823 research outputs found

    Comparative organization of the claustrum: what does structure tell us about function?

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    The claustrum is a subcortical nucleus present in all placental mammals. Many anatomical studies have shown that its inputs are predominantly from the cerebral cortex and its outputs are back to the cortex. This connectivity thus suggests that the claustrum serves to amplify or facilitate information processing in the cerebral cortex. The size and the complexity of the cerebral cortex change dramatically over evolution. Rodents are lissencephalic, with few cortical areas, while many primates have a greatly expanded cortex and many cortical areas. This evolutionary diversity in the cerebral cortex raises several questions about the claustrum. Does its volume expand in coordination with the expansion of cortex and does it acquire new functions related to the new cortical functions? We have examined the organization of the claustrum in animals with large brains, including great apes and cetaceans. Our data suggest that the claustrum is not always a continuous structure. In monkeys and gorillas there are a few isolated islands of cells near the main body of the nucleus. In cetaceans, however, there are many isolated cell islands. These data suggest constraints on the possible function of the claustrum. Some authors propose that the claustrum has a more global role in perception or consciousness that requires intraclaustral integration of information. These theories postulate mechanisms like gap junctions between claustral cells or a syncytium to mediate intraclaustral processing. The presence of discontinuities in the structure of the claustrum, present but minimal in primates, but dramatically clear in cetaceans, argues against the proposed mechanisms of intraclaustral processing of information. The best interpretation of function, then, is that each functional subdivision of the claustrum simply contributes to the function of its cortical partner

    De-Criminalizing the Classroom in Mississippi: How Alternative School Discipline Procedures Help Curb Crime

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    Mississippi's school discipline procedures have prompted nationwide concern for several years, as the state's schooldistricts have some of the highest suspension, expulsion, and involvement of law enforcement rates in the nation,particularly for students of color. Fortunately, Mississippi law enforcement leaders know several alternative procedures that work to both address disruptive classroom behavior and promote educational achievement throughout the school.We believe that school administrators must have the authority to suspend, expel or take other school action when dealing with weapons offenses, violent crimes or drug sales, yet we know that less serious offenses, such as talking back to a teacher or using inappropriate language, can be better addressed with other approaches. Models such as the Good Behavior Game, the Incredible Years, Restorative Justice, and Positive Behavioral Intervention and Supportshelp reduce suspensions and expulsions while ensuring that schools are safe. Research has found that these models help ameliorate students' behavior, lead to improvements in the schools' environments, increase academic achievement for all students, and prevent later crime. When students succeed academically, their likelihood of coming into contact with law enforcement decreases tremendously. This is how, together, we will build safer communities

    The Influence of Local Government and BID Initiatives on CUCA Che Guevara as a Center for Social Inclusion

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    Fortaleza, Brazil, is a city known for its extreme levels of social inequality in between the center of the city and the periphery. Over time, these have led to high rates of social problems among youth living on the outer reaches of the city, including truancy and lack of employability. These problems have led many of the youth in the city to become excluded from general society, and more likely to engage in risky behaviors, including crime and early pregnancy. After abandoning these areas for many years, the local government decided to create a physical center to promote the employability and social inclusion of these youth. After consulting with the community, the Prefeitura government decided to create six massive centers where youth could practice sports, engage in cultural programs, and attend professional courses. The first of these centers, CUCA Che Guevara, has been fully operational since October 2010, thanks in part to a nearly $25 million USD loan from BIDiii. Though international lending institutions are traditionally known for changing the scope and scale of development projects, BID had almost no interference with the plans behind the CUCA centers. This allowed the Prefeitura government to implement the programs that they believed were the best for the community, and ensured that the relationship between the Prefeitura and BID remained amicable. However, in the haste to begin construction on CUCA Che Guevara before the end of the previous term, the government decided to build CUCA Che Guevara in a place that does not maximize accessibility for the people of the communityiv. In addition, attendance in many of CUCA’s programs continues to be low, particularly among people living within CUCA’s immediate surroundings. The Prefeitura government must find ways to remedy these two serious issues before they use the same methodology to run Baizer 5 future CUCAs within the city. If they do not, the Center’s effects on youth social inclusion will be much less detectable

    Aminolysis Reaction of Glycerol Carbonate in Organic and Hydroorganic Medium

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    Aminolysis reaction of glycerol carbonate with primary amine in organic and hydroorganic media leads to the formation of two hydroxyurethane isomers and a partial decomposition of glycerol carbonate into glycerol. Aminolysis with a secondary amine promotes the condensation reaction and limits the formation of glycerol. The ratio of α versus β was determined by zgig 13C NMR. This technique permits computing the yield of α and β products in the medium. The quantity of glycerol was determined by GC analysis. The ratio of the isomers and the amount of glycerol depend on the amine and the solvent. Kinetic investigations reveal that, in hydroorganic medium, the more the alkyl chain of the amine increased, the less glycerol was formed. On the contrary, in organic medium, the alkyl chain of the amine does not play a major role in the formation of glycerol

    Overturning established chemoselectivities : selective reduction of arenes over malonates and cyanoacetates by photoactivated organic electron donors

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    The prevalence of metal-based reducing reagents, including metals, metal complexes, and metal salts, has produced an empirical order of reactivity that governs our approach to chemical synthesis. However, this reactivity may be influenced by stabilization of transition states, intermediates, and products through substrate-metal bonding. This article reports that in the absence of such stabilizing interactions, established chemoselectivities can be overthrown. Thus, photoactivation of the recently developed neutral organic superelectron donor 5 selectively reduces alkyl-substituted benzene rings in the presence of activated esters and nitriles, in direct contrast to metal-based reductions, opening a new perspective on reactivity. The altered outcomes arising from the organic electron donors are attributed to selective interactions between the neutral organic donors and the arene rings of the substrates

    The neuroscience of vision-based grasping: a functional review for computational modeling and bio-inspired robotics

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    The topic of vision-based grasping is being widely studied using various techniques and with different goals in humans and in other primates. The fundamental related findings are reviewed in this paper, with the aim of providing researchers from different fields, including intelligent robotics and neural computation, a comprehensive but accessible view on the subject. A detailed description of the principal sensorimotor processes and the brain areas involved in them is provided following a functional perspective, in order to make this survey especially useful for computational modeling and bio-inspired robotic application

    Identification of neural networks that contribute to motion sickness through principal components analysis of fos labeling induced by galvanic vestibular stimulation

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    Motion sickness is a complex condition that includes both overt signs (e.g., vomiting) and more covert symptoms (e.g., anxiety and foreboding). The neural pathways that mediate these signs and symptoms are yet to identified. This study mapped the distribution of c-fos protein (Fos)-like immunoreactivity elicited during a galvanic vestibular stimulation paradigm that is known to induce motion sickness in felines. A principal components analysis was used to identify networks of neurons activated during this stimulus paradigm from functional correlations between Fos labeling in different nuclei. This analysis identified five principal components (neural networks) that accounted for greater than 95% of the variance in Fos labeling. Two of the components were correlated with the severity of motion sickness symptoms, and likely participated in generating the overt signs of the condition. One of these networks included neurons in locus coeruleus, medial, inferior and lateral vestibular nuclei, lateral nucleus tractus solitarius, medial parabrachial nucleus and periaqueductal gray. The second included neurons in the superior vestibular nucleus, precerebellar nuclei, periaqueductal gray, and parabrachial nuclei, with weaker associations of raphe nuclei. Three additional components (networks) were also identified that were not correlated with the severity of motion sickness symptoms. These networks likely mediated the covert aspects of motion sickness, such as affective components. The identification of five statistically independent component networks associated with the development of motion sickness provides an opportunity to consider, in network activation dimensions, the complex progression of signs and symptoms that are precipitated in provocative environments. Similar methodology can be used to parse the neural networks that mediate other complex responses to environmental stimuli. © 2014 Balaban et al

    A Mouse Model of Timothy Syndrome: a Complex Autistic Disorder Resulting from a Point Mutation in Cav1.2

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    Timothy Syndrome (TS) arises from a point mutation in the human voltage-gated L-type Ca2+ channel (Cav1.2). TS is associated with cardiac arrhythmias and sudden cardiac death, as well as congenital heart disease, impaired cognitive function, and autism spectrum disorders. TS results from a de novo gain-of-function mutation which affects the voltage dependent component of Cav1.2 inactivation. We created a knock-in TS mouse. No homozygous TS mice survived, but heterozygous TS2-NEO mice (with the mutation and the neocassette in situ) had a normal outward appearance and survived to reproductive age. Previously, we have demonstrated that these mice exhibit the triad of Autistic traits. In this paper we document other aspects of these mice including Cav1.2 isoform expression levels, normal physical strength, brain anatomy and a marked propensity towards self-injurious scratching. Gross brain anatomy was not markedly different in TS2-NEO mice compared to control littermates, and no missing structures were noted. The lack of obvious changes in brain structure is consistent with theTS2-NEO mice may provide a significant tool in understanding the role of calcium channel inactivation in both cardiac function and brain development

    The transcription factor Nfix is essential for normal brain development

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    Background: The Nuclear Factor I (NFI) multi-gene family encodes site-specific transcription factors essential for the development of a number of organ systems. We showed previously that Nfia-deficient mice exhibit agenesis of the corpus callosum and other forebrain defects; Nfib-deficient mice have defects in lung maturation and show callosal agenesis and forebrain defects resembling those seen in Nfia-deficient animals, while Nficdeficient mice have defects in tooth root formation. Recently the Nfix gene has been disrupted and these studies indicated that there were largely uncharacterized defects in brain and skeletal development in Nfix-deficient mice. Results: Here we show that disruption of Nfix by Cre-recombinase mediated excision of the 2nd exon results in defects in brain development that differ from those seen in Nfia and Nfib KO mice. In particular, complete callosal agenesis is not seen in Nfix-/- mice but rather there appears to be an overabundance of aberrant Pax6- and doublecortin-positive cells in the lateral ventricles of Nfix-/- mice, increased brain weight, expansion of the cingulate cortex and entire brain along the dorsal ventral axis, and aberrant formation of the hippocampus. On standard lab chow Nfix-/- animals show a decreased growth rate from ~P8 to P14, lose weight from ~P14 to P22 and die at ~P22. If their food is supplemented with a soft dough chow from P10, Nfix-/- animals show a lag in weight gain from P8 to P20 but then increase their growth rate. A fraction of the animals survive to adulthood and are fertile. The weight loss correlates with delayed eye and ear canal opening and suggests a delay in the development of several epithelial structures in Nfix-/- animals. Conclusion: These data show that Nfix is essential for normal brain development and may be required for neural stem cell homeostasis. The delays seen in eye and ear opening and the brain morphology defects appear independent of the nutritional deprivation, as rescue of perinatal lethality with soft dough does not eliminate these defects
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