acid gas impurities from synthesis gas or natural gas can be achieved using several physical solvents. Examples of solvents applied on a commercial scale include methanol (Rectisol), poly(ethylene glycol) dimethyl ethers (Selexol), n-methyl-2-pyrrolidone (Purisol), and propylene carbonate (Fluor solvent). Continuous Fractional Component Monte Carlo (CFCMC) simulations in the osmotic ensemble were used to compute the Henry coefficients of the pure gases CO (Formula presented.), CH (Formula presented.), C (Formula presented.) H (Formula presented.), CO, H (Formula presented.), N (Formula presented.), N (Formula presented.) O, and H (Formula presented.) S in the aforementioned solvents. The predicted Henry coefficients are in good agreement with the experimental results. The Monte Carlo method correctly predicts the gas solubility trend in these physical solvents, which obeys the following order: H (Formula presented.) S > CO (Formula presented.) > C (Formula presented.) H (Formula presented.) > CH (Formula presented.) > CO > N (Formula presented.) > H (Formula presented.). The gas separation selectivities for the precombustion process and the natural gas sweetening process are calculated from the pure gas Henry coefficients. The CO (Formula presented.) /N (Formula presented.) O analogy is verified for the solubility in these solvents.Engineering Thermodynamic

Computing bubble-points of CO₂/CH₄ gas mixtures in ionic liquids from Monte Carlo simulations

Computing bubble-points of multicomponent mixtures using Monte Carlo simulations is a non-trivial task. A new method is used to compute gas compositions from a known temperature, bubble-point pressure, and liquid composition. Monte Carlo simulations are used to calculate the bubble-points of carbon dioxide (CO2) and methane (CH4) mixtures in the ionic liquids (ILs) 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][Tf2N] and 1-ethyl-3-methylimidazolium diethylphosphate [emim][dep]. The Continuous Fractional Component Monte Carlo (CFCMC) method in the osmotic ensemble has been used to compute the solubility of CO2/CH4 gas mixtures at different temperatures (T), pressures (P), and gas compositions (yi). The effect of T, P, and yi on the real CO2/CH4 selectivity (i.e., the selectivity of CO2 in the presence of CH4) is investigated. The real selectivity will differ from the ideal selectivity, which is defined as the ratio of the Henry's constants, if the solubility of CO2 is influenced by the presence of CH4. The computed real selectivities are compared with the experimentally obtained real and ideal selectivities. The real CO2/CH4 selectivity decreases with increasing temperature and pressure, while the gas phase composition has a minor effect. The real selectivity is approximately identical to the ideal selectivity for relatively low pressures and low solute concentrations in the liquid phase. The real selectivity deviates from the ideal selectivity as the solute concentration in the liquid phase increases.Accepted Author ManuscriptEngineering Thermodynamic

Charting brain growth in tandem with brain templates for schoolchildren

Brain growth charts and age-normed brain templates are essential resources for researchers to eventually contribute to the care of individuals with atypical developmental trajectories. The present work generates age-normed brain templates for children and adolescents at one-year intervals and the corresponding growth charts to investigate the influences of age and ethnicity using a common pediatric neuroimaging protocol. Two accelerated longitudinal cohorts with the identical experimental design were implemented in the United States and China. Anatomical magnetic resonance imaging (MRI) of typically developing school-age children (TDC) was obtained up to three times at nominal intervals of 1.25 years. The protocol generated and compared population- and age-specific brain templates and growth charts, respectively. A total of 674 Chinese pediatric MRI scans were obtained from 457 Chinese TDC and 190 American pediatric MRI scans were obtained from 133 American TDC. Population- and age-specific brain templates were used to quantify warp cost, the differences between individual brains and brain templates. Volumetric growth charts for labeled brain network areas were generated. Shape analyses of cost functions supported the necessity of age-specific and ethnicity-matched brain templates, which was confirmed by growth chart analyses. These analyses revealed volumetric growth differences between the two ethnicities primarily in lateral frontal and parietal areas, regions which are most variable across individuals in regard to their structure and function. Age- and ethnicity-specific brain templates facilitate establishing unbiased pediatric brain growth charts, indicating the necessity of the brain charts and brain templates generated in tandem. These templates and growth charts as well as related codes have been made freely available to the public for open neuroscience (https://github.com/zuoxinian/CCS/tree/master/H3/GrowthCharts)