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Sample records for brain evolution implications

  1. Energetic and nutritional constraints on infant brain development: implications for brain expansion during human evolution.

    Science.gov (United States)

    Cunnane, Stephen C; Crawford, Michael A

    2014-12-01

    The human brain confronts two major challenges during its development: (i) meeting a very high energy requirement, and (ii) reliably accessing an adequate dietary source of specific brain selective nutrients needed for its structure and function. Implicitly, these energetic and nutritional constraints to normal brain development today would also have been constraints on human brain evolution. The energetic constraint was solved in large measure by the evolution in hominins of a unique and significant layer of body fat on the fetus starting during the third trimester of gestation. By providing fatty acids for ketone production that are needed as brain fuel, this fat layer supports the brain's high energy needs well into childhood. This fat layer also contains an important reserve of the brain selective omega-3 fatty acid, docosahexaenoic acid (DHA), not available in other primates. Foremost amongst the brain selective minerals are iodine and iron, with zinc, copper and selenium also being important. A shore-based diet, i.e., fish, molluscs, crustaceans, frogs, bird's eggs and aquatic plants, provides the richest known dietary sources of brain selective nutrients. Regular access to these foods by the early hominin lineage that evolved into humans would therefore have helped free the nutritional constraint on primate brain development and function. Inadequate dietary supply of brain selective nutrients still has a deleterious impact on human brain development on a global scale today, demonstrating the brain's ongoing vulnerability. The core of the shore-based paradigm of human brain evolution proposes that sustained access by certain groups of early Homo to freshwater and marine food resources would have helped surmount both the nutritional as well as the energetic constraints on mammalian brain development.

  2. Scaling of brain metabolism with a fixed energy budget per neuron: implications for neuronal activity, plasticity and evolution.

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    Herculano-Houzel, Suzana

    2011-03-01

    It is usually considered that larger brains have larger neurons, which consume more energy individually, and are therefore accompanied by a larger number of glial cells per neuron. These notions, however, have never been tested. Based on glucose and oxygen metabolic rates in awake animals and their recently determined numbers of neurons, here I show that, contrary to the expected, the estimated glucose use per neuron is remarkably constant, varying only by 40% across the six species of rodents and primates (including humans). The estimated average glucose use per neuron does not correlate with neuronal density in any structure. This suggests that the energy budget of the whole brain per neuron is fixed across species and brain sizes, such that total glucose use by the brain as a whole, by the cerebral cortex and also by the cerebellum alone are linear functions of the number of neurons in the structures across the species (although the average glucose consumption per neuron is at least 10× higher in the cerebral cortex than in the cerebellum). These results indicate that the apparently remarkable use in humans of 20% of the whole body energy budget by a brain that represents only 2% of body mass is explained simply by its large number of neurons. Because synaptic activity is considered the major determinant of metabolic cost, a conserved energy budget per neuron has several profound implications for synaptic homeostasis and the regulation of firing rates, synaptic plasticity, brain imaging, pathologies, and for brain scaling in evolution.

  3. DUF1220-domain copy number implicated in human brain-size pathology and evolution.

    Science.gov (United States)

    Dumas, Laura J; O'Bleness, Majesta S; Davis, Jonathan M; Dickens, C Michael; Anderson, Nathan; Keeney, J G; Jackson, Jay; Sikela, Megan; Raznahan, Armin; Giedd, Jay; Rapoport, Judith; Nagamani, Sandesh S C; Erez, Ayelet; Brunetti-Pierri, Nicola; Sugalski, Rachel; Lupski, James R; Fingerlin, Tasha; Cheung, Sau Wai; Sikela, James M

    2012-09-07

    DUF1220 domains show the largest human-lineage-specific increase in copy number of any protein-coding region in the human genome and map primarily to 1q21, where deletions and reciprocal duplications have been associated with microcephaly and macrocephaly, respectively. Given these findings and the high correlation between DUF1220 copy number and brain size across primate lineages (R(2) = 0.98; p = 1.8 × 10(-6)), DUF1220 sequences represent plausible candidates for underlying 1q21-associated brain-size pathologies. To investigate this possibility, we used specialized bioinformatics tools developed for scoring highly duplicated DUF1220 sequences to implement targeted 1q21 array comparative genomic hybridization on individuals (n = 42) with 1q21-associated microcephaly and macrocephaly. We show that of all the 1q21 genes examined (n = 53), DUF1220 copy number shows the strongest association with brain size among individuals with 1q21-associated microcephaly, particularly with respect to the three evolutionarily conserved DUF1220 clades CON1(p = 0.0079), CON2 (p = 0.0134), and CON3 (p = 0.0116). Interestingly, all 1q21 DUF1220-encoding genes belonging to the NBPF family show significant correlations with frontal-occipital-circumference Z scores in the deletion group. In a similar survey of a nondisease population, we show that DUF1220 copy number exhibits the strongest correlation with brain gray-matter volume (CON1, p = 0.0246; and CON2, p = 0.0334). Notably, only DUF1220 sequences are consistently significant in both disease and nondisease populations. Taken together, these data strongly implicate the loss of DUF1220 copy number in the etiology of 1q21-associated microcephaly and support the view that DUF1220 domains function as general effectors of evolutionary, pathological, and normal variation in brain size.

  4. Localization of cerebellin-2 in late embryonic chicken brain: implications for a role in synapse formation and for brain evolution.

    Science.gov (United States)

    Reiner, Anton; Yang, Mao; Cagle, Michael C; Honig, Marcia G

    2011-08-01

    Cerebellin-1 (Cbln1), the most studied member of the cerebellin family of secreted proteins, is necessary for the formation and maintenance of parallel fiber-Purkinje cell synapses. However, the roles of the other Cblns have received little attention. We previously identified the chicken homolog of Cbln2 and examined its expression in dorsal root ganglia and spinal cord (Yang et al. [2010] J Comp Neurol 518:2818-2840). Interestingly, Cbln2 is expressed by mechanoreceptive and proprioceptive neurons and in regions of the spinal cord where those afferents terminate, as well as by preganglionic sympathetic neurons and their sympathetic ganglia targets. These findings suggest that Cbln2 may demonstrate a tendency to be expressed by synaptically connected neuronal populations. To further assess this possibility, we examined Cbln2 expression in chick brain. We indeed found that Cbln2 is frequently expressed by synaptically connected neurons, although there are exceptions, and we discuss the implications of these findings for Cbln2 function. Cbln2 expression tends to be more common in primary sensory neurons and in second-order sensory regions than it is in motor areas of the brain. Moreover, we found that the level of Cbln2 expression for many regions of the chicken brain is very similar to that of the mammalian homologs, consistent with the view that the expression patterns of molecules playing fundamental roles in processes such as neuronal communication are evolutionarily conserved. There are, however, large differences in the pattern of Cbln2 expression in avian as compared to mammalian telencephalon and in other regions that show the most divergence between the two lineages.

  5. Comparative expression analysis of the phosphocreatine circuit in extant primates: Implications for human brain evolution.

    Science.gov (United States)

    Pfefferle, Adam D; Warner, Lisa R; Wang, Catrina W; Nielsen, William J; Babbitt, Courtney C; Fedrigo, Olivier; Wray, Gregory A

    2011-02-01

    While the hominid fossil record clearly shows that brain size has rapidly expanded over the last ~2.5 M.yr. the forces driving this change remain unclear. One popular hypothesis proposes that metabolic adaptations in response to dietary shifts supported greater encephalization in humans. An increase in meat consumption distinguishes the human diet from that of other great apes. Creatine, an essential metabolite for energy homeostasis in muscle and brain tissue, is abundant in meat and was likely ingested in higher quantities during human origins. Five phosphocreatine circuit proteins help regulate creatine utilization within energy demanding cells. We compared the expression of all five phosphocreatine circuit genes in cerebral cortex, cerebellum, and skeletal muscle tissue for humans, chimpanzees, and rhesus macaques. Strikingly, SLC6A8 and CKB transcript levels are higher in the human brain, which should increase energy availability and turnover compared to non-human primates. Combined with other well-documented differences between humans and non-human primates, this allocation of energy to the cerebral cortex and cerebellum may be important in supporting the increased metabolic demands of the human brain.

  6. Neocortical neuron types in Xenarthra and Afrotheria: implications for brain evolution in mammals.

    Science.gov (United States)

    Sherwood, Chet C; Stimpson, Cheryl D; Butti, Camilla; Bonar, Christopher J; Newton, Alisa L; Allman, John M; Hof, Patrick R

    2009-02-01

    Interpreting the evolution of neuronal types in the cerebral cortex of mammals requires information from a diversity of species. However, there is currently a paucity of data from the Xenarthra and Afrotheria, two major phylogenetic groups that diverged close to the base of the eutherian mammal adaptive radiation. In this study, we used immunohistochemistry to examine the distribution and morphology of neocortical neurons stained for nonphosphorylated neurofilament protein, calbindin, calretinin, parvalbumin, and neuropeptide Y in three xenarthran species-the giant anteater (Myrmecophaga tridactyla), the lesser anteater (Tamandua tetradactyla), and the two-toed sloth (Choloepus didactylus)-and two afrotherian species-the rock hyrax (Procavia capensis) and the black and rufous giant elephant shrew (Rhynchocyon petersi). We also studied the distribution and morphology of astrocytes using glial fibrillary acidic protein as a marker. In all of these species, nonphosphorylated neurofilament protein-immunoreactive neurons predominated in layer V. These neurons exhibited diverse morphologies with regional variation. Specifically, high proportions of atypical neurofilament-enriched neuron classes were observed, including extraverted neurons, inverted pyramidal neurons, fusiform neurons, and other multipolar types. In addition, many projection neurons in layers II-III were found to contain calbindin. Among interneurons, parvalbumin- and calbindin-expressing cells were generally denser compared to calretinin-immunoreactive cells. We traced the evolution of certain cortical architectural traits using phylogenetic analysis. Based on our reconstruction of character evolution, we found that the living xenarthrans and afrotherians show many similarities to the stem eutherian mammal, whereas other eutherian lineages display a greater number of derived traits.

  7. Evolution of Brain and Language

    Science.gov (United States)

    Schoenemann, P. Thomas

    2009-01-01

    The evolution of language and the evolution of the brain are tightly interlinked. Language evolution represents a special kind of adaptation, in part because language is a complex behavior (as opposed to a physical feature) but also because changes are adaptive only to the extent that they increase either one's understanding of others, or one's…

  8. On the relationships of postcanine tooth size with dietary quality and brain volume in primates: implications for hominin evolution.

    Science.gov (United States)

    Jiménez-Arenas, Juan Manuel; Pérez-Claros, Juan Antonio; Aledo, Juan Carlos; Palmqvist, Paul

    2014-01-01

    Brain volume and cheek-tooth size have traditionally been considered as two traits that show opposite evolutionary trends during the evolution of Homo. As a result, differences in encephalization and molarization among hominins tend to be interpreted in paleobiological grounds, because both traits were presumably linked to the dietary quality of extinct species. Here we show that there is an essential difference between the genus Homo and the living primate species, because postcanine tooth size and brain volume are related to negative allometry in primates and show an inverse relationship in Homo. However, when size effects are removed, the negative relationship between encephalization and molarization holds only for platyrrhines and the genus Homo. In addition, there is no general trend for the relationship between postcanine tooth size and dietary quality among the living primates. If size and phylogeny effects are both removed, this relationship vanishes in many taxonomic groups. As a result, the suggestion that the presence of well-developed postcanine teeth in extinct hominins should be indicative of a poor-quality diet cannot be generalized to all extant and extinct primates.

  9. On the Relationships of Postcanine Tooth Size with Dietary Quality and Brain Volume in Primates: Implications for Hominin Evolution

    Directory of Open Access Journals (Sweden)

    Juan Manuel Jiménez-Arenas

    2014-01-01

    Full Text Available Brain volume and cheek-tooth size have traditionally been considered as two traits that show opposite evolutionary trends during the evolution of Homo. As a result, differences in encephalization and molarization among hominins tend to be interpreted in paleobiological grounds, because both traits were presumably linked to the dietary quality of extinct species. Here we show that there is an essential difference between the genus Homo and the living primate species, because postcanine tooth size and brain volume are related to negative allometry in primates and show an inverse relationship in Homo. However, when size effects are removed, the negative relationship between encephalization and molarization holds only for platyrrhines and the genus Homo. In addition, there is no general trend for the relationship between postcanine tooth size and dietary quality among the living primates. If size and phylogeny effects are both removed, this relationship vanishes in many taxonomic groups. As a result, the suggestion that the presence of well-developed postcanine teeth in extinct hominins should be indicative of a poor-quality diet cannot be generalized to all extant and extinct primates.

  10. On the Relationships of Postcanine Tooth Size with Dietary Quality and Brain Volume in Primates: Implications for Hominin Evolution

    Science.gov (United States)

    Jiménez-Arenas, Juan Manuel; Pérez-Claros, Juan Antonio; Aledo, Juan Carlos; Palmqvist, Paul

    2014-01-01

    Brain volume and cheek-tooth size have traditionally been considered as two traits that show opposite evolutionary trends during the evolution of Homo. As a result, differences in encephalization and molarization among hominins tend to be interpreted in paleobiological grounds, because both traits were presumably linked to the dietary quality of extinct species. Here we show that there is an essential difference between the genus Homo and the living primate species, because postcanine tooth size and brain volume are related to negative allometry in primates and show an inverse relationship in Homo. However, when size effects are removed, the negative relationship between encephalization and molarization holds only for platyrrhines and the genus Homo. In addition, there is no general trend for the relationship between postcanine tooth size and dietary quality among the living primates. If size and phylogeny effects are both removed, this relationship vanishes in many taxonomic groups. As a result, the suggestion that the presence of well-developed postcanine teeth in extinct hominins should be indicative of a poor-quality diet cannot be generalized to all extant and extinct primates. PMID:24592388

  11. Comparative genomics of brain size evolution

    OpenAIRE

    2014-01-01

    Which genetic changes took place during mammalian, primate and human evolution to build a larger brain? To answer this question, one has to correlate genetic changes with brain size changes across a phylogeny. Such a comparative genomics approach provides unique information to better understand brain evolution and brain development. However, its statistical power is limited for example due to the limited number of species, the presumably complex genetics of brain size evolution and the large ...

  12. Human brain evolution: insights from microarrays.

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    Preuss, Todd M; Cáceres, Mario; Oldham, Michael C; Geschwind, Daniel H

    2004-11-01

    Several recent microarray studies have compared gene-expression patterns n humans, chimpanzees and other non-human primates to identify evolutionary changes that contribute to the distinctive cognitive and behavioural characteristics of humans. These studies support the surprising conclusion that the evolution of the human brain involved an upregulation of gene expression relative to non-human primates, a finding that could be relevant to understanding human cerebral physiology and function. These results show how genetic and genomic methods can shed light on the basis of human neural and cognitive specializations, and have important implications for neuroscience, anthropology and medicine.

  13. Effects of brain evolution on human nutrition and metabolism.

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    Leonard, William R; Snodgrass, J Josh; Robertson, Marcia L

    2007-01-01

    The evolution of large human brain size has had important implications for the nutritional biology of our species. Large brains are energetically expensive, and humans expend a larger proportion of their energy budget on brain metabolism than other primates. The high costs of large human brains are supported, in part, by our energy- and nutrient-rich diets. Among primates, relative brain size is positively correlated with dietary quality, and humans fall at the positive end of this relationship. Consistent with an adaptation to a high-quality diet, humans have relatively small gastrointestinal tracts. In addition, humans are relatively "undermuscled" and "over fat" compared with other primates, features that help to offset the high energy demands of our brains. Paleontological evidence indicates that rapid brain evolution occurred with the emergence of Homo erectus 1.8 million years ago and was associated with important changes in diet, body size, and foraging behavior.

  14. Genetic basis of human brain evolution.

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    Vallender, Eric J; Mekel-Bobrov, Nitzan; Lahn, Bruce T

    2008-12-01

    Human evolution is characterized by a rapid increase in brain size and complexity. Decades of research have made important strides in identifying anatomical and physiological substrates underlying the unique features of the human brain. By contrast, it has become possible only very recently to examine the genetic basis of human brain evolution. Through comparative genomics, tantalizing insights regarding human brain evolution have emerged. The genetic changes that potentially underlie human brain evolution span a wide range from single-nucleotide substitutions to large-scale structural alterations of the genome. Similarly, the functional consequences of these genetic changes vary greatly, including protein-sequence alterations, cis-regulatory changes and even the emergence of new genes and the extinction of existing ones. Here, we provide a general review of recent findings into the genetic basis of human brain evolution, highlight the most notable trends that have emerged and caution against over-interpretation of current data.

  15. Brain evolution and human neuropsychology: the inferential brain hypothesis.

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    Koscik, Timothy R; Tranel, Daniel

    2012-05-01

    Collaboration between human neuropsychology and comparative neuroscience has generated invaluable contributions to our understanding of human brain evolution and function. Further cross-talk between these disciplines has the potential to continue to revolutionize these fields. Modern neuroimaging methods could be applied in a comparative context, yielding exciting new data with the potential of providing insight into brain evolution. Conversely, incorporating an evolutionary base into the theoretical perspectives from which we approach human neuropsychology could lead to novel hypotheses and testable predictions. In the spirit of these objectives, we present here a new theoretical proposal, the Inferential Brain Hypothesis, whereby the human brain is thought to be characterized by a shift from perceptual processing to inferential computation, particularly within the social realm. This shift is believed to be a driving force for the evolution of the large human cortex. (JINS, 2012, 18, 394-401).

  16. Reconstructing cetacean brain evolution using computed tomography.

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    Marino, Lori; Uhen, Mark D; Pyenson, Nicholas D; Frohlich, Bruno

    2003-05-01

    Until recently, there have been relatively few studies of brain mass and morphology in fossil cetaceans (dolphins, whales, and porpoises) because of difficulty accessing the matrix that fills the endocranial cavity of fossil cetacean skulls. As a result, our knowledge about cetacean brain evolution has been quite limited. By applying the noninvasive technique of computed tomography (CT) to visualize, measure, and reconstruct the endocranial morphology of fossil cetacean skulls, we can gain vastly more information at an unprecedented rate about cetacean brain evolution. Here, we discuss our method and demonstrate it with several examples from our fossil cetacean database. This approach will provide new insights into the little-known evolutionary history of cetacean brain evolution.

  17. We Recognize Ourselves as Being Similar to Others: Implications of the “Social Brain Hypothesis” for the Biological Evolution of the Intuition of Freedom

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    Eckart Voland

    2007-07-01

    Full Text Available Consistent with and in extension of the “social brain hypothesis,” I discuss the idea that the intuition of free will emerged during the course of primate social evolution. If, as the “social brain hypothesis” alleges, the main selective pressure among primates is on generating social knowledge about one's cooperators and competitors, then it is the knowledge about others and not the knowledge about oneself that is the scarce cognitive resource. It is beneficial to make the others predictable and to form hypotheses about their probable behavioral tendencies. This is done by behavior reading and mind reading and by classifying the recurring stochastic patterns in everyday language as the “will.” Thus, the idea of free will emerged first as a social attribution and not as an introspectively gained insight. The fact that ego applies the idea of freedom also to itself and considers itself to be as free as it considers the social partners to be free, i.e. unpredictable, is in this view a non-selected by-product of social intelligence.

  18. Brain Research: Implications for Learning.

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    Soares, Louise M.; Soares, Anthony T.

    Brain research has illuminated several areas of the learning process: (1) learning as association; (2) learning as reinforcement; (3) learning as perception; (4) learning as imitation; (5) learning as organization; (6) learning as individual style; and (7) learning as brain activity. The classic conditioning model developed by Pavlov advanced…

  19. Evolution of the base of the brain in highly encephalized human species.

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    Bastir, Markus; Rosas, Antonio; Gunz, Philipp; Peña-Melian, Angel; Manzi, Giorgio; Harvati, Katerina; Kruszynski, Robert; Stringer, Chris; Hublin, Jean-Jacques

    2011-12-13

    The increase of brain size relative to body size-encephalization-is intimately linked with human evolution. However, two genetically different evolutionary lineages, Neanderthals and modern humans, have produced similarly large-brained human species. Thus, understanding human brain evolution should include research into specific cerebral reorganization, possibly reflected by brain shape changes. Here we exploit developmental integration between the brain and its underlying skeletal base to test hypotheses about brain evolution in Homo. Three-dimensional geometric morphometric analyses of endobasicranial shape reveal previously undocumented details of evolutionary changes in Homo sapiens. Larger olfactory bulbs, relatively wider orbitofrontal cortex, relatively increased and forward projecting temporal lobe poles appear unique to modern humans. Such brain reorganization, beside physical consequences for overall skull shape, might have contributed to the evolution of H. sapiens' learning and social capacities, in which higher olfactory functions and its cognitive, neurological behavioral implications could have been hitherto underestimated factors.

  20. Darwin's evolution theory, brain oscillations, and complex brain function in a new "Cartesian view".

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    Başar, Erol; Güntekin, Bahar

    2009-01-01

    Comparatively analyses of electrophysiological correlates across species during evolution, alpha activity during brain maturation, and alpha activity in complex cognitive processes are presented to illustrate a new multidimensional "Cartesian System" brain function. The main features are: (1) The growth of the alpha activity during evolution, increase of alpha during cognitive processes, and decrease of the alpha entropy during evolution provide an indicator for evolution of brain cognitive performance. (2) Human children younger than 3 years are unable to produce higher cognitive processes and do not show alpha activity till the age of 3 years. The mature brain can perform higher cognitive processes and demonstrates regular alpha activity. (3) Alpha activity also is significantly associated with highly complex cognitive processes, such as the recognition of facial expressions. The neural activity reflected by these brain oscillations can be considered as constituent "building blocks" for a great number of functions. An overarching statement on the alpha function is presented by extended analyzes with multiple dimensions that constitute a "Cartesian Hyperspace" as the basis for oscillatory function. Theoretical implications are considered.

  1. The Molecular Basis of Human Brain Evolution.

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    Enard, Wolfgang

    2016-10-24

    Humans are a remarkable species, especially because of the remarkable properties of their brain. Since the split from the chimpanzee lineage, the human brain has increased three-fold in size and has acquired abilities for vocal learning, language and intense cooperation. To better understand the molecular basis of these changes is of great biological and biomedical interest. However, all the about 16 million fixed genetic changes that occurred during human evolution are fully correlated with all molecular, cellular, anatomical and behavioral changes that occurred during this time. Hence, as humans and chimpanzees cannot be crossed or genetically manipulated, no direct evidence for linking particular genetic and molecular changes to human brain evolution can be obtained. Here, I sketch a framework how indirect evidence can be obtained and review findings related to the molecular basis of human cognition, vocal learning and brain size. In particular, I discuss how a comprehensive comparative approach, leveraging cellular systems and genomic technologies, could inform the evolution of our brain in the future.

  2. Schizophrenia, abnormal connection, and brain evolution.

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    Randall, P L

    1983-03-01

    Abnormalities of functional connection between specialized areas in the human brain may underlie the symptoms which constitute the schizophrenia syndrome. Callosal and intrahemispheric fibres may be equally involved. The clinical emergence of symptoms in the later stages of brain maturation may be dependent on myelination of these fibre groups, both of which have extended myelination cycles. Ontogenetically earlier variants of the same mechanism could theoretically result in dyslexia and the syndromes of Kanner and Gilles de la Tourette. As new and unique extensions of specialized function emerge within the evolving brain, biological trial and error of connection both within and between them may produce individuals possessing phylogenetically advanced abilities, or equally, others possessing a wide range of abnormalities including those which comprise the schizophrenia syndrome. A dormant phenotypic potential for schizophrenia may exist in individuals who never develop symptoms during the course of a lifetime though some of these may become clinically apparent under the influence of various precipitating factors. It is concluded that abnormal functional connection and its normal and "supernormal" counterparts may be natural, essential, and inevitable consequences of brain evolution, and that this may have been so throughout the history of vertebrate brain evolution.

  3. Molecular insights into human brain evolution.

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    Hill, Robert Sean; Walsh, Christopher A

    2005-09-01

    Rapidly advancing knowledge of genome structure and sequence enables new means for the analysis of specific DNA changes associated with the differences between the human brain and that of other mammals. Recent studies implicate evolutionary changes in messenger RNA and protein expression levels, as well as DNA changes that alter amino acid sequences. We can anticipate having a systematic catalogue of DNA changes in the lineage leading to humans, but an ongoing challenge will be relating these changes to the anatomical and functional differences between our brain and that of our ancient and more recent ancestors.

  4. Human brain evolution writ large and small.

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    Sherwood, Chet C; Bauernfeind, Amy L; Bianchi, Serena; Raghanti, Mary Ann; Hof, Patrick R

    2012-01-01

    Human evolution was marked by an extraordinary increase in total brain size relative to body size. While it is certain that increased encephalization is an important factor contributing to the origin of our species-specific cognitive abilities, it is difficult to disentangle which aspects of human neural structure and function are correlated by-products of brain size expansion from those that are specifically related to particular psychological specializations, such as language and enhanced "mentalizing" abilities. In this chapter, we review evidence from allometric scaling studies demonstrating that much of human neocortical organization can be understood as a product of brain enlargement. Defining extra-allometric specializations in humans is often hampered by a severe lack of comparative data from the same neuroanatomical variables across a broad range of primates. When possible, we highlight evidence for features of human neocortical architecture and function that cannot be easily explained as correlates of brain size and, hence, might be more directly associated with the evolution of uniquely human cognitive capacities.

  5. [Evolution of human brain and intelligence].

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    Lakatos, László; Janka, Zoltán

    2008-07-30

    The biological evolution, including human evolution is mainly driven by environmental changes. Accidental genetic modifications and their innovative results make the successful adaptation possible. As we know the human evolution started 7-8 million years ago in the African savannah, where upright position and bipedalism were significantly advantageous. The main drive of improving manual actions and tool making could be to obtain more food. Our ancestor got more meat due to more successful hunting, resulting in more caloric intake, more protein and essential fatty acid in the meal. The nervous system uses disproportionally high level of energy, so better quality of food was a basic condition for the evolution of huge human brain. The size of human brain was tripled during 3.5 million years, it increased from the average of 450 cm3 of Australopithecinae to the average of 1350 cm3 of Homo sapiens. A genetic change in the system controlling gene expression could happen about 200 000 years ago, which influenced the development of nervous system, the sensorimotor function and learning ability for motor processes. The appearance and stabilisation of FOXP2 gene structure as feature of modern man coincided with the first presence and quick spread of Homo sapiens on the whole Earth. This genetic modification made opportunity for human language, as the basis of abrupt evolution of human intelligence. The brain region being responsible for human language is the left planum temporale, which is much larger in left hemisphere. This shows the most typical human brain asymmetry. In this case the anatomical asymmetry means a clearly defined functional asymmetry as well, where the brain hemispheres act differently. The preference in using hands, the lateralised using of tools resulted in the brain asymmetry, which is the precondition of human language and intelligence. However, it cannot be held anymore, that only humans make tools, because our closest relatives, the chimpanzees are

  6. Evolution, brain, and the nature of language.

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    Berwick, Robert C; Friederici, Angela D; Chomsky, Noam; Bolhuis, Johan J

    2013-02-01

    Language serves as a cornerstone for human cognition, yet much about its evolution remains puzzling. Recent research on this question parallels Darwin's attempt to explain both the unity of all species and their diversity. What has emerged from this research is that the unified nature of human language arises from a shared, species-specific computational ability. This ability has identifiable correlates in the brain and has remained fixed since the origin of language approximately 100 thousand years ago. Although songbirds share with humans a vocal imitation learning ability, with a similar underlying neural organization, language is uniquely human.

  7. Phylogeny and adaptive evolution of the brain-development gene microcephalin (MCPH1 in cetaceans

    Directory of Open Access Journals (Sweden)

    Montgomery Stephen H

    2011-04-01

    Full Text Available Abstract Background Representatives of Cetacea have the greatest absolute brain size among animals, and the largest relative brain size aside from humans. Despite this, genes implicated in the evolution of large brain size in primates have yet to be surveyed in cetaceans. Results We sequenced ~1240 basepairs of the brain development gene microcephalin (MCPH1 in 38 cetacean species. Alignments of these data and a published complete sequence from Tursiops truncatus with primate MCPH1 were utilized in phylogenetic analyses and to estimate ω (rate of nonsynonymous substitution/rate of synonymous substitution using site and branch models of molecular evolution. We also tested the hypothesis that selection on MCPH1 was correlated with brain size in cetaceans using a continuous regression analysis that accounted for phylogenetic history. Our analyses revealed widespread signals of adaptive evolution in the MCPH1 of Cetacea and in other subclades of Mammalia, however, there was not a significant positive association between ω and brain size within Cetacea. Conclusion In conjunction with a recent study of Primates, we find no evidence to support an association between MCPH1 evolution and the evolution of brain size in highly encephalized mammalian species. Our finding of significant positive selection in MCPH1 may be linked to other functions of the gene.

  8. Thinking in water : Brain size evolution in Cichlidae and Syngnathidae

    OpenAIRE

    2015-01-01

    Brain size varies greatly among vertebrates. It has been proposed that the diversity of brain size is produced and maintained through a balance of adaptations to different types and levels of cognitive ability and constraints for adaptive evolution. Phylogenetic comparative studies have made major contributions to our understanding of brain size evolution. However, previous studies have nearly exclusively focused on mammalian and avian taxa and almost no attempts have been made to investigate...

  9. Sexual Selection and the Evolution of Brain Size in Primates

    OpenAIRE

    2006-01-01

    Reproductive competition among males has long been considered a powerful force in the evolution of primates. The evolution of brain size and complexity in the Order Primates has been widely regarded as the hallmark of primate evolutionary history. Despite their importance to our understanding of primate evolution, the relationship between sexual selection and the evolutionary development of brain size is not well studied. The present research examines the evolutionary relationship between bra...

  10. Microglia priming in the aging brain : Implications for neurodegeneration

    NARCIS (Netherlands)

    Darwin Arulseeli, Divya; Biber, Knut

    2016-01-01

    The primary aim of the thesis “Microglia priming in the aging brain: Implications for neurodegeneration” was to understand microglia phenotypes associated with brain aging and the potential mechanisms for this age-associated change. Microglia in the aging brain assume a hypersensitive proinflammator

  11. Temporal and spatial evolution of brain network topology during the first two years of life.

    Directory of Open Access Journals (Sweden)

    Wei Gao

    Full Text Available The mature brain features high wiring efficiency for information transfer. However, the emerging process of such an efficient topology remains elusive. With resting state functional MRI and a large cohort of normal pediatric subjects (n = 147 imaged during a critical time period of brain development, 3 wk- to 2 yr-old, the temporal and spatial evolution of brain network topology is revealed. The brain possesses the small world topology immediately after birth, followed by a remarkable improvement in whole brain wiring efficiency in 1 yr olds and becomes more stable in 2 yr olds. Regional developments of brain wiring efficiency and the evolution of functional hubs suggest differential development trend for primary and higher order cognitive functions during the first two years of life. Simulations of random errors and targeted attacks reveal an age-dependent improvement of resilience. The lower resilience to targeted attack observed in 3 wk old group is likely due to the fact that there are fewer well-established long-distance functional connections at this age whose elimination might have more profound implications in the overall efficiency of information transfer. Overall, our results offer new insights into the temporal and spatial evolution of brain topology during early brain development.

  12. Temporal and spatial evolution of brain network topology during the first two years of life.

    Science.gov (United States)

    Gao, Wei; Gilmore, John H; Giovanello, Kelly S; Smith, Jeffery Keith; Shen, Dinggang; Zhu, Hongtu; Lin, Weili

    2011-01-01

    The mature brain features high wiring efficiency for information transfer. However, the emerging process of such an efficient topology remains elusive. With resting state functional MRI and a large cohort of normal pediatric subjects (n = 147) imaged during a critical time period of brain development, 3 wk- to 2 yr-old, the temporal and spatial evolution of brain network topology is revealed. The brain possesses the small world topology immediately after birth, followed by a remarkable improvement in whole brain wiring efficiency in 1 yr olds and becomes more stable in 2 yr olds. Regional developments of brain wiring efficiency and the evolution of functional hubs suggest differential development trend for primary and higher order cognitive functions during the first two years of life. Simulations of random errors and targeted attacks reveal an age-dependent improvement of resilience. The lower resilience to targeted attack observed in 3 wk old group is likely due to the fact that there are fewer well-established long-distance functional connections at this age whose elimination might have more profound implications in the overall efficiency of information transfer. Overall, our results offer new insights into the temporal and spatial evolution of brain topology during early brain development.

  13. Evolution, development, and plasticity of the human brain: from molecules to bones.

    Science.gov (United States)

    Hrvoj-Mihic, Branka; Bienvenu, Thibault; Stefanacci, Lisa; Muotri, Alysson R; Semendeferi, Katerina

    2013-10-30

    Neuroanatomical, molecular, and paleontological evidence is examined in light of human brain evolution. The brain of extant humans differs from the brains of other primates in its overall size and organization, and differences in size and organization of specific cortical areas and subcortical structures implicated into complex cognition and social and emotional processing. The human brain is also characterized by functional lateralizations, reflecting specializations of the cerebral hemispheres in humans for different types of processing, facilitating fast and reliable communication between neural cells in an enlarged brain. The features observed in the adult brain reflect human-specific patterns of brain development. Compared to the brains of other primates, the human brain takes longer to mature, promoting an extended period for establishing cortical microcircuitry and its modifications. Together, these features may underlie the prolonged period of learning and acquisition of technical and social skills necessary for survival, creating a unique cognitive and behavioral niche typical of our species. The neuroanatomical findings are in concordance with molecular analyses, which suggest a trend toward heterochrony in the expression of genes implicated in different functions. These include synaptogenesis, neuronal maturation, and plasticity in humans, mutations in genes implicated in neurite outgrowth and plasticity, and an increased role of regulatory mechanisms, potentially promoting fast modification of neuronal morphologies in response to new computational demands. At the same time, endocranial casts of fossil hominins provide an insight into the timing of the emergence of uniquely human features in the course of evolution. We conclude by proposing several ways of combining comparative neuroanatomy, molecular biology and insights gained from fossil endocasts in future research.

  14. Evolution, development, and plasticity of the human brain: from molecules to bones

    Directory of Open Access Journals (Sweden)

    Branka eHrvoj-Mihic

    2013-10-01

    Full Text Available Neuroanatomical, molecular, and paleontological evidence is examined in light of human brain evolution. The brain of extant humans differs from the brains of other primates in its overall size and organization, and differences in size and organization of specific cortical areas and subcortical structures implicated into complex cognition and social and emotional processing. The human brain is also characterized by functional lateralizations, reflecting specializations of the cerebral hemispheres in humans for different types of processing, facilitating fast and reliable communication between neural cells in an enlarged brain. The features observed in the adult brain reflect human-specific patterns of brain development. Compared to the brains of other primates, the human brain takes longer to mature, promoting an extended period for establishing cortical microcircuitry and its modifications. Together, these features may underlie the prolonged period of learning and acquisition of technical and social skills necessary for survival, creating a unique cognitive and behavioral niche typical of our species.The neuroanatomical findings are in concordance with molecular analyses, which suggest a trend toward heterochrony in the expression of genes implicated in different functions. These include synaptogenesis, neuronal maturation and plasticity in humans, mutations in genes implicated in neurite outgrowth and plasticity, and an increased role of regulatory mechanisms, potentially promoting fast modification of neuronal morphologies in response to new computational demands. At the same time, endocranial casts of fossil hominins provide an insight into the timing of the emergence of uniquely human features in the course of evolution. We conclude by proposing several ways of combining comparative neuroanatomy, molecular biology and insights gained from fossil endocasts in future research.

  15. Plausible mechanisms for brain structural and size changes in human evolution.

    Science.gov (United States)

    Blazek, Vladimir; Brùzek, Jaroslav; Casanova, Manuel F

    2011-09-01

    Encephalization has many contexts and implications. On one hand, it is concerned with the transformation of eating habits, social relationships and communication, cognitive skills and the mind. Along with the increase in brain size on the other hand, encephalization is connected with the creation of more complex brain structures, namely in the cerebral cortex. It is imperative to inquire into the mechanisms which are linked with brain growth and to find out which of these mechanisms allow it and determine it. There exist a number of theories for understanding human brain evolution which originate from neurological sciences. These theories are the concept of radial units, minicolumns, mirror neurons, and neurocognitive networks. Over the course of evolution, it is evident that a whole range of changes have taken place in regards to heredity. These changes include new mutations of genes in the microcephalin complex, gene duplications, gene co-expression, and genomic imprinting. This complex study of the growth and reorganization of the brain and the functioning of hereditary factors and their external influences creates an opportunity to consider the implications of cultural evolution and cognitive faculties.

  16. The evolution of the brain in Canidae (Mammalia: Carnivora)

    NARCIS (Netherlands)

    Lyras, G.A.

    2009-01-01

    Canid brain evolution followed three independent, yet convergent paths. Each of the three canid subfamilies (Hesperocyoninae, Borophaginae and Caninae) started with a simple brain, which gradually became more complicated as the cerebral cortex became larger and more fissured, the cerebellar hemisphe

  17. Mind, Brain and Education: A Decade of Evolution

    Science.gov (United States)

    Schwartz, Marc

    2015-01-01

    This article examines the evolution of Mind, Brain, and Education (MBE), the field, alongside that of the International Mind, Brain and Education Society (IMBES). The reflections stem mostly from my observations while serving as vice president, president-elect, and president of IMBES during the past 10 years. The article highlights the evolution…

  18. Astrocytes and the evolution of the human brain.

    Science.gov (United States)

    Robertson, James M

    2014-02-01

    Cells within the astroglial lineage are proposed as the origin of human brain evolution. It is now widely accepted that they direct mammalian fetal neurogenesis, gliogenesis, laminar cytoarchitectonics, synaptic connectivity and neuronal network formation. Furthermore, genetic, anatomical and functional studies have recently identified multiple astrocyte exaptations that strongly suggest a direct relation to the increased size and complexity of the human brain.

  19. Advances in Brain Research: Implications for Educators

    Science.gov (United States)

    Stickel, Sue A.

    2005-01-01

    Cognitive neuroscience will provide theoretical foundations for areas of educational policy and practice. Educators will benefit from knowledge in the basic sciences related to brain development and function. Brain development begins at birth and the brain remains capable of complex changes throughout the lifespan. Educators will want to be aware…

  20. Brain Research: Implications to Diverse Learners

    Science.gov (United States)

    Madrazo, Gerry M., Jr.; Motz, LaMoine L.

    2005-01-01

    This article deals with brain research. It discusses how a growing understanding of the way the brain functions offers new insights into the minds of students at all stages of development. Brain-based research deals with classroom-relevant concerns, such as sensory perception, attention, memory, and how emotions affect learning. The goals for…

  1. Implications of Music and Brain Research.

    Science.gov (United States)

    Hodges, Donald A.

    2000-01-01

    Introduces the issue theme of Music Educators Journal on music and the brain summarizing the articles in this special focus. Offers an overview of neuromusical research and articulates some basic premises derived from the studies focusing on topics such as the resilience of the musical brain and that the musical brain operates at birth. (CMK)

  2. Comparative primate neuroimaging: insights into human brain evolution.

    Science.gov (United States)

    Rilling, James K

    2014-01-01

    Comparative neuroimaging can identify unique features of the human brain and teach us about human brain evolution. Comparisons with chimpanzees, our closest living primate relative, are critical in this endeavor. Structural magnetic resonance imaging (MRI) has been used to compare brain size development, brain structure proportions and brain aging. Positron emission tomography (PET) imaging has been used to compare resting brain glucose metabolism. Functional MRI (fMRI) has been used to compare auditory and visual system pathways, as well as resting-state networks of connectivity. Finally, diffusion-weighted imaging (DWI) has been used to compare structural connectivity. Collectively, these methods have revealed human brain specializations with respect to development, cortical organization, connectivity, and aging. These findings inform our knowledge of the evolutionary changes responsible for the special features of the modern human mind.

  3. Effect of cocaine dependence on brain connections: Clinical implications

    Science.gov (United States)

    Ma, Liangsuo; Steinberg, Joel L.; Moeller, F. Gerard; Johns, Sade E.; Narayana, Ponnada A.

    2015-01-01

    Cocaine dependence (CD) is associated with several cognitive deficits. Accumulating evidence, based on human and animal studies, has led to models for interpreting the neural basis of cognitive functions as interactions between functionally related brain regions. In this review, we focus on the magnetic resonance imaging (MRI) studies using brain connectivity techniques as related to CD. The majority of these brain connectivity studies indicated that cocaine use is associated with altered brain connectivity between different structures, including cortical-striatal regions and default mode network. In cocaine users, some of the altered brain connectivity measures are associated with behavioral performance, history of drug use, and treatment outcome. The implications of these brain connectivity findings to the treatment of CD and the pros and cons of the major brain connectivity techniques are discussed. Finally potential future directions in cocaine use disorder research using brain connectivity techniques are briefly described. PMID:26512421

  4. Adaptive evolution of four microcephaly genes and the evolution of brain size in anthropoid primates.

    Science.gov (United States)

    Montgomery, Stephen H; Capellini, Isabella; Venditti, Chris; Barton, Robert A; Mundy, Nicholas I

    2011-01-01

    The anatomical basis and adaptive function of the expansion in primate brain size have long been studied; however, we are only beginning to understand the genetic basis of these evolutionary changes. Genes linked to human primary microcephaly have received much attention as they have accelerated evolutionary rates along lineages leading to humans. However, these studies focus narrowly on apes, and the link between microcephaly gene evolution and brain evolution is disputed. We analyzed the molecular evolution of four genes associated with microcephaly (ASPM, CDK5RAP2, CENPJ, MCPH1) across 21 species representing all major clades of anthropoid primates. Contrary to prevailing assumptions, positive selection was not limited to or intensified along the lineage leading to humans. In fact we show that all four loci were subject to positive selection across the anthropoid primate phylogeny. We developed clearly defined hypotheses to explicitly test if selection on these loci was associated with the evolution of brain size. We found positive relationships between both CDK5RAP2 and ASPM and neonatal brain mass and somewhat weaker relationships between these genes and adult brain size. In contrast, there is no evidence linking CENPJ and MCPH1 to brain size evolution. The stronger association of ASPM and CDK5RAP2 evolution with neonatal brain size than with adult brain size is consistent with these loci having a direct effect on prenatal neuronal proliferation. These results suggest that primate brain size may have at least a partially conserved genetic basis. Our results contradict a previous study that linked adaptive evolution of ASPM to changes in relative cortex size; however, our analysis indicates that this conclusion is not robust. Our finding that the coding regions of two widely expressed loci has experienced pervasive positive selection in relation to a complex, quantitative developmental phenotype provides a notable counterexample to the commonly asserted

  5. Human brain evolution and the "Neuroevolutionary Time-depth Principle:" Implications for the Reclassification of fear-circuitry-related traits in DSM-V and for studying resilience to warzone-related posttraumatic stress disorder.

    Science.gov (United States)

    Bracha, H Stefan

    2006-07-01

    The DSM-III, DSM-IV, DSM-IV-TR and ICD-10 have judiciously minimized discussion of etiologies to distance clinical psychiatry from Freudian psychoanalysis. With this goal mostly achieved, discussion of etiological factors should be reintroduced into the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). A research agenda for the DSM-V advocated the "development of a pathophysiologically based classification system". The author critically reviews the neuroevolutionary literature on stress-induced and fear circuitry disorders and related amygdala-driven, species-atypical fear behaviors of clinical severity in adult humans. Over 30 empirically testable/falsifiable predictions are presented. It is noted that in DSM-IV-TR and ICD-10, the classification of stress and fear circuitry disorders is neither mode-of-acquisition-based nor brain-evolution-based. For example, snake phobia (innate) and dog phobia (overconsolidational) are clustered together. Similarly, research on blood-injection-injury-type-specific phobia clusters two fears different in their innateness: 1) an arguably ontogenetic memory-trace-overconsolidation-based fear (hospital phobia) and 2) a hardwired (innate) fear of the sight of one's blood or a sharp object penetrating one's skin. Genetic architecture-charting of fear-circuitry-related traits has been challenging. Various, non-phenotype-based architectures can serve as targets for research. In this article, the author will propose one such alternative genetic architecture. This article was inspired by the following: A) Nesse's "Smoke-Detector Principle", B) the increasing suspicion that the "smooth" rather than "lumpy" distribution of complex psychiatric phenotypes (including fear-circuitry disorders) may in some cases be accounted for by oligogenic (and not necessarily polygenic) transmission, and C) insights from the initial sequence of the chimpanzee genome and comparison with the human genome by the Chimpanzee Sequencing

  6. Genetic architecture supports mosaic brain evolution and independent brain-body size regulation.

    Science.gov (United States)

    Hager, Reinmar; Lu, Lu; Rosen, Glenn D; Williams, Robert W

    2012-01-01

    The mammalian brain consists of distinct parts that fulfil different functions. Finlay and Darlington have argued that evolution of the mammalian brain is constrained by developmental programs, suggesting that different brain parts are not free to respond individually to selection and evolve independent of other parts or overall brain size. However, comparisons among mammals with matched brain weights often reveal greater differences in brain part size, arguing against strong developmental constraints. Here we test these hypotheses using a quantitative genetic approach involving over 10,000 mice. We identify independent loci for size variation in seven key parts of the brain, and observe that brain parts show low or no phenotypic correlation, as is predicted by a mosaic scenario. We also demonstrate that variation in brain size is independently regulated from body size. The allometric relations seen at higher phylogenetic levels are thus unlikely to be the product of strong developmental constraints.

  7. [Evolution of brain development in amphibians].

    Science.gov (United States)

    Savel'ev, S V

    2009-01-01

    Principal events in the early embryonic development of the nervous system, from neurulation to primary differentiation, are considered in different amphibian species. Attention is paid to numerous interspecific differences in the structure of neuroepithelium and the patterns of neurulation and embryonic brain segmentation. The data presented indicate that similarity in brain developmental patterns is apparently explained by universality of morphogenetic mechanisms rather than by the common origin of particular species. A hypothesis is proposed that similarity in the shape of the developing amphibian brain is determined by mechanisms of coding positional information necessary for histogenetic differentiation.

  8. Increased morphological asymmetry, evolvability and plasticity in human brain evolution.

    Science.gov (United States)

    Gómez-Robles, Aida; Hopkins, William D; Sherwood, Chet C

    2013-06-22

    The study of hominin brain evolution relies mostly on evaluation of the endocranial morphology of fossil skulls. However, only some general features of external brain morphology are evident from endocasts, and many anatomical details can be difficult or impossible to examine. In this study, we use geometric morphometric techniques to evaluate inter- and intraspecific differences in cerebral morphology in a sample of in vivo magnetic resonance imaging scans of chimpanzees and humans, with special emphasis on the study of asymmetric variation. Our study reveals that chimpanzee-human differences in cerebral morphology are mainly symmetric; by contrast, there is continuity in asymmetric variation between species, with humans showing an increased range of variation. Moreover, asymmetric variation does not appear to be the result of allometric scaling at intraspecific levels, whereas symmetric changes exhibit very slight allometric effects within each species. Our results emphasize two key properties of brain evolution in the hominine clade: first, evolution of chimpanzee and human brains (and probably their last common ancestor and related species) is not strongly morphologically constrained, thus making their brains highly evolvable and responsive to selective pressures; second, chimpanzee and, especially, human brains show high levels of fluctuating asymmetry indicative of pronounced developmental plasticity. We infer that these two characteristics can have a role in human cognitive evolution.

  9. Sperm competition and brain size evolution in mammals.

    Science.gov (United States)

    Lemaître, J-F; Ramm, S A; Barton, R A; Stockley, P

    2009-11-01

    The 'expensive tissue hypothesis' predicts a size trade-off between the brain and other energetically costly organs. A specific version of this hypothesis, the 'expensive sexual tissue hypothesis', argues that selection for larger testes under sperm competition constrains brain size evolution. We show here that there is no general evolutionary trade-off between brain and testis mass in mammals. The predicted negative relationship between these traits is not found for rodents, ungulates, primates, carnivores, or across combined mammalian orders, and neither does total brain mass vary according to the level of sperm competition as determined by mating system classifications. Although we are able to confirm previous reports of a negative relationship between brain and testis mass in echolocating bats, our results suggest that mating system may be a better predictor of brain size in this group. We conclude that the expensive sexual tissue hypothesis accounts for little or none of the variance in brain size in mammals, and suggest that a broader framework is required to understand the costs of brain size evolution and how these are met.

  10. Reflecting on the philosophical implications of evolution

    Directory of Open Access Journals (Sweden)

    I.H. Horn

    2003-08-01

    Full Text Available Evolution as paradigm is a prescribed topic in contemporary South African education. This means that macro-evolution – the idea that life evolved progressively from inert matter to humankind’s coming into being – must form the foundation of South African education. The aim of this article is to reflect, in a spirit of respectful yet critical enquiry, on three issues with regard to macro-evolution: First, the theory of macro-evolution is placed in its historical context which indicates that although this theory owes its widespread acceptance to Charles Darwin, it did not originate with him. Second, the scientific status of the theory of macro-evolution is scrutinised. Karl Popper’s view of this theory as a metaphysical framework for research is given, accompanied by a brief discussion. Third, three evolutionary worldviews are identified and discussed.

  11. [Survival of the fattest: the key to human brain evolution].

    Science.gov (United States)

    Cunnane, Stephen C

    2006-01-01

    The circumstances of human brain evolution are of central importance to accounting for human origins, yet are still poorly understood. Human evolution is usually portrayed as having occurred in a hot, dry climate in East Africa where the earliest human ancestors became bipedal and evolved tool-making skills and language while struggling to survive in a wooded or savannah environment. At least three points need to be recognised when constructing concepts of human brain evolution : (1) The human brain cannot develop normally without a reliable supply of several nutrients, notably docosahexaenoic acid, iodine and iron. (2) At term, the human fetus has about 13 % of body weight as fat, a key form of energy insurance supporting brain development that is not found in other primates. (3) The genome of humans and chimpanzees is different, so if they both evolved in essentially the same habitat, how did the human brain become so much larger, and how was its present-day nutritional vulnerability circumvented during 5-6 million years of hominid evolution ? The abundant presence of fish bones and shellfish remains in many African hominid fossil sites dating to 2 million years ago implies human ancestors commonly inhabited the shores, but this point is usually overlooked in conceptualizing how the human brain evolved. Shellfish, fish and shore-based animals and plants are the richest dietary sources of the key nutrients needed by the brain. Whether on the shores of lakes, marshes, rivers or the sea, the consumption of most shore-based foods requires no specialized skills or tools. The presence of key brain nutrients and a rich energy supply in shore-based foods would have provided the essential metabolic and nutritional support needed to gradually expand the hominid brain. Abundant availability of these foods also provided the time needed to develop and refine proto-human attributes that subsequently formed the basis of language, culture, tool making and hunting. The presence

  12. Split Brain Theory: Implications for Nurse Educators.

    Science.gov (United States)

    de Meneses, Mary

    1980-01-01

    Discusses incorporating nontraditional concepts of learning in nursing education. Elements explored include the split brain theory, school design, teaching styles, teacher's role, teaching strategies, adding variety to the curriculum, and modular learning. (CT)

  13. Asymmetry of the Brain: Development and Implications.

    Science.gov (United States)

    Duboc, Véronique; Dufourcq, Pascale; Blader, Patrick; Roussigné, Myriam

    2015-01-01

    Although the left and right hemispheres of our brains develop with a high degree of symmetry at both the anatomical and functional levels, it has become clear that subtle structural differences exist between the two sides and that each is dominant in processing specific cognitive tasks. As the result of evolutionary conservation or convergence, lateralization of the brain is found in both vertebrates and invertebrates, suggesting that it provides significant fitness for animal life. This widespread feature of hemispheric specialization has allowed the emergence of model systems to study its development and, in some cases, to link anatomical asymmetries to brain function and behavior. Here, we present some of what is known about brain asymmetry in humans and model organisms as well as what is known about the impact of environmental and genetic factors on brain asymmetry development. We specifically highlight the progress made in understanding the development of epithalamic asymmetries in zebrafish and how this model provides an exciting opportunity to address brain asymmetry at different levels of complexity.

  14. Spectral properties of the temporal evolution of brain network structure

    Science.gov (United States)

    Wang, Rong; Zhang, Zhen-Zhen; Ma, Jun; Yang, Yong; Lin, Pan; Wu, Ying

    2015-12-01

    The temporal evolution properties of the brain network are crucial for complex brain processes. In this paper, we investigate the differences in the dynamic brain network during resting and visual stimulation states in a task-positive subnetwork, task-negative subnetwork, and whole-brain network. The dynamic brain network is first constructed from human functional magnetic resonance imaging data based on the sliding window method, and then the eigenvalues corresponding to the network are calculated. We use eigenvalue analysis to analyze the global properties of eigenvalues and the random matrix theory (RMT) method to measure the local properties. For global properties, the shifting of the eigenvalue distribution and the decrease in the largest eigenvalue are linked to visual stimulation in all networks. For local properties, the short-range correlation in eigenvalues as measured by the nearest neighbor spacing distribution is not always sensitive to visual stimulation. However, the long-range correlation in eigenvalues as evaluated by spectral rigidity and number variance not only predicts the universal behavior of the dynamic brain network but also suggests non-consistent changes in different networks. These results demonstrate that the dynamic brain network is more random for the task-positive subnetwork and whole-brain network under visual stimulation but is more regular for the task-negative subnetwork. Our findings provide deeper insight into the importance of spectral properties in the functional brain network, especially the incomparable role of RMT in revealing the intrinsic properties of complex systems.

  15. Brain size of Homo floresiensis and its evolutionary implications.

    Science.gov (United States)

    Kubo, Daisuke; Kono, Reiko T; Kaifu, Yousuke

    2013-06-07

    The extremely small endocranial volume (ECV) of LB1, the type specimen of Homo floresiensis, poses a challenge in our understanding of human brain evolution. Some researchers hypothesize dramatic dwarfing of relative brain size from Homo erectus presumably without significant decrease in intellectual function, whereas others expect a lesser degree of brain diminution from a more primitive, small-brained form of hominin currently undocumented in eastern Asia. However, inconsistency in the published ECVs for LB1 (380-430 cc), unclear human intraspecific brain-body size scaling and other uncertainties have hampered elaborative modelling of its brain size reduction. In this study, we accurately determine the ECV of LB1 using high-resolution micro-CT scan. The ECV of LB1 thus measured, 426 cc, is larger than the commonly cited figure in previous studies (400 cc). Coupled with brain-body size correlation in Homo sapiens calculated based on a sample from 20 worldwide modern human populations, we construct new models of the brain size reduction in the evolution of H. floresiensis. The results show a more significant contribution of scaling effect than previously claimed.

  16. Evolution of the human brain : when bigger is better

    NARCIS (Netherlands)

    Hofman, Michel A

    2014-01-01

    Comparative studies of the brain in mammals suggest that there are general architectural principles governing its growth and evolutionary development. We are beginning to understand the geometric, biophysical and energy constraints that have governed the evolution and functional organization of the

  17. MCPH1: a window into brain development and evolution

    Directory of Open Access Journals (Sweden)

    Jeannette eNardelli

    2015-03-01

    Full Text Available The development of the mammalian cerebral cortex involves a series of mechanisms: from patterning, progenitor cell proliferation and differentiation, to neuronal migration. Many factors influence the development of the cerebral cortex to its normal size and neuronal composition. Of these, the mechanisms that influence the proliferation and differentiation of neural progenitor cells are of particular interest, as they may have the greatest consequence on brain size, not only during development but also in evolution. In this context, causative genes of human autosomal recessive primary microcephaly, such as ASPM and MCPH1, are attractive candidates, as many of them show positive selection during primate evolution. MCPH1 causes microcephaly in mice and humans and is involved in a diverse array of molecular functions beyond brain development, including DNA repair and chromosome condensation. Positive selection of MCPH1 in the primate lineage has led to much insight and discussion of its role in brain size evolution. In this review, we will present an overview of MCPH1 from these multiple angles, and whilst its specific role in brain size regulation during development and evolution remain elusive, the pieces of the puzzle will be discussed with the aim of putting together the full picture of this fascinating gene.

  18. Stem Cells Expand Insights into Human Brain Evolution.

    Science.gov (United States)

    Dyer, Michael A

    2016-04-07

    Substantial expansion in the number of cerebral cortex neurons is thought to underlie cognitive differences between humans and other primates, although the mechanisms underlying this expansion are unclear. Otani et al. (2016) utilize PSC-derived brain organoids to study how species-specific differences in cortical progenitor proliferation may underlie cortical evolution.

  19. Sibling rivalry among paralogs promotes evolution of the human brain.

    Science.gov (United States)

    Tyler-Smith, Chris; Xue, Yali

    2012-05-11

    Geneticists have long sought to identify the genetic changes that made us human, but pinpointing the functionally relevant changes has been challenging. Two papers in this issue suggest that partial duplication of SRGAP2, producing an incomplete protein that antagonizes the original, contributed to human brain evolution.

  20. Transcriptomic insights into human brain evolution: acceleration, neutrality, heterochrony.

    Science.gov (United States)

    Somel, Mehmet; Rohlfs, Rori; Liu, Xiling

    2014-12-01

    Primate brain transcriptome comparisons within the last 12 years have yielded interesting but contradictory observations on how the transcriptome evolves, and its adaptive role in human cognitive evolution. Since the human-chimpanzee common ancestor, the human prefrontal cortex transcriptome seems to have evolved more than that of the chimpanzee. But at the same time, most expression differences among species, especially those observed in adults, appear as consequences of neutral evolution at cis-regulatory sites. Adaptive expression changes in the human brain may be rare events involving timing shifts, or heterochrony, in specific neurodevelopmental processes. Disentangling adaptive and neutral expression changes, and associating these with human-specific features of the brain require improved methods, comparisons across more species, and further work on comparative development.

  1. Should Alzheimer's disease be equated with human brain ageing? A maladaptive interaction between brain evolution and senescence.

    Science.gov (United States)

    Neill, David

    2012-01-01

    In this review Alzheimer's disease is seen as a maladaptive interaction between human brain evolution and senescence. It is predicted to occur in everyone although does not necessarily lead to dementia. The pathological process is initiated in relation to a senescence mediated functional down-regulation in the posteromedial cortex (Initiation Phase). This leads to a loss of glutamatergic excitatory input to layer II entorhinal cortex neurons. A human specific maladaptive neuroplastic response is initiated in these neurons leading to neuronal dysfunction, NFT formation and death. This leads to further loss of glutamatergic excitatory input and propagation of the maladaptive response along excitatory pathways linking evolutionary progressed vulnerable neurons (Propagation Phase). Eventually neurons are affected in many brain areas resulting in dementia. Possible therapeutic approaches include enhancing glutamatergic transmission. The theory may have implications with regards to how Alzheimer's disease is classified.

  2. Increased cortical expression of two synaptogenic thrombospondins in human brain evolution.

    Science.gov (United States)

    Cáceres, Mario; Suwyn, Carolyn; Maddox, Marcelia; Thomas, James W; Preuss, Todd M

    2007-10-01

    Thrombospondins are extracellular-matrix glycoproteins implicated in the control of synaptogenesis and neurite growth. Previous microarray studies suggested that one gene of this family, thrombospondin 4 (THBS4), was upregulated during human brain evolution. Using independent techniques to examine thrombospondin expression patterns in adult brain samples, we report approximately 6-fold and approximately 2-fold greater expression of THBS4 and THBS2 messenger RNA (mRNA), respectively, in human cerebral cortex compared with chimpanzees and macaques, with corresponding differences in protein levels. In humans and chimpanzees, thrombospondin expression differences were observed in the forebrain (cortex and caudate), whereas the cerebellum and most nonbrain tissues exhibited similar levels of the 2 mRNAs. Histological examination revealed THBS4 mRNA and protein expression in numerous pyramidal and glial cells in the 3 species but humans also exhibited very prominent immunostaining of the synapse-rich cortical neuropil. In humans, additionally, THBS4 antibodies labeled beta-amyloid containing plaques in Alzheimer's cases and some control cases. This is the first detailed characterization of gene-expression changes in human evolution that involve specific brain regions, including portions of cerebral cortex. Increased expression of thrombospondins in human brain evolution could result in changes in synaptic organization and plasticity, and contribute to the distinctive cognitive abilities of humans, as well as to our unique vulnerability to neurodegenerative disease.

  3. Modeling evolution using the probability of fixation: history and implications.

    Science.gov (United States)

    McCandlish, David M; Stoltzfus, Arlin

    2014-09-01

    Many models of evolution calculate the rate of evolution by multiplying the rate at which new mutations originate within a population by a probability of fixation. Here we review the historical origins, contemporary applications, and evolutionary implications of these "origin-fixation" models, which are widely used in evolutionary genetics, molecular evolution, and phylogenetics. Origin-fixation models were first introduced in 1969, in association with an emerging view of "molecular" evolution. Early origin-fixation models were used to calculate an instantaneous rate of evolution across a large number of independently evolving loci; in the 1980s and 1990s, a second wave of origin-fixation models emerged to address a sequence of fixation events at a single locus. Although origin fixation models have been applied to a broad array of problems in contemporary evolutionary research, their rise in popularity has not been accompanied by an increased appreciation of their restrictive assumptions or their distinctive implications. We argue that origin-fixation models constitute a coherent theory of mutation-limited evolution that contrasts sharply with theories of evolution that rely on the presence of standing genetic variation. A major unsolved question in evolutionary biology is the degree to which these models provide an accurate approximation of evolution in natural populations.

  4. Microscopic computation in human brain evolution.

    Science.gov (United States)

    Wallace, R

    1995-04-01

    When human psychological performance is viewed in terms of cognitive modules, our species displays remarkable differences in computational power. Algorithmically simple computations are generally difficult to perform, whereas optimal routing or "Traveling Salesman" Problems (TSP) of far greater complexity are solved on an everyday basis. It is argued that even "simple" instances of TSP are not purely Euclidian problems in human computations, but involve emotional, autonomic, and cognitive constraints. They therefore require a level of parallel processing not possible in a macroscopic system to complete the algorithm within a brief period of time. A microscopic neurobiological model emphasizing the computational power of excited atoms within the neuronal membrane is presented as an alternative to classical connectionist approaches. The evolution of the system is viewed in terms of specific natural selection pressures driving satisfying computations toward global optimization. The relationship of microscopic computation to the nature of consciousness is examined, and possible mathematical models as a basis for simulation studies are briefly discussed.

  5. Metabolic costs and evolutionary implications of human brain development.

    Science.gov (United States)

    Kuzawa, Christopher W; Chugani, Harry T; Grossman, Lawrence I; Lipovich, Leonard; Muzik, Otto; Hof, Patrick R; Wildman, Derek E; Sherwood, Chet C; Leonard, William R; Lange, Nicholas

    2014-09-09

    The high energetic costs of human brain development have been hypothesized to explain distinctive human traits, including exceptionally slow and protracted preadult growth. Although widely assumed to constrain life-history evolution, the metabolic requirements of the growing human brain are unknown. We combined previously collected PET and MRI data to calculate the human brain's glucose use from birth to adulthood, which we compare with body growth rate. We evaluate the strength of brain-body metabolic trade-offs using the ratios of brain glucose uptake to the body's resting metabolic rate (RMR) and daily energy requirements (DER) expressed in glucose-gram equivalents (glucosermr% and glucoseder%). We find that glucosermr% and glucoseder% do not peak at birth (52.5% and 59.8% of RMR, or 35.4% and 38.7% of DER, for males and females, respectively), when relative brain size is largest, but rather in childhood (66.3% and 65.0% of RMR and 43.3% and 43.8% of DER). Body-weight growth (dw/dt) and both glucosermr% and glucoseder% are strongly, inversely related: soon after birth, increases in brain glucose demand are accompanied by proportionate decreases in dw/dt. Ages of peak brain glucose demand and lowest dw/dt co-occur and subsequent developmental declines in brain metabolism are matched by proportionate increases in dw/dt until puberty. The finding that human brain glucose demands peak during childhood, and evidence that brain metabolism and body growth rate covary inversely across development, support the hypothesis that the high costs of human brain development require compensatory slowing of body growth rate.

  6. Origin and evolution of deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Vittorio Alessandro eSironi

    2011-08-01

    Full Text Available This paper briefly describes how the electrical stimulation, used since antiquity to modulate the nervous system, has been a fundamental tool of neurophysiologic investigation in the second half of the 18th century and was subsequently used by the early 20th century, even for therapeutic purposes. In mid-20th century the advent of stereotactic procedures has allowed the drift from lesional to stimulating technique of deep nuclei of the brain for therapeutic purposes. In this way, DBS was born, that, over the last two decades, has led to positive results for the treatment of medically refractory Parkinson's disease, essential tremor and dystonia. In recent years, the indications for therapeutic use of DBS have been extended to epilepsy, Tourette's syndrome, psychiatric diseases (depression, obsessive-compulsive disorder, some kinds of headache, eating disorders and the minimally conscious state. The potentials of the DBS for therapeutic use are fascinating, but there are still many unresolved technical and ethical problems, concerning the identification of the targets for each disease, the selection of the patients and the evaluation of the results.

  7. Evolution of Brain Tumor and Stability of Geometric Invariants

    Directory of Open Access Journals (Sweden)

    K. Tawbe

    2008-01-01

    Full Text Available This paper presents a method to reconstruct and to calculate geometric invariants on brain tumors. The geometric invariants considered in the paper are the volume, the area, the discrete Gauss curvature, and the discrete mean curvature. The volume of a tumor is an important aspect that helps doctors to make a medical diagnosis. And as doctors seek a stable calculation, we propose to prove the stability of some invariants. Finally, we study the evolution of brain tumor as a function of time in two or three years depending on patients with MR images every three or six months.

  8. The quantum brain theory and implications

    CERN Document Server

    Stern, A

    1994-01-01

    While for the majority of physicists the problem of the deciphering of the brain code, the intelligence code, is a matter for future generations, the author boldly and forcefully disagrees. Breaking with the dogma of classical logic he develops in the form of the conversion postulate a concrete working hypothesis for the actual thought mechanism. The reader is invited on a fascinating mathematical journey to the very edges of modern scientific knowledge. From lepton and quark to mind, from cognition to a logic analogue of the Schrödinger equation, from Fibonacci numbers to logic quantum numb

  9. Energetics and the evolution of human brain size.

    Science.gov (United States)

    Navarrete, Ana; van Schaik, Carel P; Isler, Karin

    2011-11-09

    The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis. Nonetheless, consistent with the existence of energy trade-offs with brain size, we find that the size of brains and adipose depots are negatively correlated in mammals, indicating that encephalization and fat storage are compensatory strategies to buffer against starvation. However, these two strategies can be combined if fat storage does not unduly hamper locomotor efficiency. We propose that human encephalization was made possible by a combination of stabilization of energy inputs and a redirection of energy from locomotion, growth and reproduction.

  10. Brain evolution and development: adaptation, allometry and constraint

    Science.gov (United States)

    Barton, Robert A.

    2016-01-01

    Phenotypic traits are products of two processes: evolution and development. But how do these processes combine to produce integrated phenotypes? Comparative studies identify consistent patterns of covariation, or allometries, between brain and body size, and between brain components, indicating the presence of significant constraints limiting independent evolution of separate parts. These constraints are poorly understood, but in principle could be either developmental or functional. The developmental constraints hypothesis suggests that individual components (brain and body size, or individual brain components) tend to evolve together because natural selection operates on relatively simple developmental mechanisms that affect the growth of all parts in a concerted manner. The functional constraints hypothesis suggests that correlated change reflects the action of selection on distributed functional systems connecting the different sub-components, predicting more complex patterns of mosaic change at the level of the functional systems and more complex genetic and developmental mechanisms. These hypotheses are not mutually exclusive but make different predictions. We review recent genetic and neurodevelopmental evidence, concluding that functional rather than developmental constraints are the main cause of the observed patterns. PMID:27629025

  11. Cultural evolution: implications for understanding the human language faculty and its evolution.

    Science.gov (United States)

    Smith, Kenny; Kirby, Simon

    2008-11-12

    Human language is unique among the communication systems of the natural world: it is socially learned and, as a consequence of its recursively compositional structure, offers open-ended communicative potential. The structure of this communication system can be explained as a consequence of the evolution of the human biological capacity for language or the cultural evolution of language itself. We argue, supported by a formal model, that an explanatory account that involves some role for cultural evolution has profound implications for our understanding of the biological evolution of the language faculty: under a number of reasonable scenarios, cultural evolution can shield the language faculty from selection, such that strongly constraining language-specific learning biases are unlikely to evolve. We therefore argue that language is best seen as a consequence of cultural evolution in populations with a weak and/or domain-general language faculty.

  12. Human brain evolution: harnessing the genomics (r)evolution to link genes, cognition, and behavior.

    Science.gov (United States)

    Konopka, Genevieve; Geschwind, Daniel H

    2010-10-21

    The evolution of the human brain has resulted in numerous specialized features including higher cognitive processes such as language. Knowledge of whole-genome sequence and structural variation via high-throughput sequencing technology provides an unprecedented opportunity to view human evolution at high resolution. However, phenotype discovery is a critical component of these endeavors and the use of nontraditional model organisms will also be critical for piecing together a complete picture. Ultimately, the union of developmental studies of the brain with studies of unique phenotypes in a myriad of species will result in a more thorough model of the groundwork the human brain was built upon. Furthermore, these integrative approaches should provide important insights into human diseases.

  13. Archaebacterial rhodopsin sequences: Implications for evolution

    Science.gov (United States)

    Lanyi, J. K.

    1991-01-01

    It was proposed over 10 years ago that the archaebacteria represent a separate kingdom which diverged very early from the eubacteria and eukaryotes. It follows that investigations of archaebacterial characteristics might reveal features of early evolution. So far, two genes, one for bacteriorhodopsin and another for halorhodopsin, both from Halobacterium halobium, have been sequenced. We cloned and sequenced the gene coding for the polypeptide of another one of these rhodopsins, a halorhodopsin in Natronobacterium pharaonis. Peptide sequencing of cyanogen bromide fragments, and immuno-reactions of the protein and synthetic peptides derived from the C-terminal gene sequence, confirmed that the open reading frame was the structural gene for the pharaonis halorhodopsin polypeptide. The flanking DNA sequences of this gene, as well as those of other bacterial rhodopsins, were compared to previously proposed archaebacterial consensus sequences. In pairwise comparisons of the open reading frame with DNA sequences for bacterio-opsin and halo-opsin from Halobacterium halobium, silent divergences were calculated. These indicate very considerable evolutionary distance between each pair of genes, even in the dame organism. In spite of this, three protein sequences show extensive similarities, indicating strong selective pressures.

  14. DUF1220 domains, cognitive disease, and human brain evolution.

    Science.gov (United States)

    Dumas, L; Sikela, J M

    2009-01-01

    We have established that human genome sequences encoding a novel protein domain, DUF1220, show a dramatically elevated copy number in the human lineage (>200 copies in humans vs. 1 in mouse/rat) and may be important to human evolutionary adaptation. Copy-number variations (CNVs) in the 1q21.1 region, where most DUF1220 sequences map, have now been implicated in numerous diseases associated with cognitive dysfunction, including autism, autism spectrum disorder, mental retardation, schizophrenia, microcephaly, and macrocephaly. We report here that these disease-related 1q21.1 CNVs either encompass or are directly flanked by DUF1220 sequences and exhibit a dosage-related correlation with human brain size. Microcephaly-producing 1q21.1 CNVs are deletions, whereas macrocephaly-producing 1q21.1 CNVs are duplications. Similarly, 1q21.1 deletions and smaller brain size are linked with schizophrenia, whereas 1q21.1 duplications and larger brain size are associated with autism. Interestingly, these two diseases are thought to be phenotypic opposites. These data suggest a model which proposes that (1) DUF1220 domain copy number may be involved in influencing human brain size and (2) the evolutionary advantage of rapidly increasing DUF1220 copy number in the human lineage has resulted in favoring retention of the high genomic instability of the 1q21.1 region, which, in turn, has precipitated a spectrum of recurrent human brain and developmental disorders.

  15. The glia/neuron ratio: how it varies uniformly across brain structures and species and what that means for brain physiology and evolution.

    Science.gov (United States)

    Herculano-Houzel, Suzana

    2014-09-01

    It is a widespread notion that the proportion of glial to neuronal cells in the brain increases with brain size, to the point that glial cells represent "about 90% of all cells in the human brain." This notion, however, is wrong on both counts: neither does the glia/neuron ratio increase uniformly with brain size, nor do glial cells represent the majority of cells in the human brain. This review examines the origin of interest in the glia/neuron ratio; the original evidence that led to the notion that it increases with brain size; the extent to which this concept can be applied to white matter and whole brains and the recent supporting evidence that the glia/neuron ratio does not increase with brain size, but rather, and in surprisingly uniform fashion, with decreasing neuronal density due to increasing average neuronal cell size, across brain structures and species. Variations in the glia/neuron ratio are proposed to be related not to the supposed larger metabolic cost of larger neurons (given that this cost is not found to vary with neuronal density), but simply to the large variation in neuronal sizes across brain structures and species in the face of less overall variation in glial cell sizes, with interesting implications for brain physiology. The emerging evidence that the glia/neuron ratio varies uniformly across the different brain structures of mammalian species that diverged as early as 90 million years ago in evolution highlights how fundamental for brain function must be the interaction between glial cells and neurons.

  16. Cosmic evolution: the context for astrobiology and its cultural implications

    Science.gov (United States)

    Dick, Steven J.

    2012-10-01

    Astrobiology must be seen in the context of cosmic evolution, the 13.7 billion-year master narrative of the universe. The idea of an evolving universe dates back only to the 19th century, and became a guiding principle for astronomical research only in the second half of the 20th century. The modern synthesis in evolutionary biology hastened the acceptance of the idea in its cosmic setting, as did the confirmation of the Big Bang theory for the origin of the universe. NASA programmes such as Origins incorporated it as a guiding principle. Cosmic evolution encompasses physical, biological and cultural evolution, and may result in a physical, biological or postbiological universe, each with its own implications for long-term human destiny, and each imbuing the meaning of life with different values. It has the status of an increasingly accepted worldview that is beginning to have a profound effect not only in science but also in religion and philosophy.

  17. Functional constraints in the evolution of brain circuits

    Science.gov (United States)

    Bosman, Conrado A.; Aboitiz, Francisco

    2015-01-01

    Regardless of major anatomical and neurodevelopmental differences, the vertebrate isocortex shows a remarkably well-conserved organization. In the isocortex, reciprocal connections between excitatory and inhibitory neurons are distributed across multiple layers, encompassing modular, dynamical and recurrent functional networks during information processing. These dynamical brain networks are often organized in neuronal assemblies interacting through rhythmic phase relationships. Accordingly, these oscillatory interactions are observed across multiple brain scale levels, and they are associated with several sensory, motor, and cognitive processes. Most notably, oscillatory interactions are also found in the complete spectrum of vertebrates. Yet, it is unknown why this functional organization is so well conserved in evolution. In this perspective, we propose some ideas about how functional requirements of the isocortex can account for the evolutionary stability observed in microcircuits across vertebrates. We argue that isocortex architectures represent canonical microcircuits resulting from: (i) the early selection of neuronal architectures based on the oscillatory excitatory-inhibitory balance, which lead to the implementation of compartmentalized oscillations and (ii) the subsequent emergence of inferential coding strategies (predictive coding), which are able to expand computational capacities. We also argue that these functional constraints may be the result of several advantages that oscillatory activity contributes to brain network processes, such as information transmission and code reliability. In this manner, similarities in mesoscale brain circuitry and input-output organization between different vertebrate groups may reflect evolutionary constraints imposed by these functional requirements, which may or may not be traceable to a common ancestor. PMID:26388716

  18. Clearance systems in the brain-implications for Alzheimer disease.

    Science.gov (United States)

    Tarasoff-Conway, Jenna M; Carare, Roxana O; Osorio, Ricardo S; Glodzik, Lidia; Butler, Tracy; Fieremans, Els; Axel, Leon; Rusinek, Henry; Nicholson, Charles; Zlokovic, Berislav V; Frangione, Blas; Blennow, Kaj; Ménard, Joël; Zetterberg, Henrik; Wisniewski, Thomas; de Leon, Mony J

    2015-08-01

    Accumulation of toxic protein aggregates-amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles-is the pathological hallmark of Alzheimer disease (AD). Aβ accumulation has been hypothesized to result from an imbalance between Aβ production and clearance; indeed, Aβ clearance seems to be impaired in both early and late forms of AD. To develop efficient strategies to slow down or halt AD, it is critical to understand how Aβ is cleared from the brain. Extracellular Aβ deposits can be removed from the brain by various clearance systems, most importantly, transport across the blood-brain barrier. Findings from the past few years suggest that astroglial-mediated interstitial fluid (ISF) bulk flow, known as the glymphatic system, might contribute to a larger portion of extracellular Aβ (eAβ) clearance than previously thought. The meningeal lymphatic vessels, discovered in 2015, might provide another clearance route. Because these clearance systems act together to drive eAβ from the brain, any alteration to their function could contribute to AD. An understanding of Aβ clearance might provide strategies to reduce excess Aβ deposits and delay, or even prevent, disease onset. In this Review, we describe the clearance systems of the brain as they relate to proteins implicated in AD pathology, with the main focus on Aβ.

  19. Genetic architecture supports mosaic brain evolution and independent brain–body size regulation

    OpenAIRE

    Hager, Reinmar; Lu, Lu; Rosen, Glenn D.; Robert W Williams

    2012-01-01

    The mammalian brain consists of distinct parts that fulfil different functions. Finlay and Darlington have argued that evolution of the mammalian brain is constrained by developmental programs, suggesting that different brain parts are not free to respond individually to selection and evolve independent of other parts or overall brain size. However, comparisons among mammals with matched brain weights often reveal greater differences in brain part size, arguing against strong developmental co...

  20. Quantitative genetic analysis of brain size variation in sticklebacks: support for the mosaic model of brain evolution.

    Science.gov (United States)

    Noreikiene, Kristina; Herczeg, Gábor; Gonda, Abigél; Balázs, Gergely; Husby, Arild; Merilä, Juha

    2015-07-07

    The mosaic model of brain evolution postulates that different brain regions are relatively free to evolve independently from each other. Such independent evolution is possible only if genetic correlations among the different brain regions are less than unity. We estimated heritabilities, evolvabilities and genetic correlations of relative size of the brain, and its different regions in the three-spined stickleback (Gasterosteus aculeatus). We found that heritabilities were low (average h(2) = 0.24), suggesting a large plastic component to brain architecture. However, evolvabilities of different brain parts were moderate, suggesting the presence of additive genetic variance to sustain a response to selection in the long term. Genetic correlations among different brain regions were low (average rG = 0.40) and significantly less than unity. These results, along with those from analyses of phenotypic and genetic integration, indicate a high degree of independence between different brain regions, suggesting that responses to selection are unlikely to be severely constrained by genetic and phenotypic correlations. Hence, the results give strong support for the mosaic model of brain evolution. However, the genetic correlation between brain and body size was high (rG = 0.89), suggesting a constraint for independent evolution of brain and body size in sticklebacks.

  1. Developmental modes and developmental mechanisms can channel brain evolution

    Directory of Open Access Journals (Sweden)

    Christine J Charvet

    2011-02-01

    Full Text Available Anseriform birds (ducks and geese as well as parrots and songbirds have evolved a disproportionately enlarged telencephalon compared with many other birds. However, parrots and songbirds differ from anseriform birds in their mode of development. Whereas ducks and geese are precocial (e.g., hatchlings feed on their own, parrots and songbirds are altricial (e.g., hatchlings are fed by their parents. We here consider how developmental modes may limit and facilitate specific changes in the mechanisms of brain development. We suggest that altriciality facilitates the evolution of telencephalic expansion by delaying telencephalic neurogenesis. We further hypothesize that delays in telencephalic neurogenesis generate delays in telencephalic maturation, which in turn foster neural adaptations that facilitate learning. Specifically, we propose that delaying telencephalic neurogenesis was a prerequisite for the evolution of neural circuits that allow parrots and songbirds to produce learned vocalizations. Overall, we argue that developmental modes have influenced how some lineages of birds increased the size of their telencephalon and that this, in turn, has influenced subsequent changes in brain circuits and behavior.

  2. Developmental Modes and Developmental Mechanisms can Channel Brain Evolution.

    Science.gov (United States)

    Charvet, Christine J; Striedter, Georg F

    2011-01-01

    Anseriform birds (ducks and geese) as well as parrots and songbirds have evolved a disproportionately enlarged telencephalon compared with many other birds. However, parrots and songbirds differ from anseriform birds in their mode of development. Whereas ducks and geese are precocial (e.g., hatchlings feed on their own), parrots and songbirds are altricial (e.g., hatchlings are fed by their parents). We here consider how developmental modes may limit and facilitate specific changes in the mechanisms of brain development. We suggest that altriciality facilitates the evolution of telencephalic expansion by delaying telencephalic neurogenesis. We further hypothesize that delays in telencephalic neurogenesis generate delays in telencephalic maturation, which in turn foster neural adaptations that facilitate learning. Specifically, we propose that delaying telencephalic neurogenesis was a prerequisite for the evolution of neural circuits that allow parrots and songbirds to produce learned vocalizations. Overall, we argue that developmental modes have influenced how some lineages of birds increased the size of their telencephalon and that this, in turn, has influenced subsequent changes in brain circuits and behavior.

  3. An examination of cetacean brain structure with a novel hypothesis correlating thermogenesis to the evolution of a big brain.

    Science.gov (United States)

    Manger, Paul R

    2006-05-01

    This review examines aspects of cetacean brain structure related to behaviour and evolution. Major considerations include cetacean brain-body allometry, structure of the cerebral cortex, the hippocampal formation, specialisations of the cetacean brain related to vocalisations and sleep phenomenology, paleoneurology, and brain-body allometry during cetacean evolution. These data are assimilated to demonstrate that there is no neural basis for the often-asserted high intellectual abilities of cetaceans. Despite this, the cetaceans do have volumetrically large brains. A novel hypothesis regarding the evolution of large brain size in cetaceans is put forward. It is shown that a combination of an unusually high number of glial cells and unihemispheric sleep phenomenology make the cetacean brain an efficient thermogenetic organ, which is needed to counteract heat loss to the water. It is demonstrated that water temperature is the major selection pressure driving an altered scaling of brain and body size and an increased actual brain size in cetaceans. A point in the evolutionary history of cetaceans is identified as the moment in which water temperature became a significant selection pressure in cetacean brain evolution. This occurred at the Archaeoceti - modern cetacean faunal transition. The size, structure and scaling of the cetacean brain continues to be shaped by water temperature in extant cetaceans. The alterations in cetacean brain structure, function and scaling, combined with the imperative of producing offspring that can withstand the rate of heat loss experienced in water, within the genetic confines of eutherian mammal reproductive constraints, provides an explanation for the evolution of the large size of the cetacean brain. These observations provide an alternative to the widely held belief of a correlation between brain size and intelligence in cetaceans.

  4. Endocasts-the direct evidence and recent advances in the study of human brain evolution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Brain evolution is one of the most important aspects of human evolution, usually studied through endocasts. Analysis of fossil hominid endocasts allows inferences on functional anatomy, physiology, and phylogeny. In this paper, we describe the general features of endocast studies and review some of the major topics in paleoneurology. These are: absolute and relative brain size evolution; brain shape variation; brain asymmetry and lateralization; middle meningeal vessels and venous sinuses; application of computed tomography and virtual imaging; the history of Chinese brain endocast studies. In particular, this review emphasizes endocast studies on Chinese hominin fossils.

  5. A Hot Climate on Early Earth: Implications to Biospheric Evolution

    Science.gov (United States)

    Schwartzman, D. W.; Knauth, L. P.

    2009-12-01

    There is now robust evidence for a much warmer climate on the early Earth than now. Both oxygen and silicon isotopes in sedimentary chert and the compelling case for a near constant isotopic oxygen composition of seawater over geologic time support thermophilic surface temperatures until about 1.5-2 billion years ago, aside from a glacial episode in the early Proterozoic. This temperature scenario has important implications to biospheric evolution, including a temperature constraint that held back the emergence of major organismal groups, starting with phototrophs. A geophysiology of biospheric evolution raises the potential of similar coevolutionary relationships of life and its environment on Earth-like planets around Sun-like stars.

  6. Evolution of ASPM is associated with both increases and decreases in brain size in primates.

    Science.gov (United States)

    Montgomery, Stephen H; Mundy, Nicholas I

    2012-03-01

    A fundamental trend during primate evolution has been the expansion of brain size. However, this trend was reversed in the Callitrichidae (marmosets and tamarins), which have secondarily evolved smaller brains associated with a reduction in body size. The recent pursuit of the genetic basis of brain size evolution has largely focused on episodes of brain expansion, but new insights may be gained by investigating episodes of brain size reduction. Previous results suggest two genes (ASPM and CDK5RAP2) associated with microcephaly, a human neurodevelopmental disorder, may have an evolutionary function in primate brain expansion. Here we use new sequences encoding key functional domains from 12 species of callitrichids to show that positive selection has acted on ASPM across callitrichid evolution and the rate of ASPM evolution is significantly negatively correlated with callitrichid brain size, whereas the evolution of CDK5RAP2 shows no correlation with brain size. Our findings strongly suggest that ASPM has a previously unsuspected role in the evolution of small brains in primates. ASPM is therefore intimately linked to both evolutionary increases and decreases in brain size in anthropoids and is a key target for natural selection acting on brain size.

  7. Accelerated evolution of the ASPM gene controlling brain size begins prior to human brain expansion.

    Directory of Open Access Journals (Sweden)

    Natalay Kouprina

    2004-05-01

    Full Text Available Primary microcephaly (MCPH is a neurodevelopmental disorder characterized by global reduction in cerebral cortical volume. The microcephalic brain has a volume comparable to that of early hominids, raising the possibility that some MCPH genes may have been evolutionary targets in the expansion of the cerebral cortex in mammals and especially primates. Mutations in ASPM, which encodes the human homologue of a fly protein essential for spindle function, are the most common known cause of MCPH. Here we have isolated large genomic clones containing the complete ASPM gene, including promoter regions and introns, from chimpanzee, gorilla, orangutan, and rhesus macaque by transformation-associated recombination cloning in yeast. We have sequenced these clones and show that whereas much of the sequence of ASPM is substantially conserved among primates, specific segments are subject to high Ka/Ks ratios (nonsynonymous/synonymous DNA changes consistent with strong positive selection for evolutionary change. The ASPM gene sequence shows accelerated evolution in the African hominoid clade, and this precedes hominid brain expansion by several million years. Gorilla and human lineages show particularly accelerated evolution in the IQ domain of ASPM. Moreover, ASPM regions under positive selection in primates are also the most highly diverged regions between primates and nonprimate mammals. We report the first direct application of TAR cloning technology to the study of human evolution. Our data suggest that evolutionary selection of specific segments of the ASPM sequence strongly relates to differences in cerebral cortical size.

  8. Multiphasic growth models and the evolution of prolonged growth exemplified by human brain evolution.

    Science.gov (United States)

    Vrba, E S

    1998-02-07

    New models for multiphasic growth are presented. They are illustrated by analysis of brain growth in humans and chimpanzees, and the results are used to test the hypothesis of evolution by proportional growth prolongation: that all descendant growth phases are extended by the same factor while each remains at the ancestral growth rate. The results are consistent with the hypothesis and imply that gross brain weight increase towards humans required change in only one growth parameter: prolongation of the nonlinear ancestral growth phases. The restricted and orderly nature of the developmental changes hints at a basis in few genetic changes. Proportional growth prolongation is of general evolutionary importance because it can reorganize body proportions.

  9. Language evolution as cultural evolution: how language is shaped by the brain.

    Science.gov (United States)

    Chater, Nick; Christiansen, Morten H

    2010-09-01

    This paper reviews arguments against the evolutionary plausibility of a traditional genetically specified universal grammar. We argue that no such universal grammar could have evolved, either by a process of natural selection or by other evolutionary mechanisms. Instead, we propose that the close fit between languages and language learners, which make language acquisition possible, arises not because humans possess a specialized biological adaptation for language, but because language has been shaped to fit the brain, a process of cultural evolution. On this account, many aspects of the structure of human languages may be explained as cultural adaptations to the human brain. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

  10. Regional selection of the brain size regulating gene CASC5 provides new insight into human brain evolution.

    Science.gov (United States)

    Shi, Lei; Hu, Enzhi; Wang, Zhenbo; Liu, Jiewei; Li, Jin; Li, Ming; Chen, Hua; Yu, Chunshui; Jiang, Tianzi; Su, Bing

    2017-02-01

    Human evolution is marked by a continued enlargement of the brain. Previous studies on human brain evolution focused on identifying sequence divergences of brain size regulating genes between humans and nonhuman primates. However, the evolutionary pattern of the brain size regulating genes during recent human evolution is largely unknown. We conducted a comprehensive analysis of the brain size regulating gene CASC5 and found that in recent human evolution, CASC5 has accumulated many modern human specific amino acid changes, including two fixed changes and six polymorphic changes. Among human populations, 4 of the 6 amino acid polymorphic sites have high frequencies of derived alleles in East Asians, but are rare in Europeans and Africans. We proved that this between-population allelic divergence was caused by regional Darwinian positive selection in East Asians. Further analysis of brain image data of Han Chinese showed significant associations of the amino acid polymorphic sites with gray matter volume. Hence, CASC5 may contribute to the morphological and structural changes of the human brain during recent evolution. The observed between-population divergence of CASC5 variants was driven by natural selection that tends to favor a larger gray matter volume in East Asians.

  11. Rate of evolution in brain-expressed genes in humans and other primates.

    Directory of Open Access Journals (Sweden)

    Hurng-Yi Wang

    2007-02-01

    Full Text Available Brain-expressed genes are known to evolve slowly in mammals. Nevertheless, since brains of higher primates have evolved rapidly, one might expect acceleration in DNA sequence evolution in their brain-expressed genes. In this study, we carried out full-length cDNA sequencing on the brain transcriptome of an Old World monkey (OWM and then conducted three-way comparisons among (i mouse, OWM, and human, and (ii OWM, chimpanzee, and human. Although brain-expressed genes indeed appear to evolve more rapidly in species with more advanced brains (apes > OWM > mouse, a similar lineage effect is observable for most other genes. The broad inclusion of genes in the reference set to represent the genomic average is therefore critical to this type of analysis. Calibrated against the genomic average, the rate of evolution among brain-expressed genes is probably lower (or at most equal in humans than in chimpanzee and OWM. Interestingly, the trend of slow evolution in coding sequence is no less pronounced among brain-specific genes, vis-à-vis brain-expressed genes in general. The human brain may thus differ from those of our close relatives in two opposite directions: (i faster evolution in gene expression, and (ii a likely slowdown in the evolution of protein sequences. Possible explanations and hypotheses are discussed.

  12. Evolution and development of brain sensory organs in molgulid ascidians.

    Science.gov (United States)

    Jeffery, William R

    2004-01-01

    The ascidian tadpole larva has two brain sensory organs containing melanocytes: the otolith, a gravity receptor, and the ocellus, part of a photoreceptor. One or both of these sensory organs are absent in molgulid ascidians. We show here that developmental changes leading to the loss of sensory pigment cells occur by different mechanisms in closely related molgulid species. Sensory pigment cells are formed through a bilateral determination pathway in which two or more precursor cells are specified as an equivalence group on each side of the embryo. The precursor cells subsequently converge at the midline after neurulation and undergo cell interactions that decide the fates of the otolith and ocellus. Molgula occidentalis and M. oculata, which exhibit a tadpole larva with an otolith but lacking an ocellus, have conserved the bilateral pigment cell determination pathway. Programmed cell death (PCD) is superimposed on this pathway late in development to eliminate the ocellus precursor and supernumerary pigment cells, which do not differentiate into either an otolith or ocellus. In contrast to molgulids with tadpole larvae, no pigment cell precursors are specified on either side of the M. occulta embryo, which forms a tailless (anural) larva lacking both sensory organs, suggesting that the bilateral pigment cell determination pathway has been lost. The bilateral pigment cell determination pathway and superimposed PCD can be restored in hybrids obtained by fertilizing M. occulta eggs with M. oculata sperm, indicating control by a zygotic process. We conclude that PCD plays an important role in the evolution and development of brain sensory organs in molgulid ascidians.

  13. Evolution of oxytocin pathways in the brain of vertebrates

    Directory of Open Access Journals (Sweden)

    H. Sophie Knobloch

    2014-02-01

    Full Text Available The central oxytocin system transformed tremendously during the evolution, thereby adapting to the expanding properties of species. In more basal vertebrates (paraphyletic taxon Anamnia, which includes agnathans, fish and amphibians, magnocellular neurosecretory neurons producing oxytocin, vasopressin and their homologs reside in the wall of the third ventricle of the hypothalamus composing a single hypothalamic structure, the preoptic nucleus. This nucleus further diverged in advanced vertebrates (monophyletic taxon Amniota, which includes reptiles, birds and mammals into the paraventricular and supraoptic nuclei with accessory nuclei between them. The individual magnocellular neurons underwent a process of transformation from primitive uni- or bipolar neurons into highly differentiated neurons. Due to these microanatomical and cytological changes, the ancient release modes of oxytocin into the cerebrospinal fluid were largely replaced by vascular release. However, the most fascinating feature of the progressive transformations of the oxytocin system has been the expansion of oxytocin axonal projections to forebrain regions. In the present review we provide a background on these evolutionary advancements. Furthermore, we draw attention to the non-synaptic axonal release in small and defined brain regions with the aim to clearly distinguish this way of oxytocin action from the classical synaptic transmission on one side and from dendritic release followed by a global diffusion on the other side. Finally, we will summarize the effects of oxytocin and its homologs on pro-social reproductive behaviors in representatives of the phylogenetic tree and will propose anatomically plausible pathways of oxytocin release contributing to these behaviors in basal vertebrates and amniots.

  14. Developmental origins of mosaic brain evolution: Morphometric analysis of the developing zebra finch brain.

    Science.gov (United States)

    Charvet, Christine J; Striedter, Georg F

    2009-05-10

    In adult zebra finches (Taeniopygia guttata), the telencephalon occupies 64% of the entire brain. This fraction is similar to what is seen in parrots, but many other birds possess a significantly smaller telencephalon. The aim of the present study was to determine the developmental time course and cellular basis of telencephalic enlargement in zebra finches, and then to compare these findings with what is known about telencephalic enlargement in other birds. To this end we estimated the volumes of all major brain regions from serial sections in embryonic and post-hatching zebra finches. We also labeled proliferating cells with antibodies against proliferating cell nuclear antigen and phosphorylated histone H3. An important finding to emerge from this work is that the telencephalon of zebra finches at hatching contains a thick proliferative subventricular zone (SVZ) that extends from the subpallium into the dorsal pallium. The data also show that the onset and offset of telencephalic neurogenesis are both delayed in zebra finches relative to quail (Galliformes). This delay in neurogenesis, in conjunction with the expanded SVZ, probably accounts for most of the telencephalic enlargement in passerines such as the zebra finch. In addition, passerines enlarged their telencephalon by decreasing the proportional size of their midbrain tectum. Because the presumptive tectum is proportionally smaller in zebra finches than quail before neurogenesis begins, this difference in tectum size cannot be due to evolutionary alterations in neurogenesis timing. Collectively these findings indicate that several different developmental mechanisms underlie the evolution of a large telencephalon in passerines.

  15. An integrative view of dynamic genomic elements influencing human brain evolution and individual neurodevelopment.

    Science.gov (United States)

    Gericke, G S

    2008-09-01

    An increasing number of reports of rearranged and aneuploid chromosomes in brain cells suggest an unexpected link between developmental chromosomal instability and brain genome diversity. Unstable chromosomal fragile sites (FS), endogenously or exogenously induced by replicative stressors, participate in genetic rearrangement and may be key features of epigenetically modified neuroplasticity. Certain common chromosomal FS are known to function as signals for RAG complex targets. Recombinase activation gene RAG-1 directed V(D)J recombination affecting specific recognition sequences allows the immune system to encode memories of a vast array of antigens. The finding that RAG-1 is transcribed in the central nervous system raised the consideration that immunoglobulin-like somatic DNA recombination could be involved in recognition and memory processes in brain development and function. Cognitive stress induced somatic hypermutation in neurons, similar to what happens after antigenic challenge in lymphocytes, could underly a massive increase in the synthesis of novel macromolecules to function as coded information bits which get selected for memory storage. This process may involve mobile element activation, which may also play a role in recombinational repair. As a source of tested, successful new open reading frames, somatic hypermutation may confer a selective advantage if somatically acquired information is fed back to germline V gene arrays and the human brain could have adopted a similar process to manage the information captured in rearranged sequences. In neuroevolution and individual brain development, germline information could thus represent a crucial component. The brain itself may, from an evolutionary genetic point of view, represent nothing more than a highly specialized and individually diversified information accrual and memory system to increase the overall phenotypically validated information content of the immortal germline. In the evolution of rapid

  16. Ontogenetic Shape Change in the Chicken Brain: Implications for Paleontology.

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    Soichiro Kawabe

    Full Text Available Paleontologists have investigated brain morphology of extinct birds with little information on post-hatching changes in avian brain morphology. Without the knowledge of ontogenesis, assessing brain morphology in fossil taxa could lead to misinterpretation of the phylogeny or neurosensory development of extinct species. Hence, it is imperative to determine how avian brain morphology changes during post-hatching growth. In this study, chicken brain shape was compared at various developmental stages using three-dimensional (3D geometric morphometric analysis and the growth rate of brain regions was evaluated to explore post-hatching morphological changes. Microscopic MRI (μMRI was used to acquire in vivo data from living and post-mortem chicken brains. The telencephalon rotates caudoventrally during growth. This change in shape leads to a relative caudodorsal rotation of the cerebellum and myelencephalon. In addition, all brain regions elongate rostrocaudally and this leads to a more slender brain shape. The growth rates of each brain region were constant and the slopes from the growth formula were parallel. The dominant pattern of ontogenetic shape change corresponded with interspecific shape changes due to increasing brain size. That is, the interspecific and ontogenetic changes in brain shape due to increased size have similar patterns. Although the shape of the brain and each brain region changed considerably, the volume ratio of each brain region did not change. This suggests that the brain can change its shape after completing functional differentiation of the brain regions. Moreover, these results show that consideration of ontogenetic changes in brain shape is necessary for an accurate assessment of brain morphology in paleontological studies.

  17. Ontogenetic Shape Change in the Chicken Brain: Implications for Paleontology.

    Science.gov (United States)

    Kawabe, Soichiro; Matsuda, Seiji; Tsunekawa, Naoki; Endo, Hideki

    2015-01-01

    Paleontologists have investigated brain morphology of extinct birds with little information on post-hatching changes in avian brain morphology. Without the knowledge of ontogenesis, assessing brain morphology in fossil taxa could lead to misinterpretation of the phylogeny or neurosensory development of extinct species. Hence, it is imperative to determine how avian brain morphology changes during post-hatching growth. In this study, chicken brain shape was compared at various developmental stages using three-dimensional (3D) geometric morphometric analysis and the growth rate of brain regions was evaluated to explore post-hatching morphological changes. Microscopic MRI (μMRI) was used to acquire in vivo data from living and post-mortem chicken brains. The telencephalon rotates caudoventrally during growth. This change in shape leads to a relative caudodorsal rotation of the cerebellum and myelencephalon. In addition, all brain regions elongate rostrocaudally and this leads to a more slender brain shape. The growth rates of each brain region were constant and the slopes from the growth formula were parallel. The dominant pattern of ontogenetic shape change corresponded with interspecific shape changes due to increasing brain size. That is, the interspecific and ontogenetic changes in brain shape due to increased size have similar patterns. Although the shape of the brain and each brain region changed considerably, the volume ratio of each brain region did not change. This suggests that the brain can change its shape after completing functional differentiation of the brain regions. Moreover, these results show that consideration of ontogenetic changes in brain shape is necessary for an accurate assessment of brain morphology in paleontological studies.

  18. Endocasts: possibilities and limitations for the interpretation of human brain evolution.

    Science.gov (United States)

    Neubauer, Simon

    2014-01-01

    Brains are not preserved in the fossil record but endocranial casts are. These are casts of the internal bony braincase, revealing approximate brain size and shape, and they are also informative about brain surface morphology. Endocasts are the only direct evidence of human brain evolution, but they provide only limited data ('paleoneurology'). This review discusses some new fossil endocasts and recent methodological advances that have allowed novel analyses of old endocasts, leading to intriguing findings and hypotheses. The interpretation of paleoneurological data always relies on comparative information from living species whose brains and behavior can be directly investigated. It is therefore important that future studies attempt to better integrate different approaches. Only then will we be able to gain a better understanding about hominin brain evolution. © 2014 S. Karger AG, Basel.

  19. Slip of the tongue: Implications for evolution and language development.

    Science.gov (United States)

    Forrester, Gillian S; Rodriguez, Alina

    2015-08-01

    A prevailing theory regarding the evolution of language implicates a gestural stage prior to the emergence of speech. In support of a transition of human language from a gestural to a vocal system, articulation of the hands and the tongue are underpinned by overlapping left hemisphere dominant neural regions. Behavioral studies demonstrate that human adults perform sympathetic mouth actions in imitative synchrony with manual actions. Additionally, right-handedness for precision manual actions in children has been correlated with the typical development of language, while a lack of hand bias has been associated with psychopathology. It therefore stands to reason that sympathetic mouth actions during fine precision motor action of the hands may be lateralized. We employed a fine-grained behavioral coding paradigm to provide the first investigation of tongue protrusions in typically developing 4-year old children. Tongue protrusions were investigated across a range of cognitive tasks that required varying degrees of manual action: precision motor action, gross motor action and no motor actions. The rate of tongue protrusions was influenced by the motor requirements of the task and tongue protrusions were significantly right-biased for only precision manual motor action (p<.001). From an evolutionary perspective, tongue protrusions can drive new investigations regarding how an early human communication system transitioned from hand to mouth. From a developmental perspective, the present study may serve to reveal patterns of tongue protrusions during the motor development of typically developing children.

  20. Orbital Dynamics, Environmental Heterogeneity, and the Evolution of the Human Brain

    Science.gov (United States)

    Grove, Matt

    2012-01-01

    Many explanations have been proposed for the evolution of our anomalously large brains, including social, ecological, and epiphenomenal hypotheses. Recently, an additional hypothesis has emerged, suggesting that advanced cognition and, by inference, increases in brain size, have been driven over evolutionary time by the need to deal with…

  1. The Evolution of Human Intelligence and the Coefficient of Additive Genetic Variance in Human Brain Size

    Science.gov (United States)

    Miller, Geoffrey F.; Penke, Lars

    2007-01-01

    Most theories of human mental evolution assume that selection favored higher intelligence and larger brains, which should have reduced genetic variance in both. However, adult human intelligence remains highly heritable, and is genetically correlated with brain size. This conflict might be resolved by estimating the coefficient of additive genetic…

  2. Comparative primate neurobiology and the evolution of brain language systems.

    Science.gov (United States)

    Rilling, James K

    2014-10-01

    Human brain specializations supporting language can be identified by comparing human with non-human primate brains. Comparisons with chimpanzees are critical in this endeavor. Human brains are much larger than non-human primate brains, but human language capabilities cannot be entirely explained by brain size. Human brain specializations that potentially support our capacity for language include firstly, wider cortical minicolumns in both Broca's and Wernicke's areas compared with great apes; secondly, leftward asymmetries in Broca's area volume and Wernicke's area minicolumn width that are not found in great apes; and thirdly, arcuate fasciculus projections beyond Wernicke's area to a region of expanded association cortex in the middle and inferior temporal cortex involved in processing word meaning.

  3. The evolution of the brain, the human nature of cortical circuits and intellectual creativity

    Directory of Open Access Journals (Sweden)

    Javier eDeFelipe

    2011-05-01

    Full Text Available The tremendous expansion and the differentiation of the neocortex constitute two major events in the evolution of the mammalian brain. The increase in size and complexity of our brains opened the way to a spectacular development of cognitive and mental skills. This expansion during evolution facilitated the addition of archetypical microcircuits, which increased the complexity of the human brain and contributed to its uniqueness. However, fundamental differences even exist between distinct mammalian species. Here, we shall discuss the issue of our humanity from a neurobiological and historical perspective.

  4. The Evolution of the Brain, the Human Nature of Cortical Circuits, and Intellectual Creativity

    Science.gov (United States)

    DeFelipe, Javier

    2011-01-01

    The tremendous expansion and the differentiation of the neocortex constitute two major events in the evolution of the mammalian brain. The increase in size and complexity of our brains opened the way to a spectacular development of cognitive and mental skills. This expansion during evolution facilitated the addition of microcircuits with a similar basic structure, which increased the complexity of the human brain and contributed to its uniqueness. However, fundamental differences even exist between distinct mammalian species. Here, we shall discuss the issue of our humanity from a neurobiological and historical perspective. PMID:21647212

  5. Theoretical Implications of Contemporary Brain Science for Japanese EFL Learning

    Science.gov (United States)

    Clayton, John Lloyd

    2015-01-01

    Recent advances in brain science show that adult native Japanese speakers utilize a different balance of language processing routes in the brain as compared to native English speakers. Biologically this represents the remarkable flexibility of the human brain to adapt universal human cognitive processes to fit the specific needs of linguistic and…

  6. The Isoenergetic Brain : The Idea and Some Implications

    NARCIS (Netherlands)

    Korf, Jakob

    2010-01-01

    The brain is often considered an ensemble of clusters of independently interacting neurons. Here the brain is proposed as an isoenergetic structure having little energy barriers that limit the distribution of neuronal information, thereby facilitating unitary brain functioning. Isoenergicity is achi

  7. Brain-Based Education: Its Pedagogical Implications and Research Relevance

    Science.gov (United States)

    Laxman, Kumar; Chin, Yap Kueh

    2010-01-01

    The brain, being the organ of learning, must be understood if classrooms are to be places of meaningful learning. Understanding the brain has the potential to alter the foundation of education, transform traditional classrooms to interactive learning environments and promote better instructional approaches amongst teachers. Brain-based education…

  8. Brain size and thermoregulation during the evolution of the genus Homo.

    Science.gov (United States)

    Naya, Daniel E; Naya, Hugo; Lessa, Enrique P

    2016-01-01

    Several hypotheses have been proposed to explain the evolution of an energetically costly brain in the genus Homo. Some of these hypotheses are based on the correlation between climatic factors and brain size recorded for this genus during the last millions of years. In this study, we propose a complementary climatic hypothesis that is based on the mechanistic connection between temperature, thermoregulation, and size of internal organs in endothermic species. We hypothesized that global cooling during the last 3.2 my may have imposed an increased energy expenditure for thermoregulation, which in the case of hominids could represent a driver for the evolution of an expanded brain, or at least, it could imply the relaxation of a negative selection pressure acting upon this costly organ. To test this idea, here we (1) assess variation in the energetic costs of thermoregulation and brain maintenance for the last 3.2 my, and (2) evaluate the relationship between Earth temperature and brain maintenance cost for the same period, taking into account the effects of body mass and fossil age. We found that: (1) the energetic cost associated with brain enlargement represents an important fraction (between 47.5% and 82.5%) of the increase in energy needed for thermoregulation; (2) fossil age is a better predictor of brain maintenance cost than Earth temperature, suggesting that (at least) another factor correlated with time was more relevant than ambient temperature in brain size evolution; and (3) there is a significant negative correlation between the energetic cost of brain and Earth temperature, even after accounting for the effect of body mass and fossil age. Thus, our results expand the current energetic framework for the study of brain size evolution in our lineage by suggesting that a fall in Earth temperature during the last millions of years may have facilitated brain enlargement.

  9. The immune system mediates blood-brain barrier damage; Possible implications for pathophysiology of neuropsychiatric illnesses

    NARCIS (Netherlands)

    VanderWerf, YD; DeJongste, MJL; terHorst, GJ

    1995-01-01

    The immune system mediates blood-brain barrier damage; possible implications for pathophysiology of neuropsychiatric illnesses. In this investigation the effects of immune activation on the brain are characterized In order to study this, we used a model for chronic immune activation, the myocardial

  10. Development of the Adolescent Brain: Implications for Executive Function and Social Cognition

    Science.gov (United States)

    Blakemore, Sarah-Jayne; Choudhury, Suparna

    2006-01-01

    Adolescence is a time of considerable development at the level of behaviour, cognition and the brain. This article reviews histological and brain imaging studies that have demonstrated specific changes in neural architecture during puberty and adolescence, outlining trajectories of grey and white matter development. The implications of brain…

  11. Predator-driven brain size evolution in natural populations of Trinidadian killifish (Rivulus hartii).

    Science.gov (United States)

    Walsh, Matthew R; Broyles, Whitnee; Beston, Shannon M; Munch, Stephan B

    2016-07-13

    Vertebrates exhibit extensive variation in relative brain size. It has long been assumed that this variation is the product of ecologically driven natural selection. Yet, despite more than 100 years of research, the ecological conditions that select for changes in brain size are unclear. Recent laboratory selection experiments showed that selection for larger brains is associated with increased survival in risky environments. Such results lead to the prediction that increased predation should favour increased brain size. Work on natural populations, however, foreshadows the opposite trajectory of evolution; increased predation favours increased boldness, slower learning, and may thereby select for a smaller brain. We tested the influence of predator-induced mortality on brain size evolution by quantifying brain size variation in a Trinidadian killifish, Rivulus hartii, from communities that differ in predation intensity. We observed strong genetic differences in male (but not female) brain size between fish communities; second generation laboratory-reared males from sites with predators exhibited smaller brains than Rivulus from sites in which they are the only fish present. Such trends oppose the results of recent laboratory selection experiments and are not explained by trade-offs with other components of fitness. Our results suggest that increased male brain size is favoured in less risky environments because of the fitness benefits associated with faster rates of learning and problem-solving behaviour.

  12. Evolution of brain size in the Palaeognath lineage, with an emphasis on new zealand ratites.

    Science.gov (United States)

    Corfield, Jeremy R; Wild, J Martin; Hauber, Mark E; Parsons, Stuart; Kubke, M Fabiana

    2008-01-01

    Brain size in vertebrates varies principally with body size. Although many studies have examined the variation of brain size in birds, there is little information on Palaeognaths, which include the ratite lineage of kiwi, emu, ostrich and extinct moa, as well as the tinamous. Therefore, we set out to determine to what extent the evolution of brain size in Palaeognaths parallels that of other birds, i.e., Neognaths, by analyzing the variation in the relative sizes of the brain and cerebral hemispheres of several species of ratites and tinamous. Our results indicate that the Palaeognaths possess relatively smaller brains and cerebral hemispheres than the Neognaths, with the exception of the kiwi radiation (Apteryx spp.). The external morphology and relatively large size of the brain of Apteryx, as well as the relatively large size of its telencephalon, contrast with other Palaeognaths, including two species of historically sympatric moa, suggesting that unique selective pressures towards increasing brain size accompanied the evolution of kiwi. Indeed, the size of the cerebral hemispheres with respect to total brain size of kiwi is rivaled only by a handful of parrots and songbirds, despite a lack of evidence of any advanced behavioral/cognitive abilities such as those reported for parrots and crows. In addition, the enlargement in brain and telencephalon size of the kiwi occurs despite the fact that this is a precocial bird. These findings form an exception to, and hence challenge, the current rules that govern changes in relative brain size in birds.

  13. Sexual selection uncouples the evolution of brain and body size in pinnipeds.

    Science.gov (United States)

    Fitzpatrick, J L; Almbro, M; Gonzalez-Voyer, A; Hamada, S; Pennington, C; Scanlan, J; Kolm, N

    2012-07-01

    The size of the vertebrate brain is shaped by a variety of selective forces. Although larger brains (correcting for body size) are thought to confer fitness advantages, energetic limitations of this costly organ may lead to trade-offs, for example as recently suggested between sexual traits and neural tissue. Here, we examine the patterns of selection on male and female brain size in pinnipeds, a group where the strength of sexual selection differs markedly among species and between the sexes. Relative brain size was negatively associated with the intensity of sexual selection in males but not females. However, analyses of the rates of body and brain size evolution showed that this apparent trade-off between sexual selection and brain mass is driven by selection for increasing body mass rather than by an actual reduction in male brain size. Our results suggest that sexual selection has important effects on the allometric relationships of neural development.

  14. The evolution of the female sexual response concept: Treatment implications

    Directory of Open Access Journals (Sweden)

    Damjanović Aleksandar

    2013-01-01

    Full Text Available Sexual dysfunctions have been the most prevalent group of sexual disorders and include a large number of populations of both sexes. The research of sexual behavior and treatment of women with sexual distress arises many questions related to differences in sexual response of men and women. The conceptualization of this response in modern sexology has changed over time. The objective of our paper was to present the changes and evolution of the female’s sexual response concept in a summarized and integrated way, to analyze the expanded and revised definitions of the female sexual response as well as implications and recommendations of new approaches to diagnostics and treatment according to the established changes. The lack of adequate empirical basis of the female sexual response model is a critical question in the literature dealing with this issue. Some articles report that linear models demonstrate more correctly and precisely the sexual response of women with normal sexual functions in relation to women with sexual dysfunction. Modification of this model later resulted in a circular model which more adequately presented the sexual response of women with sexual function disorder than of women with normal sexual function. The nonlinear model of female sexual response constructed by Basson incorporates the value of emotional intimacy, sexual stimulus and satisfaction with the relationship. Female functioning is significantly affected by multiple psychosocial factors such as satisfaction with the relationship, self-image, earlier negative sexual experience, etc. Newly revised, expanded definitions of female sexual dysfunction try to contribute to new knowledge about a highly contextual nature of woman’s sexuality so as to enhance clinical treatment of dysfunctions. The definitions emphasize the evaluation of the context of women’s problematic sexual experiences.

  15. The evolution of the female sexual response concept: treatment implications.

    Science.gov (United States)

    Damjanović, Aleksandar; Duisin, Dragana; Barisić, Jasmina

    2013-01-01

    Sexual dysfunctions have been the most prevalent group of sexual disorders and include a large number of populations of both sexes.The research of sexual behavior and treatment of women with sexual distress arises many questions related to differences in sexual response of men and women. The conceptualization of this response in modern sexology has changed over time.The objective of our paper was to present the changes and evolution of the female's sexual response concept in a summarized and integrated way, to analyze the expanded and revised definitions of the female sexual response as well as implications and recommendations of new approaches to diagnostics and treatment according to the established changes.The lack of adequate empirical basis of the female sexual response model is a critical question in the literature dealing with this issue. Some articles report that linear models demonstrate more correctly and precisely the sexual response of women with normal sexual functions in relation to women with sexual dysfunction. Modification of this model later resulted in a circular model which more adequately presented the sexual response of women with sexual function disorder than of women with normal sexual function.The nonlinear model of female sexual response constructed by Basson incorporates the value of emotional intimacy, sexual stimulus and satisfaction with the relationship. Female functioning is significantly affected by multiple psychosocial factors such as satisfaction with the relationship, self-image, earlier negative sexual experience, etc. Newly revised, expanded definitions of female sexual dysfunction try to contribute to new knowledge about a highly contextual nature of woman's sexuality so as to enhance clinical treatment of dysfunctions.The definitions emphasize the evaluation of the context of women's problematic sexual experiences.

  16. Brain structure evolution in a basal vertebrate clade: evidence from phylogenetic comparative analysis of cichlid fishes

    Directory of Open Access Journals (Sweden)

    Kolm Niclas

    2009-09-01

    Full Text Available Abstract Background The vertebrate brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. On the one hand, according to the 'mosaic evolution hypothesis', because of the elevated metabolic cost of brain tissue, selection is expected to target specific structures mediating the cognitive abilities which are being favored. On the other hand, the 'concerted evolution hypothesis' argues that developmental constraints limit such mosaic evolution and instead the size of the entire brain varies in response to selection on any of its constituent parts. To date, analyses of these hypotheses of brain evolution have been limited to mammals and birds; excluding Actinopterygii, the basal and most diverse class of vertebrates. Using a combination of recently developed phylogenetic multivariate allometry analyses and comparative methods that can identify distinct rates of evolution, even in highly correlated traits, we studied brain structure evolution in a highly variable clade of ray-finned fishes; the Tanganyikan cichlids. Results Total brain size explained 86% of the variance in brain structure volume in cichlids, a lower proportion than what has previously been reported for mammals. Brain structures showed variation in pair-wise allometry suggesting some degree of independence in evolutionary changes in size. This result is supported by variation among structures on the strength of their loadings on the principal size axis of the allometric analysis. The rate of evolution analyses generally supported the results of the multivariate allometry analyses, showing variation among several structures in their evolutionary patterns. The olfactory bulbs and hypothalamus were found to evolve faster than other structures while the dorsal medulla presented the slowest evolutionary rate. Conclusion Our results favor a mosaic model of brain evolution, as certain

  17. Sex differences in brain organization: implications for human communication.

    Science.gov (United States)

    Hanske-Petitpierre, V; Chen, A C

    1985-12-01

    This article reviews current knowledge in two major research domains: sex differences in neuropsychophysiology, and in human communication. An attempt was made to integrate knowledge from several areas of brain research with human communication and to clarify how such a cooperative effort may be beneficial to both fields of study. By combining findings from the area of brain research, a communication paradigm was developed which contends that brain-related sex differences may reside largely in the area of communication of emotion.

  18. Art and brain: insights from neuropsychology, biology and evolution.

    Science.gov (United States)

    Zaidel, Dahlia W

    2010-02-01

    Art is a uniquely human activity associated fundamentally with symbolic and abstract cognition. Its practice in human societies throughout the world, coupled with seeming non-functionality, has led to three major brain theories of art. (1) The localized brain regions and pathways theory links art to multiple neural regions. (2) The display of art and its aesthetics theory is tied to the biological motivation of courtship signals and mate selection strategies in animals. (3) The evolutionary theory links the symbolic nature of art to critical pivotal brain changes in Homo sapiens supporting increased development of language and hierarchical social grouping. Collectively, these theories point to art as a multi-process cognition dependent on diverse brain regions and on redundancy in art-related functional representation.

  19. Toward the Language-Ready Brain: Biological Evolution and Primate Comparisons.

    Science.gov (United States)

    Arbib, Michael A

    2017-02-01

    The approach to language evolution suggested here focuses on three questions: How did the human brain evolve so that humans can develop, use, and acquire languages? How can the evolutionary quest be informed by studying brain, behavior, and social interaction in monkeys, apes, and humans? How can computational modeling advance these studies? I hypothesize that the brain is language ready in that the earliest humans had protolanguages but not languages (i.e., communication systems endowed with rich and open-ended lexicons and grammars supporting a compositional semantics), and that it took cultural evolution to yield societies (a cultural constructed niche) in which language-ready brains could become language-using brains. The mirror system hypothesis is a well-developed example of this approach, but I offer it here not as a closed theory but as an evolving framework for the development and analysis of conflicting subhypotheses in the hope of their eventual integration. I also stress that computational modeling helps us understand the evolving role of mirror neurons, not in and of themselves, but only in their interaction with systems "beyond the mirror." Because a theory of evolution needs a clear characterization of what it is that evolved, I also outline ideas for research in neurolinguistics to complement studies of the evolution of the language-ready brain. A clear challenge is to go beyond models of speech comprehension to include sign language and models of production, and to link language to visuomotor interaction with the physical and social world.

  20. Adolescent Brain Development and Implications for Classroom Management

    Science.gov (United States)

    Mears, Derrick

    2012-01-01

    Studies using Magnetic Resonance Imaging (MRI) to observe the adolescent brain have shown that during adolescence multiple changes are occurring. This can provide a potential explanation for the sporadic and seemingly unpredictable behaviors that appear. It is believed that the brain of an adolescent goes through a profound neurological…

  1. Plasticity in the Developing Brain: Implications for Rehabilitation

    Science.gov (United States)

    Johnston, Michael V.

    2009-01-01

    Neuronal plasticity allows the central nervous system to learn skills and remember information, to reorganize neuronal networks in response to environmental stimulation, and to recover from brain and spinal cord injuries. Neuronal plasticity is enhanced in the developing brain and it is usually adaptive and beneficial but can also be maladaptive…

  2. Familial Alzheimer's disease: genetic analysis related to disease heterogeneity, Down syndrome and human brain evolution.

    Science.gov (United States)

    Schapiro, M B; Rapoport, S I

    1989-01-01

    Etiologically heterogeneous subgroups of patients with Alzheimer's disease (AD) exist and need to be distinguished so as to better identify genetic causes of familial cases. Furthermore, the presence of AD neuropathology in Down syndrome (trisomy 21) subjects older than 35 years suggests that AD in some cases is caused by dysregulation of expression of genes on chromosome 21. Cerebral metabolic abnormalities in life, and the distribution of AD neuropathology in the post-mortem brain, indicate that AD involves the association neocortices and subcortical regions with which they evolved during evolution of the human brain. Accordingly, understanding the molecular basis of this evolution should elucidate the genetic basis of AD, whereas knowing the genetics of AD should be informative about the genomic changes which promoted brain evolution.

  3. The Evolution of the Language Faculty: Clarifications and Implications

    Science.gov (United States)

    Fitch, W. Tecumseh; Hauser, Marc D.; Chomsky, Noam

    2005-01-01

    In this response to Pinker and Jackendoff's critique, we extend our previous framework for discussion of language evolution, clarifying certain distinctions and elaborating on a number of points. In the first half of the paper, we reiterate that profitable research into the biology and evolution of language requires fractionation of ''language''…

  4. Brain-computer interface supported collaborative work: Implications for rehabilitation.

    Science.gov (United States)

    Nam, C S; Lee, J; Bahn, S

    2013-01-01

    Working together and collaborating in a group can provide greater benefits for people with severe motor disability. However, it is still not clear how collaboration should be supported by BCI systems. The present study explored BCI-supported collaborative work by investigating differences in performance and brain activity between when a pair of users performs a task jointly with each other and when they do alone only through means of their brain activity. We found differences in performance and brain activity between different work conditions. The results of this research should provide fundamental knowledge of BCI-supported cooperative work.

  5. The effect of brain size evolution on feeding propensity, digestive efficiency, and juvenile growth.

    Science.gov (United States)

    Kotrschal, Alexander; Corral-Lopez, Alberto; Szidat, Sönke; Kolm, Niclas

    2015-11-01

    One key hypothesis in the study of brain size evolution is the expensive tissue hypothesis; the idea that increased investment into the brain should be compensated by decreased investment into other costly organs, for instance the gut. Although the hypothesis is supported by both comparative and experimental evidence, little is known about the potential changes in energetic requirements or digestive traits following such evolutionary shifts in brain and gut size. Organisms may meet the greater metabolic requirements of larger brains despite smaller guts via increased food intake or better digestion. But increased investment in the brain may also hamper somatic growth. To test these hypotheses we here used guppy (Poecilia reticulata) brain size selection lines with a pronounced negative association between brain and gut size and investigated feeding propensity, digestive efficiency (DE), and juvenile growth rate. We did not find any difference in feeding propensity or DE between large- and small-brained individuals. Instead, we found that large-brained females had slower growth during the first 10 weeks after birth. Our study provides experimental support that investment into larger brains at the expense of gut tissue carries costs that are not necessarily compensated by a more efficient digestive system.

  6. Brain evolution: when is a group not a group?

    Science.gov (United States)

    Byrne, Richard W; Bates, Lucy A

    2007-10-23

    In testing the 'social brain hypothesis' with comparative data, most research has used group size as an index of cognitive challenge. Recent work suggests that this measure is too crude to apply to a wide range of species, and biologists may need to develop other ways of extending these analyses.

  7. Allomaternal care, life history and brain size evolution in mammals.

    Science.gov (United States)

    Isler, Karin; van Schaik, Carel P

    2012-07-01

    Humans stand out among the apes by having both an extremely large brain and a relatively high reproductive output, which has been proposed to be a consequence of cooperative breeding. Here, we test for general correlates of allomaternal care in a broad sample of 445 mammal species, by examining life history traits, brain size, and different helping behaviors, such as provisioning, carrying, huddling or protecting the offspring and the mother. As predicted from an energetic-cost perspective, a positive correlation between brain size and the amount of help by non-mothers is found among mammalian clades as a whole and within most groups, especially carnivores, with the notable exception of primates. In the latter group, the presence of energy subsidies during breeding instead resulted in increased fertility, up to the extreme of twinning in callitrichids, as well as a more altricial state at birth. In conclusion, humans exhibit a combination of the pattern found in provisioning carnivores, and the enhanced fertility shown by cooperatively breeding primates. Our comparative results provide support for the notion that cooperative breeding allowed early humans to sidestep the generally existing trade-off between brain size and reproductive output, and suggest an alternative explanation to the controversial 'obstetrical dilemma'-argument for the relatively altricial state of human neonates at birth.

  8. The implications of brain connectivity in the neuropsychology of autism

    OpenAIRE

    2014-01-01

    Autism is a neurodevelopmental disorder that has been associated with atypical brain functioning. Functional connectivity MRI (fcMRI) studies examining neural networks in autism have seen an exponential rise over the last decade. Such investigations have led to characterization of autism as a distributed neural systems disorder. Studies have found widespread cortical underconnectivity, local overconnectivity, and mixed results suggesting disrupted brain connectivity as a potential neural sign...

  9. Human brain evolution: from gene discovery to phenotype discovery.

    Science.gov (United States)

    Preuss, Todd M

    2012-06-26

    The rise of comparative genomics and related technologies has added important new dimensions to the study of human evolution. Our knowledge of the genes that underwent expression changes or were targets of positive selection in human evolution is rapidly increasing, as is our knowledge of gene duplications, translocations, and deletions. It is now clear that the genetic differences between humans and chimpanzees are far more extensive than previously thought; their genomes are not 98% or 99% identical. Despite the rapid growth in our understanding of the evolution of the human genome, our understanding of the relationship between genetic changes and phenotypic changes is tenuous. This is true even for the most intensively studied gene, FOXP2, which underwent positive selection in the human terminal lineage and is thought to have played an important role in the evolution of human speech and language. In part, the difficulty of connecting genes to phenotypes reflects our generally poor knowledge of human phenotypic specializations, as well as the difficulty of interpreting the consequences of genetic changes in species that are not amenable to invasive research. On the positive side, investigations of FOXP2, along with genomewide surveys of gene-expression changes and selection-driven sequence changes, offer the opportunity for "phenotype discovery," providing clues to human phenotypic specializations that were previously unsuspected. What is more, at least some of the specializations that have been proposed are amenable to testing with noninvasive experimental techniques appropriate for the study of humans and apes.

  10. Brain evolution, the determinates of food choice, and the omnivore's dilemma.

    Science.gov (United States)

    Armelagos, George J

    2014-01-01

    A coevolutionary paradigm using a biocultural perspective can help to unravel the complex interactions that led to the contemporary pattern of eating. Evolutionary history helps to understand the adaptation of diet and its nutritional implications. Anatomical and behavioral changes linked to changing dietary patterns in the Paleolithic resulted in an adaptive framework that affects modern diet. The evolution of an expanding brain, a shrinking large intestine, and lengthening small intestine necessitated a demand for nutritionally dense foods. The key to these changes is an understanding of the response to the omnivore's dilemma. Omnivores in their search for new items to feed their varied diet (neophilia) have a challenge when they fear (neophobia) novel items that may be poisonous and can cause death. The inborn mechanism initiates palate fatigue (sensory-specific satiety) ensuring a variety of foods will be eaten. Variety will limit the impact of toxins ingested and provide a more balanced diet. The development of cuisine, a momentous event in history, mediated the conflict, and changed the course of human evolution. The cuisine, a biocultural construct, defines which items found in nature are edible, how these products are transformed into food, the flavors used to add a sensory dimension to foods, and rules of eating or etiquette. Etiquette defines how, when, and with whom we eat. Patterns of eating in the modern setting are the end product of the way that Homo sapiens evolved and resolved the omnivore's dilemma. Control of fire and cooking expanded the range of available foods by creating a class of foods that are "predigested." An essential element to the evolution of the human diet was the transition to agriculture as the primary mode of subsistence. The Neolithic revolution dramatically narrowed the dietary niche by decreasing the variety of available foods, with the shift to intensive agriculture creating a dramatic decline in human nutrition. The recent

  11. The importance of energy and nutrient supply in human brain evolution.

    Science.gov (United States)

    Cunnane, S C; Harbige, L S; Crawford, M A

    1993-01-01

    Current evolutionary theories do not adequately address the question of how the human brain evolved to be larger and more sophisticated than that of other primates. The human brain/body weight ratio is 4-5 times higher than in primates and, relative to the rest of the body, requires up to 10 times as much energy as in other land-based mammals. Human brain evolution must therefore have required a stable food supply providing a reliable source of both high dietary energy and a cluster of 'brain-specific' nutrients over a long period of time. These nutrient and energy requirements are available in the marine and shore-based food chain but are difficult if not impossible to obtain in the terrestrial food chain. We suggest that marine and estuarine ecosystems provided hominids with the appropriate stimulus to develop a relatively large brain. This occurred in conjunction with the evolution of other uniquely human features, particularly relative hairlessness, bipedalism and abundant neonatal subcutaneous fat. Invertebrates, molluscs, small or slow-moving fish, and marine algae would have provided a stable, abundant supply of energy, long chain polyunsaturates and other nutrients essential for the brain and would have done so with comparatively little mammalian competition. The land-water interface would thus have allowed the hominid brain to develop sufficient neurological complexity to enable sophisticated tool and behaviour patterns to evolve in humans as a natural sequel to such a biochemical and environmental stimulus.

  12. Brain Behavior Evolution during Learning: Emergence of Hierarchical Temporal Memory

    Science.gov (United States)

    2013-08-30

    ORGANIZATION NAMES AND ADDRESSES U.S. Army Research Office P.O. Box 12211 Research Triangle Park , NC 27709-2211 15. SUBJECT TERMS brain model, Hopfield... topological organization that is commonly found in several complex systems. As an organization tool, it detects and measures significant features...nodes that are already highly connected are more likely to receive one of the new connections [5]. These networks reflect a theme described as “the

  13. Convergent evolution of brain morphology and communication modalities in lizards

    Institute of Scientific and Technical Information of China (English)

    Christopher D.ROBINSON; Michael S.PATTON; Brittney M.ANDRE; Michele A.JOHNSON

    2015-01-01

    Animals communicate information within their environments via visual,chemical,auditory,and/or tactile modalities.The use of each modalityis generally linked to particular brain regions,but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species.Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey,and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals.Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals.For each species,we performed behavioral observations and quantified rates of visual and chemical behaviors.We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lateral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus).With analyses conducted in a phylogenetic context,we found that species that performed higher rates of visual displays had a denser lateral geniculatc nucleus,and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus.These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors [Current Zoology 61 (2):281-291,2015].

  14. History and evolution of brain tumor imaging: insights through radiology.

    Science.gov (United States)

    Castillo, Mauricio

    2014-11-01

    This review recounts the history of brain tumor diagnosis from antiquity to the present and, indirectly, the history of neuroradiology. Imaging of the brain has from the beginning held an enormous interest because of the inherent difficulty of this endeavor due to the presence of the skull. Because of this, most techniques when newly developed have always been used in neuroradiology and, although some have proved to be inappropriate for this purpose, many were easily incorporated into the specialty. The first major advance in modern neuroimaging was contrast agent-enhanced computed tomography, which permitted accurate anatomic localization of brain tumors and, by virtue of contrast enhancement, malignant ones. The most important advances in neuroimaging occurred with the development of magnetic resonance imaging and diffusion-weighted sequences that allowed an indirect estimation of tumor cellularity; this was further refined by the development of perfusion and permeability mapping. From its beginnings with indirect and purely anatomic imaging techniques, neuroradiology now uses a combination of anatomic and physiologic techniques that will play a critical role in biologic tumor imaging and radiologic genomics.

  15. Evolution of brain and culture: the neurological and cognitive journey from Australopithecus to Albert Einstein.

    Science.gov (United States)

    Falk, Dean

    2016-06-20

    Fossil and comparative primatological evidence suggest that alterations in the development of prehistoric hominin infants kindled three consecutive evolutionary-developmental (evo-devo) trends that, ultimately, paved the way for the evolution of the human brain and cognition. In the earliest trend, infants' development of posture and locomotion became delayed because of anatomical changes that accompanied the prolonged evolution of bipedalism. Because modern humans have inherited these changes, our babies are much slower than other primates to reach developmental milestones such as standing, crawling, and walking. The delay in ancestral babies' physical development eventually precipitated an evolutionary reversal in which they became increasing unable to cling independently to their mothers. For the first time in prehistory, babies were, thus, periodically deprived of direct physical contact with their mothers. This prompted the emergence of a second evo-devo trend in which infants sought contact comfort from caregivers using evolved signals, including new ways of crying that are conserved in modern babies. Such signaling stimulated intense reciprocal interactions between prehistoric mothers and infants that seeded the eventual emergence of motherese and, subsequently, protolanguage. The third trend was for an extreme acceleration in brain growth that began prior to the last trimester of gestation and continued through infants' first postnatal year (early "brain spurt"). Conservation of this trend in modern babies explains why human brains reach adult sizes that are over three times those of chimpanzees. The fossil record of hominin cranial capacities together with comparative neuroanatomical data suggest that, around 3 million years ago, early brain spurts began to facilitate an evolutionary trajectory for increasingly large adult brains in association with neurological reorganization. The prehistoric increase in brain size eventually caused parturition to become

  16. Relative brain size, gut size, and evolution in New World monkeys.

    Science.gov (United States)

    Hartwig, Walter; Rosenberger, Alfred L; Norconk, Marilyn A; Owl, Marcus Young

    2011-12-01

    The dynamics of brain evolution in New World monkeys are poorly understood. New data on brain weight and body weight from 162 necropsied adult individuals, and a second series on body weight and gut size from 59 individuals, are compared with previously published reports based on smaller samples as well as large databases derived from museum records. We confirm elevated brain sizes for Cebus and Saimiri and also report that Cacajao and Chiropotes have relatively large brains. From more limited data we show that gut size and brain mass have a strongly inverse relationship at the low end of the relative brain size scale but a more diffuse interaction at the upper end, where platyrrhines with relatively high encephalization quotients may have either relatively undifferentiated guts or similar within-gut proportions to low-EQ species. Three of the four main platyrrhine clades exhibit a wide range of relative brain sizes, suggesting each may have differentiated while brains were relatively small and a multiplicity of forces acting to maintain or drive encephalization. Alouatta is a likely candidate for de-encephalization, although its "starting point" is difficult to establish. Factors that may have compelled parallel evolution of relatively large brains in cebids, atelids and pitheciids may involve large social group sizes as well as complex foraging strategies, with both aspects exaggerated in the hyper-encephalized Cebus. With diet playing an important role selecting for digestive strategies among the seed-eating pitheciins, comparable in ways to folivores, Chiropotes evolved a relatively larger brain in conjunction with a moderately large and differentiated gut.

  17. Elephant brain. Part I: gross morphology, functions, comparative anatomy, and evolution.

    Science.gov (United States)

    Shoshani, Jeheskel; Kupsky, William J; Marchant, Gary H

    2006-06-30

    We report morphological data on brains of four African, Loxodonta africana, and three Asian elephants, Elephas maximus, and compare findings to literature. Brains exhibit a gyral pattern more complex and with more numerous gyri than in primates, humans included, and in carnivores, but less complex than in cetaceans. Cerebral frontal, parietal, temporal, limbic, and insular lobes are well developed, whereas the occipital lobe is relatively small. The insula is not as opercularized as in man. The temporal lobe is disproportionately large and expands laterally. Humans and elephants have three parallel temporal gyri: superior, middle, and inferior. Hippocampal sizes in elephants and humans are comparable, but proportionally smaller in elephant. A possible carotid rete was observed at the base of the brain. Brain size appears to be related to body size, ecology, sociality, and longevity. Elephant adult brain averages 4783 g, the largest among living and extinct terrestrial mammals; elephant neonate brain averages 50% of its adult brain weight (25% in humans). Cerebellar weight averages 18.6% of brain (1.8 times larger than in humans). During evolution, encephalization quotient has increased by 10-fold (0.2 for extinct Moeritherium, approximately 2.0 for extant elephants). We present 20 figures of the elephant brain, 16 of which contain new material. Similarities between human and elephant brains could be due to convergent evolution; both display mosaic characters and are highly derived mammals. Humans and elephants use and make tools and show a range of complex learning skills and behaviors. In elephants, the large amount of cerebral cortex, especially in the temporal lobe, and the well-developed olfactory system, structures associated with complex learning and behavioral functions in humans, may provide the substrate for such complex skills and behavior.

  18. Brain CB2 Receptors: Implications for Neuropsychiatric Disorders

    Directory of Open Access Journals (Sweden)

    Michelle Roche

    2010-08-01

    Full Text Available Although previously thought of as the peripheral cannabinoid receptor, it is now accepted that the CB2 receptor is expressed in the central nervous system on microglia, astrocytes and subpopulations of neurons. Expression of the CB2 receptor in the brain is significantly lower than that of the CB1 receptor. Conflicting findings have been reported on the neurological effects of pharmacological agents targeting the CB2 receptor under normal conditions. Under inflammatory conditions, CB2 receptor expression in the brain is enhanced and CB2 receptor agonists exhibit potent anti-inflammatory effects. These findings have prompted research into the CB2 receptor as a possible target for the treatment of neuroinflammatory and neurodegenerative disorders. Neuroinflammatory alterations are also associated with neuropsychiatric disorders and polymorphisms in the CB2 gene have been reported in depression, eating disorders and schizophrenia. This review will examine the evidence to date for a role of brain CB2 receptors in neuropsychiatric disorders.

  19. A Video Game for Learning Brain Evolution: A Resource or a Strategy?

    Science.gov (United States)

    Barbosa Gomez, Luisa Fernanda; Bohorquez Sotelo, Maria Cristina; Roja Higuera, Naydu Shirley; Rodriguez Mendoza, Brigitte Julieth

    2016-01-01

    Learning resources are part of the educational process of students. However, how video games act as learning resources in a population that has not selected the virtual formation as their main methodology? The aim of this study was to identify the influence of a video game in the learning process of brain evolution. For this purpose, the opinions…

  20. Cloning Dropouts: Implications for Galaxy Evolution at High Redshift

    CERN Document Server

    Bouwens, R J; Illingworth, G D; Bouwens, Rychard J.; Broadhurst, Tom; Illingworth, Garth

    2003-01-01

    The evolution of high redshift galaxies in the two Hubble Deep Fields, HDF-N and HDF-S, is investigated using a cloning technique that replicates z~ 2-3 U dropouts to higher redshifts, allowing a comparison with the observed B and V dropouts at higher redshifts (z ~ 4-5). We treat each galaxy selected for replication as a set of pixels that are k-corrected to higher redshift, accounting for resampling, shot-noise, surface-brightness dimming, and the cosmological model. We find evidence for size evolution (a 1.7x increase) from z ~ 5 to z ~ 2.7 for flat geometries (Omega_M+Omega_LAMBDA=1.0). Simple scaling laws for this cosmology predict that size evolution goes as (1+z)^{-1}, consistent with our result. The UV luminosity density shows a similar increase (1.85x) from z ~ 5 to z ~ 2.7, with minimal evolution in the distribution of intrinsic colors for the dropout population. In general, these results indicate less evolution than was previously reported, and therefore a higher luminosity density at z ~ 4-5 (~ 50...

  1. Detecting positive darwinian selection in brain-expressed genes during human evolution

    Institute of Scientific and Technical Information of China (English)

    QI XueBin; Alice A. LIN; Luca L. CAVALLI-SFORZA; WANG Jun; SU Bing; YANG Su; ZHENG HongKun; WANG YinQiu; LIAO ChengHong; LIU Ying; CHEN XiaoHua; SHI Hong; YU XiaoJing

    2007-01-01

    To understand the genetic basis that underlies the phenotypic divergence between human and nonhuman primates, we screened a total of 7176 protein-coding genes expressed in the human brain and compared them with the chimpanzee orthologs to identify genes that show evidence of rapid evolution in the human lineage. Our results showed that the nonsynonymous/synonymous substitution (Ka/Ks) ratio for genes expressed in the brain of human and chimpanzee is 0.3854, suggesting that the brain-expressed genes are under functional constraint. The X-linked human brain-expressed genes evolved more rapidly than autosomal ones. We further dissected the molecular evolutionary patterns of 34 candidate genes by sequencing representative primate species to identify lineage-specific adaptive evolution. Fifteen out of the 34 candidate genes showed evidence of positive Darwinian selection in human and/or chimpanzee lineages. These genes are predicted to play diverse functional roles in embryonic development, spermatogenesis and male fertility, signal transduction, sensory nociception, and neural function. This study together with others demonstrated the usefulness and power of phylogenetic comparison of multiple closely related species in detecting lineage-specific adaptive evolution, and the identification of the positively selected brain-expressed genes may add new knowledge to the understanding of molecular mechanism of human origin.

  2. Comparative Methylome Analyses Identify Epigenetic Regulatory Loci of Human Brain Evolution.

    Science.gov (United States)

    Mendizabal, Isabel; Shi, Lei; Keller, Thomas E; Konopka, Genevieve; Preuss, Todd M; Hsieh, Tzung-Fu; Hu, Enzhi; Zhang, Zhe; Su, Bing; Yi, Soojin V

    2016-11-01

    How do epigenetic modifications change across species and how do these modifications affect evolution? These are fundamental questions at the forefront of our evolutionary epigenomic understanding. Our previous work investigated human and chimpanzee brain methylomes, but it was limited by the lack of outgroup data which is critical for comparative (epi)genomic studies. Here, we compared whole genome DNA methylation maps from brains of humans, chimpanzees and also rhesus macaques (outgroup) to elucidate DNA methylation changes during human brain evolution. Moreover, we validated that our approach is highly robust by further examining 38 human-specific DMRs using targeted deep genomic and bisulfite sequencing in an independent panel of 37 individuals from five primate species. Our unbiased genome-scan identified human brain differentially methylated regions (DMRs), irrespective of their associations with annotated genes. Remarkably, over half of the newly identified DMRs locate in intergenic regions or gene bodies. Nevertheless, their regulatory potential is on par with those of promoter DMRs. An intriguing observation is that DMRs are enriched in active chromatin loops, suggesting human-specific evolutionary remodeling at a higher-order chromatin structure. These findings indicate that there is substantial reprogramming of epigenomic landscapes during human brain evolution involving noncoding regions.

  3. The implications of brain connectivity in the neuropsychology of autism.

    Science.gov (United States)

    Maximo, Jose O; Cadena, Elyse J; Kana, Rajesh K

    2014-03-01

    Autism is a neurodevelopmental disorder that has been associated with atypical brain functioning. Functional connectivity MRI (fcMRI) studies examining neural networks in autism have seen an exponential rise over the last decade. Such investigations have led to the characterization of autism as a distributed neural systems disorder. Studies have found widespread cortical underconnectivity, local overconnectivity, and mixed results suggesting disrupted brain connectivity as a potential neural signature of autism. In this review, we summarize the findings of previous fcMRI studies in autism with a detailed examination of their methodology, in order to better understand its potential and to delineate the pitfalls. We also address how a multimodal neuroimaging approach (incorporating different measures of brain connectivity) may help characterize the complex neurobiology of autism at a global level. Finally, we also address the potential of neuroimaging-based markers in assisting neuropsychological assessment of autism. The quest for a neural marker for autism is still ongoing, yet new findings suggest that aberrant brain connectivity may be a promising candidate.

  4. Brain expressed microRNAs implicated in schizophrenia etiology

    DEFF Research Database (Denmark)

    Hansen, Thomas; Olsen, Line; Lindow, Morten;

    2007-01-01

    Protein encoding genes have long been the major targets for research in schizophrenia genetics. However, with the identification of regulatory microRNAs (miRNAs) as important in brain development and function, miRNAs genes have emerged as candidates for schizophrenia-associated genetic factors...

  5. Evolution of the aging brain transcriptome and synaptic regulation.

    Directory of Open Access Journals (Sweden)

    Patrick M Loerch

    Full Text Available Alzheimer's disease and other neurodegenerative disorders of aging are characterized by clinical and pathological features that are relatively specific to humans. To obtain greater insight into how brain aging has evolved, we compared age-related gene expression changes in the cortex of humans, rhesus macaques, and mice on a genome-wide scale. A small subset of gene expression changes are conserved in all three species, including robust age-dependent upregulation of the neuroprotective gene apolipoprotein D (APOD and downregulation of the synaptic cAMP signaling gene calcium/calmodulin-dependent protein kinase IV (CAMK4. However, analysis of gene ontology and cell type localization shows that humans and rhesus macaques have diverged from mice due to a dramatic increase in age-dependent repression of neuronal genes. Many of these age-regulated neuronal genes are associated with synaptic function. Notably, genes associated with GABA-ergic inhibitory function are robustly age-downregulated in humans but not in mice at the level of both mRNA and protein. Gene downregulation was not associated with overall neuronal or synaptic loss. Thus, repression of neuronal gene expression is a prominent and recently evolved feature of brain aging in humans and rhesus macaques that may alter neural networks and contribute to age-related cognitive changes.

  6. Cognition in patients with newly diagnosed brain metastasis: profiles and implications.

    Science.gov (United States)

    Gerstenecker, Adam; Nabors, Louis B; Meneses, Karen; Fiveash, John B; Marson, Daniel C; Cutter, Gary; Martin, Roy C; Meyers, Christina A; Triebel, Kristen L

    2014-10-01

    Cognitive impairment is a common symptom in patients with brain metastasis, and significant cognitive dysfunction is prevalent in a majority of patients who are still able to engage in basic self-care activities. In the current study, the neurocognitive performance of 32 patients with brain metastasis and 32 demographically-matched controls was examined using a battery of standardized neuropsychological tests, with the goal of comprehensively examining the cognitive functioning of newly diagnosed brain metastasis patients. The cognition of all patients was assessed within 1 week of beginning treatment for brain metastasis. Results indicated impairments in verbal memory, attention, executive functioning, and language in relation to healthy controls. Performance in relation to appropriate normative groups was also examined. Overall, cognitive deficits were prevalent and memory was the most common impairment. Given that cognitive dysfunction was present in this cohort of patients with largely minimal functional impairment, these results have implications for patients, caregivers and health care providers treating patients with brain metastasis.

  7. Evolutionary development of embryonic cerebrospinal fluid composition and regulation: an open research field with implications for brain development and function.

    Science.gov (United States)

    Bueno, David; Garcia-Fernàndez, Jordi

    2016-03-15

    Within the consolidated field of evolutionary development, there is emerging research on evolutionary aspects of central nervous system development and its implications for adult brain structure and function, including behaviour. The central nervous system is one of the most intriguing systems in complex metazoans, as it controls all body and mind functions. Its failure is responsible for a number of severe and largely incurable diseases, including neurological and neurodegenerative ones. Moreover, the evolution of the nervous system is thought to be a critical step in the adaptive radiation of vertebrates. Brain formation is initiated early during development. Most embryological, genetic and evolutionary studies have focused on brain neurogenesis and regionalisation, including the formation and function of organising centres, and the comparison of homolog gene expression and function among model organisms from different taxa. The architecture of the vertebrate brain primordium also reveals the existence of connected internal cavities, the cephalic vesicles, which in fetuses and adults become the ventricular system of the brain. During embryonic and fetal development, brain cavities and ventricles are filled with a complex, protein-rich fluid called cerebrospinal fluid (CSF). However, CSF has not been widely analysed from either an embryological or evolutionary perspective. Recently, it has been demonstrated in higher vertebrates that embryonic cerebrospinal fluid has key functions in delivering diffusible signals and nutrients to the developing brain, thus contributing to the proliferation, differentiation and survival of neural progenitor cells, and to the expansion and patterning of the brain. Moreover, it has been shown that the composition and homeostasis of CSF are tightly controlled in a time-dependent manner from the closure of the anterior neuropore, just before the initiation of primary neurogenesis, up to the formation of functional choroid plexuses. In

  8. Adult sex ratio variation : Implications for breeding system evolution

    NARCIS (Netherlands)

    Szekely, T.; Weissing, F. J.; Komdeur, J.

    2014-01-01

    Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to

  9. Metabolic constraint imposes tradeoff between body size and number of brain neurons in human evolution.

    Science.gov (United States)

    Fonseca-Azevedo, Karina; Herculano-Houzel, Suzana

    2012-11-06

    Despite a general trend for larger mammals to have larger brains, humans are the primates with the largest brain and number of neurons, but not the largest body mass. Why are great apes, the largest primates, not also those endowed with the largest brains? Recently, we showed that the energetic cost of the brain is a linear function of its numbers of neurons. Here we show that metabolic limitations that result from the number of hours available for feeding and the low caloric yield of raw foods impose a tradeoff between body size and number of brain neurons, which explains the small brain size of great apes compared with their large body size. This limitation was probably overcome in Homo erectus with the shift to a cooked diet. Absent the requirement to spend most available hours of the day feeding, the combination of newly freed time and a large number of brain neurons affordable on a cooked diet may thus have been a major positive driving force to the rapid increased in brain size in human evolution.

  10. Adolescent Brain and Cognitive Developments: Implications for Clinical Assessment in Traumatic Brain Injury

    Science.gov (United States)

    Ciccia, Angela Hein; Meulenbroek, Peter; Turkstra, Lyn S.

    2009-01-01

    Adolescence is a time of significant physical, social, and emotional developments, accompanied by changes in cognitive and language skills. Underlying these are significant developments in brain structures and functions including changes in cortical and subcortical gray matter and white matter tracts. Among the brain regions that develop during…

  11. Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution

    Science.gov (United States)

    Seymour, Roger S.; Bosiocic, Vanya; Snelling, Edward P.

    2016-08-01

    The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.

  12. Convergent evolution of complex brains and high intelligence.

    Science.gov (United States)

    Roth, Gerhard

    2015-12-19

    Within the animal kingdom, complex brains and high intelligence have evolved several to many times independently, e.g. among ecdysozoans in some groups of insects (e.g. blattoid, dipteran, hymenopteran taxa), among lophotrochozoans in octopodid molluscs, among vertebrates in teleosts (e.g. cichlids), corvid and psittacid birds, and cetaceans, elephants and primates. High levels of intelligence are invariantly bound to multimodal centres such as the mushroom bodies in insects, the vertical lobe in octopodids, the pallium in birds and the cerebral cortex in primates, all of which contain highly ordered associative neuronal networks. The driving forces for high intelligence may vary among the mentioned taxa, e.g. needs for spatial learning and foraging strategies in insects and cephalopods, for social learning in cichlids, instrumental learning and spatial orientation in birds and social as well as instrumental learning in primates.

  13. The evolution of relative brain size in marsupials is energetically constrained but not driven by behavioral complexity.

    Science.gov (United States)

    Weisbecker, Vera; Blomberg, Simon; Goldizen, Anne W; Brown, Meredeth; Fisher, Diana

    2015-01-01

    Evolutionary increases in mammalian brain size relative to body size are energetically costly but are also thought to confer selective advantages by permitting the evolution of cognitively complex behaviors. However, many suggested associations between brain size and specific behaviors - particularly related to social complexity - are possibly confounded by the reproductive diversity of placental mammals, whose brain size evolution is the most frequently studied. Based on a phylogenetic generalized least squares analysis of a data set on the reproductively homogenous clade of marsupials, we provide the first quantitative comparison of two hypotheses based on energetic constraints (maternal investment and seasonality) with two hypotheses that posit behavioral selection on relative brain size (social complexity and environmental interactions). We show that the two behavioral hypotheses have far less support than the constraint hypotheses. The only unambiguous associates of brain size are the constraint variables of litter size and seasonality. We also found no association between brain size and specific behavioral complexity categories within kangaroos, dasyurids, and possums. The largest-brained marsupials after phylogenetic correction are from low-seasonality New Guinea, supporting the notion that low seasonality represents greater nutrition safety for brain maintenance. Alternatively, low seasonality might improve the maternal support of offspring brain growth. The lack of behavioral brain size associates, found here and elsewhere, supports the general 'cognitive buffer hypothesis' as the best explanatory framework of mammalian brain size evolution. However, it is possible that brain size alone simply does not provide sufficient resolution on the question of how brain morphology and cognitive capacities coevolve.

  14. Progress on the paternal brain: theory, animal models, human brain research, and mental health implications.

    Science.gov (United States)

    Swain, J E; Dayton, C J; Kim, P; Tolman, R M; Volling, B L

    2014-01-01

    With a secure foundation in basic research across mammalian species in which fathers participate in the raising of young, novel brain-imaging approaches are outlining a set of consistent brain circuits that regulate paternal thoughts and behaviors in humans. The newest experimental paradigms include increasingly realistic baby-stimuli to provoke paternal cognitions and behaviors with coordinated hormone measures to outline brain networks that regulate motivation, reflexive caring, emotion regulation, and social brain networks with differences and similarities to those found in mothers. In this article, on the father brain, we review all brain-imaging studies on PubMed to date on the human father brain and introduce the topic with a selection of theoretical models and foundational neurohormonal research on animal models in support of the human work. We discuss potentially translatable models for the identification and treatment of paternal mood and father-child relational problems, which could improve infant mental health and developmental trajectories with potentially broad public health importance.

  15. [Some implications of the "consciousness and brain" problem].

    Science.gov (United States)

    Ivanitskiĭ, A M; Ivanitskiĭ, G A

    2009-10-01

    Three issues are discussed: the possible mechanism of subjective events, the rhythmic coding of thinking operations and the possible brain basis of understanding. 1. Several approaches have been developed to explain how subjective experience emerges from brain activity. One of them is the return of the nervous impulses to the sites of their primary projections, providing a synthesis of sensory information with memory and motivation. Support for the existence of such a mechanism stems from studies upon the brain activity that underlies perception (visual and somatosensory) and thought (verbal and imaginative). The cortical centers for information synthesis have been found. For perception, these are located in projection areas: for thinking,--in frontal and temporal-parietal associative cortex. Closely related ideas were also developed by G. Edelman in his re-entry theory of consciousness. Both theories emphasize the key role of memory and motivation in the origin of conscious function. 2. Rearrangements of EEC rhythms underlie mental functions. Certain rhythmical patterns are related with definite types of mental activity. The dependence of one upon the other is rather pronounced and expressive, so it becomes possible to recognize the type of mental operation being performed in mind with few seconds of the ongoing EEG, provided that the analysis of rhythms is accomplished using an artificial neural network. 3. It is commonly recognized that the computer, in contrast to the living brain, can calculate, yet cannot understand. Comprehension implies the comparison of new and old information that requires the ability to search for associations, group similar objects together, and distinguish different objects one from another. However, these functions may also be implemented on a computer. Still, it is believed that computers perform these complicated operations without genuine understanding. Evidently, comprehension additionally has to be based upon some biologically

  16. The evolution of tianxia cosmology and its philosophical implications

    Institute of Scientific and Technical Information of China (English)

    Liu Junping

    2006-01-01

    The terminology tianxia has both historical evolution and cultural and philosophical connotations.This concept not only denotes a geographical and spatial meaning,but also implies the moral construct of metaphysics.A systematic study of its historical and cultural repercussions can show that the evolution of the meaning"tianxia"not only embodies the cosmological construction,moral belief and SeIf-identity of the Chinese nation,but also manifests the historical processes of modern China evolving from"tianxia"to a modern nation-state.Meanwhile,the deconstruction of the tianxia cosmology has shattered the old Chinese concept of a single united tianxia,or the whole world under one Heaven.Also,"Confucian China"has been increasingly losing its vitality and strong hold on the people,while the concept of nation-state has gained its way into people's consciousness,which has added more diversity and open-mindedness to the concept of tianxia.

  17. Origin and Evolution of Planetary Atmospheres Implications for Habitability

    CERN Document Server

    Lammer, Helmut

    2013-01-01

    Based on the author’s own work and results obtained by international teams he coordinated, this SpringerBrief offers a concise discussion of the origin and early evolution of atmospheres of terrestrial planets during the active phase of their host stars, as well as of the environmental conditions which are necessary in order for planets like the Earth to obtain N_2-rich atmospheres. Possible thermal and non-thermal atmospheric escape processes are discussed in a comparative way between the planets in the Solar System and exoplanets. Lastly, a hypothesis for how to test and study the discussed atmosphere evolution theories using future UV transit observations of terrestrial exoplanets within the orbits of dwarf stars is presented.

  18. Genetic evolution of enterovirus 71: epidemiological and pathological implications.

    Science.gov (United States)

    Bible, Jon M; Pantelidis, Panagiotis; Chan, Paul K S; Tong, C Y William

    2007-01-01

    Since its discovery in the 1970s, enterovirus 71 (EV71) has become one of the most pathogenic enterovirus serotypes causing recurrent outbreaks in different parts of the world. Three waves of outbreaks globally have been recorded over the last three decades and more recently active circulation of EV71 is evident amongst countries in South East Asia and beyond. There is evidence of a continuous evolution in its genetic make up which is likely to impact on its epidemiology and pathological potential. This review examines the molecular genetics and evolution of EV71 in relation to its epidemiological and pathological properties. A thorough understanding of the relationship between the genetic changes and the resulting host-virus interaction is essential for successful control.

  19. Analysis of ribosomal protein gene structures: implications for intron evolution.

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available Many spliceosomal introns exist in the eukaryotic nuclear genome. Despite much research, the evolution of spliceosomal introns remains poorly understood. In this paper, we tried to gain insights into intron evolution from a novel perspective by comparing the gene structures of cytoplasmic ribosomal proteins (CRPs and mitochondrial ribosomal proteins (MRPs, which are held to be of archaeal and bacterial origin, respectively. We analyzed 25 homologous pairs of CRP and MRP genes that together had a total of 527 intron positions. We found that all 12 of the intron positions shared by CRP and MRP genes resulted from parallel intron gains and none could be considered to be "conserved," i.e., descendants of the same ancestor. This was supported further by the high frequency of proto-splice sites at these shared positions; proto-splice sites are proposed to be sites for intron insertion. Although we could not definitively disprove that spliceosomal introns were already present in the last universal common ancestor, our results lend more support to the idea that introns were gained late. At least, our results show that MRP genes were intronless at the time of endosymbiosis. The parallel intron gains between CRP and MRP genes accounted for 2.3% of total intron positions, which should provide a reliable estimate for future inferences of intron evolution.

  20. Friends with social benefits: host-microbe interactions as a driver of brain evolution and development?

    Science.gov (United States)

    Stilling, Roman M; Bordenstein, Seth R; Dinan, Timothy G; Cryan, John F

    2014-01-01

    The tight association of the human body with trillions of colonizing microbes that we observe today is the result of a long evolutionary history. Only very recently have we started to understand how this symbiosis also affects brain function and behavior. In this hypothesis and theory article, we propose how host-microbe associations potentially influenced mammalian brain evolution and development. In particular, we explore the integration of human brain development with evolution, symbiosis, and RNA biology, which together represent a "social triangle" that drives human social behavior and cognition. We argue that, in order to understand how inter-kingdom communication can affect brain adaptation and plasticity, it is inevitable to consider epigenetic mechanisms as important mediators of genome-microbiome interactions on an individual as well as a transgenerational time scale. Finally, we unite these interpretations with the hologenome theory of evolution. Taken together, we propose a tighter integration of neuroscience fields with host-associated microbiology by taking an evolutionary perspective.

  1. Friends with Social Benefits: Host-Microbe Interactions as a Driver of Brain Evolution and Development?

    Directory of Open Access Journals (Sweden)

    Roman M Stilling

    2014-10-01

    Full Text Available The tight association of the human body with trillions of colonizing microbes that we observe today is the result of a long evolutionary history. Only very recently have we started to understand how this symbiosis also affects brain function and behaviour. Here in this hypothesis and theory article, we propose how host-microbe associations potentially influenced mammalian brain evolution and development. In particular, we explore the integration of human brain development with evolution, symbiosis, and RNA biology, which together represent a ‘social triangle’ that drives human social behaviour and cognition. We argue that, in order to understand how inter-kingdom communication can affect brain adaptation and plasticity, it is inevitable to consider epigenetic mechanisms as important mediators of genome-microbiome interactions on an individual as well as a transgenerational time scale. Finally, we unite these interpretations with the hologenome theory of evolution. Taken together, we propose a tighter integration of neuroscience fields with host-associated microbiology by taking an evolutionary perspective.

  2. Has an aquatic diet been necessary for hominin brain evolution and functional development?

    Science.gov (United States)

    Langdon, John H

    2006-07-01

    A number of authors have argued that only an aquatic-based diet can provide the necessary quantity of DHA to support the human brain, and that a switch to such a diet early in hominin evolution was critical to human brain evolution. This paper identifies the premises behind this hypothesis and critiques them on the basis of clinical literature. Both tissue levels and certain functions of the developing infant brain are sensitive to extreme variations in the supply of DHA in artificial feeding, and it can be shown that levels in human milk reflect maternal diet. However, both the maternal and infant bodies have mechanisms to store and buffer the supply of DHA, so that functional deficits are generally resolved without compensatory diets. There is no evidence that human diets based on terrestrial food chains with traditional nursing practices fail to provide adequate levels of DHA or other n-3 fatty acids. Consequently, the hypothesis that DHA has been a limiting resource in human brain evolution must be considered to be unsupported.

  3. CART in the brain of vertebrates: circuits, functions and evolution.

    Science.gov (United States)

    Subhedar, Nishikant K; Nakhate, Kartik T; Upadhya, Manoj A; Kokare, Dadasaheb M

    2014-04-01

    Cocaine- and amphetamine-regulated transcript peptide (CART) with its wide distribution in the brain of mammals has been the focus of considerable research in recent years. Last two decades have witnessed a steady rise in the information on the genes that encode this neuropeptide and regulation of its transcription and translation. CART is highly enriched in the hypothalamic nuclei and its relevance to energy homeostasis and neuroendocrine control has been understood in great details. However, the occurrence of this peptide in a range of diverse circuitries for sensory, motor, vegetative, limbic and higher cortical areas has been confounding. Evidence that CART peptide may have role in addiction, pain, reward, learning and memory, cognition, sleep, reproduction and development, modulation of behavior and regulation of autonomic nervous system are accumulating, but an integration has been missing. A steady stream of papers has been pointing at the therapeutic potentials of CART. The current review is an attempt at piecing together the fragments of available information, and seeks meaning out of the CART elements in their anatomical niche. We try to put together the CART containing neuronal circuitries that have been conclusively demonstrated as well as those which have been proposed, but need confirmation. With a view to finding out the evolutionary antecedents, we visit the CART systems in sub-mammalian vertebrates and seek the answer why the system is shaped the way it is. We enquire into the conservation of the CART system and appreciate its functional diversity across the phyla.

  4. Malnutritive obesity ('malnubesity'): is it driven by human brain evolution?

    Science.gov (United States)

    McGill, Anne-Thea

    2008-12-01

    Abstract Health messages on low-energy diets for healthy weight loss are muddled and not working, and obesity rates are rising. Are there missing links? Accumulating evidence shows that humans have well developed 'self-addictive' appetite pathways to enhance the uptake of highly energy-dense food. Humans synthesize fewer co-factors and vitamins than other mammals and must ingest them. Both processes probably arose to maximize available energy for the developing, large association cortex of the human brain. The default phenotype resulting from consuming an 'addictive', westernized, highly refined, energy-dense, hypomicronutrient diet is 'malnutritive obesity' or 'malnubesity'. A relative lack of antioxidant (and other) co-factors contributes to inefficiently oxidized energy. This 'stress' leads to central fat deposition, disordered energy use by cell mitochondria, especially in muscle and liver, and malfunctioning immune, coagulation, endothelial, and other systems. The resultant problems appear to range from epigenetic reprogramming in utero to end organ damage of the metabolic syndrome and the immune failure of cancer. Treatment of 'malnubesity' may require: (1) understanding the drivers and mechanisms of addictions, (2) reprioritizing satiating, micronutrient-dense whole foods, (3) nonjudgmental general, psychological, and medical support for those at risk or affected by obesity; and (4) practical incentives/regulation for healthy food production and distribution.

  5. Brain expressed microRNAs implicated in schizophrenia etiology

    DEFF Research Database (Denmark)

    Hansen, Thomas; Olsen, Line; Lindow, Morten

    2007-01-01

    Protein encoding genes have long been the major targets for research in schizophrenia genetics. However, with the identification of regulatory microRNAs (miRNAs) as important in brain development and function, miRNAs genes have emerged as candidates for schizophrenia-associated genetic factors....... Indeed, the growing understanding of the regulatory properties and pleiotropic effects that miRNA have on molecular and cellular mechanisms, suggests that alterations in the interactions between miRNAs and their mRNA targets may contribute to phenotypic variation....

  6. Ketones and brain development: Implications for correcting deteriorating brain glucose metabolism during aging

    Directory of Open Access Journals (Sweden)

    Nugent Scott

    2016-01-01

    Full Text Available Brain energy metabolism in Alzheimer’s disease (AD is characterized mainly by temporo-parietal glucose hypometabolism. This pattern has been widely viewed as a consequence of the disease, i.e. deteriorating neuronal function leading to lower demand for glucose. This review will address deteriorating glucose metabolism as a problem specific to glucose and one that precedes AD. Hence, ketones and medium chain fatty acids (MCFA could be an alternative source of energy for the aging brain that could compensate for low brain glucose uptake. MCFA in the form of dietary medium chain triglycerides (MCT have a long history in clinical nutrition and are widely regarded as safe by government regulatory agencies. The importance of ketones in meeting the high energy and anabolic requirements of the infant brain suggest they may be able to contribute in the same way in the aging brain. Clinical studies suggest that ketogenesis from MCT may be able to bypass the increasing risk of insufficient glucose uptake or metabolism in the aging brain sufficiently to have positive effects on cognition.

  7. THE SIGNIFICANCE OF THE SUBPLATE FOR EVOLUTION AND DEVELOPMENTAL PLASTICITY OF THE HUMAN BRAIN

    Directory of Open Access Journals (Sweden)

    MILOS eJUDAS

    2013-08-01

    Full Text Available The human life-history is characterized by long development and introduction of new developmental stages, such as childhood and adolescence. The developing brain had important role in these life-history changes because it is expensive tissue which uses up to 80% of resting metabolic rate in the newborn and continues to use almost 50% of it during the first 5 postnatal years. Our hominid ancestors managed to lift-up metabolic constraints to increase in brain size by several interrelated ecological, behavioral and social adaptations, such as dietary change, invention of cooking, creation of family-bonded reproductive units, and life-history changes. This opened new vistas for the developing brain, because it became possible to metabolically support transient patterns of brain organization as well as developmental brain plasticity for much longer period and with much greater number of neurons and connectivity combinations in comparison to apes. This included the shaping of cortical connections through the interaction with infant's social environment, which probably enhanced typically human evolution of language, cognition and self-awareness. In this review, we propose that the transient subplate zone and its postnatal remnant (interstitial neurons of the gyral white matter probably served as the main playground for evolution of these developmental shifts, and describe various features that makes human subplate uniquely positioned to have such a role in comparison with other primates.

  8. Linking brains and brawn: exercise and the evolution of human neurobiology.

    Science.gov (United States)

    Raichlen, David A; Polk, John D

    2013-01-07

    The hunting and gathering lifestyle adopted by human ancestors around 2 Ma required a large increase in aerobic activity. High levels of physical activity altered the shape of the human body, enabling access to new food resources (e.g. animal protein) in a changing environment. Recent experimental work provides strong evidence that both acute bouts of exercise and long-term exercise training increase the size of brain components and improve cognitive performance in humans and other taxa. However, to date, researchers have not explored the possibility that the increases in aerobic capacity and physical activity that occurred during human evolution directly influenced the human brain. Here, we hypothesize that proximate mechanisms linking physical activity and neurobiology in living species may help to explain changes in brain size and cognitive function during human evolution. We review evidence that selection acting on endurance increased baseline neurotrophin and growth factor signalling (compounds responsible for both brain growth and for metabolic regulation during exercise) in some mammals, which in turn led to increased overall brain growth and development. This hypothesis suggests that a significant portion of human neurobiology evolved due to selection acting on features unrelated to cognitive performance.

  9. The Bilingual Brain: Human Evolution and Second Language Acquisition

    Directory of Open Access Journals (Sweden)

    L. Kirk Hagen

    2008-01-01

    Full Text Available For the past half-century, psycholinguistic research has concerned itself with two mysteries of human cognition: (1 that children universally acquire a highly abstract, computationally complex set of linguistic rules rapidly and effortlessly, and (2 that second language acquisition (SLA among adults is, conversely, slow, laborious, highly variable, and virtually never results in native fluency. We now have a decent, if approximate, understanding of the biological foundations of first language acquisition, thanks in large part to Lenneberg's (1964, 1984 seminal work on the critical period hypothesis. More recently, the elements of a promising theory of language and evolution have emerged as well (see e.g. Bickerton, 1981, 1990; Leiberman, 1984, 1987. I argue here that the empirical foundations of an evolutionary theory of language are now solid enough to support an account of bilingualism and adult SLA as well. Specifically, I will show that evidence from the environment of evolutionary adaptation of paleolithic humans suggests that for our nomadic ancestors, the ability to master a language early in life was an eminently useful adaptation. However, the ability to acquire another language in adulthood was not, and consequently was not selected for propagation.

  10. Brain lesions and their implications in criminal responsibility.

    Science.gov (United States)

    Batts, Shelley

    2009-01-01

    For over 200 years, Western courts have considered pleas of "not guilty by reason of insanity" (NGRI) for defendants in possession of a mental defect rendering them unable to understand the wrongfulness of their act. Until recently, determining the mental state of a defendant has fallen largely upon the shoulders of court psychologists and experts in psychiatry for qualitative assessments related to NGRI pleas and mitigation at sentencing. However, advances in neuroscience--particularly neurological scanning techniques such as magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), computed tomography scanning (CT), and positron emission tomography scanning (PET)--may provide additional, pertinent biological evidence as to whether an organically based mental defect exists. With increasing frequency, criminal defense attorneys are integrating neuroimaging data into hearings related to determinations of guilt and sentencing mitigation. This is of concern, since not all brain lesions and abnormalities indicate a compromised mental state that is relevant to knowing whether the act was wrong at the time of commission, and juries may be swayed by neuroscientific evidence that is not relevant to the determination of the legal question before them. This review discusses historical and modern cases involving the intersection of brain lesions and criminality, neuroscientific perspectives of how particular types of lesions may contribute to a legally relevant mental defect, and how such evidence might best be integrated into a criminal trial.

  11. Brain-derived neurotrophic factor and its clinical implications.

    Science.gov (United States)

    Bathina, Siresha; Das, Undurti N

    2015-12-10

    Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival and growth, serves as a neurotransmitter modulator, and participates in neuronal plasticity, which is essential for learning and memory. It is widely expressed in the CNS, gut and other tissues. BDNF binds to its high affinity receptor TrkB (tyrosine kinase B) and activates signal transduction cascades (IRS1/2, PI3K, Akt), crucial for CREB and CBP production, that encode proteins involved in β cell survival. BDNF and insulin-like growth factor-1 have similar downstream signaling mechanisms incorporating both p-CAMK and MAPK that increase the expression of pro-survival genes. Brain-derived neurotrophic factor regulates glucose and energy metabolism and prevents exhaustion of β cells. Decreased levels of BDNF are associated with neurodegenerative diseases with neuronal loss, such as Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Thus, BDNF may be useful in the prevention and management of several diseases including diabetes mellitus.

  12. The evolution of the language faculty: clarifications and implications.

    Science.gov (United States)

    Fitch, W Tecumseh; Hauser, Marc D; Chomsky, Noam

    2005-09-01

    In this response to Pinker and Jackendoff's critique, we extend our previous framework for discussion of language evolution, clarifying certain distinctions and elaborating on a number of points. In the first half of the paper, we reiterate that profitable research into the biology and evolution of language requires fractionation of "language" into component mechanisms and interfaces, a non-trivial endeavor whose results are unlikely to map onto traditional disciplinary boundaries. Our terminological distinction between FLN and FLB is intended to help clarify misunderstandings and aid interdisciplinary rapprochement. By blurring this distinction, Pinker and Jackendoff mischaracterize our hypothesis 3 which concerns only FLN, not "language" as a whole. Many of their arguments and examples are thus irrelevant to this hypothesis. Their critique of the minimalist program is for the most part equally irrelevant, because very few of the arguments in our original paper were tied to this program; in an online appendix we detail the deep inaccuracies in their characterization of this program. Concerning evolution, we believe that Pinker and Jackendoff's emphasis on the past adaptive history of the language faculty is misplaced. Such questions are unlikely to be resolved empirically due to a lack of relevant data, and invite speculation rather than research. Preoccupation with the issue has retarded progress in the field by diverting research away from empirical questions, many of which can be addressed with comparative data. Moreover, offering an adaptive hypothesis as an alternative to our hypothesis concerning mechanisms is a logical error, as questions of function are independent of those concerning mechanism. The second half of our paper consists of a detailed response to the specific data discussed by Pinker and Jackendoff. Although many of their examples are irrelevant to our original paper and arguments, we find several areas of substantive disagreement that could be

  13. Changing the brain, changing the society: clinical and ethical implications of neuromodulation techniques in neurology and psychiatry.

    Science.gov (United States)

    Vuilleumier, Patrik; Sander, David; Baertschi, Bernard

    2014-01-01

    New neurotechnologies for modulating brain functions are becoming increasingly powerful and applicable to diverse diseases, but raise new questions for clinicians, ethicists, policy makers, and laymen. This issue of Brain Topography gathers several papers exploring the clinical and ethical implications of several invasive and noninvasive neuromodulation approaches. The opportunities and challenges associated with the emergence of neuro-engineering solutions to brain research and brain repair require a close dialogue between multiple disciplines, as well as open discussion with the general public.

  14. Mechanisms of brain evolution: regulation of neural progenitor cell diversity and cell cycle length.

    Science.gov (United States)

    Borrell, Victor; Calegari, Federico

    2014-09-01

    In the last few years, several studies have revisited long-held assumptions in the field of brain development and evolution providing us with a fundamentally new vision on the mechanisms controlling its size and shape, hence function. Among these studies, some described hitherto unforeseeable subtypes of neural progenitors while others reinterpreted long-known observations about their cell cycle in alternative new ways. Most remarkably, this knowledge combined has allowed the generation of mammalian model organisms in which brain size and folding has been selectively increased giving us the means to understand the mechanisms underlying the evolution of the most complex and sophisticated organ. Here we review the key findings made in this area and make a few conjectures about their evolutionary meaning including the likelihood of Martians conquering our planet.

  15. Metabolic Genes within Cyanophage Genomes: Implications for Diversity and Evolution

    Directory of Open Access Journals (Sweden)

    E-Bin Gao

    2016-09-01

    Full Text Available Cyanophages, a group of viruses specifically infecting cyanobacteria, are genetically diverse and extensively abundant in water environments. As a result of selective pressure, cyanophages often acquire a range of metabolic genes from host genomes. The host-derived genes make a significant contribution to the ecological success of cyanophages. In this review, we summarize the host-derived metabolic genes, as well as their origin and roles in cyanophage evolution and important host metabolic pathways, such as the light-dependent reactions of photosynthesis, the pentose phosphate pathway, nutrient acquisition and nucleotide biosynthesis. We also discuss the suitability of the host-derived metabolic genes as potential diagnostic markers for the detection of genetic diversity of cyanophages in natural environments.

  16. Manual praxis in stone tool manufacture: implications for language evolution.

    Science.gov (United States)

    Ruck, Lana

    2014-12-01

    Alternative functions of the left-hemisphere dominant Broca's region have induced hypotheses regarding the evolutionary parallels between manual praxis and language in humans. Many recent studies on Broca's area reveal several assumptions about the cognitive mechanisms that underlie both functions, including: (1) an accurate, finely controlled body schema, (2) increasing syntactical abilities, particularly for goal-oriented actions, and (3) bilaterality and fronto-parietal connectivity. Although these characteristics are supported by experimental paradigms, many researchers have failed to acknowledge a major line of evidence for the evolutionary development of these traits: stone tools. The neuroscience of stone tool manufacture is a viable proxy for understanding evolutionary aspects of manual praxis and language, and may provide key information for evaluating competing hypotheses on the co-evolution of these cognitive domains in our species.

  17. Dental patterning in the earliest sharks: Implications for tooth evolution.

    Science.gov (United States)

    Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

    2014-05-01

    Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes.

  18. Evolution of Martian atmospheric argon: Implications for sources of volatiles

    Science.gov (United States)

    Hutchins, Kevin S.; Jakosky, Bruce M.

    We have examined processes affecting isotopes of argon (36Ar, 38Ar, 40Ar) in order to determine important atmospheric sources and sinks. Our simple model for argon evolution incorporates production of radiogenic argon in the mantle, outgassing of all argon species by extrusive and intrusive volcanism, and loss to space by knock-on sputtering above the exobase. Sputtering has been shown previously to be an important loss process for atmospheric species, especially isotopes of noble gases, which have few other mechanisms of escape. The integrated evolution of argon (36Ar, 38Ar, and 40Ar, respectively) is modeled in terms of these variables: (1) the planetary concentration of potassium, (2) the fraction of juvenile argon released catastrophically during the first 600 Myr., (3) potential variation in the time-history of sputtering loss from that suggested by Luhmann et al. [1992], and (4) the volume of total outgassing to the surface as compared to outgassing contributed by volcanic release. Our results indicate that Mars has lost between 85-95% of 36Ar and 70-88% of outgassed 40Ar. Due to this substantial loss, the planet must have outgassed the equivalent of between 10 and 100 times the total volume of gases released by extrusive and intrusive volcanics. This indicates that volcanic outgassing, alone, is insufficient to explain the present-day abundances of 36Ar and 40Ar in the Martian atmosphere. Similar calculations for 20Ne suggest outgassed volumes of between 100 and 1800 times in excess of that due to volcanism. This results in a distinct Ne/Ar elemental fractionation, with a preference for outgassing argon, of the order of 10 to 17. Although the results must be evaluated within the model uncertainties, the results are compelling in that they unequivocally show the existence of additional sources of atmospheric volatiles and helps define a means to identify them.

  19. Traumatic brain injury alters methionine metabolism: implications for pathophysiology

    Directory of Open Access Journals (Sweden)

    Pramod K Dash

    2016-04-01

    Full Text Available Methionine is an essential proteinogenic amino acid that is obtained from the diet. In addition to its requirement for protein biosynthesis, methionine is metabolized to generate metabolites that play key roles in a number of cellular functions. Metabolism of methionine via the transmethylation pathway generates S-adenosylmethionine (SAM that serves as the principal methyl (-CH3 donor for DNA and histone methyltransferases to regulate epigenetic changes in gene expression. SAM is also required for methylation of other cellular proteins that serve various functions and phosphatidylcholine synthesis that participate in cellular signaling.. Under conditions of oxidative stress, homocysteine (which is derived from SAM enters the transsulfuration pathway to generate glutathione, an important cytoprotective molecule against oxidative damage. As both experimental and clinical studies have shown that traumatic brain injury (TBI alters DNA and histone methylation and causes oxidative stress, we examined if TBI alters the plasma levels of methionine and its metabolites in human patients. Blood samples were collected from healthy volunteers (n = 20 and patients with mild TBI (GCS > 12; n = 20 or severe TBI (GCS < 8; n = 20 within the first 24 hours of injury. The levels of methionine and its metabolites in the plasma samples were analyzed by either liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry (LC-MS or GC-MS. Severe TBI decreased the levels of methionine, SAM, betaine and 2-methylglycine as compared to healthy volunteers, indicating a decrease in metabolism through the transmethylation cycle. In addition, precursors for the generation of glutathione, cysteine and glycine were also found to be decreased as were intermediate metabolites of the gamma-glutamyl cycle (gamma-glutamyl amino acids and 5-oxoproline. Mild TBI also decreased the levels of methionine, α-ketobutyrate, 2 hydroxybutyrate and glycine, albeit to lesser

  20. Skull Flexure from Blast Waves: A Mechanism for Brain Injury with Implications for Helmet Design

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2009-04-30

    Traumatic brain injury [TBI] has become a signature injury of current military conflicts, with debilitating, costly, and long-lasting effects. Although mechanisms by which head impacts cause TBI have been well-researched, the mechanisms by which blasts cause TBI are not understood. From numerical hydrodynamic simulations, we have discovered that non-lethal blasts can induce sufficient skull flexure to generate potentially damaging loads in the brain, even without a head impact. The possibility that this mechanism may contribute to TBI has implications for injury diagnosis and armor design.

  1. Head motions while riding roller coasters: implications for brain injury.

    Science.gov (United States)

    Pfister, Bryan J; Chickola, Larry; Smith, Douglas H

    2009-12-01

    The risk of traumatic brain injury (TBI) while riding roller coasters has received substantial attention. Case reports of TBI around the time of riding roller coasters have led many medical professionals to assert that the high gravitational forces (G-forces) induced by roller coasters pose a significant TBI risk. Head injury research, however, has shown that G-forces alone cannot predict TBI. Established head injury criterions and procedures were employed to compare the potential of TBI between daily activities and roller coaster riding. Three-dimensional head motions were measured during 3 different roller coaster rides, a pillow fight, and car crash simulations. Data was analyzed and compared with published data, using similar analyses of head motions. An 8.05 m/s car crash lead to the largest head injury criterion measure of 28.1 and head impact power of 3.41, over 6 times larger than the roller coaster rides of 4.1 and 0.36. Notably, the linear and rotational components of head acceleration during roller coaster rides were milder than those induced by many common activities. As such, there appears to be an extremely low risk of TBI due to the head motions induced by roller coaster rides.

  2. Ipsilateral motor pathways after stroke: implications for noninvasive brain stimulation

    Directory of Open Access Journals (Sweden)

    Lynley V Bradnam

    2013-05-01

    Full Text Available In humans the two cerebral hemispheres have essential roles in controlling the upper limb. The purpose of this article is to draw attention to the potential importance of ipsilateral descending pathways for functional recovery after stroke, and the use of noninvasive brain stimulation (NBS protocols of the contralesional primary motor cortex (M1. Conventionally NBS is used to suppress contralesional M1, and to attenuate transcallosal inhibition onto the ipsilesional M1. There has been little consideration of the fact that contralesional M1 suppression may also reduce excitability of ipsilateral descending pathways that may be important for paretic upper limb control for some patients. One such ipsilateral pathway is the cortico-reticulo-propriospinal pathway (CRPP. In this review we outline a neurophysiological model to explain how contralesional M1 may gain control of the paretic arm via the CRPP. We conclude that the relative importance of the CRPP for motor control in individual patients must be considered before using NBS to suppress contralesional M1. Neurophysiological, neuroimaging and clinical assessments can assist this decision making and facilitate the translation of NBS into the clinical setting.

  3. Molecular evolution of SRP cycle components: functional implications.

    Science.gov (United States)

    Althoff, S; Selinger, D; Wise, J A

    1994-06-11

    Signal recognition particle (SRP) is a cytoplasmic ribonucleoprotein that targets a subset of nascent presecretory proteins to the endoplasmic reticulum membrane. We have considered the SRP cycle from the perspective of molecular evolution, using recently determined sequences of genes or cDNAs encoding homologs of SRP (7SL) RNA, the Srp54 protein (Srp54p), and the alpha subunit of the SRP receptor (SR alpha) from a broad spectrum of organisms, together with the remaining five polypeptides of mammalian SRP. Our analysis provides insight into the significance of structural variation in SRP RNA and identifies novel conserved motifs in protein components of this pathway. The lack of congruence between an established phylogenetic tree and size variation in 7SL homologs implies the occurrence of several independent events that eliminated more than half the sequence content of this RNA during bacterial evolution. The apparently non-essential structures are domain I, a tRNA-like element that is constant in archaea, varies in size among eucaryotes, and is generally missing in bacteria, and domain III, a tightly base-paired hairpin that is present in all eucaryotic and archeal SRP RNAs but is invariably absent in bacteria. Based on both structural and functional considerations, we propose that the conserved core of SRP consists minimally of the 54 kDa signal sequence-binding protein complexed with the loosely base-paired domain IV helix of SRP RNA, and is also likely to contain a homolog of the Srp68 protein. Comparative sequence analysis of the methionine-rich M domains from a diverse array of Srp54p homologs reveals an extended region of amino acid identity that resembles a recently identified RNA recognition motif. Multiple sequence alignment of the G domains of Srp54p and SR alpha homologs indicates that these two polypeptides exhibit significant similarity even outside the four GTPase consensus motifs, including a block of nine contiguous amino acids in a location

  4. Response to Deep Brain Stimulation in Three Brain Targets with Implications in Mental Disorders: A PET Study in Rats

    Science.gov (United States)

    Casquero-Veiga, Marta; Hadar, Ravit; Pascau, Javier; Winter, Christine; Desco, Manuel; Soto-Montenegro, María Luisa

    2016-01-01

    Objective To investigate metabolic changes in brain networks by deep brain stimulation (DBS) of the medial prefrontal cortex (mPFC), nucleus accumbens (NAcc) and dorsomedial thalamus (DM) using positron emission tomography (PET) in naïve rats. Methods 43 male Wistar rats underwent stereotactic surgery and concentric bipolar platinum-iridium electrodes were bilaterally implanted into one of the three brain sites. [18F]-fluoro-2-deoxy-glucose-PET (18FDG-PET) and computed tomography (CT) scans were performed at the 7th (without DBS) and 9th day (with DBS) after surgery. Stimulation period matched tracer uptake period. Images were acquired with a small-animal PET-CT scanner. Differences in glucose uptake between groups were assessed with Statistical Parametric Mapping. Results DBS induced site-specific metabolic changes, although a common increased metabolic activity in the piriform cortex was found for the three brain targets. mPFC-DBS increased metabolic activity in the striatum, temporal and amygdala, and reduced it in the cerebellum, brainstem (BS) and periaqueductal gray matter (PAG). NAcc-DBS increased metabolic activity in the subiculum and olfactory bulb, and decreased it in the BS, PAG, septum and hypothalamus. DM-DBS increased metabolic activity in the striatum, NAcc and thalamus and decreased it in the temporal and cingulate cortex. Conclusions DBS induced significant changes in 18FDG uptake in brain regions associated with the basal ganglia-thalamo-cortical circuitry. Stimulation of mPFC, NAcc and DM induced different patterns of 18FDG uptake despite interacting with the same circuitries. This may have important implications to DBS research suggesting individualized target selection according to specific neural modulatory requirements. PMID:28033356

  5. Implication of evolution and diversity in arbuscular and ectomycorrhizal symbioses.

    Science.gov (United States)

    Buscot, François

    2015-01-01

    Being highly sensitive to ecological variations, symbiotic associations should inherently have a limited occurrence in nature. To circumvent this sensitivity and reach their universal distribution, symbioses used three strategies during their evolution, which all generated high biodiversity levels: (i) specialization to a specific environment, (ii) protection of one partner via its internalization into the other, (iii) frequent partner exchange. Mycorrhizal associations follow the 3rd strategy, but also present traits of internalization. As most ancient type, arbuscular mycorrhiza (AM) formed by a monophyletic fungal group with reduced species richness did constantly support the mineral nutrition of terrestrial plants and enabled their ecological radiation and actual biodiversity level. In contrast ectomycorrhiza (EM) evolved later and independently within different taxa of fungi able to degrade complex organic plant residues, and the diversity levels of EM fungal and tree partners are balanced. Despite their different origins and diversity levels, AM and EM fungi display similar patterns of diversity dynamics in ecosystems. At each time or succession interval, a few dominant and many rare fungi are recruited by plants roots from a wide reservoir of propagules. However, the dominant fungal partners are frequently replaced in relation to changes in the vegetation or ecological conditions. While the initial establishment of AM and EM fungal communities corresponds to a neutral recruitment, their further succession is rather driven by niche differentiation dynamics.

  6. Implications for Galaxy Evolution from the Cosmic Evolution of Supernova Rate Density

    CERN Document Server

    Oda, T; Yasuda, N; Sumi, T; Morokuma, T; Doi, M; Kosugi, G

    2008-01-01

    We report a comprehensive statistical analysis of the observational data of the cosmic evolution of supernova (SN) rate density, to derive constraints on cosmic star formation history and the nature of type Ia supernova (SN Ia) progenitor. We use all available information of magnitude, SN type, and redshift information of both type Ia and core-collapse (CC) SNe in GOODS and SDF, as well as SN Ia rate densities reported in the literature. Furthermore, we also add 157 SN candidates in the past Subaru/Suprime-Cam data that are newly reported here, to increase the statistics. We find that the current data set of SN rate density evolution already gives a meaningful constraint on the evolution of the cosmic star formation rate (SFR) at z <~ 1, though strong constraints cannot be derived for the delay time distribution (DTD) of SNe Ia. We derive a constraint of the evolutionary index of SFR density alpha ~ 3--4 [(1+z)^alpha at z <~ 1] with an evidence for a significant evolution of mean extinction of CC SNe [E...

  7. Comparative genetic approaches to the evolution of human brain and behavior.

    Science.gov (United States)

    Vallender, Eric J

    2011-01-01

    With advances in genomic technologies, the amount of genetic data available to scientists today is vast. Genomes are now available or planned for 14 different primate species and complete resequencing of numerous human individuals from numerous populations is underway. Moreover, high-throughput deep sequencing is quickly making whole genome efforts within the reach of single laboratories allowing for unprecedented studies. Comparative genetic approaches to the identification of the underlying basis of human brain, behavior, and cognitive ability are moving to the forefront. Two approaches predominate: inter-species divergence comparisons and intra-species polymorphism studies. These methodological differences are useful for different time scales of evolution and necessarily focus on different evolutionary events in the history of primate and hominin evolution. Inter-species divergence is more useful in studying large scale primate, or hominoid, evolution whereas intra-species polymorphism can be more illuminating of recent hominin evolution. These differences in methodological utility also extend to studies of differing genetic substrates; current divergence studies focus primarily on protein evolution whereas polymorphism studies are substrate ambivalent. Some of the issues inherent in these studies can be ameliorated by current sequencing capabilities whereas others remain intractable. New avenues are also being opened that allow for the incorporation of novel substrates and approaches. In the post-genomic era, the study of human evolution, specifically as it relates to the brain, is becoming more complete focusing increasingly on the totality of the system and better conceptualizing the entirety of the genetic changes that have lead to the human phenotype today.

  8. Evolution of public cooperation in a monitored society with implicated punishment and within-group enforcement.

    Science.gov (United States)

    Chen, Xiaojie; Sasaki, Tatsuya; Perc, Matjaž

    2015-11-24

    Monitoring with implicated punishment is common in human societies to avert freeriding on common goods. But is it effective in promoting public cooperation? We show that the introduction of monitoring and implicated punishment is indeed effective, as it transforms the public goods game to a coordination game, thus rendering cooperation viable in infinite and finite well-mixed populations. We also show that the addition of within-group enforcement further promotes the evolution of public cooperation. However, although the group size in this context has nonlinear effects on collective action, an intermediate group size is least conductive to cooperative behaviour. This contradicts recent field observations, where an intermediate group size was declared optimal with the conjecture that group-size effects and within-group enforcement are responsible. Our theoretical research thus clarifies key aspects of monitoring with implicated punishment in human societies, and additionally, it reveals fundamental group-size effects that facilitate prosocial collective action.

  9. Evolution of public cooperation in a monitored society with implicated punishment and within-group enforcement

    Science.gov (United States)

    Chen, Xiaojie; Sasaki, Tatsuya; Perc, Matjaž

    2015-11-01

    Monitoring with implicated punishment is common in human societies to avert freeriding on common goods. But is it effective in promoting public cooperation? We show that the introduction of monitoring and implicated punishment is indeed effective, as it transforms the public goods game to a coordination game, thus rendering cooperation viable in infinite and finite well-mixed populations. We also show that the addition of within-group enforcement further promotes the evolution of public cooperation. However, although the group size in this context has nonlinear effects on collective action, an intermediate group size is least conductive to cooperative behaviour. This contradicts recent field observations, where an intermediate group size was declared optimal with the conjecture that group-size effects and within-group enforcement are responsible. Our theoretical research thus clarifies key aspects of monitoring with implicated punishment in human societies, and additionally, it reveals fundamental group-size effects that facilitate prosocial collective action.

  10. Microevolutionary, macroevolutionary, ecological and taxonomical implications of punctuational theories of adaptive evolution.

    Science.gov (United States)

    Flegr, Jaroslav

    2013-01-16

    Punctuational theories of evolution suggest that adaptive evolution proceeds mostly, or even entirely, in the distinct periods of existence of a particular species. The mechanisms of this punctuated nature of evolution suggested by the various theories differ. Therefore the predictions of particular theories concerning various evolutionary phenomena also differ.Punctuational theories can be subdivided into five classes, which differ in their mechanism and their evolutionary and ecological implications. For example, the transilience model of Templeton (class III), genetic revolution model of Mayr (class IV) or the frozen plasticity theory of Flegr (class V), suggests that adaptive evolution in sexual species is operative shortly after the emergence of a species by peripatric speciation--while it is evolutionary plastic. To a major degree, i.e. throughout 98-99% of their existence, sexual species are evolutionarily frozen (class III) or elastic (class IV and V) on a microevolutionary time scale and evolutionarily frozen on a macroevolutionary time scale and can only wait for extinction, or the highly improbable return of a population segment to the plastic state due to peripatric speciation.The punctuational theories have many evolutionary and ecological implications. Most of these predictions could be tested empirically, and should be analyzed in greater depth theoretically. The punctuational theories offer many new predictions that need to be tested, but also provide explanations for a much broader spectrum of known biological phenomena than classical gradualistic evolutionary theories.

  11. Modelling rate distributions using character compatibility: implications for morphological evolution among fossil invertebrates.

    Science.gov (United States)

    Wagner, Peter J

    2012-02-23

    Rate distributions are important considerations when testing hypotheses about morphological evolution or phylogeny. They also have implications about general processes underlying character evolution. Molecular systematists often assume that rates are Poisson processes with gamma distributions. However, morphological change is the product of multiple probabilistic processes and should theoretically be affected by hierarchical integration of characters. Both factors predict lognormal rate distributions. Here, a simple inverse modelling approach assesses the best single-rate, gamma and lognormal models given observed character compatibility for 115 invertebrate groups. Tests reject the single-rate model for nearly all cases. Moreover, the lognormal outperforms the gamma for character change rates and (especially) state derivation rates. The latter in particular is consistent with integration affecting morphological character evolution.

  12. Reorganization of the injured brain: Implications for studies of the neural substrate of cognition

    Directory of Open Access Journals (Sweden)

    Jesper eMogensen

    2011-01-01

    Full Text Available In the search for a neural substrate of cognitive processes, a frequently utilized method is the scrutiny of posttraumatic symptoms exhibited by individuals suffering focal injury to the brain. For instance, the presence or absence of conscious awareness within a particular domain may, combined with knowledge of which regions of the brain have been injured, provide important data in the search for neural correlates of consciousness. Like all studies addressing the consequences of brain injury, however, such research has to face the fact that in most cases, posttraumatic impairments are accompanied by a functional recovery during which symptoms are reduced or eliminated. The apparent contradiction between localization and recovery, respectively, of functions constitutes a problem to almost all aspects of cognitive neuroscience. Several lines of investigation indicate that although the brain remains highly plastic throughout life, the posttraumatic plasticity does not recreate a copy of the neural mechanisms lost to injury. Instead, the uninjured parts of the brain are functionally reorganized in a manner which – in spite of not recreating the basic information processing lost to injury – is able to allow a more or less complete return of the surface phenomena (including manifestations of consciousness originally impaired by the trauma. A novel model (the REF-model of these processes is presented – and some of its implications discussed relative to studies of the neural substrates of cognition and consciousness.

  13. Metabolism as a tool for understanding human brain evolution: lipid energy metabolism as an example.

    Science.gov (United States)

    Wang, Shu Pei; Yang, Hao; Wu, Jiang Wei; Gauthier, Nicolas; Fukao, Toshiyuki; Mitchell, Grant A

    2014-12-01

    Genes and the environment both influence the metabolic processes that determine fitness. To illustrate the importance of metabolism for human brain evolution and health, we use the example of lipid energy metabolism, i.e. the use of fat (lipid) to produce energy and the advantages that this metabolic pathway provides for the brain during environmental energy shortage. We briefly describe some features of metabolism in ancestral organisms, which provided a molecular toolkit for later development. In modern humans, lipid energy metabolism is a regulated multi-organ pathway that links triglycerides in fat tissue to the mitochondria of many tissues including the brain. Three important control points are each suppressed by insulin. (1) Lipid reserves in adipose tissue are released by lipolysis during fasting and stress, producing fatty acids (FAs) which circulate in the blood and are taken up by cells. (2) FA oxidation. Mitochondrial entry is controlled by carnitine palmitoyl transferase 1 (CPT1). Inside the mitochondria, FAs undergo beta oxidation and energy production in the Krebs cycle and respiratory chain. (3) In liver mitochondria, the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) pathway produces ketone bodies for the brain and other organs. Unlike most tissues, the brain does not capture and metabolize circulating FAs for energy production. However, the brain can use ketone bodies for energy. We discuss two examples of genetic metabolic traits that may be advantageous under most conditions but deleterious in others. (1) A CPT1A variant prevalent in Inuit people may allow increased FA oxidation under nonfasting conditions but also predispose to hypoglycemic episodes. (2) The thrifty genotype theory, which holds that energy expenditure is efficient so as to maximize energy stores, predicts that these adaptations may enhance survival in periods of famine but predispose to obesity in modern dietary environments.

  14. Evidence for the unique function of DHA during the evolution of the modern hominid brain

    Directory of Open Access Journals (Sweden)

    Crawford M.A.

    2004-01-01

    Full Text Available The African savanna ecosystem of the large mammals and primates was associated with a dramatic decline in relative brain capacity. This reduction happened to be associated with a decline in docosahexaenoic acid (DHA from the food chain. DHA is required for brain structures and growth. The biochemistry implies that the expansion of the human brain required a plentiful source of preformed DHA. The richest source of DHA is the marine food chain while the savannah environment offers very little of it. Consequently H. sapiens could not have evolved on the savannahs. Recent fossil evidence indicates that the lacustrine and marine food chain was being extensively exploited at the time cerebral expansion took place and suggests the alternative that the transition from the archaic to modern humans took place at the land\\\\water interface. Contemporary data on tropical lake shore dwellers reaffirms the above view. Lacustrine habitats provide nutritional support for the vascular system, the development of which would have been a prerequisite for cerebral expansion. Both arachidonic acid (AA and DHA would have been freely available from such habitats providing the double stimulus of preformed acyl components for the developing blood vessels and brain. The w3 docosapentaenoic acid precursor (w3DPA was the major w3 metabolite in the savanna mammals. Despite this abundance, neither it or the corresponding w6DPA were used for the photoreceptor nor the synapse. A substantial difference between DHA and other fatty acids is required to explain this high specificity. Studies on fluidity and other mechanical features of cell membranes have not revealed a difference of such magnitude between even a-linolenic acid (LNA and DHA sufficient to explain the exclusive use of DHA. We suggest that the evolution of the large human brain depended on a rich source of DHA from the land\\\\water interface. We review a number of proposals for the possible influence of DHA on

  15. Metabolic acceleration and the evolution of human brain size and life history.

    Science.gov (United States)

    Pontzer, Herman; Brown, Mary H; Raichlen, David A; Dunsworth, Holly; Hare, Brian; Walker, Kara; Luke, Amy; Dugas, Lara R; Durazo-Arvizu, Ramon; Schoeller, Dale; Plange-Rhule, Jacob; Bovet, Pascal; Forrester, Terrence E; Lambert, Estelle V; Thompson, Melissa Emery; Shumaker, Robert W; Ross, Stephen R

    2016-05-19

    Humans are distinguished from the other living apes in having larger brains and an unusual life history that combines high reproductive output with slow childhood growth and exceptional longevity. This suite of derived traits suggests major changes in energy expenditure and allocation in the human lineage, but direct measures of human and ape metabolism are needed to compare evolved energy strategies among hominoids. Here we used doubly labelled water measurements of total energy expenditure (TEE; kcal day(-1)) in humans, chimpanzees, bonobos, gorillas and orangutans to test the hypothesis that the human lineage has experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longevity. In multivariate regressions including body size and physical activity, human TEE exceeded that of chimpanzees and bonobos, gorillas and orangutans by approximately 400, 635 and 820 kcal day(-1), respectively, readily accommodating the cost of humans' greater brain size and reproductive output. Much of the increase in TEE is attributable to humans' greater basal metabolic rate (kcal day(-1)), indicating increased organ metabolic activity. Humans also had the greatest body fat percentage. An increased metabolic rate, along with changes in energy allocation, was crucial in the evolution of human brain size and life history.

  16. Molecular evolution of the human SRPX2 gene that causes brain disorders of the Rolandic and Sylvian speech areas

    Directory of Open Access Journals (Sweden)

    Levasseur Anthony

    2007-10-01

    Full Text Available Abstract Background The X-linked SRPX2 gene encodes a Sushi Repeat-containing Protein of unknown function and is mutated in two disorders of the Rolandic/Sylvian speech areas. Since it is linked to defects in the functioning and the development of brain areas for speech production, SRPX2 may thus have participated in the adaptive organization of such brain regions. To address this issue, we have examined the recent molecular evolution of the SRPX2 gene. Results The complete coding region was sequenced in 24 human X chromosomes from worldwide populations and in six representative nonhuman primate species. One single, fixed amino acid change (R75K has been specifically incorporated in human SRPX2 since the human-chimpanzee split. The R75K substitution occurred in the first sushi domain of SRPX2, only three amino acid residues away from a previously reported disease-causing mutation (Y72S. Three-dimensional structural modeling of the first sushi domain revealed that Y72 and K75 are both situated in the hypervariable loop that is usually implicated in protein-protein interactions. The side-chain of residue 75 is exposed, and is located within an unusual and SRPX-specific protruding extension to the hypervariable loop. The analysis of non-synonymous/synonymous substitution rate (Ka/Ks ratio in primates was performed in order to test for positive selection during recent evolution. Using the branch models, the Ka/Ks ratio for the human branch was significantly different (p = 0.027 from that of the other branches. In contrast, the branch-site tests did not reach significance. Genetic analysis was also performed by sequencing 9,908 kilobases (kb of intronic SRPX2 sequences. Despite low nucleotide diversity, neither the HKA (Hudson-Kreitman-Aguadé test nor the Tajima's D test reached significance. Conclusion The R75K human-specific variation occurred in an important functional loop of the first sushi domain of SRPX2, indicating that this evolutionary

  17. An Improved Brain Storm Optimization with Differential Evolution Strategy for Applications of ANNs

    Directory of Open Access Journals (Sweden)

    Zijian Cao

    2015-01-01

    Full Text Available Brain Storm Optimization (BSO algorithm is a swarm intelligence algorithm inspired by human being’s behavior of brainstorming. The performance of BSO is maintained by the creating process of ideas, but when it cannot find a better solution for some successive iterations, the result will be so inefficient that the population might be trapped into local optima. In this paper, we propose an improved BSO algorithm with differential evolution strategy and new step size method. Firstly, differential evolution strategy is incorporated into the creating operator of ideas to allow BSO jump out of stagnation, owing to its strong searching ability. Secondly, we introduce a new step size control method that can better balance exploration and exploitation at different searching generations. Finally, the proposed algorithm is first tested on 14 benchmark functions of CEC 2005 and then is applied to train artificial neural networks. Comparative experimental results illustrate that the proposed algorithm performs significantly better than the original BSO.

  18. Recurrent evolution of life history ecotypes in sockeye salmon: implications for conservation and future evolution.

    Science.gov (United States)

    Wood, Chris C; Bickham, John W; John Nelson, R; Foote, Chris J; Patton, John C

    2008-05-01

    We examine the evolutionary history and speculate about the evolutionary future of three basic life history ecotypes that contribute to the biocomplexity of sockeye salmon (Oncorhynchus nerka). The 'recurrent evolution' (RE) hypothesis claims that the sea/river ecotype is ancestral, a 'straying' form with poorly differentiated (meta)population structure, and that highly structured populations of lake-type sockeye and kokanee have evolved repeatedly in parallel adaptive radiations between recurrent glaciations of the Pleistocene Epoch. Basic premises of this hypothesis are consistent with new, independent evidence from recent surveys of genetic variation in mitochondrial and microsatellite DNA: (1) sockeye salmon are most closely related to pink (O. gorbuscha) and chum (O. keta) salmon with sea-type life histories; (2) the sockeye life history ecotypes exist as polyphyletic lineages within large drainages and geographic regions; (3) the sea/river ecotype exhibits less genetic differentiation among populations than the lake or kokanee ecotypes both within and among drainages; and (4) genetic diversity is typically higher in the sea/river ecotype than in the lake and kokanee ecotypes. Anthropogenic modification of estuarine habitat and intensive coastal fisheries have likely reduced and fragmented historic metapopulations of the sea/river ecotype, particularly in southern areas. In contrast, the kokanee ecotype appears to be favoured by marine fisheries and predicted changes in climate.

  19. Skull Flexure from Blast Waves: A New Mechanism for Brain Injury with Implications for Helmet Design

    CERN Document Server

    Moss, William C; Blackman, Eric G

    2008-01-01

    Traumatic brain injury [TBI] has become the signature injury of current military conflicts. The debilitating effects of TBI on society are long-lasting and costly. Although the mechanisms by which impacts cause TBI have been well researched, the mechanisms by which blasts cause TBI are not understood. Various mechanisms, including impacts caused by the blast, have been investigated, but blast-induced deformation of the skull has been neglected. Through the use of hydrodynamical numerical simulations, we have discovered that non-lethal blasts can induce sufficient flexure of the skull to generate potentially damaging loads in the brain, even if no impact occurs. This mechanism has implications for the diagnosis of TBI in soldiers and the design of protective equipment such as helmets.

  20. Skull flexure from blast waves: a mechanism for brain injury with implications for helmet design

    Energy Technology Data Exchange (ETDEWEB)

    Moss, W C; King, M J; Blackman, E G

    2009-04-14

    Traumatic brain injury [TBI] has become a signature injury of current military conflicts. The debilitating effects of TBI are long-lasting and costly. Although the mechanisms by which impacts cause TBI have been well researched, the mechanisms by which blasts cause TBI are not understood. Various possibilities have been investigated, but blast-induced deformation of the skull has been neglected. From numerical hydrodynamic simulations, we have discovered that nonlethal blasts can induce sufficient flexure of the skull to generate potentially damaging loads in the brain, even if no impact occurs. The possibility that this mechanism may contribute to TBI has implications for the diagnosis of soldiers and the design of protective equipment such as helmets.

  1. New insight in expression, transport, and secretion of brain-derived neurotrophic factor: Implications in brainrelated diseases

    Institute of Scientific and Technical Information of China (English)

    Naoki; Adachi; Tadahiro; Numakawa; Misty; Richards; Shingo; Nakajima; Hiroshi; Kunugi

    2014-01-01

    Brain-derived neurotrophic factor(BDNF) attracts increasing attention from both research and clinical fields because of its important functions in the central nervous system. An adequate amount of BDNF is critical to develop and maintain normal neuronal circuits in the brain. Given that loss of BDNF function has beenreported in the brains of patients with neurodegenerative or psychiatric diseases, understanding basic properties of BDNF and associated intracellular processes is imperative. In this review, we revisit the gene structure, transcription, translation, transport and secretion mechanisms of BDNF. We also introduce implications of BDNF in several brain-related diseases including Alzheimer’s disease, Huntington’s disease, depression and schizophrenia.

  2. Elements of Climate Evolution in yhe Area Between Prut and Dniester Rivers. Landscape and Pedogenetic Implications

    Directory of Open Access Journals (Sweden)

    Jigău Gheorghe

    2015-05-01

    Full Text Available Component part of the Carpathian-Danubian-Pontic space, the interfluve area between Prut and Dniester is subject to the regional process of climate evolution and change. In what regards the concept of human-influenced pedogenesis, the role of the biological factor is significantly reduced. As a consequence the direction and intensity of the elementary landscape and pedogenetic processes are determined by the relations between climate and the geomorphological factor. In the conditions of a relative stability of the geomorphological factor, the determining role is held by climate. To this is added soil vulnerability to the implications of climate changes, determined by the degree of soil physical degradation but also by a series of intrinsic and external (drainage factors. This implies the idea of the control and management of the landscape and pedogenetic implications of climate changes by improving soil physical characteristics.

  3. Evolution of double white dwarf binaries undergoing direct-impact accretion: Implications for gravitational wave astronomy

    Science.gov (United States)

    Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

    2017-01-01

    For close double white dwarf binaries, the mass-transfer phenomenon known as direct-impact accretion (when the mass transfer stream impacts the accretor directly rather than forming a disc) may play a pivotal role in the long-term evolution of the systems. In this analysis, we explore the long-term evolution of white dwarf binaries accreting through direct-impact and explore implications of such systems to gravitational wave astronomy. We cover a broad range of parameter space which includes initial component masses and the strength of tidal coupling, and show that these systems, which lie firmly within the LISA frequency range, show strong negative chirps which can last as long as several million years. Detections of double white dwarf systems in the direct-impact phase by detectors such as LISA would provide astronomers with unique ways of probing the physics governing close compact object binaries.

  4. Evolution of binary stars and its implications for evolutionary population synthesis

    CERN Document Server

    Han, Z; Zhang, F; Podsiadlowski, Ph

    2009-01-01

    Most stars are members of binaries, and the evolution of a star in a close binary system differs from that of an ioslated star due to the proximity of its companion star. The components in a binary system interact in many ways and binary evolution leads to the formation of many peculiar stars, including blue stragglers and hot subdwarfs. We will discuss binary evolution and the formation of blue stragglers and hot subdwarfs, and show that those hot objects are important in the study of evolutionary population synthesis (EPS), and conclude that binary interactions should be included in the study of EPS. Indeed, binary interactions make a stellar population younger (hotter), and the far-ultraviolet (UV) excess in elliptical galaxies is shown to be most likely resulted from binary interactions. This has major implications for understanding the evolution of the far-UV excess and elliptical galaxies in general. In particular, it implies that the far-UV excess is not a sign of age, as had been postulated prviously ...

  5. Microevolutionary, macroevolutionary, ecological and taxonomical implications of punctuational theories of adaptive evolution

    Directory of Open Access Journals (Sweden)

    Flegr Jaroslav

    2013-01-01

    Full Text Available Abstract Punctuational theories of evolution suggest that adaptive evolution proceeds mostly, or even entirely, in the distinct periods of existence of a particular species. The mechanisms of this punctuated nature of evolution suggested by the various theories differ. Therefore the predictions of particular theories concerning various evolutionary phenomena also differ. Punctuational theories can be subdivided into five classes, which differ in their mechanism and their evolutionary and ecological implications. For example, the transilience model of Templeton (class III, genetic revolution model of Mayr (class IV or the frozen plasticity theory of Flegr (class V, suggests that adaptive evolution in sexual species is operative shortly after the emergence of a species by peripatric speciation – while it is evolutionary plastic. To a major degree, i.e. throughout 98-99% of their existence, sexual species are evolutionarily frozen (class III or elastic (class IV and V on a microevolutionary time scale and evolutionarily frozen on a macroevolutionary time scale and can only wait for extinction, or the highly improbable return of a population segment to the plastic state due to peripatric speciation. The punctuational theories have many evolutionary and ecological implications. Most of these predictions could be tested empirically, and should be analyzed in greater depth theoretically. The punctuational theories offer many new predictions that need to be tested, but also provide explanations for a much broader spectrum of known biological phenomena than classical gradualistic evolutionary theories. Reviewers This article was reviewed by Claus Wilke, Pierre Pantarotti and David Penny (nominated by Anthony Poole.

  6. Scattering of Sculpted Light in Intact Brain Tissue, with implications for Optogenetics

    Science.gov (United States)

    Favre-Bulle, Itia A.; Preece, Daryl; Nieminen, Timo A.; Heap, Lucy A.; Scott, Ethan K.; Rubinsztein-Dunlop, Halina

    2015-06-01

    Optogenetics uses light to control and observe the activity of neurons, often using a focused laser beam. As brain tissue is a scattering medium, beams are distorted and spread with propagation through neural tissue, and the beam’s degradation has important implications in optogenetic experiments. To address this, we present an analysis of scattering and loss of intensity of focused laser beams at different depths within the brains of zebrafish larvae. Our experimental set-up uses a 488 nm laser and a spatial light modulator to focus a diffraction-limited spot of light within the brain. We use a combination of experimental measurements of back-scattered light in live larvae and computational modelling of the scattering to determine the spatial distribution of light. Modelling is performed using the Monte Carlo method, supported by generalised Lorenz-Mie theory in the single-scattering approximation. Scattering in areas rich in cell bodies is compared to that of regions of neuropil to identify the distinct and dramatic contributions that cell nuclei make to scattering. We demonstrate the feasibility of illuminating individual neurons, even in nucleus-rich areas, at depths beyond 100 μm using a spatial light modulator in combination with a standard laser and microscope optics.

  7. The Co-evolution of Language and the Brain: A Review of Two Contrastive Views (Pinker & Deacon)

    DEFF Research Database (Denmark)

    Christensen, Ken Ramshøj

    2001-01-01

    in a larger symbolic computational chain controlled by regions in the frontal parts of the brain. To Deacon, a symbolic learning algorithm drives language acquisition. The increase in size of the human brain in relation to the body may be due to a “cognitive arms race”. Both Pinker and Deacon agree......This article is a review of two contrastive views on the co-evolution of language and the brain – The Language Instinct by Steven Pinker (1994) and The Symbolic Species by Terrence Deacon (1997). As language is a trait unique to mankind it can not be equated with nonlinguistic communication – human...... or nonhuman. This points to a special human brain architecture. Pinker’s claim is that certain areas on the left side of the brain constitute a language organ and that language acquisition is instinctual. To Deacon, however, those areas are non-language-specific computational centers. Moreover, they are parts...

  8. Organization and evolution of brain lipidome revealed by large-scale analysis of human, chimpanzee, macaque, and mouse tissues.

    Science.gov (United States)

    Bozek, Katarzyna; Wei, Yuning; Yan, Zheng; Liu, Xiling; Xiong, Jieyi; Sugimoto, Masahiro; Tomita, Masaru; Pääbo, Svante; Sherwood, Chet C; Hof, Patrick R; Ely, John J; Li, Yan; Steinhauser, Dirk; Willmitzer, Lothar; Giavalisco, Patrick; Khaitovich, Philipp

    2015-02-18

    Lipids are prominent components of the nervous system. Here we performed a large-scale mass spectrometry-based analysis of the lipid composition of three brain regions as well as kidney and skeletal muscle of humans, chimpanzees, rhesus macaques, and mice. The human brain shows the most distinct lipid composition: 76% of 5,713 lipid compounds examined in our study are either enriched or depleted in the human brain. Concentration levels of lipids enriched in the brain evolve approximately four times faster among primates compared with lipids characteristic of non-neural tissues and show further acceleration of change in human neocortical regions but not in the cerebellum. Human-specific concentration changes are supported by human-specific expression changes for corresponding enzymes. These results provide the first insights into the role of lipids in human brain evolution.

  9. Précis of Foundations of language: brain, meaning, grammar, evolution.

    Science.gov (United States)

    Jackendoff, Ray

    2003-12-01

    The goal of this study is to reintegrate the theory of generative grammar into the cognitive sciences. Generative grammar was right to focus on the child's acquisition of language as its central problem, leading to the hypothesis of an innate Universal Grammar. However, generative grammar was mistaken in assuming that the syntactic component is the sole course of combinatoriality, and that everything else is "interpretive." The proper approach is a parallel architecture, in which phonology, syntax, and semantics are autonomous generative systems linked by interface components. The parallel architecture leads to an integration within linguistics, and to a far better integration with the rest of cognitive neuroscience. It fits naturally into the larger architecture of the mind/brain and permits a properly mentalistic theory of semantics. It results in a view of linguistic performance in which the rules of grammar are directly involved in processing. Finally, it leads to a natural account of the incremental evolution of the language capacity.

  10. Adrenal Disorders and the Paediatric Brain: Pathophysiological Considerations and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Vincenzo Salpietro

    2014-01-01

    Full Text Available Various neurological and psychiatric manifestations have been recorded in children with adrenal disorders. Based on literature review and on personal case-studies and case-series we focused on the pathophysiological and clinical implications of glucocorticoid-related, mineralcorticoid-related, and catecholamine-related paediatric nervous system involvement. Childhood Cushing syndrome can be associated with long-lasting cognitive deficits and abnormal behaviour, even after resolution of the hypercortisolism. Exposure to excessive replacement of exogenous glucocorticoids in the paediatric age group (e.g., during treatments for adrenal insufficiency has been reported with neurological and magnetic resonance imaging (MRI abnormalities (e.g., delayed myelination and brain atrophy due to potential corticosteroid-related myelin damage in the developing brain and the possible impairment of limbic system ontogenesis. Idiopathic intracranial hypertension (IIH, a disorder of unclear pathophysiology characterised by increased cerebrospinal fluid (CSF pressure, has been described in children with hypercortisolism, adrenal insufficiency, and hyperaldosteronism, reflecting the potential underlying involvement of the adrenal-brain axis in the regulation of CSF pressure homeostasis. Arterial hypertension caused by paediatric adenomas or tumours of the adrenal cortex or medulla has been associated with various hypertension-related neurological manifestations. The development and maturation of the central nervous system (CNS through childhood is tightly regulated by intrinsic, paracrine, endocrine, and external modulators, and perturbations in any of these factors, including those related to adrenal hormone imbalance, could result in consequences that affect the structure and function of the paediatric brain. Animal experiments and clinical studies demonstrated that the developing (i.e., paediatric CNS seems to be particularly vulnerable to alterations induced by

  11. Diversification of CYCLOIDEA-like genes in Dipsacaceae (Dipsacales: implications for the evolution of capitulum inflorescences

    Directory of Open Access Journals (Sweden)

    Carlson Sara E

    2011-11-01

    Full Text Available Abstract Background CYCLOIDEA (CYC-like genes have been implicated in the development of capitulum inflorescences (i.e. flowering heads in Asteraceae, where many small flowers (florets are packed tightly into an inflorescence that resembles a single flower. Several rounds of duplication of CYC-like genes have occurred in Asteraceae, and this is hypothesized to be correlated with the evolution of the capitulum, which in turn has been implicated in the evolutionary success of the group. We investigated the evolution of CYC-like genes in Dipsacaceae (Dipsacales, a plant clade in which capitulum inflorescences originated independently of Asteraceae. Two main inflorescence types are present in Dipsacaceae: (1 radiate species contain two kinds of floret within the flowering head (disk and ray, and (2 discoid species contain only disk florets. To test whether a dynamic pattern of gene duplication, similar to that documented in Asteraceae, is present in Dipsacaceae, and whether these patterns are correlated with different inflorescence types, we inferred a CYC-like gene phylogeny for Dipsacaceae based on representative species from the major lineages. Results We recovered within Dipsacaceae the three major forms of CYC-like genes that have been found in most core eudicots, and identified several additional duplications within each of these clades. We found that the number of CYC-like genes in Dipsacaceae is similar to that reported for members of Asteraceae and that the same gene lineages (CYC1-like and CYC2B-like genes have duplicated in a similar fashion independently in both groups. The number of CYC-like genes recovered for radiate versus discoid species differed, with discoid species having fewer copies of CYC1-like and CYC2B-like genes. Conclusions CYC-like genes have undergone extensive duplication in Dipsacaceae, with radiate species having more copies than discoid species, suggesting a potential role for these genes in the evolution of disk and

  12. The Evolution of Galaxy Number Density at z < 8 and its Implications

    CERN Document Server

    Conselice, Christopher J; Duncan, Kenneth; Mortlock, Alice

    2016-01-01

    The evolution of the number density of galaxies in the universe, and thus also the total number of galaxies, is a fundamental question with implications for a host of astrophysical problems including galaxy evolution and cosmology. However there has never been a detailed study of this important measurement, nor a clear path to answer it. To address this we use observed galaxy stellar mass functions up to $z\\sim8$ to determine how the number densities of galaxies changes as a function of time and mass limit. We show that the increase in the total number density of galaxies ($\\phi_{\\rm T}$), more massive than M$_{*} = 10^{6}$ M_0, decreases as $\\phi_{\\rm T} \\sim t^{-1}$, where $t$ is the age of the universe. We further show that this evolution turns-over and rather increases with time at higher mass lower limits of M$_{*}>10^{7}$ M_0. By using the M$_{*}=10^{6}$ M_0 lower limit we further show that the total number of galaxies in the universe up to $z = 10$ is $2.0^{+0.7}_{-0.6} \\times 10^{12}$ (two trillion), ...

  13. Evolution of the brain: from behavior to consciousness in 3.4 billion years.

    Science.gov (United States)

    Oró, John J

    2004-06-01

    Once life began as single-cell organisms, evolution favored those able to seek nutrients and avoid risks. Receptors sensed the environment, memory traces were laid, and adaptive responses were made. Environmental stress, at times as dramatic as the collision of an asteroid, resulted in extinctions that favored small predators with dorsal nerve cords and cranially positioned brains. Myelination, and later thermoregulation, led to increasingly efficient neural processing. As somatosensory, visual, and auditory input increased, a neocortex developed containing both sensory and motor neural maps. Hominids, with their free hands, pushed cortical development further and began to make simple stone tools. Tools and increasing cognition allowed procurement of a richer diet that led to a smaller gut, thus freeing more energy for brain expansion. Multimodal association areas, initially developed for processing incoming sensory information, blossomed and began to provide the organism with an awareness of self and environment. Advancements in memory storage and retrieval gave the organism a sense of continuity through time. This developing consciousness eventually left visible traces, which today are dramatically evident on cave walls in France and Spain. We will take this journey from the single cell to human consciousness.

  14. Morphological and pathological evolution of the brain microcirculation in aging and Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Jesse M Hunter

    Full Text Available Key pathological hallmarks of Alzheimer's disease (AD, including amyloid plaques, cerebral amyloid angiopathy (CAA and neurofibrillary tangles do not completely account for cognitive impairment, therefore other factors such as cardiovascular and cerebrovascular pathologies, may contribute to AD. In order to elucidate the microvascular changes that contribute to aging and disease, direct neuropathological staining and immunohistochemistry, were used to quantify the structural integrity of the microvasculature and its innervation in three oldest-old cohorts: 1 nonagenarians with AD and a high amyloid plaque load; 2 nonagenarians with no dementia and a high amyloid plaque load; 3 nonagenarians without dementia or amyloid plaques. In addition, a non-demented (ND group (average age 71 years with no amyloid plaques was included for comparison. While gray matter thickness and overall brain mass were reduced in AD compared to ND control groups, overall capillary density was not different. However, degenerated string capillaries were elevated in AD, potentially suggesting greater microvascular "dysfunction" compared to ND groups. Intriguingly, apolipoprotein ε4 carriers had significantly higher string vessel counts relative to non-ε4 carriers. Taken together, these data suggest a concomitant loss of functional capillaries and brain volume in AD subjects. We also demonstrated a trend of decreasing vesicular acetylcholine transporter staining, a marker of cortical cholinergic afferents that contribute to arteriolar vasoregulation, in AD compared to ND control groups, suggesting impaired control of vasodilation in AD subjects. In addition, tyrosine hydroxylase, a marker of noradrenergic vascular innervation, was reduced which may also contribute to a loss of control of vasoconstriction. The data highlight the importance of the brain microcirculation in the pathogenesis and evolution of AD.

  15. Directed evolution of brain-derived neurotrophic factor for improved folding and expression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Burns, Michael L; Malott, Thomas M; Metcalf, Kevin J; Hackel, Benjamin J; Chan, Jonah R; Shusta, Eric V

    2014-09-01

    Brain-derived neurotrophic factor (BDNF) plays an important role in nervous system function and has therapeutic potential. Microbial production of BDNF has resulted in a low-fidelity protein product, often in the form of large, insoluble aggregates incapable of binding to cognate TrkB or p75 receptors. In this study, employing Saccharomyces cerevisiae display and secretion systems, it was found that BDNF was poorly expressed and partially inactive on the yeast surface and that BDNF was secreted at low levels in the form of disulfide-bonded aggregates. Thus, for the purpose of increasing the compatibility of yeast as an expression host for BDNF, directed-evolution approaches were employed to improve BDNF folding and expression levels. Yeast surface display was combined with two rounds of directed evolution employing random mutagenesis and shuffling to identify BDNF mutants that had 5-fold improvements in expression, 4-fold increases in specific TrkB binding activity, and restored p75 binding activity, both as displayed proteins and as secreted proteins. Secreted BDNF mutants were found largely in the form of soluble homodimers that could stimulate TrkB phosphorylation in transfected PC12 cells. Site-directed mutagenesis studies indicated that a particularly important mutational class involved the introduction of cysteines proximal to the native cysteines that participate in the BDNF cysteine knot architecture. Taken together, these findings show that yeast is now a viable alternative for both the production and the engineering of BDNF.

  16. Temporal evolution of brain reorganization under cross-modal training: insights into the functional architecture of encoding and retrieval networks

    Science.gov (United States)

    Likova, Lora T.

    2015-03-01

    This study is based on the recent discovery of massive and well-structured cross-modal memory activation generated in the primary visual cortex (V1) of totally blind people as a result of novel training in drawing without any vision (Likova, 2012). This unexpected functional reorganization of primary visual cortex was obtained after undergoing only a week of training by the novel Cognitive-Kinesthetic Method, and was consistent across pilot groups of different categories of visual deprivation: congenitally blind, late-onset blind and blindfolded (Likova, 2014). These findings led us to implicate V1 as the implementation of the theoretical visuo-spatial 'sketchpad' for working memory in the human brain. Since neither the source nor the subsequent 'recipient' of this non-visual memory information in V1 is known, these results raise a number of important questions about the underlying functional organization of the respective encoding and retrieval networks in the brain. To address these questions, an individual totally blind from birth was given a week of Cognitive-Kinesthetic training, accompanied by functional magnetic resonance imaging (fMRI) both before and just after training, and again after a two-month consolidation period. The results revealed a remarkable temporal sequence of training-based response reorganization in both the hippocampal complex and the temporal-lobe object processing hierarchy over the prolonged consolidation period. In particular, a pattern of profound learning-based transformations in the hippocampus was strongly reflected in V1, with the retrieval function showing massive growth as result of the Cognitive-Kinesthetic memory training and consolidation, while the initially strong hippocampal response during tactile exploration and encoding became non-existent. Furthermore, after training, an alternating patch structure in the form of a cascade of discrete ventral regions underwent radical transformations to reach complete functional

  17. [Prenatal imaging of the fetal brain--indications and developmental implications of fetal MRI].

    Science.gov (United States)

    Ben Sira, Liat; Garel, Catherine; Leitner, Yael; Gross-Tsur, Varda

    2008-01-01

    Cerebral anomalies at birth account for approximately 9% of all isolated anomalies and are present in 15.9% of babies with multiple malformations and, thereby, warrant concern in antenatal diagnosis. Ultrasonography is the basic screening examination for the pregnant woman due to its efficiency, availability, low cost and real time capability. Many of the major anomalies can be diagnosed by ultrasound during the first trimester of pregnancy. However subtle abnormalities can be missed by ultrasonography or detected only in later stages of pregnancy. Fetal MRI has proved itself to be an effective adjuvant imaging tool and is indicated whenever there is a diagnostic query on ultrasound or a need to define a suspected brain anomaly. The information obtained from fetal MRI has significant implications for parental counseling regarding both the type of malformation as well as the neurological and developmental prognosis. Current indications for fetal MRI, focusing on various common fetal cerebral pathologies, will be addressed in this review.

  18. DEVELOPMENTAL CHANGES IN SEROTONIN SIGNALING: IMPLICATIONS FOR EARLY BRAIN FUNCTION, BEHAVIOR AND ADAPTATION

    Science.gov (United States)

    BRUMMELTE, S.; GLANAGHY, E. MC; BONNIN, A.; OBERLANDER, T. F.

    2017-01-01

    The neurotransmitter serotonin (5-HT) plays a central role in brain development, regulation of mood, stress reactivity and risk of psychiatric disorders, and thus alterations in 5-HT signaling early in life have critical implications for behavior and mental health across the life span. Drawing on preclinical and emerging human evidence this narrative review paper will examine three key aspects when considering the consequences of early life changes in 5-HT: (1) developmental origins of variations of 5-HT signaling; (2) influence of genetic and epigenetic factors; and (3) preclinical and clinical consequences of 5-HT-related changes associated with antidepressant exposure (SSRIs). The developmental consequences of altered prenatal 5-HT signaling varies greatly and outcomes depend on an ongoing interplay between biological (genetic/epigenetic variations) and environmental factors, both pre and postnatally. Emerging evidence suggests that variations in 5-HT signaling may increase sensitivity to risky home environments, but may also amplify a positive response to a nurturing environment. In this sense, factors that change central 5-HT levels may act as ‘plasticity’ rather than ‘risk’ factors associated with developmental vulnerability. Understanding the impact of early changes in 5-HT levels offers critical insights that might explain the variations in early typical brain development that underlies behavioral risk. PMID:26905950

  19. Maternal brain death, pregnancy and the foetus: the medico-legal implications for Ireland.

    Science.gov (United States)

    Sheikh, Asim A; Cusack, Denis A

    2004-01-01

    This paper examines some of the medico-legal issues that arose as a result of a situation which occurred in May 2001 in Ireland when a woman who was a British citizen and who was fourteen weeks pregnant collapsed and suffered a brain haemorrhage. She was taken to hospital where she was placed on life support but declared brain-dead. As a result of the uncertainty regarding the hospital's obligation to the foetus, life-support was maintained until further opinion was sought. After two weeks the foetus died and life support was only then discontinued. In Ireland there currently exists neither medical guidelines nor legislation to regulate such areas of medical practice. Also, the courts have not had the opportunity to comment on this particular matter and thus there exists widespread concern as to how healthcare providers will act if such situation were to occur again in the future. This article examines the following difficult medico-legal implications that arise from the above situation and especially in light of the constitutional protection of the unborn child in Ireland.

  20. Glutathione in Cerebral Microvascular Endothelial Biology and Pathobiology: Implications for Brain Homeostasis

    Directory of Open Access Journals (Sweden)

    Wei Li

    2012-01-01

    Full Text Available The integrity of the vascular endothelium of the blood-brain barrier (BBB is central to cerebrovascular homeostasis. Given the function of the BBB as a physical and metabolic barrier that buffers the systemic environment, oxidative damage to the endothelial monolayer will have significant deleterious impact on the metabolic, immunological, and neurological functions of the brain. Glutathione (GSH is a ubiquitous major thiol within mammalian cells that plays important roles in antioxidant defense, oxidation-reduction reactions in metabolic pathways, and redox signaling. The existence of distinct GSH pools within the subcellular organelles supports an elegant mode for independent redox regulation of metabolic processes, including those that control cell fate. GSH-dependent homeostatic control of neurovascular function is relatively unexplored. Significantly, GSH regulation of two aspects of endothelial function is paramount to barrier preservation, namely, GSH protection against oxidative endothelial cell injury and GSH control of postdamage cell proliferation in endothelial repair and/or wound healing. This paper highlights our current insights and hypotheses into the role of GSH in cerebral microvascular biology and pathobiology with special focus on endothelial GSH and vascular integrity, oxidative disruption of endothelial barrier function, GSH regulation of endothelial cell proliferation, and the pathological implications of GSH disruption in oxidative stress-associated neurovascular disorders, such as diabetes and stroke.

  1. Soft X-ray Irradiation of Silicates: Implications on Dust Evolution in Protoplanetary Disks

    CERN Document Server

    Ciaravella, A; Chen, Y -J; Caro, G M Muñoz; Huang, C -H; Jiménez-Escobar, A; Venezia, A M

    2016-01-01

    The processing of energetic photons on bare silicate grains was simulated experimentally on silicate ?lms submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted solgel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray irradiated protoplanetary disks.

  2. Soft X-Ray Irradiation of Silicates: Implications for Dust Evolution in Protoplanetary Disks

    Science.gov (United States)

    Ciaravella, A.; Cecchi-Pestellini, C.; Chen, Y.-J.; Muñoz Caro, G. M.; Huang, C.-H.; Jiménez-Escobar, A.; Venezia, A. M.

    2016-09-01

    The processing of energetic photons on bare silicate grains was simulated experimentally on silicate films submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted sol-gel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray-irradiated protoplanetary disks.

  3. TNF signaling inhibition in the CNS: implications for normal brain function and neurodegenerative disease

    Directory of Open Access Journals (Sweden)

    Tansey Malú G

    2008-10-01

    Full Text Available Abstract The role of tumor necrosis factor (TNF as an immune mediator has long been appreciated but its function in the brain is still unclear. TNF receptor 1 (TNFR1 is expressed in most cell types, and can be activated by binding of either soluble TNF (solTNF or transmembrane TNF (tmTNF, with a preference for solTNF; whereas TNFR2 is expressed primarily by microglia and endothelial cells and is preferentially activated by tmTNF. Elevation of solTNF is a hallmark of acute and chronic neuroinflammation as well as a number of neurodegenerative conditions including ischemic stroke, Alzheimer's (AD, Parkinson's (PD, amyotrophic lateral sclerosis (ALS, and multiple sclerosis (MS. The presence of this potent inflammatory factor at sites of injury implicates it as a mediator of neuronal damage and disease pathogenesis, making TNF an attractive target for therapeutic development to treat acute and chronic neurodegenerative conditions. However, new and old observations from animal models and clinical trials reviewed here suggest solTNF and tmTNF exert different functions under normal and pathological conditions in the CNS. A potential role for TNF in synaptic scaling and hippocampal neurogenesis demonstrated by recent studies suggest additional in-depth mechanistic studies are warranted to delineate the distinct functions of the two TNF ligands in different parts of the brain prior to large-scale development of anti-TNF therapies in the CNS. If inactivation of TNF-dependent inflammation in the brain is warranted by additional pre-clinical studies, selective targeting of TNFR1-mediated signaling while sparing TNFR2 activation may lessen adverse effects of anti-TNF therapies in the CNS.

  4. Evolution of technetium-99m-HMPAO SPECT and brain mapping in a patient presenting with echolalia and palilalia.

    Science.gov (United States)

    Dierckx, R A; Saerens, J; De Deyn, P P; Verslegers, W; Marien, P; Vandevivere, J

    1991-08-01

    A 78-yr-old woman presented with transient echolalia and palilalia. She had suffered from Parkinson's disease for 2 yr. Routine laboratory examination showed hypotonic hyponatremia, but was otherwise unremarkable. Brain mapping revealed a bifrontal delta focus, more pronounced on the right. Single photon emission computed tomography (SPECT) of the brain with technetium-99m labeled d,l hexamethylpropylene-amine oxime (99mTc-HMPAO), performed during the acute episode showed relative frontoparietal hypoactivity. Brain mapping performed after disappearance of the echolalia and palilalia, which persisted only for 1 day, was normal. By contrast, SPECT findings persisted for more than 3 wk. Features of particular interest in the presented patient are the extensive defects seen on brain SPECT despite the absence of morphologic lesions, the congruent electrophysiologic changes and their temporal relationship with the clinical evolution.

  5. Amphioxus and lamprey AP-2 genes: implications for neural crest evolution and migration patterns

    Science.gov (United States)

    Meulemans, Daniel; Bronner-Fraser, Marianne

    2002-01-01

    The neural crest is a uniquely vertebrate cell type present in the most basal vertebrates, but not in cephalochordates. We have studied differences in regulation of the neural crest marker AP-2 across two evolutionary transitions: invertebrate to vertebrate, and agnathan to gnathostome. Isolation and comparison of amphioxus, lamprey and axolotl AP-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of AP-2 genes by neural crest cells early in vertebrate evolution. Expression in non-neural ectoderm is a conserved feature in amphioxus and vertebrates, suggesting an ancient role for AP-2 genes in this tissue. There is also common expression in subsets of ventrolateral neurons in the anterior neural tube, consistent with a primitive role in brain development. Comparison of AP-2 expression in axolotl and lamprey suggests an elaboration of cranial neural crest patterning in gnathostomes. However, migration of AP-2-expressing neural crest cells medial to the pharyngeal arch mesoderm appears to be a primitive feature retained in all vertebrates. Because AP-2 has essential roles in cranial neural crest differentiation and proliferation, the co-option of AP-2 by neural crest cells in the vertebrate lineage was a potentially crucial event in vertebrate evolution.

  6. Implications of WMAP observations on Li abundance and stellar evolution models

    CERN Document Server

    Richard, O; Richer, J; Richard, Olivier; Michaud, Georges; Richer, Jacques

    2004-01-01

    The WMAP determination of the baryon-to-photon ratio implies, through Big Bang nucleosynthesis, a cosmological Li abundance larger, by a factor of 2 to 3, than the Li abundance plateau observed in the oldest Pop II stars. It is however inescapable that there be a reduction by a factor of at least 1.6 to 2.0 of the surface Li abundance during the evolution of Pop II field stars with [Fe/H] < -1.5. That the observed Li be lower than cosmologically produced Li is expected from stellar evolution models. Since at turnoff most of the Li abundance reduction is caused by gravitational settling, the presence of Lithium 6 in some turnoff stars is also understood. Given that the WMAP implications for Li cosmological abundance and the Li Spite plateau can be naturally explained by gravitational settling in the presence of weak turbulence, there appears little need for exotic physics as suggested by some authors. Instead, there is a need for a better understanding of turbulent transport in the radiative zones of stars....

  7. Avian sleep homeostasis: convergent evolution of complex brains, cognition and sleep functions in mammals and birds.

    Science.gov (United States)

    Rattenborg, Niels C; Martinez-Gonzalez, Dolores; Lesku, John A

    2009-03-01

    Birds are the only taxonomic group other than mammals that exhibit high-amplitude slow-waves in the electroencephalogram (EEG) during sleep. This defining feature of slow-wave sleep (SWS) apparently evolved independently in mammals and birds, as reptiles do not exhibit similar EEG activity during sleep. In mammals, the level of slow-wave activity (SWA) (low-frequency spectral power density) during SWS increases and decreases as a function of prior time spent awake and asleep, respectively, and therefore reflects homeostatically regulated sleep processes potentially tied to the function of SWS. Although birds also exhibit SWS, previous sleep deprivation studies in birds did not detect a compensatory increase in SWS-related SWA during recovery, as observed in similarly sleep-deprived mammals. This suggested that, unlike mammalian SWS, avian SWS is not homeostatically regulated, and therefore might serve a different function. However, we recently demonstrated that SWA during SWS increases in pigeons following short-term sleep deprivation. Herein we summarize research on avian sleep homeostasis, and cast our evidence for this phenomenon within the context of theories for the function of SWS in mammals. We propose that the convergent evolution of homeostatically regulated SWS in mammals and birds was directly linked to the convergent evolution of large, heavily interconnected brains capable of performing complex cognitive processes in each group. Specifically, as has been proposed for mammals, the interconnectivity that forms the basis of complex cognition in birds may also instantiate slow, synchronous network oscillations during SWS that in turn maintain interconnectivity and cognition at an optimal level.

  8. Automatic Evolution of Multimodal Behavior with Multi-Brain HyperNEAT

    DEFF Research Database (Denmark)

    Schrum, Jacob; Lehman, Joel; Risi, Sebastian

    2016-01-01

    them. The resulting Multi-Brain HyperNEAT can exploit human-specified task divisions, or can automatically discover when brains should be used, and how many to use. Experiments show that multi-brain approaches are more effective than HyperNEAT without multimodal extensions, and that brains without...

  9. Molecular Evidence for Convergence and Parallelism in Evolution of Complex Brains of Cephalopod Molluscs: Insights from Visual Systems.

    Science.gov (United States)

    Yoshida, M A; Ogura, A; Ikeo, K; Shigeno, S; Moritaki, T; Winters, G C; Kohn, A B; Moroz, L L

    2015-12-01

    Coleoid cephalopods show remarkable evolutionary convergence with vertebrates in their neural organization, including (1) eyes and visual system with optic lobes, (2) specialized parts of the brain controlling learning and memory, such as vertical lobes, and (3) unique vasculature supporting such complexity of the central nervous system. We performed deep sequencing of eye transcriptomes of pygmy squids (Idiosepius paradoxus) and chambered nautiluses (Nautilus pompilius) to decipher the molecular basis of convergent evolution in cephalopods. RNA-seq was complemented by in situ hybridization to localize the expression of selected genes. We found three types of genomic innovations in the evolution of complex brains: (1) recruitment of novel genes into morphogenetic pathways, (2) recombination of various coding and regulatory regions of different genes, often called "evolutionary tinkering" or "co-option", and (3) duplication and divergence of genes. Massive recruitment of novel genes occurred in the evolution of the "camera" eye from nautilus' "pinhole" eye. We also showed that the type-2 co-option of transcription factors played important roles in the evolution of the lens and visual neurons. In summary, the cephalopod convergent morphological evolution of the camera eyes was driven by a mosaic of all types of gene recruitments. In addition, our analysis revealed unexpected variations of squids' opsins, retinochromes, and arrestins, providing more detailed information, valuable for further research on intra-ocular and extra-ocular photoreception of the cephalopods.

  10. Implications of prion adaptation and evolution paradigm for human neurodegenerative diseases.

    Science.gov (United States)

    Kabir, M Enamul; Safar, Jiri G

    2014-01-01

    There is a growing body of evidence indicating that number of human neurodegenerative diseases, including Alzheimer disease, Parkinson disease, fronto-temporal dementias, and amyotrophic lateral sclerosis, propagate in the brain via prion-like intercellular induction of protein misfolding. Prions cause lethal neurodegenerative diseases in humans, the most prevalent being sporadic Creutzfeldt-Jakob disease (sCJD); they self-replicate and spread by converting the cellular form of prion protein (PrP(C)) to a misfolded pathogenic conformer (PrP(Sc)). The extensive phenotypic heterogeneity of human prion diseases is determined by polymorphisms in the prion protein gene, and by prion strain-specific conformation of PrP(Sc). Remarkably, even though informative nucleic acid is absent, prions may undergo rapid adaptation and evolution in cloned cells and upon crossing the species barrier. In the course of our investigation of this process, we isolated distinct populations of PrP(Sc) particles that frequently co-exist in sCJD. The human prion particles replicate independently and undergo competitive selection of those with lower initial conformational stability. Exposed to mutant substrate, the winning PrP(Sc) conformers are subject to further evolution by natural selection of the subpopulation with the highest replication rate due to the lowest stability. Thus, the evolution and adaptation of human prions is enabled by a dynamic collection of distinct populations of particles, whose evolution is governed by the selection of progressively less stable, faster replicating PrP(Sc) conformers. This fundamental biological mechanism may explain the drug resistance that some prions gained after exposure to compounds targeting PrP(Sc). Whether the phenotypic heterogeneity of other neurodegenerative diseases caused by protein misfolding is determined by the spectrum of misfolded conformers (strains) remains to be established. However, the prospect that these conformers may evolve and

  11. Age, origin and evolution of Antarctic debris-covered glaciers: Implications for landscape evolution and long-term climate change

    Science.gov (United States)

    Mackay, Sean Leland

    Antarctic debris-covered glaciers are potential archives of long-term climate change. However, the geomorphic response of these systems to climate forcing is not well understood. To address this concern, I conducted a series of field-based and numerical modeling studies in the McMurdo Dry Valleys of Antarctica (MDV), with a focus on Mullins and Friedman glaciers. I used data and results from geophysical surveys, ice-core collection and analysis, geomorphic mapping, micro-meteorological stations, and numerical-process models to (1) determine the precise origin and distribution of englacial and supraglacial debris within these buried-ice systems, (2) quantify the fundamental processes and feedbacks that govern interactions among englacial and supraglacial debris, (3) establish a process-based model to quantify the inventory of cosmogenic nuclides within englacial and supraglacial debris, and (4) isolate the governing relationships between the evolution of englacial /supraglacial debris and regional climate forcing. Results from 93 field excavations, 21 ice cores, and 24 km of ground-penetrating radar data show that Mullins and Friedman glaciers contain vast areas of clean glacier ice interspersed with inclined layers of concentrated debris. The similarity in the pattern of englacial debris bands across both glaciers, along with model results that call for negligible basal entrainment, is best explained by episodic environmental change at valley headwalls. To constrain better the timing of debris-band formation, I developed a modeling framework that tracks the accumulation of cosmogenic 3He in englacial and supraglacial debris. Results imply that ice within Mullins Glacier increases in age non-linearly from 12 ka to ˜220 ka in areas of active flow (up to >> 1.6 Ma in areas of slow-moving-to-stagnant ice) and that englacial debris bands originate with a periodicity of ˜41 ka. Modeling studies suggest that debris bands originate in synchronicity with changes in

  12. Adaptive evolution of interleukin-3 (IL3), a gene associated with brain volume variation in general human populations.

    Science.gov (United States)

    Li, Ming; Huang, Liang; Li, Kaiqin; Huo, Yongxia; Chen, Chunhui; Wang, Jinkai; Liu, Jiewei; Luo, Zhenwu; Chen, Chuansheng; Dong, Qi; Yao, Yong-gang; Su, Bing; Luo, Xiong-jian

    2016-04-01

    Greatly expanded brain volume is one of the most characteristic traits that distinguish humans from other primates. Recent studies have revealed genes responsible for the dramatically enlarged human brain size (i.e., the microcephaly genes), and it has been well documented that many microcephaly genes have undergone accelerated evolution along the human lineage. In addition to being far larger than other primates, human brain volume is also highly variable in general populations. However, the genetic basis underlying human brain volume variation remains elusive and it is not known whether genes regulating human brain volume variation also have experienced positive selection. We have previously shown that genetic variants (near the IL3 gene) on 5q33 were significantly associated with brain volume in Chinese population. Here, we provide further evidence that support the significant association of genetic variants on 5q33 with brain volume. Bioinformatic analyses suggested that rs31480 is likely to be the causal variant among the studied SNPs. Molecular evolutionary analyses suggested that IL3 might have undergone positive selection in primates and humans. Neutrality tests further revealed signatures of positive selection of IL3 in Han Chinese and Europeans. Finally, extended haplotype homozygosity (EHH) and relative EHH analyses showed that the C allele of SNP rs31480 might have experienced recent positive selection in Han Chinese. Our results suggest that IL3 is an important genetic regulator for human brain volume variation and implied that IL3 might have experienced weak or modest positive selection in the evolutionary history of humans, which may be due to its contribution to human brain volume.

  13. The practices of do-it-yourself brain stimulation: implications for ethical considerations and regulatory proposals.

    Science.gov (United States)

    Wexler, Anna

    2016-04-01

    Scientists and neuroethicists have recently drawn attention to the ethical and regulatory issues surrounding the do-it-yourself (DIY) brain stimulation community, which comprises individuals stimulating their own brains with transcranial direct current stimulation (tDCS) for self-improvement. However, to date, existing regulatory proposals and ethical discussions have been put forth without engaging those involved in the DIY tDCS community or attempting to understand the nature of their practices. I argue that to better contend with the growing ethical and safety concerns surrounding DIY tDCS, we need to understand the practices of the community. This study presents the results of a preliminary inquiry into the DIY tDCS community, with a focus on knowledge that is formed, shared and appropriated within it. I show that when making or acquiring a device, DIYers (as some members call themselves) produce a body of knowledge that is completely separate from that of the scientific community, and share it via online forums, blogs, videos and personal communications. However, when applying tDCS, DIYers draw heavily on existing scientific knowledge, posting links to academic journal articles and scientific resources and adopting the standardised electrode placement system used by scientists. Some DIYers co-opt scientific knowledge and modify it by creating their own manuals and guides based on published papers. Finally, I explore how DIYers cope with the methodological limitations inherent in self-experimentation. I conclude by discussing how a deeper understanding of the practices of DIY tDCS has important regulatory and ethical implications.

  14. Loss of N-glycolylneuraminic acid in humans: Mechanisms, consequences, and implications for hominid evolution.

    Science.gov (United States)

    Varki, A

    2001-01-01

    The surface of all mammalian cells is covered with a dense and complex array of sugar chains, which are frequently terminated by members of a family of molecules called sialic acids. One particular sialic acid called N-glycolylneuraminic acid (Neu5Gc) is widely expressed on most mammalian tissues, but is not easily detectable on human cells. In fact, it provokes an immune response in adult humans. The human deficiency of Neu5Gc is explained by an inactivating mutation in the gene encoding CMP-N-acetylneuraminic acid hydroxylase, the rate-limiting enzyme in generating Neu5Gc in cells of other mammals. This deficiency also results in an excess of the precursor sialic acid N-acetylneuraminic acid (Neu5Ac) in humans. This mutation appears universal to modern humans, occurred sometime after our last common ancestor with the great apes, and happens to be one of the first known human-great ape genetic differences with an obvious biochemical readout. While the original selection mechanisms and major biological consequences of this human-specific mutation remain uncertain, several interesting clues are currently being pursued. First, there is evidence that the human condition can explain differences in susceptibility or resistance to certain microbial pathogens. Second, the functions of some endogenous receptors for sialic acids in the immune system may be altered by this difference. Third, despite the lack of any obvious alternate pathway for synthesis, Neu5Gc has been reported in human tumors and possibly in human fetal tissues, and traces have even been detected in normal human tissues. One possible explanation is that this represents accumulation of Neu5Gc from dietary sources of animal origin. Finally, a markedly reduced expression of hydroxylase in the brains of other mammals raises the possibility that the human-specific mutation of this enzyme could have played a role in human brain evolution.

  15. A stereoscopic system for viewing the temporal evolution of brain activity clusters in response to linguistic stimuli

    Science.gov (United States)

    Forbes, Angus; Villegas, Javier; Almryde, Kyle R.; Plante, Elena

    2014-03-01

    In this paper, we present a novel application, 3D+Time Brain View, for the stereoscopic visualization of functional Magnetic Resonance Imaging (fMRI) data gathered from participants exposed to unfamiliar spoken languages. An analysis technique based on Independent Component Analysis (ICA) is used to identify statistically significant clusters of brain activity and their changes over time during different testing sessions. That is, our system illustrates the temporal evolution of participants' brain activity as they are introduced to a foreign language through displaying these clusters as they change over time. The raw fMRI data is presented as a stereoscopic pair in an immersive environment utilizing passive stereo rendering. The clusters are presented using a ray casting technique for volume rendering. Our system incorporates the temporal information and the results of the ICA into the stereoscopic 3D rendering, making it easier for domain experts to explore and analyze the data.

  16. A stereoscopic system for viewing the temporal evolution of brain activity clusters in response to linguistic stimuli.

    Science.gov (United States)

    Forbes, Angus; Villegas, Javier; Almryde, Kyle R; Plante, Elena

    2014-03-06

    In this paper, we present a novel application, 3D+Time Brain View, for the stereoscopic visualization of functional Magnetic Resonance Imaging (fMRI) data gathered from participants exposed to unfamiliar spoken languages. An analysis technique based on Independent Component Analysis (ICA) is used to identify statistically significant clusters of brain activity and their changes over time during different testing sessions. That is, our system illustrates the temporal evolution of participants' brain activity as they are introduced to a foreign language through displaying these clusters as they change over time. The raw fMRI data is presented as a stereoscopic pair in an immersive environment utilizing passive stereo rendering. The clusters are presented using a ray casting technique for volume rendering. Our system incorporates the temporal information and the results of the ICA into the stereoscopic 3D rendering, making it easier for domain experts to explore and analyze the data.

  17. Basic developmental rules and their implications for epilepsy in the immature brain.

    Science.gov (United States)

    Ben-Ari, Yehezkel

    2006-06-01

    The construction of the human brain with its 10(15) synapses follows a set of complex developmentally and environmentally regulated steps. A series of sequences have been described that are instrumental, in the sense that a failure of any one of them leads to dramatic, life-long consequences. Hence the importance of determining the sequential maturation of neurons, synapses and cortical maps. It is also important to determine how network-driven events become installed, as neuronal activity intervenes in all of these steps and modulates, for better or worse, the outcome. A fundamental consequence of these sequential events is that any disruption will have very different consequences depending on when it occurs, indeed, "when is as important as what". An obvious aspect of these general features is related to seizures. In fact, the developing brain has both a higher incidence of seizures in human and animal models, and experiences seizures that can produce long-lasting consequences that are also stage-dependent. This seminar and the series of slides presented are an introduction to these issues, summing up several studies made notably by INMED researchers during the last two decades (http://www.inmednet.com). It concentrates on four basic developmental rules: i) the generation by very immature neurons, of very large currents mediated by the activation of receptors in neurons that bear no synapses. This is due to the release of GABA that diffuses to distal sites and acts as a paracrine factor; ii) the excitatory/inhibitory shift of the actions of GABA during development because of a progressive reduction in the intracellular chloride concentration; iii) the sequential formation of GABAergic synapses and networks before glutamatergic ones, implying that, at an early stage, all the excitatory drive will be GABAergic; iv) the presence, at an early stage, of a unique, primitive pattern in all developing structures, this pattern disappears when most GABAergic synapses have

  18. Traumatic brain injury and the Americans with Disabilities Act: implications for the social work profession.

    Science.gov (United States)

    Cole, Portia L; Cecka, Dale Margolin

    2014-07-01

    The practice of social work has been greatly affected by the Americans with Disabilities Act of 1990 (ADA). Title I of the statute prohibits discrimination against people with disabilities, including the increasing number of workers who are returning to work after a traumatic brain injury (TBI). This article examines the extent to which the ADA protects those with TBI from being harassed, being denied reasonable workplace accommodations, or suffering other adverse actions related to perceived discrimination. To do so, it relies on judicial decisions from U.S. federal courts involving alleged workplace discrimination of this population. Implications for social work practice are noted with the intent of increasing ADA awareness among professionals providing services to people who meet the criteria for disability under the ADA as well as to those persons who do not. The authors hope to encourage social workers to rely on case law analysis as a mechanism to provide further evidence of the systematic problems faced by people with TBI and thus increase their visibility.

  19. Blood-brain barrier pathology in Alzheimer's and Parkinson's disease: implications for drug therapy.

    Science.gov (United States)

    Desai, Brinda S; Monahan, Angela J; Carvey, Paul M; Hendey, Bill

    2007-01-01

    The blood-brain barrier (BBB) is a tightly regulated barrier in the central nervous system. Though the BBB is thought to be intact during neurodegenerative diseases such as Alzheimer's (AD) and Parkinson's disease (PD), recent evidence argues otherwise. Dysfunction of the BBB may be involved in disease progression, eliciting of peripheral immune response, and, most importantly, altered drug efficacy. In this review, we will give a brief overview of the BBB, its components, and their functions. We will critically evaluate the current literature in AD and PD BBB pathology resulting from insult, neuroinflammation, and neurodegeneration. Specifically, we will discuss alterations in tight junction, transport and endothelial cell surface proteins, and vascular density changes, all of which result in altered permeability. Finally, we will discuss the implications of BBB dysfunction in current and future therapeutics. Developing a better appreciation of BBB dysfunction in AD and PD may not only provide novel strategies in treatment, but will prove an interesting milestone in understanding neurodegenerative disease etiology and progression.

  20. Rossby waves and polar spots in rapidly rotating stars: Implications for stellar wind evolution

    CERN Document Server

    Zaqarashvili, T V; Ballester, J L; Carbonell, M; Khodachenko, M L; Lammer, H; Leitzinger, M; Odert, P

    2011-01-01

    Rapidly rotating stars show short-period oscillations in magnetic activity and polar appearance of starspots. The aim of this paper is to study large-scale shallow water waves in the tachoclines of rapidly rotating stars and their connection to the periodicity and the formation of starspots at high latitudes. Shallow-water magnetohydrodynamic equations were used to study the dynamics of large-scale waves at the rapidly rotating stellar tachoclines in the presence of toroidal magnetic field. Dispersion relations and latitudinal distribution of wave modes were derived. We found that low-frequency magnetic Rossby waves tend to be located at poles, but high-frequency magnetic Poincare waves are concentrated near the equator in rapidly rotating stars. These results have important implications for the evolution of the stellar wind in young Sun-like stars. Unstable magnetic Rossby waves may lead to the local enhancement of magnetic flux at high latitudes of tachoclines in rapidly rotating stars. The enhanced magneti...

  1. Language as a multimodal phenomenon: implications for language learning, processing and evolution.

    Science.gov (United States)

    Vigliocco, Gabriella; Perniss, Pamela; Vinson, David

    2014-09-19

    Our understanding of the cognitive and neural underpinnings of language has traditionally been firmly based on spoken Indo-European languages and on language studied as speech or text. However, in face-to-face communication, language is multimodal: speech signals are invariably accompanied by visual information on the face and in manual gestures, and sign languages deploy multiple channels (hands, face and body) in utterance construction. Moreover, the narrow focus on spoken Indo-European languages has entrenched the assumption that language is comprised wholly by an arbitrary system of symbols and rules. However, iconicity (i.e. resemblance between aspects of communicative form and meaning) is also present: speakers use iconic gestures when they speak; many non-Indo-European spoken languages exhibit a substantial amount of iconicity in word forms and, finally, iconicity is the norm, rather than the exception in sign languages. This introduction provides the motivation for taking a multimodal approach to the study of language learning, processing and evolution, and discusses the broad implications of shifting our current dominant approaches and assumptions to encompass multimodal expression in both signed and spoken languages.

  2. Implications of diesel emissions control failures to emission factors and road transport NOx evolution

    Science.gov (United States)

    Ntziachristos, Leonidas; Papadimitriou, Giannis; Ligterink, Norbert; Hausberger, Stefan

    2016-09-01

    Diesel NOx emissions have been at the forefront of research and regulation scrutiny as a result of failures of late vehicle technologies to deliver on-road emissions reductions. The current study aims at identifying the actual emissions levels of late light duty vehicle technologies, including Euro 5 and Euro 6 ones. Mean NOx emission factor levels used in the most popular EU vehicle emission models (COPERT, HBEFA and VERSIT+) are compared with latest emission information collected in the laboratory over real-world driving cycles and on the road using portable emissions measurement systems (PEMS). The comparison shows that Euro 5 passenger car (PC) emission factors well reflect on road levels and that recently revealed emissions control failures do not call for any significant corrections. However Euro 5 light commercial vehicles (LCVs) and Euro 6 PCs in the 2014-2016 period exhibit on road emission levels twice as high as used in current models. Moreover, measured levels vary a lot for Euro 6 vehicles. Scenarios for future evolution of Euro 6 emission factors, reflecting different degree of effectiveness of emissions control regulations, show that total NOx emissions from diesel Euro 6 PC and LCV may correspond from 49% up to 83% of total road transport emissions in 2050. Unless upcoming and long term regulations make sure that light duty diesel NOx emissions are effectively addressed, this will have significant implications in meeting future air quality and national emissions ceilings targets.

  3. The ycf27 genes from cyanobacteria and eukaryotic algae: distribution and implications for chloroplast evolution.

    Science.gov (United States)

    Ashby, Mark K; Houmard, Jean; Mullineaux, Conrad W

    2002-08-27

    The two ycf27 genes from the filamentous cyanobacterium Tolypothrix PCC 7601 have been cloned and sequenced. These two genes, previously designated rpaA and rpaB, encode putative transcriptional regulators of the 'OmpR' family. In Synechocystis PCC 6803, homologous genes have been linked to the regulation of transfer of excitation energy from the phycobilisome to photosystem (PS) I and PSII respectively. Partial clones from Spirulina platensis, Dactylococcopsis salina and Synechococcus PCC 7002 have also been sequenced. A table of identity between the proteins confirms that RpaB belongs in the same family as the algal ycf27 proteins. However, RpaA is a rather different protein and should lose the designation ycf27. The loss of rpaB from the plastid genomes of eukaryotic algae is associated with the loss of phycobiliproteins, so it is likely that this gene performs a similar role in algae to that in cyanobacteria. The implications for chloroplast evolution are discussed along with the possible identity of the cognate histidine kinase gene in the plastid genomes.

  4. The evolution of cursorial carnivores in the Tertiary: implications of elbow-joint morphology.

    Science.gov (United States)

    Andersson, Ki; Werdelin, Lars

    2003-11-01

    The evolution of cursorial adaptations in Tertiary (65-1.65 Myr ago) carnivores has been a contentious issue. Most such studies have focused on the relationship between hind limb proportions and running speed. Here, we show morphometrically that in extant carnivores, the elbow joint has evolved in two distinct directions with mutually exclusive implications for locomotor ability and prey procurement. Some carnivores retain supinatory ability, allowing them to manipulate prey and other items with the forepaws. Such carnivores can become very large. Other carnivores lose the ability to supinate and become cursors. This allows for only moderate size increase. Modern carnivores above ca. 20 kg body mass are committed to one or other of these strategies. This threshold coincides with a postulated threshold in carnivore physiology. The biaxial pattern mostly follows phylogenetic lines, but a strong selective regime can override this signal, as shown by the extant cheetah. Oligocene (33.7-23.8 Myr ago) and early-middle Miocene (23.8-11.2 Myr ago) carnivores follow the same pattern, though in the Miocene the pattern is shifted towards larger body mass, which may be owing to the extraordinary richness of browsing ungulates at this time.

  5. Water in granulites: implications for the nature and evolution of the lower continental crust

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaozhi; XIA Qunke; Etienne DELOULE; FAN Qicheng; HAO Yantao

    2007-01-01

    The lower continental crust is one of the most important sphere-layers in the deep earth, and is the direct place where the crust-mantle interactions occur. Granulites are the dominated rocks in the lower crust, and have critical implications for the knowledge of the composition, nature and evolution of the deep crust; fluids are important mediums influencing many geochemical, geophysical and geodynamical characteristics of the lower crust, and may also play a fundamental role in the petrogenesis of granulites and the formation of the lower crusts. In this paper, we review recent advances involved with the deep continental crust, granulites and fluids, and some longstanding debates. Combined with the Fourier-transform infrared spectroscopy (FTIR) analysis performed on the mineral assemblages (cpx, opx, plag and grt) in lower crustal granulite xenoliths and terrains (exposed section) from east China, it is suggested that structural water, dominated by OH, in these nominally anhydrous phases may constitute the most important water reservoir in the deep crust. This structual water may help to understand many lower crustal geological processes and phenomena (e. G. Seismic activities and electrical conductive anomalies), and influences from these water must be taken into consideration.

  6. In vivo bioimpedance measurement of healthy and ischaemic rat brain: implications for stroke imaging using electrical impedance tomography.

    Science.gov (United States)

    Dowrick, T; Blochet, C; Holder, D

    2015-06-01

    In order to facilitate the imaging of haemorrhagic and ischaemic stroke using frequency difference electrical impedance tomography (EIT), impedance measurements of normal and ischaemic brain, and clotted blood during haemorrhage, were gathered using a four-terminal technique in an in vivo animal model, a first for ischaemic measurements. Differences of 5-10% in impedance were seen between the frequency spectrums of healthy and ischaemic brain, over the frequency range 0-3 kHz, while the spectrum of blood was predominately uniform. The implications of imaging blood/ischaemia in the brain using electrical impedance tomography are discussed, supporting the notion that it will be possible to differentiate stroke from haemorrhage.

  7. Evolution of Temperature Fluctuation in a Thermal bath and, its implications in Hadronic and Heavy-Ion Collisions

    CERN Document Server

    Bhattacharya, Trambak; Sahoo, Raghunath; Samantray, Prasant

    2016-01-01

    The evolution equation for inhomogeneous and anisotropic temperature fluctuations inside a medium is derived within the ambit of Boltzmann Transport Equation. Also, taking some existing realistic inputs we have analyzed the Fourier space variation of temperature fluctuation for the medium created after heavy-ion collisions. The effect of viscosity on the variation of fluctuations is investigated. Further, possible implications in hadronic and heavy-ion collisions are explored.

  8. Recasting developmental evolution in terms of genetic pathway and network evolution ... and the implications for comparative biology.

    Science.gov (United States)

    Wilkins, Adam S

    2005-09-15

    The morphological features of complex organisms are the outcomes of developmental processes. Developmental processes, in turn, reflect the genetic networks that underlie them. Differences in morphology must ultimately, therefore, reflect differences in the underlying genetic networks. A mutation that affects a developmental process does so by affecting either a gene whose product acts as an upstream controlling element, an intermediary connecting link, or as a downstream output of the network that governs the trait's development. Although the immense diversity of gene networks in the animal and plant kingdoms would seem to preclude any general "rules" of network evolution, the material discussed here suggests that the patterns of genetic pathway and network evolution actually fall into a number of discrete modes. The potential utility of this conceptual framework in reconstructing instances of developmental evolution and for comparative neurobiology will be discussed.

  9. Identification of brain nuclei implicated in cocaine-primed reinstatement of conditioned place preference: a behaviour dissociable from sensitization.

    Directory of Open Access Journals (Sweden)

    Robyn Mary Brown

    Full Text Available Relapse prevention represents the primary therapeutic challenge in the treatment of drug addiction. As with humans, drug-seeking behaviour can be precipitated in laboratory animals by exposure to a small dose of the drug (prime. The aim of this study was to identify brain nuclei implicated in the cocaine-primed reinstatement of a conditioned place preference (CPP. Thus, a group of mice were conditioned to cocaine, had this place preference extinguished and were then tested for primed reinstatement of the original place preference. There was no correlation between the extent of drug-seeking upon reinstatement and the extent of behavioural sensitization, the extent of original CPP or the extinction profile of mice, suggesting a dissociation of these components of addictive behaviour with a drug-primed reinstatement. Expression of the protein product of the neuronal activity marker c-fos was assessed in a number of brain regions of mice that exhibited reinstatement (R mice versus those which did not (NR mice. Reinstatement generally conferred greater Fos expression in cortical and limbic structures previously implicated in drug-seeking behaviour, though a number of regions not typically associated with drug-seeking were also activated. In addition, positive correlations were found between neural activation of a number of brain regions and reinstatement behaviour. The most significant result was the activation of the lateral habenula and its positive correlation with reinstatement behaviour. The findings of this study question the relationship between primed reinstatement of a previously extinguished place preference for cocaine and behavioural sensitization. They also implicate activation patterns of discrete brain nuclei as differentiators between reinstating and non-reinstating mice.

  10. ABCC9/SUR2 in the brain: Implications for hippocampal sclerosis of aging and a potential therapeutic target.

    Science.gov (United States)

    Nelson, Peter T; Jicha, Gregory A; Wang, Wang-Xia; Ighodaro, Eseosa; Artiushin, Sergey; Nichols, Colin G; Fardo, David W

    2015-11-01

    The ABCC9 gene and its polypeptide product, SUR2, are increasingly implicated in human neurologic disease, including prevalent diseases of the aged brain. SUR2 proteins are a component of the ATP-sensitive potassium ("KATP") channel, a metabolic sensor for stress and/or hypoxia that has been shown to change in aging. The KATP channel also helps regulate the neurovascular unit. Most brain cell types express SUR2, including neurons, astrocytes, oligodendrocytes, microglia, vascular smooth muscle, pericytes, and endothelial cells. Thus it is not surprising that ABCC9 gene variants are associated with risk for human brain diseases. For example, Cantu syndrome is a result of ABCC9 mutations; we discuss neurologic manifestations of this genetic syndrome. More common brain disorders linked to ABCC9 gene variants include hippocampal sclerosis of aging (HS-Aging), sleep disorders, and depression. HS-Aging is a prevalent neurological disease with pathologic features of both neurodegenerative (aberrant TDP-43) and cerebrovascular (arteriolosclerosis) disease. As to potential therapeutic intervention, the human pharmacopeia features both SUR2 agonists and antagonists, so ABCC9/SUR2 may provide a "druggable target", relevant perhaps to both HS-Aging and Alzheimer's disease. We conclude that more work is required to better understand the roles of ABCC9/SUR2 in the human brain during health and disease conditions.

  11. The hubs of the human connectome are generally implicated in the anatomy of brain disorders.

    Science.gov (United States)

    Crossley, Nicolas A; Mechelli, Andrea; Scott, Jessica; Carletti, Francesco; Fox, Peter T; McGuire, Philip; Bullmore, Edward T

    2014-08-01

    Brain networks or 'connectomes' include a minority of highly connected hub nodes that are functionally valuable, because their topological centrality supports integrative processing and adaptive behaviours. Recent studies also suggest that hubs have higher metabolic demands and longer-distance connections than other brain regions, and therefore could be considered biologically costly. Assuming that hubs thus normally combine both high topological value and high biological cost, we predicted that pathological brain lesions would be concentrated in hub regions. To test this general hypothesis, we first identified the hubs of brain anatomical networks estimated from diffusion tensor imaging data on healthy volunteers (n = 56), and showed that computational attacks targeted on hubs disproportionally degraded the efficiency of brain networks compared to random attacks. We then prepared grey matter lesion maps, based on meta-analyses of published magnetic resonance imaging data on more than 20 000 subjects and 26 different brain disorders. Magnetic resonance imaging lesions that were common across all brain disorders were more likely to be located in hubs of the normal brain connectome (P brain disorders had lesions that were significantly more likely to be located in hubs (P human brain networks are more likely to be anatomically abnormal than non-hubs in many (if not all) brain disorders.

  12. Molecular phylogenetics of the Brazilian giant bromeliads (Alcantarea, Bromeliaceae): implications for morphological evolution and biogeography.

    Science.gov (United States)

    Versieux, Leonardo M; Barbará, Thelma; Wanderley, Maria das Graças Lapa; Calvente, Alice; Fay, Michael F; Lexer, Christian

    2012-07-01

    The genus Alcantarea comprises near 30 species endemic to rocky outcrops from eastern Brazil. Most species are ornamental and several are threatened due to habitat loss and over collection. In this paper we examine the phylogenetics of Alcantarea and its relationship with the Brazilian members of Vriesea, a genus of which Alcantarea has been treated as a subgenus. We discuss the morphological evolution of the stamen position and its implication for pollination and the occurrence of Alcantarea in the Espinhaço mountain range rocky savanna-like habitat vegetation. DNA sequence data derived from two plastid markers (trnK-rps16, trnC-petN) and from a low copy nuclear gene (Floricaula/Leafy) together with 20 nuclear microsatellite loci were the data source to perform analyses and construct phylogenetic and Neighbor Joining trees for the genus. Alcantarea is well supported as monophyletic in both Bayesian and parsimony analyses, but sections of Vriesea, represented by the eastern Brazilian species, appear paraphyletic. Microsatellites delimit geographically isolated species groups. Nevertheless individuals belonging to a single species may appear related to distinct clusters of species, suggesting that hybridization and/or homoplasy and/or incomplete lineage sorting are also influencing the analysis based on such markers and may be the reasons for some unexpected results. Alcantarea brasiliana is hypothesized as putative hybrid between A. imperialis and A. geniculata. Spreading stamens, a morphological floral characteristic assumed to be related to Chiropterophily, apparently evolved multiple times within the genus, and invasion of rocky savanna-like habitat vegetation by Atlantic rainforest ancestors seems to have occurred multiple times as well.

  13. Nutritional contributions of insects to primate diets: implications for primate evolution.

    Science.gov (United States)

    Rothman, Jessica M; Raubenheimer, David; Bryer, Margaret A H; Takahashi, Maressa; Gilbert, Christopher C

    2014-06-01

    Insects and other invertebrates form a portion of many living and extinct primate diets. We review the nutritional profiles of insects in comparison with other dietary items, and discuss insect nutrients in relation to the nutritional needs of living primates. We find that insects are incorporated into some primate diets as staple foods whereby they are the majority of food intake. They can also be incorporated as complements to other foods in the diet, providing protein in a diet otherwise dominated by gums and/or fruits, or be incorporated as supplements to likely provide an essential nutrient that is not available in the typical diet. During times when they are very abundant, such as in insect outbreaks, insects can serve as replacements to the usual foods eaten by primates. Nutritionally, insects are high in protein and fat compared with typical dietary items like fruit and vegetation. However, insects are small in size and for larger primates (>1 kg) it is usually nutritionally profitable only to consume insects when they are available in large quantities. In small quantities, they may serve to provide important vitamins and fatty acids typically unavailable in primate diets. In a brief analysis, we found that soft-bodied insects are higher in fat though similar in chitin and protein than hard-bodied insects. In the fossil record, primates can be defined as soft- or hard-bodied insect feeders based on dental morphology. The differences in the nutritional composition of insects may have implications for understanding early primate evolution and ecology.

  14. Evolution of large body size in abalones (Haliotis): Patterns and implications

    Science.gov (United States)

    Estes, J.A.; Lindberg, D.R.; Wray, C.

    2005-01-01

    Kelps and other fleshy macroalgae - dominant reef-inhabiting organisms in cool - seasmay have radiated extensively following late Cenozoic polar cooling, thus triggering a chain of evolutionary change in the trophic ecology of nearshore temperate ecosystems. We explore this hypothesis through an analysis of body size in the abalones (Gastropoda; Haliotidae), a widely distributed group in modern oceans that displays a broad range of body sizes and contains fossil representatives from the late Cretaceous (60-75 Ma). Geographic analysis of maximum shell length in living abalones showed that small-bodied species, while most common in the Tropics, have a cosmopolitan distribution, whereas large-bodied species occur exclusively in cold-water ecosystems dominated by kelps and other macroalgae. The phylogeography of body size evolution in extant abalones was assessed by constructing a molecular phylogeny in a mix of large and small species obtained from different regions of the world. This analysis demonstrates that small body size is the plesiomorphic state and largeness has likely arisen at least twice. Finally, we compiled data on shell length from the fossil record to determine how (slowly or suddenly) and when large body size arose in the abalones. These data indicate that large body size appears suddenly at the Miocene/Pliocene boundary. Our findings support the view that fleshy-algal dominated ecosystems radiated rapidly in the coastal oceans with the onset of the most recent glacial age. We conclude with a discussion of the broader implications of this change. ?? 2005 The Paleontological Society. All rights reserved.

  15. Pathogen evolution across the agro-ecological interface: implications for disease management.

    Science.gov (United States)

    Burdon, Jeremy J; Thrall, Peter H

    2008-02-01

    Infectious disease is a major causal factor in the demography of human, plant and animal populations. While it is generally accepted in medical, veterinary and agricultural contexts that variation in host resistance and pathogen virulence and aggressiveness is of central importance to understanding patterns of infection, there has been remarkably little effort to directly investigate causal links between population genetic structure and disease dynamics, and even less work on factors influencing host-pathogen coevolution. The lack of empirical evidence is particularly surprising, given the potential for such variation to not only affect disease dynamics and prevalence, but also when or where new diseases or pathotypes emerge. Increasingly, this lack of knowledge has led to calls for an integrated approach to disease management, incorporating both ecological and evolutionary processes. Here, we argue that plant pathogens occurring in agro-ecosystems represent one clear example where the application of evolutionary principles to disease management would be of great benefit, as well as providing model systems for advancing our ability to generalize about the long-term coevolutionary dynamics of host-pathogen systems. We suggest that this is particularly the case given that agro-ecological host-pathogen interactions represent a diversity of situations ranging from those that only involve agricultural crops through to those that also include weedy crop relatives or even unrelated native plant communities. We begin by examining some of the criteria that are important in determining involvement in agricultural pathogen evolution by noncrop plants. Throughout we use empirical examples to illustrate the fact that different processes may dominate in different systems, and suggest that consideration of life history and spatial structure are central to understanding dynamics and direction of the interaction. We then discuss the implications that such interactions have for

  16. Evolution and function of the upper molar talon and its dietary implications in microbats.

    Science.gov (United States)

    Gutzwiller, Sarah C; Hunter, John P

    2015-11-01

    The evolution of mammalian molars has been marked by transitions representing significant changes in shape and function. One such transition is the addition and elaboration of the talon, the distolingual region of the ancestral tribosphenic upper molar of therian mammals and some extinct relatives. This study uses suborder Microchiroptera as a case study to explore the adaptive implications of the expansion of the talon on the tribosphenic molar, specifically focusing on the talon's role in the compression and shear of food during breakdown. Three-dimensional computer renderings of casts of the upper left first molars were created for microbat species of a variety of dietary categories (frugivore, etc.) and physical properties of food (hard and soft). Relief Index (RFI) was measured to estimate the topography and function of the whole tooth and of the talon and trigon (the remaining primitive tribosphenic region) individually, in order to examine 1) how the shape of the whole tooth, trigon, and talon reflects the compromise between their crushing and shearing functions, 2) how whole tooth, trigon, and talon function differs according to diet, and 3) how the presence of the talon affects overall molar function. Results suggest that RFI of both the whole tooth and the trigon varies according to dietary groups, with frugivores having greater crushing function when compared with the other groups. The talon, however, consistently has low RFI (a flatter topography), and its presence lowers the RFI of the whole tooth across all dietary categories, suggesting that the talon is primarily functioning in crushing during food breakdown. The potential benefits of a crushing talon for microbats of various dietary groups are discussed.

  17. Male and female brain evolution is subject to contrasting selection pressures in primates

    Directory of Open Access Journals (Sweden)

    Dunbar Robin IM

    2007-05-01

    Full Text Available Abstract The claim that differences in brain size across primate species has mainly been driven by the demands of sociality (the "social brain" hypothesis is now widely accepted. Some of the evidence to support this comes from the fact that species that live in large social groups have larger brains, and in particular larger neocortices. Lindenfors and colleagues (BMC Biology 5:20 add significantly to our appreciation of this process by showing that there are striking differences between the two sexes in the social mechanisms and brain units involved. Female sociality (which is more affiliative is related most closely to neocortex volume, but male sociality (which is more competitive and combative is more closely related to subcortical units (notably those associated with emotional responses. Thus different brain units have responded to different selection pressures.

  18. Detecting lineage-specific adaptive evolution of brain-expressed genes in human using rhesus macaque as outgroup

    DEFF Research Database (Denmark)

    Yu, Xiao-Jing; Zheng, Hong-Kun; Wang, Jun;

    2006-01-01

    Comparative genetic analysis between human and chimpanzee may detect genetic divergences responsible for human-specific characteristics. Previous studies have identified a series of genes that potentially underwent Darwinian positive selection during human evolution. However, without a closely...... related species as outgroup, it is difficult to identify human-lineage-specific changes, which is critical in delineating the biological uniqueness of humans. In this study, we conducted phylogeny-based analyses of 2633 human brain-expressed genes using rhesus macaque as the outgroup. We identified 47...... candidate genes showing strong evidence of positive selection in the human lineage. Genes with maximal expression in the brain showed a higher evolutionary rate in human than in chimpanzee. We observed that many immune-defense-related genes were under strong positive selection, and this trend was more...

  19. Brain, mind and machine: what are the implications of deep brain stimulation for perceptions of personal identity, agency and free will?

    Science.gov (United States)

    Lipsman, Nir; Glannon, Walter

    2013-11-01

    Brain implants, such as Deep Brain Stimulation (DBS), which are designed to improve motor, mood and behavioural pathology, present unique challenges to our understanding of identity, agency and free will. This is because these devices can have visible effects on persons' physical and psychological properties yet are essentially undetectable when operating correctly. They can supplement and compensate for one's inherent abilities and faculties when they are compromised by neuropsychiatric disorders. Further, unlike talk therapy or pharmacological treatments, patients need not 'do' anything for the treatment to take effect. If one accepts, as we argue here, that brain implants are unique among implantable types of devices, then this can have significant implications for what it means to persist as the same person and be the source of one's thoughts and actions. By examining two of the most common indications for DBS in current use, namely in the motor (Parkinson's Disease) and psychiatric (Major Depression) domains, we further argue that although DBS, as it is currently applied, does not necessarily represent a unique threat to personal identity and agency per se, it introduces an unprecedented 'third party' into the debate on these concepts. In this way, DBS can be used as a tool to begin probing, both conceptually and empirically, some of philosophy's most perennial metaphysical questions.

  20. A meta-analysis of non-invasive brain stimulation and autonomic functioning: Implications for brain-heart pathways to cardiovascular disease.

    Science.gov (United States)

    Makovac, Elena; Thayer, Julian F; Ottaviani, Cristina

    2017-03-01

    Given the intrinsic connection between the brain and the heart, a recent body of research emerged with the aim to influence cardiovascular system functioning by non-invasive brain stimulation (NIBS) methods such as repetitive transcranial magnetic stimulation and transcranial direct current stimulation. Despite the implications of cardiovascular activity modulation for therapeutic purposes, such effects of NIBS have not yet been quantified. The aim of this study was to meta-analyze studies on NIBS effects on blood pressure (BP), heart rate (HR) and its variability (HRV). PubMed and Scopus databases were searched for English language studies conducted in humans. Twenty-nine studies were eligible for the analyses. Pooled effect sizes (Hedges' g) were compared. Random effect models were used. NIBS was effective in reducing HR (g=0.17) and enhancing HRV (g=0.30). A marginal effect emerged for BP (g=0.21). Significant moderators were the stimulation technique and the site of stimulation. Results show that NIBS affects cardiovascular and autonomic nervous system activity, confirming a potential pathogenic brain-heart pathway to cardiovascular disease.

  1. Clinical features of brain metastases in breast cancer: an implication for hippocampal-sparing whole-brain radiation therapy

    Directory of Open Access Journals (Sweden)

    Wu S

    2016-12-01

    Full Text Available San-Gang Wu,1,* Jia-Yuan Sun,2,* Qin Tong,3 Feng-Yan Li,2 Zhen-Yu He2 1Department of Radiation Oncology, Xiamen Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, 2Department of Radiation Oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, 3Department of Radiation Oncology, The First Affiliated Hospital of University of South China, Hengyang, People’s Republic of China *These authors contributed equally to this work Objective: The objectives of this study were to describe the distribution of brain metastases (BM in breast cancer patients and investigate the risk factors for perihippocampal metastases (PHM. Patients and methods: Retrospective analysis of the clinicopathological characteristics and patterns of BM was performed. Associations between clinicopathological characteristics and PHM (the hippocampus plus 5 mm margin were evaluated using logistic regression analyses. Results: A total of 1,356 brain metastatic lesions were identified in 192 patients. Patients with 1–3 BM, 4–9 BM, and ≥10 BM accounted for 63.0%, 18.8%, and 18.2%, respectively. There were only 7 (3.6% patients with hippocampal metastases (HM and 14 (7.3% patients with PHM. On logistic regression, the number of BM was an independent risk factor for PHM. Patients with ≥10 BM had a significantly higher risk of PHM compared with those with <10 BM. Breast cancer subtype (BCS was not associated with PHM. The number of BM was significantly correlated with various BCSs. Patients with hormone receptor (HR+/human epidermal growth factor receptor 2 (HER2+, HR-/HER2+, and HR-/HER2- subtypes had a higher probability of ≥10 BM, relative to patients with an HR+/HER2- subtype. Conclusion: Our study suggests that a low incidence of PHM may be acceptable to perform hippocampal-sparing whole-brain radiation therapy for breast cancer patients

  2. 人类大脑容量及语言进化的分子生物学证据与质疑%Controversial Researches on Molecular Evolution of Language and Brain Size

    Institute of Scientific and Technical Information of China (English)

    俞建梁

    2015-01-01

    Language and larger brain size than other primates are the deifning features of human beings. The evolution of language and brain size has been the research hotspot all the time. Over the past 20 years the research in the evolution of language and brain size through molecular biology, which transcends the disputes between nature and nurture in language aquisition, has made great achievement. But many test results are incongruous or even controversial over the questions whether the evolution of FOXP2 might underlie linguistic behavior and whether the evolution of genes such as MCPH1, ASPM and etc. has undergone positive selection or implicated in the brain size and intelligence. The discussion of these questions allows us to understand the current situation of the molecular evolution of language and brain size, and the developmental trend of biolinguistics.%语言和拥有比其他灵长类动物更大的脑容量是人类的显著特征。语言与大脑的进化一直是人们研究的热点。过去近20年有关人类语言与脑容量进化的分子生物学研究超越了思辨层面的先天论和后天论之争,取得了许多重要的发现。但许多研究结果相左,有的甚至相互矛盾:FOXP2基因的进化是否与语言相关;MCPH1、ASPM等基因的进化是否受到正向选择、是否影响大脑容量以及是否与智力有关等等。这些问题在分子生物学领域引起了诸多争论和质疑。对这些问题的了解有助于认识当前有关语言与大脑容量进化的研究现状和生物语言学的发展动态。

  3. Permeabilization of the blood-brain barrier via mucosal engrafting: implications for drug delivery to the brain.

    Directory of Open Access Journals (Sweden)

    Benjamin S Bleier

    Full Text Available Utilization of neuropharmaceuticals for central nervous system(CNS disease is highly limited due to the blood-brain barrier(BBB which restricts molecules larger than 500Da from reaching the CNS. The development of a reliable method to bypass the BBB would represent an enormous advance in neuropharmacology enabling the use of many potential disease modifying therapies. Previous attempts such as transcranial catheter implantation have proven to be temporary and associated with multiple complications. Here we describe a novel method of creating a semipermeable window in the BBB using purely autologous tissues to allow for high molecular weight(HMW drug delivery to the CNS. This approach is inspired by recent advances in human endoscopic transnasal skull base surgical techniques and involves engrafting semipermeable nasal mucosa within a surgical defect in the BBB. The mucosal graft thereby creates a permanent transmucosal conduit for drugs to access the CNS. The main objective of this study was to develop a murine model of this technique and use it to evaluate transmucosal permeability for the purpose of direct drug delivery to the brain. Using this model we demonstrate that mucosal grafts allow for the transport of molecules up to 500 kDa directly to the brain in both a time and molecular weight dependent fashion. Markers up to 40 kDa were found within the striatum suggesting a potential role for this technique in the treatment of Parkinson's disease. This proof of principle study demonstrates that mucosal engrafting represents the first permanent and stable method of bypassing the BBB thereby providing a pathway for HMW therapeutics directly into the CNS.

  4. Permeabilization of the blood-brain barrier via mucosal engrafting: implications for drug delivery to the brain.

    Science.gov (United States)

    Bleier, Benjamin S; Kohman, Richie E; Feldman, Rachel E; Ramanlal, Shreshtha; Han, Xue

    2013-01-01

    Utilization of neuropharmaceuticals for central nervous system(CNS) disease is highly limited due to the blood-brain barrier(BBB) which restricts molecules larger than 500Da from reaching the CNS. The development of a reliable method to bypass the BBB would represent an enormous advance in neuropharmacology enabling the use of many potential disease modifying therapies. Previous attempts such as transcranial catheter implantation have proven to be temporary and associated with multiple complications. Here we describe a novel method of creating a semipermeable window in the BBB using purely autologous tissues to allow for high molecular weight(HMW) drug delivery to the CNS. This approach is inspired by recent advances in human endoscopic transnasal skull base surgical techniques and involves engrafting semipermeable nasal mucosa within a surgical defect in the BBB. The mucosal graft thereby creates a permanent transmucosal conduit for drugs to access the CNS. The main objective of this study was to develop a murine model of this technique and use it to evaluate transmucosal permeability for the purpose of direct drug delivery to the brain. Using this model we demonstrate that mucosal grafts allow for the transport of molecules up to 500 kDa directly to the brain in both a time and molecular weight dependent fashion. Markers up to 40 kDa were found within the striatum suggesting a potential role for this technique in the treatment of Parkinson's disease. This proof of principle study demonstrates that mucosal engrafting represents the first permanent and stable method of bypassing the BBB thereby providing a pathway for HMW therapeutics directly into the CNS.

  5. Variance in brain volume with advancing age: implications for defining the limits of normality.

    Directory of Open Access Journals (Sweden)

    David Alexander Dickie

    Full Text Available Statistical models of normal ageing brain tissue volumes may support earlier diagnosis of increasingly common, yet still fatal, neurodegenerative diseases. For example, the statistically defined distribution of normal ageing brain tissue volumes may be used as a reference to assess patient volumes. To date, such models were often derived from mean values which were assumed to represent the distributions and boundaries, i.e. percentile ranks, of brain tissue volume. Since it was previously unknown, the objective of the present study was to determine if this assumption was robust, i.e. whether regression models derived from mean values accurately represented the distributions and boundaries of brain tissue volume at older ages.We acquired T1-w magnetic resonance (MR brain images of 227 normal and 219 Alzheimer's disease (AD subjects (aged 55-89 years from publicly available databanks. Using nonlinear regression within both samples, we compared mean and percentile rank estimates of whole brain tissue volume by age.In both the normal and AD sample, mean regression estimates of brain tissue volume often did not accurately represent percentile rank estimates (errors=-74% to 75%. In the normal sample, mean estimates generally underestimated differences in brain volume at percentile ranks below the mean. Conversely, in the AD sample, mean estimates generally underestimated differences in brain volume at percentile ranks above the mean. Differences between ages at the 5(th percentile rank of normal subjects were ~39% greater than mean differences in the AD subjects.While more data are required to make true population inferences, our results indicate that mean regression estimates may not accurately represent the distributions of ageing brain tissue volumes. This suggests that percentile rank estimates will be required to robustly define the limits of brain tissue volume in normal ageing and neurodegenerative disease.

  6. Brain Research, Learning and Emotions: Implications for Education Research, Policy and Practice

    Science.gov (United States)

    Hinton, Christina; Miyamoto, Koji; Della-Chiesa, Bruno

    2008-01-01

    Recent advancements in neuroscience heighten its relevance to education. Newly developed imaging technologies enable scientists to peer into the working brain for the first time, providing powerful insights into how we learn. Research reveals that the brain is not a stable and isolated entity, but a dynamic system that is keenly responsive to…

  7. Impact of nutrition on brain development and its neuroprotective implications following preterm birth

    NARCIS (Netherlands)

    Keunen, Kristin; Van Elburg, Ruurd M.; Van Bel, Frank; Benders, Manon J N L

    2015-01-01

    The impact of nutrition on brain development in preterm infants has been increasingly appreciated. Early postnatal growth and nutrient intake have been demonstrated to influence brain growth and maturation with subsequent effects on neurodevelopment that persist into childhood and adolescence. Nutri

  8. Connecting Neurons, Concepts, and People: Brain Development and Its Implications. Preschool Policy Brief. Issue 17

    Science.gov (United States)

    Thompson, Ross A.

    2008-01-01

    The past decade has seen an upsurge in public understanding of early brain development. News reports, statements by policymakers, and commercial marketing of products for infants and young children have all contributed to a widespread understanding of the explosive growth of the brain in the early years and that stimulation acts as a catalyst to…

  9. Doublecortin-like knockdown in the adult mouse brain : implications for neurogenesis, neuroplasticity and behaviour

    NARCIS (Netherlands)

    Saaltink, Dirk-Jan

    2014-01-01

    The results in this thesis showed for the first time doublecortin-like (DCL)-specific expression in the adult mouse brain. Besides the expected regions with the capacity to generate new neurons (hippocampus and olfactory forebrain), DCL expression was found in three novel brain areas namely hypothal

  10. Brain Research: Environment and Emotions. Implications for Teaching Information Literacy Skills

    Science.gov (United States)

    Morris, Betty J.

    2004-01-01

    Library media specialists need to embrace brain research and implement its findings into the teaching of information literary skills. Research in the past two decades has used imaging techniques to allow the study of brain functions when listening to music versus composing a song or when recalling a noun or verb. Imaging allows researchers to look…

  11. Imaging of Cells and Nanoparticles : Implications for Drug Delivery to the Brain

    NARCIS (Netherlands)

    Stojanov, Katica; Zuhorn, Inge S.; Dierckx, Rudi A. J. O.; de Vries, Erik F. J.

    2012-01-01

    A major challenge in the development of central nervous system drugs is to obtain therapeutic effective drug concentrations inside the brain. Many potentially effective drugs have never reached clinical application because of poor brain penetration. Currently, devices are being developed that may im

  12. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    Science.gov (United States)

    Gavilan, L.; Jäger, C.; Simionovici, A.; Lemaire, J. L.; Sabri, T.; Foy, E.; Yagoubi, S.; Henning, T.; Salomon, D.; Martinez-Criado, G.

    2016-03-01

    Context. Protoplanetary disks, interstellar clouds, and active galactic nuclei contain X-ray-dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Aims: Our goal is to study the effects of hard X-rays on cosmic dust analogs via in situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments and provide an upper limit on the effect of hard X-rays on dust grain structure. Methods: We prepared enstatite (MgSiO3) nanograins, which are analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) before irradiation. Powder samples were prepared in X-ray transparent substrates and were irradiated with hard X-rays nanobeams (29.4 keV) provided by beamline ID16B of the European Synchrotron Radiation Facility (Grenoble). X-ray diffraction images were recorded in transmission mode, and the ensuing diffractograms were analyzed as a function of the total X-ray exposure time. Results: We detected the amorphization of polycrystalline silicates embedded in an organic matrix after an accumulated X-ray exposure of 6.4 × 1027 eV cm-2. Pure crystalline silicate grains (without resin) do not exhibit amorphization. None of the amorphous silicate samples (pure and embedded in resin) underwent crystallization. We analyze the evolution of the polycrystalline sample embedded in an organic matrix as a function of X-ray exposure. Conclusions: Loss of diffraction peak intensity, peak broadening, and the disappearance of discrete spots and arcs reveal the amorphization

  13. On the potential for lunar highlands Mg-suite extrusive volcanism and implications concerning crustal evolution

    Science.gov (United States)

    Prissel, Tabb C.; Whitten, Jennifer L.; Parman, Stephen W.; Head, James W.

    2016-10-01

    The lunar magnesian-suite (Mg-suite) was produced during the earliest periods of magmatic activity on the Moon. Based on the cumulate textures of the samples and a lack of evidence for Mg-suite extrusives in both the sample and remote sensing databases, several petrogenetic models deduce a predominantly intrusive magmatic history for Mg-suite lithologies. Considering that ∼18% of the lunar surface is covered by mare basalt flows, which are substantially higher in density than estimated Mg-suite magmas (∼2900 versus ∼2700 kg/m3), the apparent absence of low-density Mg-suite volcanics is surprising. Were Mg-suite magmas predominantly intrusive, or have their extrusive equivalents been covered by subsequent impact ejecta and/or later stage volcanism? If Mg-suite magmas were predominantly intrusive, what prevented these melts from erupting? Or, if they are present as extrusives, what regions of the Moon are most likely to contain Mg-suite volcanic deposits? This study investigates buoyancy-driven ascent of Mg-suite parental melts and is motivated by recent measurements of crustal density from GRAIL. Mg-suite dunite, troctolite, and spinel anorthosite parental melts (2742, 2699, and 2648 kg/m3, respectively) are considered, all of which have much lower melt densities relative to mare basalts and picritic glasses. Mg-suite parental melts are more dense than most of the crust and would not be expected to buoyantly erupt. However, about 10% of the lunar crust is greater in density than Mg-suite melts. These areas are primarily within the nearside southern highlands and South Pole-Aitken (SP-A) basin. Mg-suite extrusions and/or shallow intrusions were possible within these regions, assuming crustal density structure at >4.1 Ga was similar to the present day crust. We review evidence for Mg-suite activity within both the southern highlands and SP-A and discuss the implications concerning crustal evolution as well as Mg-suite petrogenesis. Lower crustal densities

  14. The crust and upper mantle of central East Greenland - implications for continental accretion and rift evolution

    Science.gov (United States)

    Schiffer, Christian; Balling, Niels; Ebbing, Jörg; Holm Jacobsen, Bo; Bom Nielsen, Søren

    2016-04-01

    The geological evolution of the North Atlantic Realm during the past 450 Myr, which has shaped the present-day topographic, crustal and upper mantle features, was dominated by the Caledonian orogeny and the formation of the North Atlantic and associated igneous activity. The distinct high altitude-low relief landscapes that accompany the North Atlantic rifted passive margins are the focus of a discussion of whether they are remnant and modified Caledonian features or, alternatively, recently uplifted peneplains. Teleseismic receiver function analysis of 11 broadband seismometers in the Central Fjord Region in East Greenland indicates the presence of a fossil subduction complex, including a slab of eclogitised mafic crust and an overlying wedge of hydrated mantle peridotite. This model is generally consistent with gravity and topography. It is shown that the entire structure including crustal thickness variations and sub-Moho heterogeneity gives a superior gravity and isostatic topographic fit compared to a model with a homogeneous lithospheric layer (1). The high topography of >1000 m in the western part of the area is supported by the c. 40 km thick crust. The eastern part requires buoyancy from the low velocity/low density mantle wedge. The geometry, velocities and densities are consistent with structures associated with a fossil subduction zone. The spatial relations with Caledonian structures suggest a Caledonian origin. The results indicate that topography is isostatically compensated by density variations within the lithosphere and that significant present-day dynamic topography seems not to be required. Further, this structure is suggested to be geophysically very similar to the Flannan reflector imaged north of Scotland, and that these are the remnants of the same fossil subduction zone, broken apart and separated during the formation of the North Atlantic in the early Cenozoic (2). 1) Schiffer, C., Jacobsen, B.H., Balling, N., Ebbing, J. and Nielsen, S

  15. Can fat explain the human brain's big bang evolution?-Horrobin's leads for comparative and functional genomics.

    Science.gov (United States)

    Erren, T C; Erren, M

    2004-04-01

    When David Horrobin suggested that phospholipid and fatty acid metabolism played a major role in human evolution, his 'fat utilization hypothesis' unified intriguing work from paleoanthropology, evolutionary biology, genetic and nervous system research in a novel and coherent lipid-related context. Interestingly, unlike most other evolutionary concepts, the hypothesis allows specific predictions which can be empirically tested in the near future. This paper summarizes some of Horrobin's intriguing propositions and suggests as to how approaches of comparative genomics published in Cell, Nature, Science and elsewhere since 1997 may be used to examine his evolutionary hypothesis. Indeed, systematic investigations of the genomic clock in the species' mitochondrial DNA, the Y and autosomal chromosomes as evidence of evolutionary relationships and distinctions can help to scrutinize associated predictions for their validity, namely that key mutations which differentiate us from Neanderthals and from great apes are in the genes coding for proteins which regulate fat metabolism, and particularly the phospholipid metabolism of the synapses of the brain. It is concluded that beyond clues to humans' relationships with living primates and to the Neanderthals' cognitive performance and their disappearance, the suggested molecular clock analyses may provide crucial insights into the biochemical evolution-and means of possible manipulation-of our brain.

  16. Dystrophins, Utrophins, and Associated Scaffolding Complexes: Role in Mammalian Brain and Implications for Therapeutic Strategies

    Directory of Open Access Journals (Sweden)

    Caroline Perronnet

    2010-01-01

    Full Text Available Two decades of molecular, cellular, and functional studies considerably increased our understanding of dystrophins function and unveiled the complex etiology of the cognitive deficits in Duchenne muscular dystrophy (DMD, which involves altered expression of several dystrophin-gene products in brain. Dystrophins are normally part of critical cytoskeleton-associated membrane-bound molecular scaffolds involved in the clustering of receptors, ion channels, and signaling proteins that contribute to synapse physiology and blood-brain barrier function. The utrophin gene also drives brain expression of several paralogs proteins, which cellular expression and biological roles remain to be elucidated. Here we review the structural and functional properties of dystrophins and utrophins in brain, the consequences of dystrophins loss-of-function as revealed by numerous studies in mouse models of DMD, and we discuss future challenges and putative therapeutic strategies that may compensate for the cognitive impairment in DMD based on experimental manipulation of dystrophins and/or utrophins brain expression.

  17. Evolution of brain-derived neurotrophic factor levels after autologous hematopietic stem cell transplantation in multiple sclerosis.

    Science.gov (United States)

    Blanco, Y; Saiz, A; Costa, M; Torres-Peraza, J F; Carreras, E; Alberch, J; Jaraquemada, D; Graus, F

    A neuroprotective role of inflammation has been suggested based on that immune cells are the main source of brain-derived neurotrophic factor (BDNF). We investigated the 3-year evolution of BDNF levels in serum, CSF and culture supernatant of peripheral blood mononuclear cells (PBMC), unstimulated and stimulated with anti-CD3 and soluble anti-CD28 antibodies, in 14 multiple sclerosis patients who underwent an autologous hematopoietic stem cell transplantation (AHSCT). BDNF levels were correlated with previously reported MRI measures that showed a reduction of T2 lesion load and increased brain atrophy, mainly at first year post-transplant. A significant decrease of serum BDNF levels was seen at 12 months post-transplant. BDNF values were found significantly lower in stimulated but not in unstimulated PBMC supernatants during the follow-up, supporting that AHSCT may induce a down-regulation of BDNF production. The only significant correlation was found between CSF BDNF levels and T2 lesion load before and 1 year after AHSCT, suggesting that BDNF reflects the past and ongoing inflammatory activity and demyelination of these highly active patients. Our study suggests that AHSCT can reduce BDNF levels to values associated with lower activity. This decrease does not seem to correlate with the brain atrophy measures observed in the MRI.

  18. MT-Stabilizer, Dictyostatin, Exhibits Prolonged Brain Retention and Activity: Potential Therapeutic Implications

    Science.gov (United States)

    2013-01-01

    Inclusions comprising the microtubule (MT)-stabilizing protein, tau, are found within neurons in the brains of patients with Alzheimer’s disease and related neurodegenerative disorders that are broadly referred to as tauopathies. The sequestration of tau into inclusions is believed to cause a loss of tau function, such that MT structure and function are compromised, leading to neuronal damage. Recent data reveal that the brain-penetrant MT-stabilizing agent, epothilone D (EpoD), improves cognitive function and decreases both neuron loss and tau pathology in transgenic mouse models of tauopathy. There is thus a need to identify additional MT-stabilizing compounds with blood–brain barrier (BBB) permeability and slow brain clearance, as observed with EpoD. We report here that the MT-stabilizing natural product, dictyostatin, crosses the BBB in mice and has extended brain retention. Moreover, a single administration of dictyostatin to mice causes prolonged stabilization of MTs in the brain. In contrast, the structurally related MT-stabilizer, discodermolide, shows significantly less brain exposure. Thus, dictyostatin merits further investigation as a potential tauopathy therapeutic. PMID:24900764

  19. MT-Stabilizer, Dictyostatin, Exhibits Prolonged Brain Retention and Activity: Potential Therapeutic Implications.

    Science.gov (United States)

    Brunden, Kurt R; Gardner, Nicola M; James, Michael J; Yao, Yuemang; Trojanowski, John Q; Lee, Virginia M-Y; Paterson, Ian; Ballatore, Carlo; Smith, Amos B

    2013-09-12

    Inclusions comprising the microtubule (MT)-stabilizing protein, tau, are found within neurons in the brains of patients with Alzheimer's disease and related neurodegenerative disorders that are broadly referred to as tauopathies. The sequestration of tau into inclusions is believed to cause a loss of tau function, such that MT structure and function are compromised, leading to neuronal damage. Recent data reveal that the brain-penetrant MT-stabilizing agent, epothilone D (EpoD), improves cognitive function and decreases both neuron loss and tau pathology in transgenic mouse models of tauopathy. There is thus a need to identify additional MT-stabilizing compounds with blood-brain barrier (BBB) permeability and slow brain clearance, as observed with EpoD. We report here that the MT-stabilizing natural product, dictyostatin, crosses the BBB in mice and has extended brain retention. Moreover, a single administration of dictyostatin to mice causes prolonged stabilization of MTs in the brain. In contrast, the structurally related MT-stabilizer, discodermolide, shows significantly less brain exposure. Thus, dictyostatin merits further investigation as a potential tauopathy therapeutic.

  20. Decoding brain responses to pixelized images in the primary visual cortex: implications for visual cortical prostheses.

    Science.gov (United States)

    Guo, Bing-Bing; Zheng, Xiao-Lin; Lu, Zhen-Gang; Wang, Xing; Yin, Zheng-Qin; Hou, Wen-Sheng; Meng, Ming

    2015-10-01

    Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only "see" pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex (the implant area) is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine (LSVM) as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.

  1. The Role of Metaphor in Darwin and the Implications for Teaching Evolution

    Science.gov (United States)

    Pramling, Niklas

    2009-01-01

    This article is about the role of metaphor in scientific knowledge formation and reasoning. These issues are studied by means of an example of the theory of evolution through natural selection. The premise is that the theory of evolution contains a set of problems regarding metaphor. A second premise is that these problems have to be handled in…

  2. Origins and clinical implications of the brain tumor stem cell hypothesis

    OpenAIRE

    2009-01-01

    With the advent of the cancer stem cell hypothesis, the field of cancer research has experienced a revolution in how we think of and approach cancer. The discovery of “brain tumor stem cells” has offered an explanation for several long-standing conundrums on why brain tumors behave the way they do to treatment. Despite the great amount of research that has been done in order to understand the molecular aspects of malignant gliomas, the prognosis of brain tumors remains dismal. The slow progre...

  3. The birth of new neurons in the maternal brain: Hormonal regulation and functional implications.

    Science.gov (United States)

    Leuner, Benedetta; Sabihi, Sara

    2016-04-01

    The maternal brain is remarkably plastic and exhibits multifaceted neural modifications. Neurogenesis has emerged as one of the mechanisms by which the maternal brain exhibits plasticity. This review highlights what is currently known about peripartum-associated changes in adult neurogenesis and the underlying hormonal mechanisms. We also consider the functional consequences of neurogenesis in the peripartum brain and extent to which this process may play a role in maternal care, cognitive function and postpartum mood. Finally, while most work investigating the effects of parenting on adult neurogenesis has focused on mothers, a few studies have examined fathers and these results are also discussed.

  4. K/Ar ages, magnetic stratigraphy and morphological evolution of La Gomera: implications for the Canary Islands hotspot evolution.

    Science.gov (United States)

    Paris, R.; Guillou, H.; Carracedo, J. C.; Pérez Torrado, F. J.

    2003-04-01

    The Canary Islands are a group of seven volcanic islands, 100-700 km west of the Sahara continental margin. The spatial and chronological evolution of the canarian volcanism, from east to west, is due to the progression of the slow-moving african plate on a hotspot. La Gomera is located between the western shield-growing stage islands (La Palma, 1,7 Ma and El Hierro, 1,1 Ma) and the central "rejuvaneted stage" islands (Tenerife, 11,9 Ma and Gran Canaria, 14,5 Ma). After 23 K-Ar ages and paleomagnetism datas, we determine the main volcanic phases of La Gomera : (1) the submarine shield volcano (> 9,5 Ma), (2) the first subaeriel shield volcano (9,43-7,36 Ma), (3) the Vallehermoso stratovolcan, (4) the peripheral "planèzes" and domes forming series (6,67-1,94 Ma) and the Garajonay horizontal series (5,42-4,25 Ma). The stratovolcano and the horizontal series fill a 10 km wide depression that is supposed to be a giant landslide embayment. The scarps of this landslide correspond to the main discontinuity in the island structure. After 4 M.y. of very scarce volcanism, the whole structure of La Gomera is in relief inversion, with a radial pattern of deep barrancos. The erosion rates are lower during the hiatus (< 0,2 m/ka) than during the shield stage (0,2-0,9 m/ka), pointing out the fact that the volcanic construction rates and the erosion rates are strongly correlated. La Gomera is one of the best example of a hiatus stage of hotspot evolution. The volcanic load La Gomera and Tenerife may have delayed the western islands volcanism, favouring a dual-line.

  5. Brain intersections of aesthetics and morals: perspectives from biology, neuroscience, and evolution.

    Science.gov (United States)

    Zaidel, D W; Nadal, M

    2011-01-01

    For centuries, only philosophers debated the relationship between aesthetics and morality. Recently, with advances in neuroscience, the debate has moved to include the brain and an evolved neural underpinning linking aesthetic reactions and moral judgment. Biological survival emphasizes mate selection strategies, and the ritual displays have been linked to human aesthetics in the arts, in faces, and in various daily decision making. In parallel, cultural human practices have evolved to emphasize altruism and morality. This article explores the biological background and discusses the neuroscientific evidence for shared brain pathways for aesthetics and morals.

  6. Acute, regional inflammatory response after traumatic brain injury: Implications for cellular therapy

    OpenAIRE

    Harting, Matthew T.; jimenez, fernando; Adams, Sasha D.; Mercer, David W.; Cox, Charles S.

    2008-01-01

    While cellular therapy has shown promise in the management of traumatic brain injury (TBI), microenvironment interactions between the intracerebral milieu and therapeutic stem cells are poorly understood. We sought to characterize the acute, regional inflammatory response after TBI.

  7. Simulating the Evolution of Functional Brain Networks in Alzheimer’s Disease: Exploring Disease Dynamics from the Perspective of Global Activity

    Science.gov (United States)

    Li, Wei; Wang, Miao; Zhu, Wenzhen; Qin, Yuanyuan; Huang, Yue; Chen, Xi

    2016-01-01

    Functional brain connectivity is altered during the pathological processes of Alzheimer’s disease (AD), but the specific evolutional rules are insufficiently understood. Resting-state functional magnetic resonance imaging indicates that the functional brain networks of individuals with AD tend to be disrupted in hub-like nodes, shifting from a small world architecture to a random profile. Here, we proposed a novel evolution model based on computational experiments to simulate the transition of functional brain networks from normal to AD. Specifically, we simulated the rearrangement of edges in a pathological process by a high probability of disconnecting edges between hub-like nodes, and by generating edges between random pair of nodes. Subsequently, four topological properties and a nodal distribution were used to evaluate our model. Compared with random evolution as a null model, our model captured well the topological alteration of functional brain networks during the pathological process. Moreover, we implemented two kinds of network attack to imitate the damage incurred by the brain in AD. Topological changes were better explained by ‘hub attacks’ than by ‘random attacks’, indicating the fragility of hubs in individuals with AD. This model clarifies the disruption of functional brain networks in AD, providing a new perspective on topological alterations. PMID:27677360

  8. Brain scaling in mammalian evolution as a consequence of concerted and mosaic changes in numbers of neurons and average neuronal cell size

    Directory of Open Access Journals (Sweden)

    Suzana eHerculano-Houzel

    2014-08-01

    Full Text Available Enough species have now been subject to systematic quantitative analysis of the relationship between the morphology and cellular composition of their brain that patterns begin to emerge and shed light on the evolutionary path that led to mammalian brain diversity. Based on an analysis of the shared and clade-specific characteristics of 41 modern mammalian species in 6 clades, and in light of the phylogenetic relationships among them, here we propose that ancestral mammal brains were composed and scaled in their cellular composition like modern afrotherian and glire brains: with an addition of neurons that is accompanied by a decrease in neuronal density and very little modification in glial cell density, implying a significant increase in average neuronal cell size in larger brains, and the allocation of approximately 2 neurons in the cerebral cortex and 8 neurons in the cerebellum for every neuron allocated to the rest of brain. We also propose that in some clades the scaling of different brain structures has diverged away from the common ancestral layout through clade-specific (or clade-defining changes in how average neuronal cell mass relates to numbers of neurons in each structure, and how numbers of neurons are differentially allocated to each structure relative to the number of neurons in the rest of brain. Thus, the evolutionary expansion of mammalian brains has involved both concerted and mosaic patterns of scaling across structures. This is, to our knowledge, the first mechanistic model that explains the generation of brains large and small in mammalian evolution, and it opens up new horizons for seeking the cellular pathways and genes involved in brain evolution.

  9. MicroRNAs and fetal brain development: Implications for ethanol teratology during the second trimester period of neurogenesis.

    Directory of Open Access Journals (Sweden)

    Rajesh eMiranda

    2012-05-01

    Full Text Available Maternal ethanol consumption during pregnancy can lead to a stereotypic cluster of fetal craniofacial, cardiovascular, skeletal and neurological deficits that are collectively termed the Fetal Alcohol Spectrum Disorder (FASD. Fetal ethanol exposure is a leading non-genetic cause of mental retardation. Mechanisms underlying the etiology of ethanol teratology are varied and complex. This review will focus on the developing brain as an important and vulnerable ethanol target. Near the end of the first trimester, and during the second trimester, fetal neural stem cells (NSCs produce most of the neurons of the adult brain, and ethanol has been shown to influence NSC renewal and maturation. We will discuss the neural developmental and teratological implications of the biogenesis and function of microRNAs (miRNAs, a class of small non-protein-coding RNAs that control the expression of gene networks by translation repression. A small but growing body of research has identified ethanol-sensitive miRNAs at different stages of NSC and brain maturation. While many microRNAs appear to be vulnerable to ethanol at specific developmental stages, a few, like the miR-9 family, appear to exhibit broad vulnerability to ethanol across multiple stages of NSC differentiation. An assessment of the regulation and function of these miRNAs provides important clues about the mechanisms that underlie fetal vulnerability to alterations in the maternal-fetal environment and yields insights into the genesis of FASD.

  10. Forelimb preferences in quadrupedal marsupials and their implications for laterality evolution in mammals

    OpenAIRE

    Giljov, Andrey; Karenina, Karina; Malashichev, Yegor

    2013-01-01

    Background Acquisition of upright posture in evolution has been argued to facilitate manual laterality in primates. Owing to the high variety of postural habits marsupials can serve as a suitable model to test whether the species-typical body posture shapes forelimb preferences in non-primates or this phenomenon emerged only in the course of primate evolution. In the present study we aimed to explore manual laterality in marsupial quadrupeds and compare them with the results in the previously...

  11. Hominins and the emergence of the modern human brain.

    Science.gov (United States)

    de Sousa, Alexandra; Cunha, Eugénia

    2012-01-01

    Evidence used to reconstruct the morphology and function of the brain (and the rest of the central nervous system) in fossil hominin species comes from the fossil and archeological records. Although the details provided about human brain evolution are scarce, they benefit from interpretations informed by interspecific comparative studies and, in particular, human pathology studies. In recent years, new information has come to light about fossil DNA and ontogenetic trajectories, for which pathology research has significant implications. We briefly describe and summarize data from the paleoarcheological and paleoneurological records about the evolution of fossil hominin brains, including behavioral data most relevant to brain research. These findings are brought together to characterize fossil hominin taxa in terms of brain structure and function and to summarize brain evolution in the human lineage.

  12. Genetic basis of human brain evolution: accelerating along the primate speedway.

    Science.gov (United States)

    Hayakawa, Toshiyuki; Altheide, Tasha K; Varki, Ajit

    2005-01-01

    Using novel variations of traditional methods, report in the December 29(th) issue of Cell that diverse genes involved in neural biology (particularly those critical in development) show higher rates of protein evolution in primates than in rodents-particularly in the lineage leading to humans.

  13. The Mind and the Machine. On the Conceptual and Moral Implications of Brain-Machine Interaction.

    Science.gov (United States)

    Schermer, Maartje

    2009-12-01

    Brain-machine interfaces are a growing field of research and application. The increasing possibilities to connect the human brain to electronic devices and computer software can be put to use in medicine, the military, and entertainment. Concrete technologies include cochlear implants, Deep Brain Stimulation, neurofeedback and neuroprosthesis. The expectations for the near and further future are high, though it is difficult to separate hope from hype. The focus in this paper is on the effects that these new technologies may have on our 'symbolic order'-on the ways in which popular categories and concepts may change or be reinterpreted. First, the blurring distinction between man and machine and the idea of the cyborg are discussed. It is argued that the morally relevant difference is that between persons and non-persons, which does not necessarily coincide with the distinction between man and machine. The concept of the person remains useful. It may, however, become more difficult to assess the limits of the human body. Next, the distinction between body and mind is discussed. The mind is increasingly seen as a function of the brain, and thus understood in bodily and mechanical terms. This raises questions concerning concepts of free will and moral responsibility that may have far reaching consequences in the field of law, where some have argued for a revision of our criminal justice system, from retributivist to consequentialist. Even without such a (unlikely and unwarranted) revision occurring, brain-machine interactions raise many interesting questions regarding distribution and attribution of responsibility.

  14. The Effects of Video Games on Cognition and Brain Structure: Potential Implications for Neuropsychiatric Disorders.

    Science.gov (United States)

    Shams, Tahireh A; Foussias, George; Zawadzki, John A; Marshe, Victoria S; Siddiqui, Ishraq; Müller, Daniel J; Wong, Albert H C

    2015-09-01

    Video games are now a ubiquitous form of entertainment that has occasionally attracted negative attention. Video games have also been used to test cognitive function, as therapeutic interventions for neuropsychiatric disorders, and to explore mechanisms of experience-dependent structural brain changes. Here, we review current research on video games published from January 2011 to April 2014 with a focus on studies relating to mental health, cognition, and brain imaging. Overall, there is evidence that specific types of video games can alter brain structure or improve certain aspects of cognitive functioning. Video games can also be useful as neuropsychological assessment tools. While research in this area is still at a very early stage, there are interesting results that encourage further work in this field, and hold promise for utilizing this technology as a powerful therapeutic and experimental tool.

  15. The evolution of brain waves in altered states of consciousness (REM sleep and meditation

    Directory of Open Access Journals (Sweden)

    Irina E. Chiş

    2009-12-01

    Full Text Available Aim: The aim of this study was to investigate the brain activity in REM sleep andmeditation; it was also studied in which way an appropriate musical background would affect theevolution of brain waves in these altered states of consciousness. Material and Method: The recordingswere done with a portable electroencephalograph, on a homogeneous group of human subjects (menaged 30-50 years. The subjects were monitored in their own bed, the length of sleep and how earlythey went to bed was up to them. This was made to avoid errors that could compromise the wholestudy. Results: It was shown that an appropriate musical background has a positive effect on brainactivity and especially on alpha waves. There were no significant results regarding REM sleep, althougha slight increase in the frequency by which the periods of REM sleep occurred was noticed. On theother hand, in meditation, the appropriate musical background had a major influence on the period inwhich the subjects entered the alpha state. This period was considerably reduced. Conclusion: Anadequate type of music can help our brain entering in, and maintaining the alpha state.

  16. Temporal Evolution of the Upper Continental Crust: Implications for the Mode of Crustal Growth and the Evolution of the Hydrosphere

    Science.gov (United States)

    Rudnick, R. L.; Gaschnig, R. M.; Li, S.; Tang, M.; Qiu, L.; Valley, J. W.; Zurkowski, C.; McDonough, W. F.

    2014-12-01

    The upper continental crust (UCC), the interface between the atmosphere and solid Earth, is the site of weathering that produces sedimentary rocks, influences ocean chemistry through runoff of soluble elements, and affects climate through CO2 draw-down. The UCC also contains more than 50% of the crust's highly incompatible element budget (including K, Th, and U). Therefore, understanding its composition and evolution provides insight into how continents have formed, evolved, and interacted with the hydrosphere. New major and trace element compositions of >100 glacial diamictites and >100 Archean shales, plus δ7Li and δ18O for a subset of these samples, combined with data from the literature, show that the average composition of the UCC has changed through time, reflecting both the rise of atmospheric oxygen and its attendant effects on weathering, as well as the mode of crust formation and differentiation. Some changes that occur as a step function near the Archean/Proterozoic boundary (increased Th/U, decreased Mo/Pr, V/Lu) reflect the rise of oxygen at the great oxidation event (GOE) and its influence on chemical weathering signatures in the UCC. Other changes are more gradual with time (e.g., higher Th/Sc and δ18O, lower Ni/Co, La/Nb, Eu/Eu* and transition metal abundances) and reflect an UCC that has transitioned from a more mafic to a more felsic bulk composition, and which experienced increased interaction with the hydrosphere with time. The gradual nature of these compositional changes likely reflects the waning heat production of the Earth, rather than an abrupt change in tectonics or style of crust formation. These more gradual changes in crust composition, which contrast with the abrupt changes associated with the GOE, suggest that a fundamental change in the nature of crust differentiation is unlikely to be responsible for the rise of atmospheric oxygen (cf. Keller and Schoene, 2012). Indeed, it appears that the opposite may be true: that the rise of

  17. Post main sequence evolution of icy minor planets: Implications for water retention and white dwarf pollution

    CERN Document Server

    Malamud, Uri

    2016-01-01

    Most observations of polluted white dwarf atmospheres are consistent with accretion of water depleted planetary material. Among tens of known cases, merely two cases involve accretion of objects that contain a considerable mass fraction of water. The purpose of this study is to investigate the relative scarcity of these detections. Based on a new and highly detailed model, we evaluate the retention of water inside icy minor planets during the high luminosity stellar evolution that follows the main sequence. Our model fully considers the thermal, physical, and chemical evolution of icy bodies, following their internal differentiation as well as water depletion, from the moment of their birth and through all stellar evolution phases preceding the formation of the white dwarf. We also account for different initial compositions and formation times. Our results show that previous studies have either underestimated or overestimated water retention. We also reaffirm that water can survive in a variety of circumstanc...

  18. Epigenetics: definition, molecular bases and implications in human health and evolution

    Directory of Open Access Journals (Sweden)

    García-Robles Reggie

    2012-04-01

    Full Text Available Epigenetics refers to inheritable changes in DNA and histones that do not involve changes in thesequence of nucleotides and that modifies structure and chromatin condensation, thus affectinggene expression and phenotype. Epigenetic modifications are DNA methylation and histone modifications. Objective: A review of the literature on the concept of Epigenetics and its impacton health. Materials and methods: A review of the literature was performed on the concept ofepigenetics, its biological basis, the impact on health and disease and its relation to evolution.Results: Epigenetic mechanisms have become increasingly important because of the growingassociation with common complex diseases as well as its impact on health of future generationsand in human evolution. Conclusions: Epigenetics has a clear impact on the health of individualsin their offspring and with the evolution of the human species

  19. Body composition in Pan paniscus compared with Homo sapiens has implications for changes during human evolution.

    Science.gov (United States)

    Zihlman, Adrienne L; Bolter, Debra R

    2015-06-16

    The human body has been shaped by natural selection during the past 4-5 million years. Fossils preserve bones and teeth but lack muscle, skin, fat, and organs. To understand the evolution of the human form, information about both soft and hard tissues of our ancestors is needed. Our closest living relatives of the genus Pan provide the best comparative model to those ancestors. Here, we present data on the body composition of 13 bonobos (Pan paniscus) measured during anatomical dissections and compare the data with Homo sapiens. These comparative data suggest that both females and males (i) increased body fat, (ii) decreased relative muscle mass, (iii) redistributed muscle mass to lower limbs, and (iv) decreased relative mass of skin during human evolution. Comparison of soft tissues between Pan and Homo provides new insights into the function and evolution of body composition.

  20. Brain activity in advantageous and disadvantageous situations: implications for reward/punishment sensitivity in different situations.

    Directory of Open Access Journals (Sweden)

    Guangheng Dong

    Full Text Available OBJECTIVE: This study modeled win and lose trials in a simple gambling task to examine the effect of entire win-lose situations (WIN, LOSS, or TIE on single win/lose trials and related neural underpinnings. METHODS: The behavior responses and brain activities of 17 participants were recorded by an MRI scanner while they performed a gambling task. Different conditions were compared to determine the effect of the task on the behavior and brain activity of the participants. Correlations between brain activity and behavior were calculated to support the imaging results. RESULTS: In win trials, LOSS caused less intense posterior cingulate activity than TIE. In lose trials, LOSS caused more intense activity in the right superior temporal gyrus, bilateral superior frontal gyrus, bilateral anterior cingulate, bilateral insula cortex, and left orbitofrontal cortex than WIN and TIE. CONCLUSIONS: The experiences of the participants in win trials showed great similarity among different win-lose situations. However, the brain activity and behavior responses of the participants in lose trials indicated that they experienced stronger negative emotion in LOSS. The participants also showed an increased desire to win in LOSS than in WIN or TIE conditions.

  1. Mitochondrial Respiration Chain Enzymatic Activities in the Human Brain: Methodological Implications for Tissue Sampling and Storage.

    Science.gov (United States)

    Ronsoni, Marcelo Fernando; Remor, Aline Pertile; Lopes, Mark William; Hohl, Alexandre; Troncoso, Iris H Z; Leal, Rodrigo Bainy; Boos, Gustavo Luchi; Kondageski, Charles; Nunes, Jean Costa; Linhares, Marcelo Neves; Lin, Kátia; Latini, Alexandra Susana; Walz, Roger

    2016-04-01

    Mitochondrial respiratory chain complexes enzymatic (MRCCE) activities were successfully evaluated in frozen brain samples. Epilepsy surgery offers an ethical opportunity to study human brain tissue surgically removed to treat drug resistant epilepsies. Epilepsy surgeries are done with hemodynamic and laboratory parameters to maintain physiology, but there are no studies analyzing the association among these parameters and MRCCE activities in the human brain tissue. We determined the intra-operative parameters independently associated with MRCCE activities in middle temporal neocortex (Cx), amygdala (AMY) and head of hippocampus (HIP) samples of patients (n = 23) who underwent temporal lobectomy using multiple linear regressions. MRCCE activities in Cx, AMY and HIP are differentially associated to trans-operative mean arterial blood pressure, O2 saturation, hemoglobin, and anesthesia duration to time of tissue sampling. The time-course between the last seizure occurrence and tissue sampling as well as the sample storage to biochemical assessments were also associated with enzyme activities. Linear regression models including these variables explain 13-17 % of MRCCE activities and show a moderate to strong effect (r = 0.37-0.82). Intraoperative hemodynamic and laboratory parameters as well as the time from last seizure to tissue sampling and storage time are associated with MRCCE activities in human samples from the Cx, AMYG and HIP. Careful control of these parameters is required to minimize confounding biases in studies using human brain samples collected from elective neurosurgery.

  2. Blood-Brain Barrier Abnormalities Caused by HIV-1 gp120: Mechanistic and Therapeutic Implications

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Louboutin

    2012-01-01

    Full Text Available The blood-brain barrier (BBB is compromised in many systemic and CNS diseases, including HIV-1 infection of the brain. We studied BBB disruption caused by HIV-1 envelope glycoprotein 120 (gp120 as a model. Exposure to gp120, whether acute [by direct intra-caudate-putamen (CP injection] or chronic [using SV(gp120, an experimental model of ongoing production of gp120] disrupted the BBB, and led to leakage of vascular contents. Gp120 was directly toxic to brain endothelial cells. Abnormalities of the BBB reflect the activity of matrix metalloproteinases (MMPs. These target laminin and attack the tight junctions between endothelial cells and BBB basal laminae. MMP-2 and MMP-9 were upregulated following gp120-injection. Gp120 reduced laminin and tight junction proteins. Reactive oxygen species (ROS activate MMPs. Injecting gp120 induced lipid peroxidation. Gene transfer of antioxidant enzymes protected against gp120-induced BBB abnormalities. NMDA upregulates the proform of MMP-9. Using the NMDA receptor (NMDAR-1 inhibitor, memantine, we observed partial protection from gp120-induced BBB injury. Thus, (1 HIV-envelope gp120 disrupts the BBB; (2 this occurs via lesions in brain microvessels, MMP activation and degradation of vascular basement membrane and vascular tight junctions; (3 NMDAR-1 activation plays a role in this BBB injury; and (4 antioxidant gene delivery as well as NMDAR-1 antagonists may protect the BBB.

  3. Academic Brain Drain: Impact and Implications for Public Higher Education Quality in Kenya

    Science.gov (United States)

    Odhiambo, George O.

    2013-01-01

    The flight of human capital is a phenomenon that has been of concern to academics and development practitioners for decades. Unfortunately, there is no systematic record of the number of skilled professionals that many African countries have continued to lose to the developed world. Termed the "brain drain", it represents the loss of…

  4. White Matter Lipids as a Ketogenic Fuel Supply in Aging Female Brain: Implications for Alzheimer's Disease.

    Science.gov (United States)

    Klosinski, Lauren P; Yao, Jia; Yin, Fei; Fonteh, Alfred N; Harrington, Michael G; Christensen, Trace A; Trushina, Eugenia; Brinton, Roberta Diaz

    2015-12-01

    White matter degeneration is a pathological hallmark of neurodegenerative diseases including Alzheimer's. Age remains the greatest risk factor for Alzheimer's and the prevalence of age-related late onset Alzheimer's is greatest in females. We investigated mechanisms underlying white matter degeneration in an animal model consistent with the sex at greatest Alzheimer's risk. Results of these analyses demonstrated decline in mitochondrial respiration, increased mitochondrial hydrogen peroxide production and cytosolic-phospholipase-A2 sphingomyelinase pathway activation during female brain aging. Electron microscopic and lipidomic analyses confirmed myelin degeneration. An increase in fatty acids and mitochondrial fatty acid metabolism machinery was coincident with a rise in brain ketone bodies and decline in plasma ketone bodies. This mechanistic pathway and its chronologically phased activation, links mitochondrial dysfunction early in aging with later age development of white matter degeneration. The catabolism of myelin lipids to generate ketone bodies can be viewed as a systems level adaptive response to address brain fuel and energy demand. Elucidation of the initiating factors and the mechanistic pathway leading to white matter catabolism in the aging female brain provides potential therapeutic targets to prevent and treat demyelinating diseases such as Alzheimer's and multiple sclerosis. Targeting stages of disease and associated mechanisms will be critical.

  5. Recent Developments in Understanding Brain Aging: Implications for Alzheimer's Disease and Vascular Cognitive Impairment.

    Science.gov (United States)

    Deak, Ferenc; Freeman, Willard M; Ungvari, Zoltan; Csiszar, Anna; Sonntag, William E

    2016-01-01

    As the population of the Western world is aging, there is increasing awareness of age-related impairments in cognitive function and a rising interest in finding novel approaches to preserve cerebral health. A special collection of articles in The Journals of Gerontology: Biological Sciences and Medical Sciences brings together information of different aspects of brain aging, from latest developments in the field of neurodegenerative disorders to cerebral microvascular mechanisms of cognitive decline. It is emphasized that although the cellular changes that occur within aging neurons have been widely studied, more research is required as new signaling pathways are discovered that can potentially protect cells. New avenues for research targeting cellular senescence, epigenetics, and endocrine mechanisms of brain aging are also discussed. Based on the current literature it is clear that understanding brain aging and reducing risk for neurological disease with age requires searching for mechanisms and treatment options beyond the age-related changes in neuronal function. Thus, comprehensive approaches need to be developed that address the multiple, interrelated mechanisms of brain aging. Attention is brought to the importance of maintenance of cerebromicrovascular health, restoring neuroendocrine balance, and the pressing need for funding more innovative research into the interactions of neuronal, neuroendocrine, inflammatory and microvascular mechanisms of cognitive impairment, and Alzheimer's disease.

  6. Brain Chemistry and Behaviour: An Update on Neuroscience Research and Its Implications for Understanding Drug Addiction

    Science.gov (United States)

    Robinson, Emma S. J.

    2011-01-01

    Psychiatric disorders such as drug addiction represent one of the biggest challenges to society. This article reviews clinical and basic science research to illustrate how developments in research methodology have enabled neuroscientists to understand more about the brain mechanisms involved in addiction biology. Treating addiction represents a…

  7. Age-related changes in brain support cells: Implications for stroke severity.

    Science.gov (United States)

    Sohrabji, Farida; Bake, Shameena; Lewis, Danielle K

    2013-10-01

    Stroke is one of the leading causes of adult disability and the fourth leading cause of mortality in the US. Stroke disproportionately occurs among the elderly, where the disease is more likely to be fatal or lead to long-term supportive care. Animal models, where the ischemic insult can be controlled more precisely, also confirm that aged animals sustain more severe strokes as compared to young animals. Furthermore, the neuroprotection usually seen in younger females when compared to young males is not observed in older females. The preclinical literature thus provides a valuable resource for understanding why the aging brain is more susceptible to severe infarction. In this review, we discuss the hypothesis that stroke severity in the aging brain may be associated with reduced functional capacity of critical support cells. Specifically, we focus on astrocytes, that are critical for detoxification of the brain microenvironment and endothelial cells, which play a crucial role in maintaining the blood brain barrier. In view of the sex difference in stroke severity, this review also discusses studies of middle-aged acyclic females as well as the effects of the estrogen on astrocytes and endothelial cells.

  8. Brain tumor delineation based on CT and MR imaging. Implications for radiotherapy treatment planning

    NARCIS (Netherlands)

    Heesters, M A; Wijrdeman, H K; Struikmans, H; Witkamp, T; Moerland, M A

    1993-01-01

    This paper deals with the impact MRI may have on radiotherapy treatment planning of brain tumors. The authors analyzed differences in size and position of treatment fields as indicated by three observers (two radiotherapists and one neuroradiologist) using CT or MR based radiotherapy planning proced

  9. Tryptophan as an evolutionarily conserved signal to brain serotonin : Molecular evidence and psychiatric implications

    NARCIS (Netherlands)

    Russo, Sascha; Kema, Ido P.; Bosker, Fokko; Haavik, Jan; Korf, Jakob

    2009-01-01

    The role of serotonin (5-HT) in psychopathology has been investigated for decades. Among others, symptoms of depression, panic, aggression and suicidality have been associated with serotonergic dysfunction. Here we summarize the evidence that low brain 5-HT signals a metabolic imbalance that is evol

  10. Implications of astrocytes in mediating the protective effects of Selective Estrogen Receptor Modulators upon brain damage

    Directory of Open Access Journals (Sweden)

    George E. Barreto

    2015-04-01

    Full Text Available Selective Estrogen Receptor Modulators (SERMs are steroidal or non-steroidal compounds that are already used in clinical practice for the treatment of breast cancer, osteoporosis and menopausal symptoms. While SERMs actions in the breast, bone, and uterus have been well characterized, their actions in the brain are less well understood. Previous works have demonstrated the beneficial effects of SERMs in different chronic neurodegenerative diseases like Alzheimer, Parkinson’s disease and Multiple sclerosis, as well as acute degeneration as stroke and traumatic brain injury. Moreover, these compounds exhibit similar protective actions as those of estradiol in the Central Nervous System, overt any secondary effect. For these reasons, in the past few years, there has been a growing interest in the neuroprotective effects exerted directly or indirectly by SERMs in the SNC. In this context, astrocytes play an important role in the maintenance of brain metabolism, and antioxidant support to neurons, thus indicating that better protection of astrocytes are an important asset targeting neuronal protection. Moreover, various clinical and experimental studies have reported that astrocytes are essential for the neuroprotective effects of SERMs during neuronal injuries, as these cells express different estrogen receptors in cell membrane, demonstrating that part of SERMs effects upon injury may be mediated by astrocytes. The present work highlights the current evidence on the protective mechanisms of SERMs, such as tamoxifen and raloxifene, in the SNC, and their modulation of astrocytic properties as promising therapeutic targets during brain damage.

  11. Assessment and Therapeutic Application of the Expressive Therapies Continuum: Implications for Brain Structures and Functions

    Science.gov (United States)

    Lusebrink, Vija B.

    2010-01-01

    The Expressive Therapies Continuum (ETC) provides a theoretical model for art-based assessments and applications of media in art therapy. The three levels of the ETC (Kinesthetic/Sensory, Perceptual/Affective, and Cognitive/Symbolic) appear to reflect different functions and structures in the brain that process visual and affective information.…

  12. A Theory of Marks and Mind: The Effect of Notational Systems on Hominid Brain Evolution and Child Development with an Emphasis on Exchanges between Mothers and Children

    Science.gov (United States)

    Sheridan, Susan Rich

    2005-01-01

    A model of human language requires a theory of meaningful marks. Humans are the only species who use marks to think. A theory of marks identifies children's scribbles as significant behavior, while hypothesizing the importance of notational systems to hominid brain evolution. By recognizing the importance of children's scribbles and drawings in…

  13. Triadic (ecological, neural, cognitive) niche construction: a scenario of human brain evolution extrapolating tool use and language from the control of reaching actions.

    Science.gov (United States)

    Iriki, Atsushi; Taoka, Miki

    2012-01-12

    Hominin evolution has involved a continuous process of addition of new kinds of cognitive capacity, including those relating to manufacture and use of tools and to the establishment of linguistic faculties. The dramatic expansion of the brain that accompanied additions of new functional areas would have supported such continuous evolution. Extended brain functions would have driven rapid and drastic changes in the hominin ecological niche, which in turn demanded further brain resources to adapt to it. In this way, humans have constructed a novel niche in each of the ecological, cognitive and neural domains, whose interactions accelerated their individual evolution through a process of triadic niche construction. Human higher cognitive activity can therefore be viewed holistically as one component in a terrestrial ecosystem. The brain's functional characteristics seem to play a key role in this triadic interaction. We advance a speculative argument about the origins of its neurobiological mechanisms, as an extension (with wider scope) of the evolutionary principles of adaptive function in the animal nervous system. The brain mechanisms that subserve tool use may bridge the gap between gesture and language--the site of such integration seems to be the parietal and extending opercular cortices.

  14. Adenosine receptors as markers of brain iron deficiency: Implications for Restless Legs Syndrome.

    Science.gov (United States)

    Quiroz, César; Gulyani, Seema; Ruiqian, Wan; Bonaventura, Jordi; Cutler, Roy; Pearson, Virginia; Allen, Richard P; Earley, Christopher J; Mattson, Mark P; Ferré, Sergi

    2016-12-01

    Deficits of sensorimotor integration with periodic limb movements during sleep (PLMS) and hyperarousal and sleep disturbances in Restless Legs Syndrome (RLS) constitute two pathophysiologically distinct but interrelated clinical phenomena, which seem to depend mostly on alterations in dopaminergic and glutamatergic neurotransmission, respectively. Brain iron deficiency is considered as a main pathogenetic mechanism in RLS. Rodents with brain iron deficiency represent a valuable pathophysiological model of RLS, although they do not display motor disturbances. Nevertheless, they develop the main neurochemical dopaminergic changes found in RLS, such as decrease in striatal dopamine D2 receptor density. On the other hand, brain iron deficient mice exhibit the characteristic pattern of hyperarousal in RLS, providing a tool to find the link between brain iron deficiency and sleep disturbances in RLS. The present study provides evidence for a role of the endogenous sleep-promoting factor adenosine. Three different experimental preparations, long-term (22 weeks) severe or moderate iron-deficient (ID) diets (3- or 7-ppm iron diet) in mice and short-term (3 weeks) severe ID diet (3-ppm iron diet) in rats, demonstrated a significant downregulation (Western blotting in mouse and radioligand binding saturation experiments in rat brain tissue) of adenosine A1 receptors (A1R) in the cortex and striatum, concomitant to striatal D2R downregulation. On the other hand, the previously reported upregulation of adenosine A2A receptors (A2AR) was only observed with severe ID in both mice and rats. The results suggest a key role for A1R downregulation in the PLMS and hyperarousal in RLS.

  15. Adaptations to vision-for-action in primate brain evolution: Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael A. Arbib

    Science.gov (United States)

    Hecht, Erin

    2016-03-01

    As Arbib [1] notes, the two-streams hypothesis [5] has provided a powerful explanatory framework for understanding visual processing. The inferotemporal ventral stream recognizes objects and agents - "what" one is seeing. The dorsal "how" or "where" stream through parietal cortex processes motion, spatial location, and visuo-proprioceptive relationships - "vision for action." Hickock and Poeppel's [3] extension of this model to the auditory system raises the question of deeper, multi- or supra-sensory themes in dorsal vs. ventral processing. Petrides and Pandya [10] postulate that the evolution of language may have been influenced by the fact that the dorsal stream terminates in posterior Broca's area (BA44) while the ventral stream terminates in anterior Broca's area (BA45). In an intriguing potential parallel, a recent ALE metanalysis of 54 fMRI studies found that semantic processing is located more anteriorly and superiorly than syntactic processing in Broca's area [13]. But clearly, macaques do not have language, nor other likely pre- or co-adaptations to language, such as complex imitation and tool use. What changed in the brain that enabled these functions to evolve?

  16. Evolution and current challenges in the teaching of functional MRI and functional brain imaging.

    Science.gov (United States)

    Savoy, Robert L

    2012-08-15

    The report of any new and successful method for studying the world triggers the need to train people in the use of that method. In the case of functional magnetic resonance imaging and its use for examining human brain function in vivo, expertise is required in a greater collection of domains than usual. Development of fMRI training programs started shortly after the announcement of BOLD-based fMRI in humans. These programs had a variety of durations and primary content areas. All programs had to deal with the challenge of bringing interested researchers from a wide variety of areas-many of whom had little or no understanding of MR physics, and/or experimental psychology, and/or the nuances of data analysis and modeling-to a sufficiently detailed level of knowledge that both the funding agencies, and the existing proprietors of the technology (often radiologists or MR physicists at hospitals) would take the research proposals of new investigators seriously. Now that fMRI-based research is well established, there are new educational challenges. Some have to do with the growing list of technologies used to study human brain function in vivo. But perhaps more daunting is the challenge of training consumers of the reports and claims based on fMRI and other brain imaging modalities. As fMRI becomes influential in contexts beyond the research environment-from the clinic to the courtroom to the legislature-training consumers of fMRI-based claims will take on increasing importance, and represents its own unique challenges for education.

  17. Phylogenetic relationships of Amazonian anole lizards (Dactyloa): taxonomic implications, new insights about phenotypic evolution and the timing of diversification.

    Science.gov (United States)

    Prates, Ivan; Rodrigues, Miguel Trefaut; Melo-Sampaio, Paulo Roberto; Carnaval, Ana Carolina

    2015-01-01

    The ecology and evolution of Caribbean anoles are well described, yet little is known about mainland anole species. Lack of phylogenetic information limits our knowledge about species boundaries, morphological evolution, and the biogeography of anoles in South America. To help fill this gap, we provide an updated molecular phylogeny of the Dactyloa (Dactyloidae), with emphasis on the punctata species group. By sampling understudied Amazonian taxa, we (i) assess the phylogenetic placement of the 'odd anole', D. dissimilis; (ii) infer the relationships of the proboscis-bearing D. phyllorhina, testing the hypothesis of independent nasal appendage evolution within the anole radiation; and (iii) examine genetic and dewlap color variation in D. punctata and D. philopunctata. Combining multiple nuclear loci with a review of the fossil record, we also (iv) estimate divergence times within the pleurodont iguanian clade of lizards, including Amazonian representatives of Dactyloa and Norops (Dactyloidae) and of Polychrus (Polychrotidae). We recover the five Dactyloa clades previously referred to as the aequatorialis, heteroderma, latifrons, punctata and roquet species groups, as well as a sixth clade composed of D. dissimilis and the non-Amazonian D. neblinina and D. calimae. We find D. phyllorhina to be nested within the punctata group, suggesting independent evolution of the anole proboscis. We consistently recover D. philopunctata nested within D. punctata, and report limited genetic divergence between distinct dewlap phenotypes. The most recent common ancestor of Dactyloa, Anolis and Norops dates back to the Eocene. Most Amazonian taxa within both Dactyloa and Norops diverged in the Miocene, but some diversification events were as old as the late Eocene and late Oligocene. Amazonian Polychrus diverged in the Pliocene. Our findings have broad implications for anole biogeography, disputing recent suggestions that modern dactyloid genera were present in the Caribbean region

  18. The GRB Redshift Distribution: Implications for Abundance Evolution, Star Formation, and Cosmology

    CERN Document Server

    Wei, Jun-Jie; Melia, Fulvio; Wei, Da-Ming; Feng, Long-Long

    2013-01-01

    It has been claimed that the \\emph{Swift} long gamma-ray bursts (LGRBs) do not trace the star formation history (SFH) in $\\Lambda$CDM. In this paper, we confirm that the latest \\emph{Swift} sample of GRBs reveals an increasing evolution in the GRB rate relative to the star formation rate (SFR) at high redshifts. One may eliminate the observed discrepancy between the GRB rate and the SFR by assuming a modest evolution, parameterized as $(1+z)^{0.5}$---an effect that perhaps implies a cosmic evolution in metallicity. However, we find a relatively higher metallicity cut of $Z=0.68Z_{\\odot}$ than was seen in previous studies, which suggested that LGRBs occur preferentially in metal poor environments, i.e., $Z\\sim0.1-0.3Z_{\\odot}$. Here, we use a simple power-law approximation to the high-\\emph{z} ($\\ga 3.8$) SFH, i.e., $R_{\\rm SF}\\propto[(1+z)/4.8]^{\\alpha}$, to examine how the high-\\emph{z} SFR may be impacted by a possible abundance evolution in the \\emph{Swift} GRB sample. For an expansion history consistent w...

  19. Implications of behavioral architecture for the evolution of self-organized division of labor

    NARCIS (Netherlands)

    Duarte, A.; Scholtens, E.; Weissing, F. J.

    2012-01-01

    Division of labor has been studied separately from a proximate self-organization and an ultimate evolutionary perspective. We aim to bring together these two perspectives. So far this has been done by choosing a behavioral mechanism a priori and considering the evolution of the properties of this me

  20. The evolution of halophytes, glycophytes and crops, and its implications for food security under saline conditions.

    Science.gov (United States)

    Cheeseman, John M

    2015-04-01

    The effective development of salt tolerant crops requires an understanding that the evolution of halophytes, glycophytes and our major grain crops has involved significantly different processes. Halophytes (and other edaphic endemics) generally arose through colonization of habitats in severe disequilibrium by pre-adapted individuals, rather than by gradual adaptation from populations of 'glycophytes'. Glycophytes, by contrast, occur in low sodium ecosystems, where sodium was and is the major limiting nutrient in herbivore diets, suggesting that their evolution reflects the fact that low sodium individuals experienced lower herbivory and had higher fitness. For domestication/evolution of crop plants, the selective pressure was human imposed and involved humans co-opting functions of defense and reproductive security. Unintended consequences of this included loss of tolerance to various stresses and loss of the genetic variability needed to correct that. Understanding, combining and manipulating all three modes of evolution are now critical to the development of salt tolerant crops, particularly those that will offer food security in countries with few economic resources and limited infrastructure. Such efforts will require exploiting the genetic structures of recently evolved halophytes, the genetic variability of model plants, and endemic halophytes and 'minor' crops that already exist.

  1. Causality, Symmetry, Brain, Evolution, DNA and a new Theory of Physics

    Science.gov (United States)

    Pissanetzky, Sergio

    2012-10-01

    THEORY. Except for black holes, our world is causal. In Physics, causal sets formalize causality. The easiest way to explain the importance of causets is: all finite algorithms and computer programs are causets. Let S be a causet model of a dynamical system. S has a symmetry of the action: set P of legal permutations of S. Hence all causets have conservation laws. Permutations in P represent trajectories in state space. But P is non-conservative. New Physics: an action functional F was observed. When F is minimized over P, conservative subset P* is obtained. In P*, conserved quantities emerge as group-theoretical block systems over S. Block systems are also causets, and iteration leads to a network of blocks. This is a new theory of Physics. PREDICTIONS. (1) Brain's dendritic trees must be optimally short. Cuntz (June 2012) observed a 2/3 optimally short power law. (2) Causal hierarchies. Fuster(2005) observes identical hierarchies in cortex. DNA (Sept 2012) is described as hierarchical networks. (3) Action functional. Lerner (Aug 2012) proposed an action functional and minimum entropy on trajectories of dynamical processes. Friston (2003) proposed an energy functional. (4) Simple computer-brain experiments (Pissanetzky 2011a). REFERENCES: www.SciControls.com.

  2. Hunter syndrome in an 11-year old girl on enzyme replacement therapy with idursulfase: brain magnetic resonance imaging features and evolution.

    Science.gov (United States)

    Manara, Renzo; Rampazzo, Angelica; Cananzi, Mara; Salviati, Leonardo; Mardari, Rodica; Drigo, Paola; Tomanin, Rosella; Gasparotto, Nicoletta; Priante, Elena; Scarpa, Maurizio

    2010-12-01

    Mucopolysaccharidosis type II (MPS-II, Hunter disease) is a X-linked recessive disorder. Affected females are extremely rare, mostly due to skewed X chromosome inactivation. A few papers outline MPS-II brain magnetic resonance imaging (MRI) "gestalt" in males, but neuroradiological reports on females are still lacking. We present an 11-year-old girl affected by the severe form of MPS-II who was followed up over a time span of 8 years, focusing on clinical and brain MRI evolution. In the last 2.5 years, the patient has been treated with enzyme replacement therapy (ERT) with idursulfase (Elaprase™, Shire Human Genetic Therapies AB, Sweden). On brain and cervical MRI examination, abnormalities in our patient did not differ from those detected in male patients: J-shaped pituitary sella, enlargement of perivascular spaces, brain atrophy, mild T2-hyperintensity in the paratrigonal white matter, diffuse platyspondylia, and mild odontoid dysplasia with odontoid cup. Brain atrophy progressed despite ERT introduction, whereas perivascular space enlargement did not change significantly before and after ERT. Cognitive impairment worsened independently from the course of white matter abnormality. Despite a profound knowledge of genetic and biochemical aspects in MPS-II, neuroradiology is still poorly characterized, especially in female patients. Spinal and brain involvement and its natural course and evolution after ERT introduction still need to be clarified.

  3. Somatic deletions implicated in functional diversity of brain cells of individuals with schizophrenia and unaffected controls.

    Science.gov (United States)

    Kim, Junho; Shin, Jong-Yeon; Kim, Jong-Il; Seo, Jeong-Sun; Webster, Maree J; Lee, Doheon; Kim, Sanghyeon

    2014-01-22

    While somatic DNA copy number variations (CNVs) have been identified in multiple tissues from normal people, they have not been well studied in brain tissues from individuals with psychiatric disorders. With ultrahigh depth sequencing data, we developed an integrated pipeline for calling somatic deletions using data from multiple tissues of the same individual or a single tissue type taken from multiple individuals. Using the pipelines, we identified 106 somatic deletions in DNA from prefrontal cortex (PFC) and/or cerebellum of two normal controls subjects and/or three individuals with schizophrenia. We then validated somatic deletions in 18 genic and in 1 intergenic region. Somatic deletions in BOD1 and CBX3 were reconfirmed using DNA isolated from non-pyramidal neurons and from cells in white matter using laser capture microdissection (LCM). Our results suggest that somatic deletions may affect metabolic processes and brain development in a region specific manner.

  4. How does transcranial magnetic stimulation modify neuronal activity in the brain? Implications for studies of cognition

    DEFF Research Database (Denmark)

    Siebner, Hartwig R; Hartwigsen, Gesa; Kassuba, Tanja

    2009-01-01

    Transcranial magnetic stimulation (TMS) uses a magnetic field to "carry" a short lasting electrical current pulse into the brain where it stimulates neurones, particularly in superficial regions of cerebral cortex. TMS can interfere with cognitive functions in two ways. A high intensity TMS pulse...... in the human brain. This transient neurodisruption has been termed a "virtual lesion". Smaller intensities of stimulation produce less activity; in such cases, cognitive operations can probably continue but are disrupted because of the added noisy input from the TMS pulse. It is usually argued that if a TMS...... causes a synchronised high frequency burst of discharge in a relatively large population of neurones that is terminated by a long lasting GABAergic inhibition. The combination of artificial synchronisation of activity followed by depression effectively disrupts perceptual, motor and cognitive processes...

  5. Limbic, associative, and motor territories within the targets for deep brain stimulation: potential clinical implications.

    Science.gov (United States)

    Sudhyadhom, Atchar; Bova, Frank J; Foote, Kelly D; Rosado, Christian A; Kirsch-Darrow, Lindsey; Okun, Michael S

    2007-07-01

    The use of deep brain stimulation (DBS) has recently been expanding for the treatment of many neurologic disorders such as Parkinson disease, dystonia, essential tremor, Tourette's syndrome, cluster headache, epilepsy, depression, and obsessive compulsive disorder. The target structures for DBS include specific segregated territories within limbic, associative, or motor regions of very small subnuclei. In this review, we summarize current clinical techniques for DBS, the cognitive/mood/motor outcomes, and the relevant neuroanatomy with respect to functional territories within specific brain targets. Future development of new techniques and technology that may include a more direct visualization of "motor" territories within target structures may prove useful for avoiding side effects that may result from stimulation of associative and limbic regions. Alternatively, newer procedures may choose and specifically target non-motor territories for chronic electrical stimulation.

  6. Role of brain-derived neurotrophic factor in the aetiology of depression: implications for pharmacological treatment.

    Science.gov (United States)

    Castrén, Eero; Rantamäki, Tomi

    2010-01-01

    Brain-derived neurotrophic factor (BDNF) is a critical mediator of activity-dependent neuronal plasticity in the cerebral cortex. Deficits in neurotrophic factors have been proposed to underlie mood disorders. However, recent evidence suggests that mood disorders may be produced by abnormalities in the adaptation of neural networks to environmental conditions. Antidepressants may act by enhancing neuronal plasticity, which allows environmental inputs to modify the neuronal networks to better fine tune the individual to the outside world. Recent observations in the visual cortex directly support this idea. According to the network hypothesis of depression, changes in the levels of neurotrophins including BDNF may not directly produce depression or an antidepressant effect, but neurotrophins may act as critical tools in the process whereby environmental conditions guide neuronal networks to better adapt to the environment. This hypothesis suggests that antidepressant drugs should not be used alone but should always be combined with rehabilitation to guide the plastic networks within the brain.

  7. Exercise and brain health--implications for multiple sclerosis: Part 1--neuronal growth factors.

    Science.gov (United States)

    White, Lesley J; Castellano, Vanessa

    2008-01-01

    The benefits of regular exercise to promote general health and reduce the risk of hypokinetic diseases associated with sedentary lifestyles are well recognized. Recent studies suggest that exercise may enhance neurobiological processes that promote brain health in aging and disease. A current frontier in the neurodegenerative disorder multiple sclerosis (MS) concerns the role of physical activity for promoting brain health through protective, regenerative and adaptive neural processes. Research on neuromodulation, raises the possibility that regular physical activity may mediate favourable changes in disease factors and symptoms associated with MS, in part through changes in neuroactive proteins. Insulin-like growth factor-I appears to act as a neuroprotective agent and studies indicate that exercise could promote this factor in MS. Neurotrophins, brain-derived neurotrophic factor (BDNF) and nerve growth factor likely play roles in neuronal survival and activity-dependent plasticity. Physical activity has also been shown to up-regulate hippocampal BDNF, which may play a role in mood states, learning and memory to lessen the decline in cognitive function associated with MS. In addition, exercise may promote anti-oxidant defences and neurotrophic support that could attenuate CNS vulnerability to neuronal degeneration. Exercise exposure (preconditioning) may serve as a mechanism to enhance stress resistance and thereby may support neuronal survival under heightened stress conditions. Considering that axonal loss and cerebral atrophy occur early in the disease, exercise prescription in the acute stage could promote neuroprotection, neuroregeneration and neuroplasticity and reduce long-term disability. This review concludes with a proposed conceptual model to connect these promising links between exercise and brain health.

  8. Effects of early life adverse experiences on brain activity: Implications from maternal separation models in rodents

    Directory of Open Access Journals (Sweden)

    Mayumi eNishi

    2014-06-01

    Full Text Available During postnatal development, adverse early life experiences can affect the formation of neuronal circuits and exert long-lasting influences on neural function. Many studies have shown that daily repeated MS, an animal model of early life stress, can modulate the hypothalamic-pituitary-adrenal axis (HPA axis and can affect subsequent brain function and emotional behavior during adulthood. However, the molecular basis of the long-lasting effects of early life stress on brain function has not been completely elucidated. In this review, we introduce various cases of MS in rodents and illustrate the alterations in HPA axis activity by focusing on corticosterone (CORT, an end product of the HPA axis in rodents. We then present a characterization of the brain regions affected by various patterns of MS, including repeated MS and single time MS at various stages before weaning, by investigating c-Fos expression, a biological marker of neuronal activity. These CORT and c-Fos studies suggest that repeated early life stress may affect neuronal function in region- and temporal-specific manners, indicating a critical period for habituation to early life stress. Next, we discuss how early life stress can impact behavior, namely by inducing depression, anxiety or eating disorders. Furthermore, alterations in gene expression in adult mice exposed to MS, especially epigenetic changes of DNA methylation, are discussed.

  9. Foxp2 regulates gene networks implicated in neurite outgrowth in the developing brain.

    Directory of Open Access Journals (Sweden)

    Sonja C Vernes

    2011-07-01

    Full Text Available Forkhead-box protein P2 is a transcription factor that has been associated with intriguing aspects of cognitive function in humans, non-human mammals, and song-learning birds. Heterozygous mutations of the human FOXP2 gene cause a monogenic speech and language disorder. Reduced functional dosage of the mouse version (Foxp2 causes deficient cortico-striatal synaptic plasticity and impairs motor-skill learning. Moreover, the songbird orthologue appears critically important for vocal learning. Across diverse vertebrate species, this well-conserved transcription factor is highly expressed in the developing and adult central nervous system. Very little is known about the mechanisms regulated by Foxp2 during brain development. We used an integrated functional genomics strategy to robustly define Foxp2-dependent pathways, both direct and indirect targets, in the embryonic brain. Specifically, we performed genome-wide in vivo ChIP-chip screens for Foxp2-binding and thereby identified a set of 264 high-confidence neural targets under strict, empirically derived significance thresholds. The findings, coupled to expression profiling and in situ hybridization of brain tissue from wild-type and mutant mouse embryos, strongly highlighted gene networks linked to neurite development. We followed up our genomics data with functional experiments, showing that Foxp2 impacts on neurite outgrowth in primary neurons and in neuronal cell models. Our data indicate that Foxp2 modulates neuronal network formation, by directly and indirectly regulating mRNAs involved in the development and plasticity of neuronal connections.

  10. Radiation-induced blood-brain barrier changes: pathophysiological mechanisms and clinical implications.

    Science.gov (United States)

    d'Avella, D; Cicciarello, R; Angileri, F F; Lucerna, S; La Torre, D; Tomasello, F

    1998-01-01

    The pathophysiology of whole-brain radiation (WBR) toxicity remains incompletely understood. The possibility of a primary change in blood-brain barrier (BBB) associated with microvascular damage was investigated. Rats were exposed to conventional fractionation in radiation (200 +/- cGy/d, 5d/wk; total dose, 4,000 cGy). BBB changes were assessed by means of the quantitative 14C-alpha-aminoisobutyric acid (AIB) technique coupled with standard electron microscopy (EM) and morphometric techniques as well as studies of the transcapillary passage of horseradish peroxidase (HRP). At 15 days after WBR, AIB transport across BBB increased significantly in cerebral cortex. EM disclosed vesicular transport of HRP across the intact endothelium without opening of the tight junctions. Ninety days after WBR, well-defined alterations of the microvasculature were observed. The main feature of cortical microvessels was their collapsed aspect, associated with perivascular edema containing cell debris. Data suggest a possible association between damage of the microvascular/glial unit of tissue injury and development of radiation-induced brain cerebral dysfunction. We hypothesize the following sequence of pathophysiological events: WBR causes an early increase in BBB permeability, which produces perivascular edema and microvascular collapse. The interference with microcirculation affects blood flow and energy supply to the tissue, resulting in structural damage on an ischemic/dysmetabolic basis.

  11. The role of microglia in brain maintenance: implications for Rett syndrome.

    Science.gov (United States)

    Derecki, Noël C; Cronk, James C; Kipnis, Jonathan

    2013-03-01

    The role of microglia in central nervous system (CNS) pathology has been studied extensively, and more recently, examination of microglia in the healthy brain has yielded important insights into their many functions. It was long assumed that microglia were essentially quiescent cells, unless provoked into activation, which was considered a hallmark of disease. More recently, however, it has become increasingly clear that they are extraordinarily dynamic cells, constantly sampling their environment and adjusting to exquisitely delicate stimuli. Along these lines, our laboratory has identified a new and unexpected role for microglial phagocytosis - or lack thereof - in the pathophysiology of Rett syndrome, a neurodevelopmental disease caused by mutation of the gene encoding methyl-CpG binding protein (MECP)2. We have shown that specific expression of wild type Mecp2 in myeloid cells of Mecp2-null mice is sufficient to arrest major symptoms associated with this devastating disease. This beneficial effect, however, is abolished if phagocytic activity of microglia is inhibited. Here, we discuss microglial origins, the role of microglia in brain development and maintenance, and the phenomenon of microglial augmentation by myeloid progenitor cells in the adult brain. Finally, we address in some detail the beneficial roles of microglia as clinical targets in Rett syndrome and other neurological disorders.

  12. Morphine induces expression of platelet-derived growth factor in human brain microvascular endothelial cells: implication for vascular permeability.

    Directory of Open Access Journals (Sweden)

    Hongxiu Wen

    Full Text Available Despite the advent of antiretroviral therapy, complications of HIV-1 infection with concurrent drug abuse are an emerging problem. Morphine, often abused by HIV-infected patients, is known to accelerate neuroinflammation associated with HIV-1 infection. Detailed molecular mechanisms of morphine action however, remain poorly understood. Platelet-derived growth factor (PDGF has been implicated in a number of pathological conditions, primarily due to its potent mitogenic and permeability effects. Whether morphine exposure results in enhanced vascular permeability in brain endothelial cells, likely via induction of PDGF, remains to be established. In the present study, we demonstrated morphine-mediated induction of PDGF-BB in human brain microvascular endothelial cells, an effect that was abrogated by the opioid receptor antagonist-naltrexone. Pharmacological blockade (cell signaling and loss-of-function (Egr-1 approaches demonstrated the role of mitogen-activated protein kinases (MAPKs, PI3K/Akt and the downstream transcription factor Egr-1 respectively, in morphine-mediated induction of PDGF-BB. Functional significance of increased PDGF-BB manifested as increased breach of the endothelial barrier as evidenced by decreased expression of the tight junction protein ZO-1 in an in vitro model system. Understanding the regulation of PDGF expression may provide insights into the development of potential therapeutic targets for intervention of morphine-mediated neuroinflammation.

  13. Molecular characterization and developmental expression pattern of the chicken apolipoprotein D gene: implications for the evolution of vertebrate lipocalins.

    Science.gov (United States)

    Ganfornina, María D; Sánchez, Diego; Pagano, Aldo; Tonachini, Laura; Descalzi-Cancedda, Fiorella; Martínez, Salvador

    2005-01-01

    The insect Lazarillo and the mammalian apolipoprotein D (ApoD) are orthologous members of the lipocalin protein family. We report the cloning and embryonic expression of chicken ApoD, the first molecularly characterized nonmammalian ApoD. We also report the ApoD expression in mouse during postnatal development and some novel aspects of the expression of the paralogous lipocalin prostaglandin D-synthase (PGDS) and discuss these results in view of the lipocalin family evolution in vertebrates. ApoD is expressed in subsets of central nervous system (CNS) neurons and glia during late chicken embryogenesis. Contrary to mouse ApoD, no expression appears in neural crest-derived cephalic mesenchyme and blood vessel pericytes. Also, ApoD is expressed in developing chicken feathers. These expressions are corroborated by quantitative reverse transcriptase-polymerase chain reaction profiles. ApoD is expressed during mouse postnatal development in a subset of CNS neurons, astrocytes and oligodendrocytes, but also in meninges and pericytes. Chicken PGDS is expressed in brain meninges and perivascular cells. Our results suggest that the amniote last common ancestor expressed ApoD and PGDS in the brain during embryogenesis. ApoD appears restricted to ectodermal derivatives, whereas PGDS is expressed by derivatives of the three germ layers.

  14. The Pricing Evolution in the Air Transportation Industry. Implication for the Romanian Tourism Sector in the Era of Globalization

    Directory of Open Access Journals (Sweden)

    Andreea Marin-Pantelescu

    2016-06-01

    Full Text Available The globalization process involves the liberalization of the services and the air transportation industry is responsive to this reality. There is a developing tendency for global alliances and strategies in major airline companies. The globalization implies extending service networks in the whole world. Currently we are witnessing lower prices for domestic and foreign airline flights with benefits for the tourists’ business and leisure activities. The last minute offers and early booking prices provide a win-win situation, for the airline companies on one side and for the customers on the other side. The positive online reviews influence people buying decision because customers are more sensitive than ever to the services prices. Under this condition it is very interesting to see the evolution of pricing in the air transportation industry and the implication for the Romanian tourism sector.

  15. On the space and time evolution of regular or irregular human heart or brain signals

    CERN Document Server

    Tuncay, Caglar

    2011-01-01

    A coupled map is suggested to investigate various spatial or temporal designs in biology: Several cells (or tissues) in an organ are considered as connected to each other in terms of some molecular diffusions or electrical potential differences and so on. The biological systems (groups of cells) start from various initial conditions for spatial designs (or initial signals for temporal designs) and they evolve in time in terms of the mentioned interactions (connections) besides some individual feedings. The basic aim of the present contribution is to mimic various empirical data for the heart (in normal, quasi-stable, unstable and post operative physiological conditions) or brain (regular or irregular; for epilepsy) signals. The mentioned empirical data are borrowed from various literatures which are cited. The suggested model (to be used besides or instead of the artificial network models) involves simple mathematics and the related software is easy. The results may be considered as in good agreement with the...

  16. Evolution of growth hormone neurosecretory disturbance after cranial irradiation for childhood brain tumours: a prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Spoudeas, H.A.; Hindmarsh, P.C.; Brook, C.G.D. [Middlesex Hospital, London (United Kingdom); Matthews, D.R. [Radcliffe Infirmary, Oxford (United Kingdom)

    1996-08-01

    To determine the aetiopathology of post-irradiation growth hormone (GH) deficiency, we performed a mixed longitudinal analysis of 56 24 h serum GH concentration profiles and 45 paired insulin-induced hypoglycaemia tests (ITT) in 35 prepubertal children, aged 1.5-11.8 years, with brain tumours in the posterior foss (n = 25) or cerebral hemispheres (n 10). Assessments were made before (n = 16), 1 year (n = 25) and 2 to 5 years (n = 15) after a cranial irradiation (DXR) dose of at least 30 Gy. Fourier transforms, occupancy percentage, first-order derivatives (FOD) and mean concentrations were determined from the GH profiles taken after neurosurgery but before radiotherapy (n = 16) and in three treatment groups: Group 1: neurosurgery only without DXR (9n 9); Group 2: {>=} 30 Gy DXR only (n = 22); Group 3: {>=} 30 Gy DXR with additional chemotherapy (n = 9). Results were compared with those from 26 short normally growing (SN) children. (author).

  17. Estrogenic modulation of brain activity:implications for schizophreniaand Parkinson's disease

    OpenAIRE

    Cyr, Michel; Calon, Frederic; Morissette, Marc; Di Paolo, Thérèse

    2002-01-01

    Evidence suggests the estrogens may play a role in various mental and neurodegenerative diseases. We review the evidence implicating estradiol in schizophrenia and Parkinson's disease. Epidemiologic and clinical studies on the effects of estrogens in schizophrenia are surveyed, and animal studies and in vitro models of the modulatory effects of estrogens on neurotransmitters associated with schizophrenia (i.e., dopamine, serotonin, glutamate) are reviewed. Epidemiologic and clinical data sugg...

  18. A theory of marks and mind: the effect of notational systems on hominid brain evolution and child development with an emphasis on exchanges between mothers and children.

    Science.gov (United States)

    Sheridan, Susan Rich

    2005-01-01

    A model of human language requires a theory of meaningful marks. Humans are the only species who use marks to think. A theory of marks identifies children's scribbles as significant behavior, while hypothesizing the importance of rotational systems to hominid brain evolution. By recognizing the importance of children's scribbles and drawings in developmental terms as well as in evolutionary terms, a marks-based rather than a predominantly speech-based theory of the human brain, language, and consciousness emerges. Combined research in anthropology, primatology, art history, neurology, child development (including research with deaf and blind children), gender studies and literacy suggests the importance of notational systems to human language, revealing the importance of mother/child interactions around marks and sounds to the development of an expressive, communicative, symbolic human brain. An understanding of human language is enriched by identifying marks carved on bone 1.9 million years ago as observational lunar calendar-keeping, pushing proto-literacy back dramatically. Neurologically, children recapitulate the meaningful marks of early hominins when they scribble and draw, reminding us that literacy belongs to humankind's earliest history. Even more than speech, such meaningful marks played - and continue to play - decisive roles in human brain evolution. The hominid brain required a model for integrative, transformative neural transfer. The research strongly suggests that humankind's multiple literacies (art, literature, scientific writing, mathematics and music) depended upon dyadic exchanges between hominid mothers and children, and that this exchange and sharing of visuo-spatial information drove the elaboration of human speech in terms of syntax, grammar and vocabulary. The human brain was spatial before it was linguistic. The child scribbles and draws before it speaks or writes. Children babble and scribble within the first two years of life. Hands

  19. Variation in anthropoid vertebral formulae: implications for homology and homoplasy in hominoid evolution.

    Science.gov (United States)

    Williams, Scott A

    2012-03-01

    Variation in vertebral formulae within and among hominoid species has complicated our understanding of hominoid vertebral evolution. Here, variation is quantified using diversity and similarity indices derived from population genetics. These indices allow for testing models of hominoid vertebral evolution that call for disparate amounts of homoplasy, and by inference, different patterns of evolution. Results are interpreted in light of "short-backed" (J Exp Zool (Mol Dev Evol) 302B:241-267) and "long-backed" (J Exp Zool (Mol Dev Evol) 314B:123-134) ancestries proposed in different models of hominin vertebral evolution. Under the long-back model, we should expect reduced variation in vertebral formulae associated with adaptively driven homoplasy (independently and repeatedly reduced lumbar regions) and the relatively strong directional selection presumably associated with it, especially in closely related taxa that diverged relatively recently (e.g., Pan troglodytes and Pan paniscus). Instead, high amounts of intraspecific variation are observed among all hominoids except humans and eastern gorillas, taxa that have likely experienced strong stabilizing selection on vertebral formulae associated with locomotor and habitat specializations. Furthermore, analyses of interspecific similarity support an evolutionary scenario in which the vertebral formulae observed in western gorillas and chimpanzees represent a reasonable approximation of the ancestral condition for great apes and humans, from which eastern gorillas, humans, and bonobos derived their unique vertebral profiles. Therefore, these results support the short-back model and are compatible with a scenario of homology of reduced lumbar regions in hominoid primates. Fossil hominin vertebral columns are discussed and shown to support, rather than contradict, the short-back model.

  20. Evolution in nuclear strategy in US and Russia and its implications in arms control

    Energy Technology Data Exchange (ETDEWEB)

    Sokov, N

    2003-07-01

    Today, there is a growing tendency in war-fighting scenarios to include limited use of nuclear weapons. New developments in nuclear policy could be attributed to changes in the international situation like the multiplication of low level conflicts and the threat of terrorism. This paper analyzes the evolution of the Russian nuclear doctrine, the transformation of the US nuclear policy and their consequences on arms control. (J.S.)

  1. Evolution of NMDA receptor cytoplasmic interaction domains: implications for organisation of synaptic signalling complexes

    Directory of Open Access Journals (Sweden)

    Emes Richard D

    2008-01-01

    Full Text Available Abstract Background Glutamate gated postsynaptic receptors in the central nervous system (CNS are essential for environmentally stimulated behaviours including learning and memory in both invertebrates and vertebrates. Though their genetics, biochemistry, physiology, and role in behaviour have been intensely studied in vitro and in vivo, their molecular evolution and structural aspects remain poorly understood. To understand how these receptors have evolved different physiological requirements we have investigated the molecular evolution of glutamate gated receptors and ion channels, in particular the N-methyl-D-aspartate (NMDA receptor, which is essential for higher cognitive function. Studies of rodent NMDA receptors show that the C-terminal intracellular domain forms a signalling complex with enzymes and scaffold proteins, which is important for neuronal and behavioural plasticity Results The vertebrate NMDA receptor was found to have subunits with C-terminal domains up to 500 amino acids longer than invertebrates. This extension was specific to the NR2 subunit and occurred before the duplication and subsequent divergence of NR2 in the vertebrate lineage. The shorter invertebrate C-terminus lacked vertebrate protein interaction motifs involved with forming a signaling complex although the terminal PDZ interaction domain was conserved. The vertebrate NR2 C-terminal domain was predicted to be intrinsically disordered but with a conserved secondary structure. Conclusion We highlight an evolutionary adaptation specific to vertebrate NMDA receptor NR2 subunits. Using in silico methods we find that evolution has shaped the NMDA receptor C-terminus into an unstructured but modular intracellular domain that parallels the expansion in complexity of an NMDA receptor signalling complex in the vertebrate lineage. We propose the NR2 C-terminus has evolved to be a natively unstructured yet flexible hub organising postsynaptic signalling. The evolution of

  2. Mesozoic evolution of the Valencia trough: Implications for the understanding of the Western Mediterranean

    Science.gov (United States)

    Etheve, Nathalie; Frizon de Lamotte, Dominique; Mohn, Geoffroy; Roca, Eduard; Gorini, Christian; Blanpied, Christian

    2014-05-01

    The Western Mediterranean records a multi-stage tectonic evolution characterized by a complex succession of rifting to compressive episodes during the Cenozoic. The Valencia through was formed in this geodynamic framework and is classically interpreted as an aborted Tertiary rift related to back-arc extension. Notably, the Tertiary rifting is superimposed to the Jurassic opening of the Tethys basin, the early Cretaceous opening of the Bay of Biscay-Pyrenees basins and the late Cretaceous-early Tertiary inversion of these basins (e.g. Iberian range, Catalan Coastal range). Since the last twenty years, many studies contributed to the understanding of the Tertiary history of this area, whereas the pre-Tertiary evolution of the Valencia trough remains poorly investigated. Therefore, we initiated a research project in the Valencia trough benefiting from the acquisition of high quality seismic surveys allowing a better imaging of the Mesozoic sequences. This PhD project aims to understand the mechanisms and the role of structural inheritance that controlled the evolution of the Valencia trough and its impact on the sedimentary infilling since the Mesozoic. The relation between the sedimentary infilling, subsidence and crustal thinning mechanisms during the Cenozoic are investigated aiming to unravel critical information on rifting processes. This study will be based on correlations between onshore and offshore observations. Structural and stratigraphic evolution will be defined on land and compared with seismic sections and well data at sea. Eventually, these data will enable us to propose coherent land-sea interpretations of the area, providing a better understanding of the tectono-stratigraphic context. Our poster show preliminary results obtained from fieldwork on the western margin of the Valencia trough coupled with seismic interpretations. Eventually, results of this study may lead to better constrain the kinematic reconstruction of the western Mediterranean

  3. Contemporary stellar evolution codes: physics under the bonnet and implications for asteroseismology

    Science.gov (United States)

    Stancliffe, Richard James

    2015-08-01

    Just how good are modern stellar models? Providing a rigorous assessment of the uncertainties is difficult because of the multiplicity of input physics. Some of the ingredients are reasonably well-known (like reaction rates and opacities). Others are not so good, with convection standing out as a particularly obvious example. In some cases, it is not clear what the ingredients should be -- what role do atomic diffusion, rotation, magnetic fields, etc. play in stellar evolution? All this is then compounded by computational method. In converting all this physics into something we can implement in a 1D evolution code, we are forced to make choices about the way the equations are solved, how we will treat mixing at convective boundaries, etc. All of this can impact the models one finally generates.In this review, I will attempt to assess the uncertainties associated with the ingredients and methods used by stellar evolution modellers, and what their impacts may be on the science that we wish to do.

  4. Neogene marine isotopic evolution and the erosion of Lesser Himalayan strata: Implications for Cenozoic tectonic history

    Science.gov (United States)

    Myrow, Paul M.; Hughes, Nigel C.; Derry, Louis A.; Ryan McKenzie, N.; Jiang, Ganqing; Webb, A. Alexander G.; Banerjee, Dhiraj M.; Paulsen, Timothy S.; Singh, Birendra P.

    2015-05-01

    An extensive, northward deepening blanket of Neoproterozoic and Cambrian sedimentary rocks once extended from the Himalayan margin far onto the Indian craton. Cambrian deposits of this "upper Lesser Himalayan" succession, which include deposits of the "outer" Lesser Himalaya tectonic unit, are enriched in radiogenic 187Os. They make up part of a proximal marine facies belt that extends onto the craton and along strike from India to Pakistan. By contrast, age-equivalent facies in the Tethyan Himalaya are more distal in nature. Neoproterozoic to Cambrian strata of the upper Lesser Himalayan succession are now missing in much of the Lesser Himalaya, with their erosion exposing older Precambrian Lesser Himalayan strata. We suggest that exhumation and weathering of the upper Lesser Himalaya and related strata caused dramatic changes in the 187Os/188Os and 87Sr/86Sr Neogene record of seawater starting at ∼ 16 Ma. First-order estimates for the volume of upper Himalayan strata, as well as the volume of all LH rock eroded since this time, and geochemical box modeling, support this idea. Exhumation at 16 Ma is a fundamental event in the evolution of the Himalayan orogeny and the geochemical evolution of the oceans, and will be a critical part of the construction of future models of Himalayan thrust belt evolution.

  5. Transverse zones controlling the structural evolution of the Zipaquira Anticline (Eastern Cordillera, Colombia): Regional implications

    Science.gov (United States)

    García, Helbert; Jiménez, Giovanny

    2016-08-01

    We report paleomagnetic, magnetic fabric and structural results from 21 sites collected in Cretaceous marine mudstones and Paleogene continental sandstones from the limbs, hinge and transverse zones of the Zipaquira Anticline (ZA). The ZA is an asymmetrical fold with one limb completely overturned by processes like gravity and salt tectonics, and marked by several axis curvatures. The ZA is controlled by at least two (2) transverse zones known as the Neusa and Zipaquira Transverse Zones (NTZ and ZTZ, respectively). Magnetic mineralogy methods were applied at different sites and the main carriers of the magnetic properties are paramagnetic components with some sites being controlled by hematite and magnetite. Magnetic fabric analysis shows rigid-body rotation for the back-limb in the ZA, while the forelimb is subjected to internal deformation. Structural and paleomagnetic data shows the influence of the NTZ and ZTZ in the evolution of the different structures like the ZA and the Zipaquira, Carupa, Rio Guandoque, Las Margaritas and Neusa faults, controlling several factors as vergence, extension, fold axis curvature and stratigraphic detatchment. Clockwise rotations unraveled a block segmentation following a discontinuos model caused by transverse zones and one site reported a counter clockwise rotation associated with a left-lateral strike slip component for transverse faults (e.g. the Neusa Fault). We propose that diverse transverse zones have been active since Paleogene times, playing an important role in the tectonic evolution of the Cundinamarca sub-basin and controlling the structural evolution of folds and faults with block segmentation and rotations.

  6. VLT\\/UVES Abundances in Four Nearby Dwarf Spheroidal Galaxies II. Implications for Understanding Galaxy Evolution

    CERN Document Server

    Tolstoy, E; Shetrone, M; Primas, F; Hill, V; Szeifert, A K T; Tolstoy, Eline

    2003-01-01

    We have used UVES on VLT-UT2 to take spectra of 15 individual red giant stars in the centers of four nearby dwarf spheroidal galaxies: Sculptor, Fornax, Carina and Leo I. We measure the abundance variations of numerous elements in these low mass stars with a range of ages (1-15Gyr old). This means that we can effectively measure the chemical evolution of these galaxies WITH TIME. Our results show a significant spread in metallicity with age, but an overall trend consistent with what might be expected from a closed (or perhaps leaky) box chemical evolution scenario over the last 10-15Gyr. We notice that each of these galaxies show broadly similar abundance patterns for all elements measured. This suggests a fairly uniform progression of chemical evolution with time, despite quite a large range of star formation histories. It seems likely that these galaxies had similar initial conditions, and evolve in a similar manner with star formation occurring at a uniformly low rate, even if at different times. With our ...

  7. Implications of the evolution pattern of human T-cell leukemia retroviruses on their pathogenic virulence (Review).

    Science.gov (United States)

    Azran, Inbal; Schavinsky-Khrapunsky, Yana; Priel, Esther; Huleihel, Mahmoud; Aboud, Mordechai

    2004-11-01

    Simian retroviruses pose a serious threat to public health, as two human pathogenic retroviruses, HIV and HTLV, have been already proved to originate from such non-human viruses. Therefore, studying their natural prevalence among wild non-human primates is important for planning strategies to prevent the emergence of additional human retroviral pathogens. This article is focused on tracing the origin and evolution of the human T-cell leukemia viruses HTLV-I and HTLV-II in comparison to that of the simian lymphotropic viruses STLV-I, STLV-II and STLV-L, which are phylo-genically classified into a common group called primate T-lymphotropic viruses (PTLV). Thus, HTLV-I and STLV-I are referred to as PTLV-I and HTLV-II and STLV-II as PTLV-II, whereas STLV-L, which is highly divergent from both HTLV types, comprises a third subgroup called PTLV-L. The phylogeny of PTLV indicates that both, HTLV-I and HTLV-II emerged from a simian origin, but their subsequent evolution continued in different patterns. HTLV-I includes 6 subtypes which evolved from STLV-I through several times of different geographic interspecies transmission between simian and human hosts. These repeated invasions to new primate species are likely to give rise to viral strains with increasing pathogenic potential. On the other hand, HTLV-II includes 4 subtypes which appear to originate from a common human ancestor virus that emerged from only one simian to human transmission, whereas the subsequent evolution of HTLV-II and STLV-II strains continued separately only within the Homo sapiens and Pan paniscus species respectively, without repeated interspecies jumps. Such evolution pattern likely involves less genetic changes and selection of viral strains with low pathogenic virulence that could co-exist with their hosts for long time. These different evolution patterns can explain the much wider implication of HTLV-I with human clinical disorders than HTLV-II. Of note, however, more recently HTLV-II started

  8. Timing of developmental sequences in different brain structures: physiological and pathological implications.

    Science.gov (United States)

    Dehorter, N; Vinay, L; Hammond, C; Ben-Ari, Y

    2012-06-01

    The developing brain is not a small adult brain. Voltage- and transmitter-gated currents, like network-driven patterns, follow a developmental sequence. Studies initially performed in cortical structures and subsequently in subcortical structures have unravelled a developmental sequence of events in which intrinsic voltage-gated calcium currents are followed by nonsynaptic calcium plateaux and synapse-driven giant depolarising potentials, orchestrated by depolarizing actions of GABA and long-lasting NMDA receptor-mediated currents. The function of these early patterns is to enable heterogeneous neurons to fire and wire together rather than to code specific modalities. However, at some stage, behaviourally relevant activities must replace these immature patterns, implying the presence of programmed stop signals. Here, we show that the developing striatum follows a developmental sequence in which immature patterns are silenced precisely when the pup starts locomotion. This is mediated by a loss of the long-lasting NMDA-NR2C/D receptor-mediated current and the expression of a voltage-gated K(+) current. At the same time, the descending inputs to the spinal cord become fully functional, accompanying a GABA/glycine polarity shift and ending the expression of developmental patterns. Therefore, although the timetable of development differs in different brain structures, the g sequence is quite similar, relying first on nonsynaptic events and then on synaptic oscillations that entrain large neuronal populations. In keeping with the 'neuroarcheology' theory, genetic mutations or environmental insults that perturb these developmental sequences constitute early signatures of developmental disorders. Birth dating developmental disorders thus provides important indicators of the event that triggers the pathological cascade leading ultimately to disease.

  9. The evolution and utility of ribosomal ITS sequences in Bambusinae and related species: divergence, pseudogenes, and implications for phylogeny

    Indian Academy of Sciences (India)

    Xui-Xing Song; Xu-Ping Gao; Ming-Yan Jiang; Guang-Li Liu; Xiao-Fang Yu; Qi-Bing Chen

    2012-08-01

    Ribosomal internal transcribed spacer (ITS) sequences are commonly used for phylogenetic reconstruction because they are highly reiterated as components of rDNA repeats, and hence are often subject to rapid homogenization through concerted evolution. Concerted evolution leads to intragenomic uniformity of repeats even between loci on nonhomologous chromosomes. However, a number of studies have shown that the ITS polymorphism within individuals is quite common. The molecular systematics of Bambusinae and related species were recently assessed by different teams using independently generated ITS sequences, and the results disagreed in some remarkable features. Here we compared the ITS sequences of the members of Bambusa s. l., the genera Dendrocalamus, Dinochloa, Gigantochloa, Guadua, Melocalamus, Monocladus, Oxytenanthera, Thyrsostachys, Pleioblastus, Pseudosasa and Schizostachyum. We have reanalysed the ITS sequences used by different research teams to reveal the underlying patterns of their different results. After excluding the sequences suspected to represent paralogous loci, a phylogenetic analysis of the subtribe Bambusinae species were performed using maximum parsimony and maximum-likelihood methods. The implications of the findings are discussed. The risk of incorporating ITS paralogues in plant evolutionary studies that can distort the phylogenetic signal should caution molecular systematists.

  10. The RNA-world and co-evolution hypothesis and the origin of life: Implications, research strategies and perspectives

    Science.gov (United States)

    Lahav, Noam

    1993-01-01

    The applicability of the RNA-world and co-evolution hypothesis to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficultites. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activites of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypothesis under consideration. It is suggested that the novel directed molecular evolution technology, and molecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a `Primordial Darwinian entity'.

  11. Cholesterol homeostasis failure in the brain: implications for synaptic dysfunction and cognitive decline.

    Science.gov (United States)

    Segatto, Marco; Leboffe, Loris; Trapani, Laura; Pallottini, Valentina

    2014-01-01

    Cholesterol is one of the most important molecules in cell physiology because of its involvement in several biological processes: for instance, it determines both physical and biochemical properties of cell membranes and proteins. Disruption to cholesterol homeostasis leads to coronary heart disease, atherosclerosis and metabolic syndrome. Strong evidence suggests that cholesterol also has a crucial role in the brain as various neurological and neurodegenerative disorders, including Alzheimer's, Huntington's and Parkinson diseases are associated with disruptions to cholesterol homeostasis. Here, we summarize the current knowledge about the role cholesterol plays at synaptic junctions and the pathological consequences caused by disruptions in the homeostatic maintenance of this compound.

  12. Dissociative states in dreams and brain chaos: Implications for creative awareness

    Directory of Open Access Journals (Sweden)

    Petr eBob

    2015-09-01

    Full Text Available This article reviews recent findings indicating some common brain processes during dissociative states and dreaming with the aim to outline a perspective that neural chaotic states during dreaming can be closely related to dissociative states that may manifest in dreams scenery. These data are in agreement with various clinical findings that dissociated states can be projected into the dream scenery in REM sleep periods and dreams may represent their specific interactions that may uncover unusual psychological potential of creativity in psychotherapy, art and scientific discoveries.

  13. Brain imaging studies of the cocaine addict: Implications for reinforcement and addiction

    Energy Technology Data Exchange (ETDEWEB)

    Volkow, N.D.; Fowler, J.S. [Brookhaven National Lab., Upton, NY (United States)]|[SUNY, Stony Brook, Stony Brook, NY (United States). Dept. of Psychiatry

    1995-07-01

    These studies document dopaminergic abnormalities in cocaine abusers. They also suggest a regulatory role of Dopamine (DA) in frontal metabolism. The correlation of striatal D{sub 2} receptor availability with metabolism was strongest for orbital frontal cortex (OFC) cingulate and prefrontal cortices. In cocaine abusers tested during early withdrawal (<1 week) the OFC was found to be hypermetabolic and metabolism in OFC and prefrontal cortices were found to be significantly associated with cocaine craving . Thus, we postulate that repeated and intermittent DA stimulation, as seen during a cocaine binge, activates the prefrontal and OFC cortices increasing the drive to compulsively self-administer cocaine. During cocaine discontinuation and protracted withdrawal and with decreased DA stimulation, these frontal cortical regions become hyponietabolic. Dopaminergic stimulation by a DA-enhancing drug and/or environmental conditioning will reactivate these frontal regions resetting the compulsion to self-administer cocaine and the inability to terminate this behavior. The pharmacokionetic studies with [11C]cocaine are consistent with behavioral and pharmacological studies in animals as well as in vitro studies which have revealed that while the mechanisms for cocaine`s reinforcing properties are complex, they partly involve the brain`s dopamine system and also highlight the importance of cocaine`s pharmacokinetic on its unique reinforcing properties.

  14. Insulin-like growth factors in the brain and their potential clinical implications.

    Science.gov (United States)

    Benarroch, Eduardo E

    2012-11-20

    Insulin and insulin-like growth factors (IGFs) including IGF1 and IGF2 are members of the insulin-like peptide superfamily and have an important role in development, cell differentiation, plasticity, and survival of the nervous system. These insulin-like peptides act at several receptors that initiate downstream phosphorylation cascades that in turn regulate transcription, synaptic maturation, and apoptosis. In the adult brain, insulin and IGF1 act as circulating signals that reach the CNS by crossing the blood-brain barrier (BBB) or the blood-CSF barrier; IGF1 and IGF2 also act as paracrine signals released from all neural cells. The bioavailability of IGF1 and IGF2 is regulated by their binding to IGF binding proteins (IGFBPs). Insulin-like peptides participate in neuroprotection and may have an important role in the pathophysiology of several neurologic disorders and as potential therapeutic targets for these conditions. The insulin-like peptides, their receptors, effects in the nervous system, and potential clinical correlations have been the subject of several recent reviews.(1-6).

  15. Functional genomics of human brain development and implications for autism spectrum disorders.

    Science.gov (United States)

    Ziats, M N; Grosvenor, L P; Rennert, O M

    2015-10-27

    Transcription of the inherited DNA sequence into copies of messenger RNA is the most fundamental process by which the genome functions to guide development. Encoded sequence information, inherited epigenetic marks and environmental influences all converge at the level of mRNA gene expression to allow for cell-type-specific, tissue-specific, spatial and temporal patterns of expression. Thus, the transcriptome represents a complex interplay between inherited genomic structure, dynamic experiential demands and external signals. This property makes transcriptome studies uniquely positioned to provide insight into complex genetic-epigenetic-environmental processes such as human brain development, and disorders with non-Mendelian genetic etiologies such as autism spectrum disorders. In this review, we describe recent studies exploring the unique functional genomics profile of the human brain during neurodevelopment. We then highlight two emerging areas of research with great potential to increase our understanding of functional neurogenomics-non-coding RNA expression and gene interaction networks. Finally, we review previous functional genomics studies of autism spectrum disorder in this context, and discuss how investigations at the level of functional genomics are beginning to identify convergent molecular mechanisms underlying this genetically heterogeneous disorder.

  16. Brain mechanisms for predictive control by switching internal models: implications for higher-order cognitive functions.

    Science.gov (United States)

    Imamizu, Hiroshi; Kawato, Mitsuo

    2009-07-01

    Humans can guide their actions toward the realization of their intentions. Flexible, rapid and precise realization of intentions and goals relies on the brain learning to control its actions on external objects and to predict the consequences of this control. Neural mechanisms that mimic the input-output properties of our own body and other objects can be used to support prediction and control, and such mechanisms are called internal models. We first summarize functional neuroimaging, behavioral and computational studies of the brain mechanisms related to acquisition, modular organization, and the predictive switching of internal models mainly for tool use. These mechanisms support predictive control and flexible switching of intentional actions. We then review recent studies demonstrating that internal models are crucial for the execution of not only immediate actions but also higher-order cognitive functions, including optimization of behaviors toward long-term goals, social interactions based on prediction of others' actions and mental states, and language processing. These studies suggest that a concept of internal models can consistently explain the neural mechanisms and computational principles needed for fundamental sensorimotor functions as well as higher-order cognitive functions.

  17. Chondroitin Sulfate Proteoglycans: Structure-Function Relationship with Implication in Neural Development and Brain Disorders

    Directory of Open Access Journals (Sweden)

    Speranta Avram

    2014-01-01

    Full Text Available Chondroitin sulfate proteoglycans (CSPGs are extracellular matrix components that contain two structural parts with distinct functions: a protein core and glycosaminoglycan (GAG side chains. CSPGs are known to be involved in important cell processes like cell adhesion and growth, receptor binding, or cell migration. It is recognized that the presence of CSPGs is critical in neuronal growth mechanisms including axon guidance following injury of nervous system components such as spinal cord and brain. CSPGs are upregulated in the central nervous system after injury and participate in the inhibition of axon regeneration mainly through their GAG side chains. Recently, it was shown that some CSPGs members like aggrecan, versican, and neurocan were strongly involved in brain disorders like bipolar disorder (BD, schizophrenia, and ADHD. In this paper, we present the chemical structure-biological functions relationship of CSPGs, both in health state and in genetic disorders, addressing methods represented by genome-wide and crystallographic data as well as molecular modeling and quantitative structure-activity relationship.

  18. Principles and clinical implications of the brain-gut-enteric microbiota axis.

    Science.gov (United States)

    Rhee, Sang H; Pothoulakis, Charalabos; Mayer, Emeran A

    2009-05-01

    While bidirectional brain-gut interactions are well known mechanisms for the regulation of gut function in both healthy and diseased states, a role of the enteric flora--including both commensal and pathogenic organisms--in these interactions has only been recognized in the past few years. The brain can influence commensal organisms (enteric microbiota) indirectly, via changes in gastrointestinal motility and secretion, and intestinal permeability, or directly, via signaling molecules released into the gut lumen from cells in the lamina propria (enterochromaffin cells, neurons, immune cells). Communication from enteric microbiota to the host can occur via multiple mechanisms, including epithelial-cell, receptor-mediated signaling and, when intestinal permeability is increased, through direct stimulation of host cells in the lamina propria. Enterochromaffin cells are important bidirectional transducers that regulate communication between the gut lumen and the nervous system. Vagal, afferent innervation of enterochromaffin cells provides a direct pathway for enterochromaffin-cell signaling to neuronal circuits, which may have an important role in pain and immune-response modulation, control of background emotions and other homeostatic functions. Disruption of the bidirectional interactions between the enteric microbiota and the nervous system may be involved in the pathophysiology of acute and chronic gastrointestinal disease states, including functional and inflammatory bowel disorders.

  19. Spinal shock and brain death': somatic pathophysiological equivalence and implications for the integrative-unity rationale.

    Science.gov (United States)

    Shewmon, D A

    1999-05-01

    The somatic pathophysiology of high spinal cord injury (SCI) not only is of interest in itself but also sheds light on one of the several rationales proposed for equating 'brain death' (BD) with death, namely that the brain confers integrative unity upon the body, which would otherwise constitute a mere conglomeration of cells and tissues. Insofar as the neuropathology of BD includes infarction down to the foramen magnum, the somatic pathophysiology of BD should resemble that of cervico-medullary junction transection plus vagotomy. The endocrinologic aspects can be made comparable either by focusing on BD patients without diabetes insipidus or by supposing the victim of high SCI to have pre-existing therapeutically compensated diabetes insipidus. The respective literatures on intensive care for BD organ donors and high SCI corroborate that the two conditions are somatically virtually identical. If SCI victims are alive at the level of the 'organism as a whole', then so must be BD patients (the only significant difference being consciousness). Comparison with SCI leads to the conclusion that if BD is to be equated with death, a more coherent reason must be adduced than that the body as a biological organism is dead.

  20. Actions and interactions of estradiol and glucocorticoids in cognition and the brain: Implications for aging women.

    Science.gov (United States)

    Herrera, Alexandra Ycaza; Mather, Mara

    2015-01-01

    Menopause involves dramatic declines in estradiol production and levels. Importantly, estradiol and the class of stress hormones known as glucocorticoids exert countervailing effects throughout the body, with estradiol exerting positive effects on the brain and cognition, glucocorticoids exerting negative effects on the brain and cognition, and estradiol able to mitigate negative effects of glucocorticoids. Although the effects of these hormones in isolation have been extensively studied, the effects of estradiol on the stress response and the neuroprotection offered against glucocorticoid exposure in humans are less well known. Here we review evidence suggesting that estradiol-related protection against glucocorticoids mitigates stress-induced interference with cognitive processes. Animal and human research indicates that estradiol-related mitigation of glucocorticoid damage and interference is one benefit of estradiol supplementation during peri-menopause or soon after menopause. The evidence for estradiol-related protection against glucocorticoids suggests that maintaining estradiol levels in post-menopausal women could protect them from stress-induced declines in neural and cognitive integrity. PMID:25929443

  1. Distribution of N-Acetylgalactosamine-Positive Perineuronal Nets in the Macaque Brain: Anatomy and Implications

    Directory of Open Access Journals (Sweden)

    Adrienne L. Mueller

    2016-01-01

    Full Text Available Perineuronal nets (PNNs are extracellular molecules that form around neurons near the end of critical periods during development. They surround neuronal cell bodies and proximal dendrites. PNNs inhibit the formation of new connections and may concentrate around rapidly firing inhibitory interneurons. Previous work characterized the important role of perineuronal nets in plasticity in the visual system, amygdala, and spinal cord of rats. In this study, we use immunohistochemistry to survey the distribution of perineuronal nets in representative areas of the primate brain. We also document changes in PNN prevalence in these areas in animals of different ages. We found that PNNs are most prevalent in the cerebellar nuclei, surrounding >90% of the neurons there. They are much less prevalent in cerebral cortex, surrounding less than 10% of neurons in every area that we examined. The incidence of perineuronal nets around parvalbumin-positive neurons (putative fast-spiking interneurons varies considerably between different areas in the brain. Our survey indicates that the presence of PNNs may not have a simple relationship with neural plasticity and may serve multiple functions in the central nervous system.

  2. Late Cenozoic genus Fupingopollenites development and its implications for the Asian summer monsoon (ASM) evolution

    Science.gov (United States)

    Miao, Y.; Song, C.; Fang, X.; Meng, Q.; Zhang, P.; Wu, F.; Yan, X.

    2015-12-01

    An extinct palynomorph, Fupingopollenites, was used as the basis for a discussion of the late Cenozoic Asian summer monsoon (ASM) evolution and its possible driving forces. Based on the spatial and temporal variations in its percentages across Inner and East Asia, we found that Fupingopollenites mainly occurred in East Asia, with boundaries to the NE of ca. 42°N, 135°E and NW of ca. 36°N, 103°E during the Early Miocene (ca. 23-17 Ma). This region enlarged westwards, reaching the eastern Qaidam Basin (ca. 36°N, 97.5°E) during the Middle Miocene (ca. 17-11 Ma), before noticeably retreating to a region bounded to the NW at ca. 33°N, 105°E during ca. 11-5.3 Ma. The region then shrank further in the Pliocene, with the NE boundary shrinking southwards to about 35°N, 120°E; the area then almost disappeared during the Pleistocene (2.6-0 Ma). The flourishing and subsequent extinction of Fupingopollenites is indicative of a narrow ecological amplitude with a critical dependence on habitat humidity and temperature (most likely mean annual precipitation (MAP) >1000 mm and mean annual temperature (MAT) >10°C). Therefore, the Fupingopollenites geographic distribution can indicate the humid ASM evolution during the late Cenozoic, revealing that the strongest ASM period occurred during the Middle Miocene Climate Optimum (MMCO, ~17-14 Ma), after which the ASM weakened coincident with global cooling. We argue that the global cooling played a critical role in the ASM evolution, while the Tibetan Plateau uplifts made a relatively small contribution. This result was supported by a Miocene pollen record at the Qaidam Basin, inner Asia and the contemporaneously compiled pollen records across the Eurasia.

  3. Partial melting in one-plate planets: Implications for thermo-chemical and atmospheric evolution

    Science.gov (United States)

    Plesa, A.-C.; Breuer, D.

    2014-08-01

    In the present work, we investigate the influence of partial melting on mantle dynamics, crustal formation, and volcanic outgassing of a one-plate planet using a 2D mantle convection code. When melt is extracted to form crust, the mantle material left behind is more buoyant than its parent material and depleted in radioactive heat sources. The extracted heat-producing elements are then enriched in the crust, which also has an insulating effect due to its lower thermal conductivity compared to the mantle. In addition, partial melting can influence the mantle rheology through the dehydration (water depletion) of the mantle material by volcanic outgassing. As a consequence, the viscosity of water-depleted regions increases more than two orders of magnitude compared to water-saturated rocks resulting in slower cooling rates. The most important parameter influencing the thermo-chemical evolution is the assumed density difference between the primitive and the depleted mantle material (i.e., between peridotite and harzburgite). With small or negligible values of compositional buoyancy, crustal formation including crustal delamination is very efficient, also resulting in efficient processing and degassing of the mantle. The convecting mantle below the stagnant lid depletes continuously with time. In contrast, with increasing compositional buoyancy, crustal formation and mantle degassing are strongly suppressed although partial melting is substantially prolonged in the thermal evolution. The crust shows strong lateral variations in thickness, and crustal delamination is reduced and occurs only locally. Furthermore, two to four different mantle reservoirs can form depending on the initial temperature distribution. Two of these reservoirs can be sustained during the entire evolution - a scenario possibly valid for Mars as it may explain the isotope characteristic of the Martian meteorites.

  4. The mineralogic evolution of the Martian surface through time: Implications from chemical reaction path modeling studies

    Science.gov (United States)

    Plumlee, G. S.; Ridley, W. I.; Debraal, J. D.; Reed, M. H.

    1993-01-01

    Chemical reaction path calculations were used to model the minerals that might have formed at or near the Martian surface as a result of volcano or meteorite impact driven hydrothermal systems; weathering at the Martian surface during an early warm, wet climate; and near-zero or sub-zero C brine-regolith reactions in the current cold climate. Although the chemical reaction path calculations carried out do not define the exact mineralogical evolution of the Martian surface over time, they do place valuable geochemical constraints on the types of minerals that formed from an aqueous phase under various surficial and geochemically complex conditions.

  5. Importance of initial buoyancy field on evolution of mantle thermal structure: Implications of surface boundary conditions

    Directory of Open Access Journals (Sweden)

    Petar Glišović

    2015-01-01

    Full Text Available Although there has been significant progress in the seismic imaging of mantle heterogeneity, the outstanding issue that remains to be resolved is the unknown distribution of mantle temperature anomalies in the distant geological past that give rise to the present-day anomalies inferred by global tomography models. To address this question, we present 3-D convection models in compressible and self-gravitating mantle initialised by different hypothetical temperature patterns. A notable feature of our forward convection modelling is the use of self-consistent coupling of the motion of surface tectonic plates to the underlying mantle flow, without imposing prescribed surface velocities (i.e., plate-like boundary condition. As an approximation for the surface mechanical conditions before plate tectonics began to operate we employ the no-slip (rigid boundary condition. A rigid boundary condition demonstrates that the initial thermally-dominated structure is preserved, and its geographical location is fixed during the evolution of mantle flow. Considering the impact of different assumed surface boundary conditions (rigid and plate-like on the evolution of thermal heterogeneity in the mantle we suggest that the intrinsic buoyancy of seven superplumes is most-likely resolved in the tomographic images of present-day mantle thermal structure. Our convection simulations with a plate-like boundary condition reveal that the evolution of an initial cold anomaly beneath the Java-Indonesian trench system yields a long-term, stable pattern of thermal heterogeneity in the lowermost mantle that resembles the present-day Large Low Shear Velocity Provinces (LLSVPs, especially below the Pacific. The evolution of subduction zones may be, however, influenced by the mantle-wide flow driven by deeply-rooted and long-lived superplumes since Archean times. These convection models also detect the intrinsic buoyancy of the Perm Anomaly that has been identified as a unique

  6. Large-scale volcanism associated with coronae on Venus - Implications for formation and evolution

    Science.gov (United States)

    Roberts, Kari M.; Head, James W.

    1993-01-01

    Large-scale volcanism, in the form of areally extensive flow fields, is a previously unrecognized important aspect of the evolution of at least 41 percent of all coronae on Venus. The timing and scale of many coronae flow fields is consistent with an origin due to the arrival and pressure-release melting of material in the head of a mantle plume or diapir. The production of voluminous amounts of volcanism at some coronae is proposed to be the result of larger plume size and/or the intersection of mantle upwellings with regions of lithospheric extension and rifting.

  7. Postcrystallization thermal evolution history of Gangdese batholithic zone and its tectonic implication

    Institute of Scientific and Technical Information of China (English)

    陈文寄; 李齐; 郝杰; 周新华; 万京林; 孙敏

    1999-01-01

    Using cooling curves of K-feldspars obtained by using specific 40Ar/39Ar stepe heating procedure and multiple diffusion domain modeling (MDD model), together with results of dating hornblends, biotite, and apatite, further work has been done to examine the characteristics of the postcrystallization thermal evolution history of Gangdese batholithic zone, to compare the starting times of rapid cooling events with the variation regularities of apatite fission track (FT) ages in the eastern and western parts of Gangdese batholithic zone, and to provide the evidence for mass transport and energy transfers in the lithosphere after the collision between Indian and Eurasian plates.

  8. Evolution of solids in the Jovian subnebula: Implications for the formation of the Galilean satellites

    Science.gov (United States)

    Ronnet, T.; Mousis, O.; Vernazza, P.

    2016-12-01

    The four Galilean satellites are thought to have formed within an accretion disk surrounding Jupiter during the late stages of its formation. Here we investigate the fate of solids of different sizes in the accretion disk. The dynamics of the solids is followed along with their thermodynamic evolution. This allows us to track the water ice-to-rock mass fraction of the planetesimals as they sublimate and lose mass when heated in the disk. We then compare our results to the known bulk composition of the Jovian moons and draw some conclusions as regards their formation.

  9. Adaptation to salinity in mangroves: Implication on the evolution of salt-tolerance

    Institute of Scientific and Technical Information of China (English)

    LIANG Shan; ZHOU RenChao; DONG SuiSui; SHI SuHua

    2008-01-01

    A plant's adaptation to its environment is one of the most important issues in evolutionary biology. Mangroves are trees that inhabit the intertidal zones with high salinity, while salt tolerance competence of different species varies. Even congeneric species usually occupy distinct positions of intertidal zones due to differential ability of salt tolerance. Some species have different ecotypes that adapt well to littoral and terrestrial environments, respectively. These characteristics of mangroves make them ideal ecological models to study adaptation of mangroves to salinity. Here, we briefly depict adaptive traits of salt tolerance in mangroves with respect to anatomy, physiology and biochemistry, and review the major advances recently made on both the genetic and genomic levels. Results from studies on individual genes or whole genomes of mangroves have confirmed conclusions drawn from studies on anatomy, physiology and biochemistry, and have further indicated that specific patterns of gene expression might contribute to adaptive evolution of mangroves under high salinity. By integrating all information from mangroves and performing comparisons among species of mangroves and non-mangroves, we could give a general picture of adaptation of mangroves to salinity, thus providing a new avenue for further studies on a molecular basis of adaptive evolution of mangroves.

  10. Whole planet coupling between climate, mantle, and core: Implications for rocky planet evolution

    Science.gov (United States)

    Foley, Bradford J.; Driscoll, Peter E.

    2016-05-01

    Earth's climate, mantle, and core interact over geologic time scales. Climate influences whether plate tectonics can take place on a planet, with cool climates being favorable for plate tectonics because they enhance stresses in the lithosphere, suppress plate boundary annealing, and promote hydration and weakening of the lithosphere. Plate tectonics plays a vital role in the long-term carbon cycle, which helps to maintain a temperate climate. Plate tectonics provides long-term cooling of the core, which is vital for generating a magnetic field, and the magnetic field is capable of shielding atmospheric volatiles from the solar wind. Coupling between climate, mantle, and core can potentially explain the divergent evolution of Earth and Venus. As Venus lies too close to the sun for liquid water to exist, there is no long-term carbon cycle and thus an extremely hot climate. Therefore, plate tectonics cannot operate and a long-lived core dynamo cannot be sustained due to insufficient core cooling. On planets within the habitable zone where liquid water is possible, a wide range of evolutionary scenarios can take place depending on initial atmospheric composition, bulk volatile content, or the timing of when plate tectonics initiates, among other factors. Many of these evolutionary trajectories would render the planet uninhabitable. However, there is still significant uncertainty over the nature of the coupling between climate, mantle, and core. Future work is needed to constrain potential evolutionary scenarios and the likelihood of an Earth-like evolution.

  11. The Evolution of Pristine Gas: Implications for Milky Way Halo Stars

    Science.gov (United States)

    Sarmento, Richard J.; Scannapieco, Evan; Pan, Liubin

    2016-06-01

    We implement a new subgrid model for turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova ejecta and the impact on the chemical composition of the Galactic Halo. Using the cosmological adaptive mesh refinement code RAMSES, we implement a model for the pollution of pristine gas as described in Pan et al. (2013). This allows us to account for the fraction of Z polluted fraction, fpol, of both the gas and stars.Additionally, we track the evolution of the “primordial metals” generated by Pop III supernovae. These metals are taken up by second-generation stars and are likely to lead to unique abundance signatures characteristic of carbon enhanced, metal poor (CEMP) stars. As an illustrative example, we associate primordial metals with abundance ratios used by Keller at al (2014) to explain the source of metals in the star SMSS J031300.36- 670839.3, finding good agreement with the observed [Fe/H], [C/H], [O/H] and [Mg/Ca] ratios in CEMP Milky Way (MW) halo stars.

  12. Molecular evolution of the infrared sensory gene TRPA1 in snakes and implications for functional studies.

    Science.gov (United States)

    Geng, Jie; Liang, Dan; Jiang, Ke; Zhang, Peng

    2011-01-01

    TRPA1 is a calcium ion channel protein recently identified as the infrared receptor in pit organ-containing snakes. Therefore, understanding the molecular evolution of TRPA1 may help to illuminate the origin of "heat vision" in snakes and reveal the molecular mechanism of infrared sensitivity for TRPA1. To this end, we sequenced the infrared sensory gene TRPA1 in 24 snake species, representing nine snake families and multiple non-snake outgroups. We found that TRPA1 is under strong positive selection in the pit-bearing snakes studied, but not in other non-pit snakes and non-snake vertebrates. As a comparison, TRPV1, a gene closely related to TRPA1, was found to be under strong purifying selection in all the species studied, with no difference in the strength of selection between pit-bearing snakes and non-pit snakes. This finding demonstrates that the adaptive evolution of TRPA1 specifically occurred within the pit-bearing snakes and may be related to the functional modification for detecting infrared radiation. In addition, by comparing the TRPA1 protein sequences, we identified 11 amino acid sites that were diverged in pit-bearing snakes but conserved in non-pit snakes and other vertebrates, 21 sites that were diverged only within pit-vipers but conserved in the remaining snakes. These specific amino acid substitutions may be potentially functional important for infrared sensing.

  13. The empirical mass distribution of hot B subdwarfs: Implications for stellar evolution theory

    Directory of Open Access Journals (Sweden)

    Green E.M.

    2013-03-01

    Full Text Available Subdwarf B (sdB stars are hot, compact, and evolved objects that form the very hot end of the horizontal branch, the so-called Extreme Horizontal Branch (EHB. Understanding the formation of sdB stars is one of the remaining challenges of stellar evolution theory. Several scenarios have been proposed to account for the existence of such objects, made of He-burning core surrounded by very thin H-rich envelope. They give quite different theoretical mass distributions for the resulting sdB stars. Detailed asteroseismic analyses, including mass estimates, of 15 pulsating hot B subdwarfs have been published since a decade. The masses have also been reliably determined by light curve modeling and spectroscopy for 7 sdB components of eclipsing and/or reflection effect binaries. These empirical mass distributions, although based on small-number statistics, can be compared with the expectations of stellar evolution theory. In particular, the two He white dwarfs merger scenario does not seem to be the dominant channel to form isolated sdB stars, while the post-red giant branch scenario is reinforced. This opens new questions on extreme mass loss of red giants to form EHB stars, possibly in connection with the recently discovered close substellar companions and planets orbiting sdB stars.

  14. Molecular evolution of the infrared sensory gene TRPA1 in snakes and implications for functional studies.

    Directory of Open Access Journals (Sweden)

    Jie Geng

    Full Text Available TRPA1 is a calcium ion channel protein recently identified as the infrared receptor in pit organ-containing snakes. Therefore, understanding the molecular evolution of TRPA1 may help to illuminate the origin of "heat vision" in snakes and reveal the molecular mechanism of infrared sensitivity for TRPA1. To this end, we sequenced the infrared sensory gene TRPA1 in 24 snake species, representing nine snake families and multiple non-snake outgroups. We found that TRPA1 is under strong positive selection in the pit-bearing snakes studied, but not in other non-pit snakes and non-snake vertebrates. As a comparison, TRPV1, a gene closely related to TRPA1, was found to be under strong purifying selection in all the species studied, with no difference in the strength of selection between pit-bearing snakes and non-pit snakes. This finding demonstrates that the adaptive evolution of TRPA1 specifically occurred within the pit-bearing snakes and may be related to the functional modification for detecting infrared radiation. In addition, by comparing the TRPA1 protein sequences, we identified 11 amino acid sites that were diverged in pit-bearing snakes but conserved in non-pit snakes and other vertebrates, 21 sites that were diverged only within pit-vipers but conserved in the remaining snakes. These specific amino acid substitutions may be potentially functional important for infrared sensing.

  15. Implications of behavioral architecture for the evolution of self-organized division of labor.

    Science.gov (United States)

    Duarte, A; Scholtens, E; Weissing, F J

    2012-01-01

    Division of labor has been studied separately from a proximate self-organization and an ultimate evolutionary perspective. We aim to bring together these two perspectives. So far this has been done by choosing a behavioral mechanism a priori and considering the evolution of the properties of this mechanism. Here we use artificial neural networks to allow for a more open architecture. We study whether emergent division of labor can evolve in two different network architectures; a simple feedforward network, and a more complex network that includes the possibility of self-feedback from previous experiences. We focus on two aspects of division of labor; worker specialization and the ratio of work performed for each task. Colony fitness is maximized by both reducing idleness and achieving a predefined optimal work ratio. Our results indicate that architectural constraints play an important role for the outcome of evolution. With the simplest network, only genetically determined specialization is possible. This imposes several limitations on worker specialization. Moreover, in order to minimize idleness, networks evolve a biased work ratio, even when an unbiased work ratio would be optimal. By adding self-feedback to the network we increase the network's flexibility and worker specialization evolves under a wider parameter range. Optimal work ratios are more easily achieved with the self-feedback network, but still provide a challenge when combined with worker specialization.

  16. Abundance Gradient from Open Clusters and Implications for the Galactic Disk Evolution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    We compile a new sample of 89 open clusters with ages, distances and metallicities available. We derive a radial iron gradient of about -0.099±0.008dex kpc-1(urweighted) for the whole sample, which is somewhat greater than the most recent determination of oxygen gradient from nebulae and young stars. By dividing the clusters into age groups, we show that the iron gradient was steeper in the past and has evolved slowly in time. Current data show a substantial scatter of the cluster metallicities indicating that the Galactic disk has undergone a very rapid, inhomogeneous enrichment. Also, based on a simple, but quite successful model of chemical evolution of the Milky Way disk, we make a detailed calculation of the iron abundance gradient and its time evolution. The predicted current iron gradient is about -0.072 dex kpc-1. The model also predicts a steady flattening of the iron gradient with time, which agrees with the result from our open cluster sample.

  17. Allometry of facial mobility in anthropoid primates: implications for the evolution of facial expression.

    Science.gov (United States)

    Dobson, Seth D

    2009-01-01

    Body size may be an important factor influencing the evolution of facial expression in anthropoid primates due to allometric constraints on the perception of facial movements. Given this hypothesis, I tested the prediction that observed facial mobility is positively correlated with body size in a comparative sample of nonhuman anthropoids. Facial mobility, or the variety of facial movements a species can produce, was estimated using a novel application of the Facial Action Coding System (FACS). I used FACS to estimate facial mobility in 12 nonhuman anthropoid species, based on video recordings of facial activity in zoo animals. Body mass data were taken from the literature. I used phylogenetic generalized least squares (PGLS) to perform a multiple regression analysis with facial mobility as the dependent variable and two independent variables: log body mass and dummy-coded infraorder. Together, body mass and infraorder explain 92% of the variance in facial mobility. However, the partial effect of body mass is much stronger than for infraorder. The results of my study suggest that allometry is an important constraint on the evolution of facial mobility, which may limit the complexity of facial expression in smaller species. More work is needed to clarify the perceptual bases of this allometric pattern.

  18. Implications of behavioral architecture for the evolution of self-organized division of labor.

    Directory of Open Access Journals (Sweden)

    A Duarte

    Full Text Available Division of labor has been studied separately from a proximate self-organization and an ultimate evolutionary perspective. We aim to bring together these two perspectives. So far this has been done by choosing a behavioral mechanism a priori and considering the evolution of the properties of this mechanism. Here we use artificial neural networks to allow for a more open architecture. We study whether emergent division of labor can evolve in two different network architectures; a simple feedforward network, and a more complex network that includes the possibility of self-feedback from previous experiences. We focus on two aspects of division of labor; worker specialization and the ratio of work performed for each task. Colony fitness is maximized by both reducing idleness and achieving a predefined optimal work ratio. Our results indicate that architectural constraints play an important role for the outcome of evolution. With the simplest network, only genetically determined specialization is possible. This imposes several limitations on worker specialization. Moreover, in order to minimize idleness, networks evolve a biased work ratio, even when an unbiased work ratio would be optimal. By adding self-feedback to the network we increase the network's flexibility and worker specialization evolves under a wider parameter range. Optimal work ratios are more easily achieved with the self-feedback network, but still provide a challenge when combined with worker specialization.

  19. Domain combination of the vertebrate-like TLR gene family: implications for their origin and evolution

    Indian Academy of Sciences (India)

    Baojun Wu; Tianxiao Huan; Jing Gong; Pin Zhou; Zengliang Bai

    2011-12-01

    Domain shuffling, which is an important mechanism in the evolution of multi-domain proteins, has shaped the evolutionary development of the immune system in animals. Toll and Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate and adaptive immune systems. Draft genome sequences provide the opportunity to compare the Toll/TLR gene repertoire among representative metazoans. In this study, we investigated the combination of Toll/interleukin-1 receptor (TIR) and leucine-rich repeat (LRR) domains of metazoan Toll/TLRs. Before Toll with both domains occurred in Cnidaria (sea anemone, Nematostella vectensis), through domain combinations, TIR-only and LRR-only proteins had already appeared in sponges (Amphimedon queenslandica). Although vertebrate-like TIR (V-TIR) domain already appeared in Cnidaria, the vertebrate-like TLR (V-TLR) with both domains appeared much later. The first combination between V-TIR domain and vertebrate-like LRR (V-LRR) domain for V-TLR may have occurred after the divergence of Cnidaria and bilateria. Then, another combination for V-TLR, a recombination of both domains, possibly occurred before or during the evolution of primitive vertebrates. Taken together, two rounds of domain combinations may thus have co-shaped the vertebrate TLRs.

  20. The First Comprehensive Phylogeny of Coptis (Ranunculaceae and Its Implications for Character Evolution and Classification.

    Directory of Open Access Journals (Sweden)

    Kun-Li Xiang

    Full Text Available Coptis (Ranunculaceae contains 15 species and is one of the pharmaceutically most important plant genera in eastern Asia. Understanding of the evolution of morphological characters and phylogenetic relationships within the genus is very limited. Here, we present the first comprehensive phylogenetic analysis of the genus based on two plastid and one nuclear markers. The phylogeny was reconstructed using Bayesian inference, as well as maximum parsimony and maximum likelihood methods. The Swofford-Olsen-Waddell-Hillis and Bayesian tests were used to assess the strength of the conflicts between traditional taxonomic units and those suggested by the phylogenetic inferences. Evolution of morphological characters was inferred using Bayesian method to identify synapomorphies for the infrageneric lineages. Our data recognize two strongly supported clades within Coptis. The first clade contains subgenus Coptis and section Japonocoptis of subgenus Metacoptis, supported by morphological characters, such as traits of the central leaflet base, petal color, and petal shape. The second clade consists of section Japonocoptis of subgenus Metacoptis. Coptis morii is not united with C. quinquefolia, in contrast with the view that C. morii is a synonym of C. quinquefolia. Two varieties of C. chinensis do not cluster together. Coptis groenlandica and C. lutescens are reduced to C. trifolia and C. japonica, respectively. Central leaflet base, sepal shape, and petal blade carry a strong phylogenetic signal in Coptis, while leaf type, sepal and petal color, and petal shape exhibit relatively higher levels of evolutionary flexibility.

  1. The Evolution of Post-Traumatic Stress Disorder following Moderate-to-Severe Traumatic Brain Injury.

    Science.gov (United States)

    Alway, Yvette; Gould, Kate Rachel; McKay, Adam; Johnston, Lisa; Ponsford, Jennie

    2016-05-01

    Increasing evidence indicates that post-traumatic stress disorder (PTSD) may develop following traumatic brain injury (TBI), despite most patients having no conscious memory of their accident. This prospective study examined the frequency, timing of onset, symptom profile, and trajectory of PTSD and its psychiatric comorbidities during the first 4 years following moderate-to-severe TBI. Participants were 85 individuals (78.8% male) with moderate or severe TBI recruited following admission to acute rehabilitation between 2005 and 2010. Using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Disorders (SCID-I), participants were evaluated for pre- and post-injury PTSD soon after injury and reassessed at 6 months, 12 months, 2 years, 3 years, and 4 years post-injury. Over the first 4 years post-injury, 17.6% developed injury-related PTSD, none of whom had PTSD prior to injury. PTSD onset peaked between 6 and 12 months post-injury. The majority of PTSD cases (66.7%) had a delayed-onset, which for a third was preceded by subsyndromal symptoms in the first 6 months post-injury. PTSD frequency increased over the first year post-injury, remained stable during the second year, and gradually declined thereafter. The majority of subjects with PTSD experienced a chronic symptom course and all developed one or more than one comorbid psychiatric disorder, with mood, other anxiety, and substance-use disorders being the most common. Despite event-related amnesia, post-traumatic stress symptoms, including vivid re-experiencing phenomena, may develop following moderate-to-severe TBI. Onset is typically delayed and symptoms may persist for several years post-injury.

  2. The evolution of preclinical Alzheimer’s disease: Implications for prevention trials

    Science.gov (United States)

    Sperling, Reisa; Mormino, Elizabeth; Johnson, Keith

    2014-01-01

    As the field begins to test the concept of preclinical neurodegenerative disease, the hypothetical stage of disease when the pathophysiological process has begun in the brain but clinical symptoms are not yet manifest, a number of intriguing questions have already arisen. In particular, in preclinical Alzheimer’s disease (AD), the temporal relationship of amyloid markers to markers of neurodegeneration and their relative utility in the prediction of cognitive decline among clinically normal older individuals remains to be fully elucidated. Secondary prevention trials in AD have already begun in both genetic-at-risk and amyloid-at-risk cohorts, with several more trials in the planning stages, that should provide critical answers about whether intervention at this very early stage of disease can truly bend the curve of clinical progression. PMID:25442939

  3. Gut brain axis: diet microbiota interactions and implications for modulation of anxiety and depression.

    Science.gov (United States)

    Luna, Ruth Ann; Foster, Jane A

    2015-04-01

    The human gut microbiome is composed of an enormous number of microorganisms, generally regarded as commensal bacteria. Without this inherent microbial community, we would be unable to digest plant polysaccharides and would have trouble extracting lipids from our diet. Resident gut bacteria are an important contributor to healthy metabolism and there is significant evidence linking gut microbiota and metabolic disorders such as obesity and diabetes. In the past few years, neuroscience research has demonstrated the importance of microbiota in the development of brain systems that are vital to both stress reactivity and stress-related behaviours. Here we review recent literature that examines the impact of diet-induced changes in the microbiota on stress-related behaviours including anxiety and depression.

  4. Consequences of brain-derived neurotrophic factor withdrawal in CNS neurons and implications in disease.

    Science.gov (United States)

    Mariga, Abigail; Mitre, Mariela; Chao, Moses V

    2017-01-01

    Growth factor withdrawal has been studied across different species and has been shown to have dramatic consequences on cell survival. In the nervous system, withdrawal of nerve growth factor (NGF) from sympathetic and sensory neurons results in substantial neuronal cell death, signifying a requirement for NGF for the survival of neurons in the peripheral nervous system (PNS). In contrast to the PNS, withdrawal of central nervous system (CNS) enriched brain-derived neurotrophic factor (BDNF) has little effect on cell survival but is indispensible for synaptic plasticity. Given that most early events in neuropsychiatric disorders are marked by a loss of synapses, lack of BDNF may thus be an important part of a cascade of events that leads to neuronal degeneration. Here we review reports on the effects of BDNF withdrawal on CNS neurons and discuss the relevance of the loss in disease.

  5. Implications of MMP9 for Blood Brain Barrier Disruption And Hemorrhagic Transformation Following Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Renee Jade Turner

    2016-03-01

    Full Text Available Numerous studies have documented increases in matrix metalloproteinases (MMPs, specifically MMP-9 levels following stroke, with such perturbations associated with disruption of the blood brain barrier (BBB, increased risk of hemorrhagic complications and worsened outcome. Despite this, controversy remains as to which cells release MMP-9 at the normal and pathological BBB, with even less clarity in the context of stroke. This may be further complicated by the influence of tissue plasminogen activator (tPA treatment. The aim of the present review is to examine the relationship between neutrophils, MMP-9 and tPA following ischemic stroke to elucidate which cells are responsible for the increases in MMP-9 and resultant barrier changes and hemorrhage observed following stroke.

  6. Implications of MMP9 for Blood Brain Barrier Disruption and Hemorrhagic Transformation Following Ischemic Stroke

    Science.gov (United States)

    Turner, Renée J.; Sharp, Frank R.

    2016-01-01

    Numerous studies have documented increases in matrix metalloproteinases (MMPs), specifically MMP-9 levels following stroke, with such perturbations associated with disruption of the blood brain barrier (BBB), increased risk of hemorrhagic complications, and worsened outcome. Despite this, controversy remains as to which cells release MMP-9 at the normal and pathological BBB, with even less clarity in the context of stroke. This may be further complicated by the influence of tissue plasminogen activator (tPA) treatment. The aim of the present review is to examine the relationship between neutrophils, MMP-9 and tPA following ischemic stroke to elucidate which cells are responsible for the increases in MMP-9 and resultant barrier changes and hemorrhage observed following stroke. PMID:26973468

  7. Perceptions of communicative competence after traumatic brain injury: implications for ecologically-driven intervention targets.

    Science.gov (United States)

    Cannizzaro, Michael; Allen, Elizabeth M; Prelock, Patricia

    2011-12-01

    The present study investigated the relationship between non-verbal behaviours and perceptions of the communication abilities of an individual with anomia secondary to traumatic brain injury (TBI). Thirty-four university students studying Communication Sciences and Disorders were randomly assigned to watch or listen to six short clips of an individual with TBI engaged in conversation. Participants rated the individual on communication parameters from a modified version of the Pragmatic Protocol and four other dependent measures of communicative competence. A significant positive correlation was identified between perceptions of gestures and ratings of overall communicative competence, and between perceptions of hand and arm movements and ratings of overall communicative competence. Participant raters who viewed the individual's movements as inappropriate also rated her overall communication abilities less favourably. This finding highlights individuality in perception of communication competence and the importance of assessing communication partners' perceptions in a client's environment to determine socially relevant treatment goals.

  8. Origins of adult pigmentation: diversity in pigment stem cell lineages and implications for pattern evolution.

    Science.gov (United States)

    Parichy, David M; Spiewak, Jessica E

    2015-01-01

    Teleosts comprise about half of all vertebrate species and exhibit an extraordinary diversity of adult pigment patterns that function in shoaling, camouflage, and mate choice and have played important roles in speciation. Here, we review studies that have identified several distinct neural crest lineages, with distinct genetic requirements, that give rise to adult pigment cells in fishes. These lineages include post-embryonic, peripheral nerve-associated stem cells that generate black melanophores and iridescent iridophores, cells derived directly from embryonic neural crest cells that generate yellow-orange xanthophores, and bipotent stem cells that generate both melanophores and xanthophores. This complexity in adult chromatophore lineages has implications for our understanding of adult traits, melanoma, and the evolutionary diversification of pigment cell lineages and patterns.

  9. Cystic metastasis versus brain abscess: Role of MR imaging in accurate diagnosis and implications on treatment

    Directory of Open Access Journals (Sweden)

    Shetty Prakash

    2010-01-01

    Full Text Available Intracranial cystic metastases are difficult to differentiate from non neoplastic lesions like a cystic abscess on routine magnetic resonance imaging (MRI sequences in patients with a known primary cancer. Diffusion weighted MRI sequences can help in differentiating between the two. This carries significant implications on the intent and nature of treatment. We present a case of a forty five-year- old patient of squamous cell carcinoma of larynx who developed an intracranial cystic ring enhancing lesion following chemotherapy. Though routine MRI was equivocal, MR diffusion was highly suggestive of an abscess and this led to surgical excision which confirmed the diagnosis. We discuss this case and review the literature regarding the role of newer MRI sequences and the ramifications on patient treatment.

  10. The early heat loss evolution of Mars and their implications for internal and environmental history.

    Science.gov (United States)

    Ruiz, Javier

    2014-03-11

    The time around 3.7 Ga ago was an epoch when substantial changes in Mars occurred: a substantial decline in aqueous erosion/degradation of landscape features; a change from abundant phyllosilicate formation to abundant acidic and evaporitic mineralogy; a change from olivine-rich volcanism to olivine-pyroxene volcanism; and maybe the cessation of the martian dynamo. Here I show that Mars also experienced profound changes in its internal dynamics in the same approximate time, including a reduction of heat flow and a drastic increasing of lithosphere strength. The reduction of heat flow indicates a limited cooling (or even a heating-up) of the deep interior for post-3.7 Ga times. The drastic increasing of lithosphere strength indicates a cold lithosphere above the inefficiently cooled (or even heated) interior. All those changes experienced by Mars were most probably linked and suggest the existence of profound interrelations between interior dynamics and environmental evolution of this planet.

  11. The evolution of high-temperature plasma in magnetar magnetospheres and its implications for giant flares

    Energy Technology Data Exchange (ETDEWEB)

    Takamoto, Makoto [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg D69117 (Germany); Kisaka, Shota [Institute of Particle and Nuclear Studies, KEK, 1-1, Oho, Tsukuba 305-0801 (Japan); Suzuki, Takeru K. [Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Terasawa, Toshio, E-mail: makoto.takamoto@mpi-hd.mpg.de, E-mail: kisaka@post.kek.jp, E-mail: stakeru@nagoya-u.jp, E-mail: terasawa@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-ha, Kashiwa city, Chiba 277-8582 (Japan)

    2014-05-20

    In this paper we propose a new mechanism describing the initial spike of giant flares in the framework of the starquake model. We investigate the evolution of a plasma on a closed magnetic flux tube in the magnetosphere of a magnetar in the case of a sudden energy release, and discuss the relationship with observations of giant flares. We perform one-dimensional, numerical simulations of the relativistic magnetohydrodynamics in Schwarzschild geometry. We assume energy is injected at the footpoints of the loop by a hot star surface containing random perturbations of the transverse velocity. Alfvén waves are generated and propagate upward, accompanying very hot plasma which is also continuously heated by nonlinearly generated compressive waves. We find that the front edges of the fireball regions collide at the top of the tube with their symmetrically launched counterparts. This collision results in an energy release that can describe the light curve of the initial spikes of giant flares.

  12. Evolution of China’s Forestry Policies since 1949 and Experience and Implications

    Institute of Scientific and Technical Information of China (English)

    Yunhong; HU; Junjie; HE

    2013-01-01

    Since 1949,the Chinese Communist Party ( CPC) and government have formulated series of policies to promote construction and development of forestry. The evolution of forestry policies brings constant deepening of understanding of the Party and government about forestry development laws. Forestry policies evolve from emergency and provisional to systematic and overall functions,making them become more scientific,pertinent and prospective. Besides,formulation of forestry policies is gradually influenced by international factors. When formulating forestry policies,it is required to follow forestry development laws,keep pace with time,and make constant improvement in practice,to suit demands of times and social development,and prudently handle the relationship between economic benefits and ecological benefits of forestry.

  13. The Geobacillus pan-genome: implications for the evolution of the genus

    Directory of Open Access Journals (Sweden)

    Oliver Keoagile Ignatius Bezuidt

    2016-05-01

    Full Text Available The genus Geobacillus is comprised of a diverse group of spore-forming Gram-positive thermophilic bacterial species and is well known for both its ecological diversity and as a source of novel thermostable enzymes. Although the mechanisms underlying the thermophilicity of the organism and the thermostability of its macromolecules are reasonably well understood, relatively little is known of the evolutionary mechanisms, which underlie the structural and functional properties of members of this genus. In this study, we have compared 29 Geobacillus genomes, with a specific focus on the elements, which comprise the conserved core and flexible genomes. Based on comparisons of conserved core and flexible genomes, we present evidence of habitat delineation with specific Geobacillus genomes linked to specific niches. Interestingly, our analysis has shown that horizontal gene transfer is a major factor deriving the evolution of Geobacillus from Bacillus, with genetic contributions from other phylogenetically distant taxa.

  14. Genetic diversity in Treponema pallidum: implications for pathogenesis, evolution and molecular diagnostics of syphilis and yaws.

    Science.gov (United States)

    Smajs, David; Norris, Steven J; Weinstock, George M

    2012-03-01

    Pathogenic uncultivable treponemes, similar to syphilis-causing Treponema pallidum subspecies pallidum, include T. pallidum ssp. pertenue, T. pallidum ssp. endemicum and Treponema carateum, which cause yaws, bejel and pinta, respectively. Genetic analyses of these pathogens revealed striking similarity among these bacteria and also a high degree of similarity to the rabbit pathogen, Treponema paraluiscuniculi, a treponeme not infectious to humans. Genome comparisons between pallidum and non-pallidum treponemes revealed genes with potential involvement in human infectivity, whereas comparisons between pallidum and pertenue treponemes identified genes possibly involved in the high invasivity of syphilis treponemes. Genetic variability within syphilis strains is considered as the basis of syphilis molecular epidemiology with potential to detect more virulent strains, whereas genetic variability within a single strain is related to its ability to elude the immune system of the host. Genome analyses also shed light on treponemal evolution and on chromosomal targets for molecular diagnostics of treponemal infections.

  15. The Geobacillus Pan-Genome: Implications for the Evolution of the Genus.

    Science.gov (United States)

    Bezuidt, Oliver K; Pierneef, Rian; Gomri, Amin M; Adesioye, Fiyin; Makhalanyane, Thulani P; Kharroub, Karima; Cowan, Don A

    2016-01-01

    The genus Geobacillus is comprised of a diverse group of spore-forming Gram-positive thermophilic bacterial species and is well known for both its ecological diversity and as a source of novel thermostable enzymes. Although the mechanisms underlying the thermophilicity of the organism and the thermostability of its macromolecules are reasonably well understood, relatively little is known of the evolutionary mechanisms, which underlie the structural and functional properties of members of this genus. In this study, we have compared 29 Geobacillus genomes, with a specific focus on the elements, which comprise the conserved core and flexible genomes. Based on comparisons of conserved core and flexible genomes, we present evidence of habitat delineation with specific Geobacillus genomes linked to specific niches. Our analysis revealed that Geobacillus and Anoxybacillus share a high proportion of genes. Moreover, the results strongly suggest that horizontal gene transfer is a major factor deriving the evolution of Geobacillus from Bacillus, with genetic contributions from other phylogenetically distant taxa.

  16. Calibrating 100 Years of Polar Faculae Measurements: Implications for the Evolution of the Heliospheric Magnetic Field

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Zhang, Jie; DeLuca, Edward E; 10.1088/0004-637X/753/2/146

    2013-01-01

    Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11-year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar-field measurements spans relatively few sunspot cycles. In this paper we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from MDI intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the ...

  17. The Implications of the Working Memory Model for the Evolution of Modern Cognition

    Directory of Open Access Journals (Sweden)

    Thomas Wynn

    2011-01-01

    Full Text Available What distinguishes the cognition of biologically modern humans from that of more archaic populations such as Neandertals? The norm in paleoanthropology has been to emphasize the role of language and symbolism. But the modern mind is more than just an archaic mind enhanced by symbol use. It also possesses an important problem solving and planning component. In cognitive neuroscience these advanced planning abilities have been extensively investigated through a formal model known as working memory. The working memory model is now well-enough established to provide a powerful lens through which paleoanthropologists can view the fossil and archaeological records. The challenge is methodological. The following essay reviews the controversial hypothesis that a recent enhancement of working memory capacity was the final piece in the evolution of modern cognition.

  18. Os isotopes in SNC meteorites and their implications to the early evolution of Mars and Earth

    Science.gov (United States)

    Jagoutz, E.; Luck, J. M.; Othman, D. Ben; Wanke, H.

    1993-01-01

    A new development on the measurement of the Os isotopic composition by mass spectrometry using negative ions opened a new field of applications. The Re-Os systematic provides time information on the differentiation of the nobel metals. The nobel metals are strongly partitioned into metal and sulphide phases, but also the generation of silicate melts might fractionate the Re-Os system. Compared to the other isotopic systems which are mainly dating the fractionation of the alkalis and alkali-earth elements, the Re-Os system is expected to disclose entirely new information about the geochemistry. Especially the differentiation and early evolution of the planets such as the formation of the core will be elucidated with this method.

  19. Geophysical mapping of Vercelli Seamount:Implications for Miocene evolution of the Tyrrhenian back arc basin

    Institute of Scientific and Technical Information of China (English)

    Luca Cocchi; Giuseppe Masetti; Filippo Muccini; Cosmo Carmisciano

    2016-01-01

    Since the Tortonian, the geodynamic evolution of the Tyrrhenian Sea has been driven by an eastward roll-back of the entire Apennine subduction system, triggering distinct episodes of back-arc basin for-mation with spots of oceanic crust. Major structural differences are observed between northern and southern portions of the Tyrrhenian Sea, reflecting two distinct evolution stages of the Ionian slab retreat. In the central portion of the Tyrrhenian Sea, the seafloor morphology is characterized by a set of magmatic intrusions and structural highs associated to an EeW magnetic lineament along the 41st geographical parallel. The Vercelli seamount represents one example of structural highs correlated to Miocene magmatic episodes along the 41st parallel zone. In this study, we discuss the results of new high resolution magnetic data and morphological mapping of the Vercelli seamount acquired during the VER2010 cruise. The seamount represents the relict part of a granitic intrusion emplaced during the Tortonian phase of Tyrrhenian rifting. Tectonic and deep-sea erosive processes have jointly modified the seamount structure that can be observed nowadays. Cumulative gradient analysis highlights an asym-metric morphology of the flanks as a result of erosive action of opposite water mass gyres which modelled the southern portion of the seamount. The joint interpretation of magnetic and bathymetric datasets identifies a high magnetized source laying close to the base of the seamount and located in correspondence to a small basin. This structure has been modelled as a post-Tortonian lava sequence emplaced between structural highs in correspondence of NeS elongated flat sedimentary basin. Modelling of new geophysical data highlights the relationship between crustal setting and magnetic evidences of the central Tyrrhenian Sea, providing a new interpretation of the 41st magnetic lineament.

  20. Coevolution of URAT1 and Uricase during Primate Evolution: Implications for Serum Urate Homeostasis and Gout

    Science.gov (United States)

    Tan, Philip K.; Farrar, Jennifer E.; Gaucher, Eric A.; Miner, Jeffrey N.

    2016-01-01

    Uric acid is the highly insoluble end-product of purine metabolism in humans. Serum levels exceeding the solubility threshold can trigger formation of urate crystals resulting in gouty arthritis. Uric acid is primarily excreted through the kidneys with 90% reabsorbed back into the bloodstream through the uric acid transporter URAT1. This reabsorption process is essential for the high serum uric acid levels found in humans. We discovered that URAT1 proteins from humans and baboons have higher affinity for uric acid compared with transporters from rats and mice. This difference in transport kinetics of URAT1 orthologs, along with inability of modern apes to oxidize uric acid due to loss of the uricase enzyme, prompted us to ask whether these events occurred concomitantly during primate evolution. Ancestral URAT1 sequences were computationally inferred and ancient transporters were resurrected and assayed, revealing that affinity for uric acid was increased during the evolution of primates. This molecular fine-tuning occurred between the origins of simians and their diversification into New- and Old-World monkey and ape lineages. Remarkably, it was driven in large-part by only a few amino acid replacements within the transporter. This alteration in primate URAT1 coincided with changes in uricase that greatly diminished the enzymatic activity and took place 27–77 Ma. These results suggest that the modifications to URAT1 transporters were potentially adaptive and that maintaining more constant, high levels of serum uric acid may have provided an advantage to our primate ancestors. PMID:27352852

  1. Untangling the evolution of Rab G proteins: implications of a comprehensive genomic analysis

    Directory of Open Access Journals (Sweden)

    Klöpper Tobias H

    2012-08-01

    Full Text Available Abstract Background Membrane-bound organelles are a defining feature of eukaryotic cells, and play a central role in most of their fundamental processes. The Rab G proteins are the single largest family of proteins that participate in the traffic between organelles, with 66 Rabs encoded in the human genome. Rabs direct the organelle-specific recruitment of vesicle tethering factors, motor proteins, and regulators of membrane traffic. Each organelle or vesicle class is typically associated with one or more Rab, with the Rabs present in a particular cell reflecting that cell's complement of organelles and trafficking routes. Results Through iterative use of hidden Markov models and tree building, we classified Rabs across the eukaryotic kingdom to provide the most comprehensive view of Rab evolution obtained to date. A strikingly large repertoire of at least 20 Rabs appears to have been present in the last eukaryotic common ancestor (LECA, consistent with the 'complexity early' view of eukaryotic evolution. We were able to place these Rabs into six supergroups, giving a deep view into eukaryotic prehistory. Conclusions Tracing the fate of the LECA Rabs revealed extensive losses with many extant eukaryotes having fewer Rabs, and none having the full complement. We found that other Rabs have expanded and diversified, including a large expansion at the dawn of metazoans, which could be followed to provide an account of the evolutionary history of all human Rabs. Some Rab changes could be correlated with differences in cellular organization, and the relative lack of variation in other families of membrane-traffic proteins suggests that it is the changes in Rabs that primarily underlies the variation in organelles between species and cell types.

  2. A model for damage load and its implications for the evolution of bacterial aging.

    Directory of Open Access Journals (Sweden)

    Lin Chao

    2010-08-01

    Full Text Available Deleterious mutations appearing in a population increase in frequency until stopped by natural selection. The ensuing equilibrium creates a stable frequency of deleterious mutations or the mutational load. Here I develop the comparable concept of a damage load, which is caused by harmful non-heritable changes to the phenotype. A damage load also ensues when the increase of damage is opposed by selection. The presence of a damage load favors the evolution of asymmetrical transmission of damage by a mother to her daughters. The asymmetry is beneficial because it increases fitness variance, but it also leads to aging or senescence. A mathematical model based on microbes reveals that a cell lineage dividing symmetrically is immortal if lifetime damage rates do not exceed a threshold. The evolution of asymmetry allows the lineage to persist above the threshold, but the lineage becomes mortal. In microbes with low genomic mutation rates, it is likely that the damage load is much greater than the mutational load. In metazoans with higher genomic mutation rates, the damage and the mutational load could be of the same magnitude. A fit of the model to experimental data shows that Escherichia coli cells experience a damage rate that is below the threshold and are immortal under the conditions examined. The model estimates the asymmetry level of E. coli to be low but sufficient for persisting at higher damage rates. The model also predicts that increasing asymmetry results in diminishing fitness returns, which may explain why the bacterium has not evolved higher asymmetry.

  3. Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

    Energy Technology Data Exchange (ETDEWEB)

    UC Davis; Cappa, Christopher D.; Wilson, Kevin R.

    2010-10-28

    Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the alpha-pinene + O3 reaction (alphaP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the alphaP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the alphaP spectra suggest that the evaporation of alphaP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from the alphaP particles existing as in a glassy state instead of having the expected liquid-like behavior. To reconcile these observations with decades of aerosol growth measurements, which indicate that OA formation is described by equilibrium partitioning, we present a conceptual model wherein the secondary OA is formed and then rapidly converted from an absorbing form to a non-absorbing form. The results suggest that although OA growth may be describable by equilibrium partitioning theory, the properties of organic aerosol once formed may differ significantly from the properties determined in the equilibrium framework.

  4. Compositions of Upper Mantle Fluids Beneath Eastern China:Implications for Mantle Evolution

    Institute of Scientific and Technical Information of China (English)

    ZHANG Mingjie; WANG Xianbin; LIU Gang; ZHANG Tongwei; BO Wenrui

    2004-01-01

    The composition of gases trapped in olivine, orthopyroxene and clinopyroxene in lherzolite xenoliths collected from different locations in eastern China has been measured by the vacuum stepped-heating mass spectrometry.These xenoliths are hosted in alkali basalts and considered as residues of partial melting of the upper mantle, and may contain evidence of mantle evolution. The results show that various kinds of fluid inclusions in lherzolite xenoliths have been released at distinct times, which could be related to different stages of mantle evolution. In general, primitive fluids of the upper mantle (PFUM) beneath eastern China are dominated by H2, CO2 and CO, and are characterized by high contents of H2 and reduced gases. The compositions of PFUM are highly variable and related to tectonic settings. CO, CO2 and H2 are the main components of the PFUM beneath cratons; the PFUM in the mantle enriched in potassic metasomatism in the northern part of northeastern China has a high content of H2, while CO2 and SO2 are the dominant components of the PFUM in the Su-Lu-Wan (Jiangsu-Shandong-Anhui) region, where recycled crustal fluids were mixed with deeper mantle components. There are several fluids with distinct compositions beneath eastern China, such as primitive fluids of upper mantle (CO, CO2 and H2), partial melting fluids (CO2 and CO) and metasomatic fluids mixed with recycled crustal fluids (CO2, N2, 8O2 and CH4) etc. Fluids of the upper mantle beneath the North China craton are different from that of the South China craton in total gases and chemical compositions: the contents of the reduced gases of the PFUM in the NCC are higher than those in the SCC.

  5. Geophysical mapping of Vercelli Seamount: Implications for Miocene evolution of the Tyrrhenian back arc basin

    Directory of Open Access Journals (Sweden)

    Luca Cocchi

    2016-09-01

    Full Text Available Since the Tortonian, the geodynamic evolution of the Tyrrhenian Sea has been driven by an eastward roll-back of the entire Apennine subduction system, triggering distinct episodes of back-arc basin formation with spots of oceanic crust. Major structural differences are observed between northern and southern portions of the Tyrrhenian Sea, reflecting two distinct evolution stages of the Ionian slab retreat. In the central portion of the Tyrrhenian Sea, the seafloor morphology is characterized by a set of magmatic intrusions and structural highs associated to an E–W magnetic lineament along the 41st geographical parallel. The Vercelli seamount represents one example of structural highs correlated to Miocene magmatic episodes along the 41st parallel zone. In this study, we discuss the results of new high resolution magnetic data and morphological mapping of the Vercelli seamount acquired during the VER2010 cruise. The seamount represents the relict part of a granitic intrusion emplaced during the Tortonian phase of Tyrrhenian rifting. Tectonic and deep-sea erosive processes have jointly modified the seamount structure that can be observed nowadays. Cumulative gradient analysis highlights an asymmetric morphology of the flanks as a result of erosive action of opposite water mass gyres which modelled the southern portion of the seamount. The joint interpretation of magnetic and bathymetric datasets identifies a high magnetized source laying close to the base of the seamount and located in correspondence to a small basin. This structure has been modelled as a post-Tortonian lava sequence emplaced between structural highs in correspondence of N–S elongated flat sedimentary basin. Modelling of new geophysical data highlights the relationship between crustal setting and magnetic evidences of the central Tyrrhenian Sea, providing a new interpretation of the 41st magnetic lineament.

  6. Increased functional connectivity between superior colliculus and brain regions implicated in bodily self-consciousness during the rubber hand illusion.

    Science.gov (United States)

    Olivé, Isadora; Tempelmann, Claus; Berthoz, Alain; Heinze, Hans-Joachim

    2015-02-01

    Bodily self-consciousness refers to bodily processes operating at personal, peripersonal, and extrapersonal spatial dimensions. Although the neural underpinnings of representations of personal and peripersonal space associated with bodily self-consciousness were thoroughly investigated, relatively few is known about the neural underpinnings of representations of extrapersonal space relevant for bodily self-consciousness. In the search to unravel brain structures generating a representation of the extrapersonal space relevant for bodily self-consciousness, we developed a functional magnetic resonance imaging (fMRI) study to investigate the implication of the superior colliculus (SC) in bodily illusions, and more specifically in the rubber hand illusion (RHi), which constitutes an established paradigm to study the neural underpinnings of bodily self-consciousness. We observed activation of the colliculus ipsilateral to the manipulated hand associated with eliciting of RHi. A generalized form of context-dependent psychophysiological interaction analysis unravelled increased illusion-dependent functional connectivity between the SC and some of the main brain areas previously involved in bodily self-consciousness: right temporoparietal junction (rTPJ), bilateral ventral premotor cortex (vPM), and bilateral postcentral gyrus. We hypothesize that the collicular map of the extrapersonal space interacts with maps of the peripersonal and personal space generated at rTPJ, vPM and the postcentral gyrus, producing a unified representation of space that is relevant for bodily self-consciousness. We suggest that processes of multisensory integration of bodily-related sensory inputs located in this unified representation of space constitute one main factor underpinning emergence of bodily self-consciousness.

  7. Anticipatory processes in brain state switching - evidence from a novel cued-switching task implicating default mode and salience networks.

    Science.gov (United States)

    Sidlauskaite, Justina; Wiersema, Jan R; Roeyers, Herbert; Krebs, Ruth M; Vassena, Eliana; Fias, Wim; Brass, Marcel; Achten, Eric; Sonuga-Barke, Edmund

    2014-09-01

    The default mode network (DMN) is the core brain system supporting internally oriented cognition. The ability to attenuate the DMN when switching to externally oriented processing is a prerequisite for effective performance and adaptive self-regulation. Right anterior insula (rAI), a core hub of the salience network (SN), has been proposed to control the switching from DMN to task-relevant brain networks. Little is currently known about the extent of anticipatory processes subserved by DMN and SN during switching. We investigated anticipatory DMN and SN modulation using a novel cued-switching task of between-state (rest-to-task/task-to-rest) and within-state (task-to-task) transitions. Twenty healthy adults performed the task implemented in an event-related functional magnetic resonance imaging (fMRI) design. Increases in activity were observed in the DMN regions in response to cues signalling upcoming rest. DMN attenuation was observed for rest-to-task switch cues. Obversely, DMN was up-regulated by task-to-rest cues. The strongest rAI response was observed to rest-to-task switch cues. Task-to-task switch cues elicited smaller rAI activation, whereas no significant rAI activation occurred for task-to-rest switches. Our data provide the first evidence that DMN modulation occurs rapidly and can be elicited by short duration cues signalling rest- and task-related state switches. The role of rAI appears to be limited to certain switch types - those implicating transition from a resting state and to tasks involving active cognitive engagement.

  8. Artificial selection on relative brain size in the guppy reveals costs and benefits of evolving a larger brain.

    Science.gov (United States)

    Kotrschal, Alexander; Rogell, Björn; Bundsen, Andreas; Svensson, Beatrice; Zajitschek, Susanne; Brännström, Ioana; Immler, Simone; Maklakov, Alexei A; Kolm, Niclas

    2013-01-21

    The large variation in brain size that exists in the animal kingdom has been suggested to have evolved through the balance between selective advantages of greater cognitive ability and the prohibitively high energy demands of a larger brain (the "expensive-tissue hypothesis"). Despite over a century of research on the evolution of brain size, empirical support for the trade-off between cognitive ability and energetic costs is based exclusively on correlative evidence, and the theory remains controversial. Here we provide experimental evidence for costs and benefits of increased brain size. We used artificial selection for large and small brain size relative to body size in a live-bearing fish, the guppy (Poecilia reticulata), and found that relative brain size evolved rapidly in response to divergent selection in both sexes. Large-brained females outperformed small-brained females in a numerical learning assay designed to test cognitive ability. Moreover, large-brained lines, especially males, developed smaller guts, as predicted by the expensive-tissue hypothesis, and produced fewer offspring. We propose that the evolution of brain size is mediated by a functional trade-off between increased cognitive ability and reproductive performance and discuss the implications of these findings for vertebrate brain evolution.

  9. The Thermal Evolution of Mercury and the Implications for Volcanism, Topography and Geoid

    Science.gov (United States)

    Ziethe, Ruth; Benkhoff, Johannes

    2010-05-01

    Because of its close proximity to the Sun, the innermost planet of our solar system, Mercury, cannot be studied from the Earth against the dark sky. Among the terrestrial planets Mercury is not only the smallest, but also the densest (after correction for self-compression), has the oldest surface and is the least explored. Understanding this 'end member' among the earth-like planets seems to be crucial to improve the understanding of the formation of the solar system and the history of the Earth. For a long time only one spacecraft has visited Mercury up to now: MARINER 10. It imaged only about half of the planet's surface, while any details of the other hemisphere of Mercury have never been seen so far. Lately MESSENGER was launched and had two flybys on Mercury already, revealing a greater portion of the hermean surface and collecting more data. The BEPICOLOMBO spacecraft will be launched in 2014, arriving in 2020. Although MESSENGER will enter its orbit in 2011 already, the data basis remains relatively poor until then. We can therefore prepare ourselves for the upcoming results and perform test that allow some anticipation of the measured data. Because no material is available, which could have been analysed in a laboratory, numerical models are the most promising tool at the moment. The model shows the typical behaviour of a one-plate-planet, meaning the surface is not broken into several tectonic plates but the outside is a single rigid shell. The thermal evolution is generally charaterized by the growth of a massive lithosphere on top of the convecting mantle. The lower mantle and core cool comparatively little and stay at temperatures between 1900 K and 2000 K until about 2.0 Ga after the simulation was started. The stagnant lid comprises roughly half the mantle after only 0.5 Ga. Since the rigid lithosphere does not take part in the convection anymore, the heat coming from the interior (due to the cooling of the large core) can only be transported through

  10. Serum and brain concentrations of methylphenidate: implications for use and abuse.

    Science.gov (United States)

    Swanson, J M; Volkow, N D

    2003-11-01

    When used to treat children with Attention Deficit Hyperactivity Disorder, methylphenidate (MPH) acts primarily by blocking the dopamine (DA) transporter (DAT) and increasing extracellular DA in the striatum. This is strikingly similar to the mechanism of action of cocaine, a primary stimulant drug of abuse. When administered intravenously, MPH like cocaine has reinforcing effects (euphoria) at doses that exceed a DAT blockade threshold of 60%. When administered orally at clinical doses, the pharmacological effects of MPH also exceed this threshold, but reinforcing effects rarely occur. Here we discuss the pharmacokinetic properties of MPH in serum (and in brain) that differ for oral and intravenous routes of administration and the importance of acute tolerance in determining pharmacodynamic effects in clinical use and illegal abuse. We suggest that intravenous administration of MPH mimics the rapid phasic cell firing of DA neurons, which may be a critical factor associated with reinforcing effects and abuse, while oral administration of MPH mimics the tonic DA cell firing, which may be a critical factor associated with clinical effects.

  11. Theory of mind and the social brain: implications for understanding the genetic basis of schizophrenia.

    Science.gov (United States)

    Martin, A K; Robinson, G; Dzafic, I; Reutens, D; Mowry, B

    2014-01-01

    Genome-wide association studies in schizophrenia have recently made significant progress in our understanding of the complex genetic architecture of this disorder. Many genetic loci have been identified and now require functional investigation. One approach involves studying their correlation with neuroimaging and neurocognitive endophenotypes. Theory of Mind (ToM) deficits are well established in schizophrenia and they appear to fulfill criteria for being considered an endophenotype. We aim to review the behavioral and neuroimaging-based studies of ToM in schizophrenia, assess its suitability as an endophenotype, discuss current findings, and propose future research directions. Suitable research articles were sourced from a comprehensive literature search and from references identified through other studies. ToM deficits are repeatable, stable, and heritable: First-episode patients, those in remission and unaffected relatives all show deficits. Activation and structural differences in brain regions believed important for ToM are also consistently reported in schizophrenia patients at all stages of illness, although no research to date has examined unaffected relatives. Studies using ToM as an endophenotype are providing interesting genetic associations with both single nucleotide polymorphisms (SNPs) and specific copy number variations (CNVs) such as the 22q11.2 deletion syndrome. We conclude that ToM is an important cognitive endophenotype for consideration in future studies addressing the complex genetic architecture of schizophrenia, and may help identify more homogeneous clinical sub-types for further study.

  12. Neutrotoxic effects of fructose administration in rat brain: implications for fructosemia.

    Science.gov (United States)

    Macongonde, Ernesto A; Costa, Naithan L F; Ferreira, Bruna K; Biella, Mairis S; Frederico, Marisa J S; Oliveira, Marcos R de; Ávila Júnior, Silvio; Silva, Fátima R M B; Ferreira, Gustavo C; Streck, Emilio L; Schuck, Patrícia F

    2015-08-01

    Fructose accumulates in tissue and body fluids of patients affected by hereditary fructose intolerance (HFI), a disorder caused by the deficiency of aldolase B. We investigated the effect of acute fructose administration on the biochemical profile and on the activities of the Krebs cycle enzymes in the cerebral cortex of young rats. Rats received a subcutaneous injection of NaCl (0.9 %; control group) or fructose solution (5 μmol/g; treated group). Twelve or 24 h after the administration, the animals were euthanized and the cerebral cortices were isolated. Peripheral blood (to obtain the serum) and cerebral spinal fluid (CSF) from the animals were also collected. It was observed that albumin levels were decreased and cholesterol levels were increased in CSF of animals 12 h after the administration of fructose. In addition, serum lactate levels were increased 12 h after the administration, as compared to control group. Furthermore, malate dehydrogenase activity was increased in cerebral cortex from treated group 24 h after the administration of this carbohydrate. Herein we demonstrate that fructose administration alters biochemical parameters in CSF and serum and bioenergetics parameters in the cerebral cortex. These findings indicate a possible role of fructose on brain alterations found in HFI patients.

  13. Neutrotoxic effects of fructose administration in rat brain: implications for fructosemia

    Directory of Open Access Journals (Sweden)

    Ernesto A. Macongonde

    2015-08-01

    Full Text Available Fructose accumulates in tissue and body fluids of patients affected by hereditary fructose intolerance (HFI, a disorder caused by the deficiency of aldolase B. We investigated the effect of acute fructose administration on the biochemical profile and on the activities of the Krebs cycle enzymes in the cerebral cortex of young rats. Rats received a subcutaneous injection of NaCl (0.9 %; control group or fructose solution (5 μmol/g; treated group. Twelve or 24 h after the administration, the animals were euthanized and the cerebral cortices were isolated. Peripheral blood (to obtain the serum and cerebral spinal fluid (CSF from the animals were also collected. It was observed that albumin levels were decreased and cholesterol levels were increased in CSF of animals 12 h after the administration of fructose. In addition, serum lactate levels were increased 12 h after the administration, as compared to control group. Furthermore, malate dehydrogenase activity was increased in cerebral cortex from treated group 24 h after the administration of this carbohydrate. Herein we demonstrate that fructose administration alters biochemical parameters in CSF and serum and bioenergetics parameters in the cerebral cortex. These findings indicate a possible role of fructose on brain alterations found in HFI patients.

  14. Recovery mechanisms of somatosensory function in stroke patients: implications of brain imaging studies

    Institute of Scientific and Technical Information of China (English)

    Sung Ho Jang

    2013-01-01

    Somatosensory dysfunction is associated with a high incidence of functional impairment and safety in patients with stroke.With developments in brain mapping techniques,many studies have addressed the recovery of various functions in such patients.However,relatively little is known about the mechanisms of recovery of somatosensory function.Based on the previous human studies,a review of 11 relevant studies on the mechanisms underlying the recovery of somatosensory function in stroke patients was conducted based on the following topics:(1) recovery of an injured somatosensory pathway,(2) peri-lesional reorganization,(3) contribution of the unaffected somatosensory cortex,(4) contribution of the secondary somatosensory cortex,and (5)mechanisms of recovery in patients with thalamic lesions.We believe that further studies in this field using combinations of diffusion tensor imaging,functional neuroimaging,and magnetoencephalography are needed.In addition,the clinical significance,critical period,and facilitatory strategies for each recovery mechanism should be clarified.

  15. Neuroimaging assessment of early and late neurobiological sequelae of traumatic brain injury: implications for CTE

    Directory of Open Access Journals (Sweden)

    Mark eSundman

    2015-09-01

    Full Text Available Traumatic brain injury (TBI has been increasingly accepted as a major external risk factor for neurodegenerative morbidity and mortality. Recent evidence indicates that the resultant chronic neurobiological sequelae following head trauma may, at least in part, contribute to a pathologically distinct disease known as Chronic Traumatic Encephalopathy (CTE. The clinical manifestation of CTE is variable, but the symptoms of this progressive disease include impaired memory and cognition, affective disorders (i.e., impulsivity, aggression, depression, suicidality, etc., and diminished motor control. Notably, mounting evidence suggests that the pathology contributing to CTE may be caused by repetitive exposure to subconcussive hits to the head, even in those with no history of a clinically evident head injury. Given the millions of athletes and military personnel with potential exposure to repetitive subconcussive insults and TBI, CTE represents an important public health issue. However, the incidence rates and pathological mechanisms are still largely unknown, primarily due to the fact that there is no in vivo diagnostic tool. The primary objective of this manuscript is to address this limitation and discuss potential neuroimaging modalities that may be capable of diagnosing CTE in vivo through the detection of tau and other known pathological features. Additionally, we will discuss the challenges of TBI research, outline the known pathology of CTE (with an emphasis on Tau, review current neuroimaging modalities to assess the potential routes for in vivo diagnosis, and discuss the future directions of CTE research.

  16. Comparative analysis of protocadherin-11 X-linked expression among postnatal rodents, non-human primates, and songbirds suggests its possible involvement in brain evolution.

    Directory of Open Access Journals (Sweden)

    Eiji Matsunaga

    Full Text Available BACKGROUND: Protocadherin-11 is a cell adhesion molecule of the cadherin superfamily. Since, only in humans, its paralog is found on the Y chromosome, it is expected that protocadherin-11X/Y plays some role in human brain evolution or sex differences. Recently, a genetic mutation of protocadherin-11X/Y was reported to be associated with a language development disorder. Here, we compared the expression of protocadherin-11 X-linked in developing postnatal brains of mouse (rodent and common marmoset (non-human primate to explore its possible involvement in mammalian brain evolution. We also investigated its expression in the Bengalese finch (songbird to explore a possible function in animal vocalization and human language faculties. METHODOLOGY/PRINCIPAL FINDINGS: Protocadherin-11 X-linked was strongly expressed in the cerebral cortex, hippocampus, amygdala and brainstem. Comparative analysis between mice and marmosets revealed that in certain areas of marmoset brain, the expression was clearly enriched. In Bengalese finches, protocadherin-11 X-linked was expressed not only in nuclei of regions of the vocal production pathway and the tracheosyringeal hypoglossal nucleus, but also in areas homologous to the mammalian amygdala and hippocampus. In both marmosets and Bengalese finches, its expression in pallial vocal control areas was developmentally regulated, and no clear expression was seen in the dorsal striatum, indicating a similarity between songbirds and non-human primates. CONCLUSIONS/SIGNIFICANCE: Our results suggest that the enriched expression of protocadherin-11 X-linked is involved in primate brain evolution and that some similarity exists between songbirds and primates regarding the neural basis for vocalization.

  17. Evolution of high-pressure mafic granulites and pelitic gneisses from NE Madagascar: Tectonic implications

    Science.gov (United States)

    Ishwar-Kumar, C.; Sajeev, K.; Windley, B. F.; Kusky, T. M.; Feng, P.; Ratheesh-Kumar, R. T.; Huang, Y.; Zhang, Y.; Jiang, X.; Razakamanana, T.; Yagi, K.; Itaya, T.

    2015-11-01

    The occurrence of high-pressure mafic-ultramafic bodies within major shear zones is one of the indicators of paleo-subduction. In mafic granulites of the Andriamena complex (north-eastern Madagascar) we document unusual textures including garnet-clinopyroxene-quartz coronas that formed after the breakdown of orthopyroxene-plagioclase-ilmenite. Textural evidence and isochemical phase diagram calculations in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2 system indicate a pressure-temperature (P-T) evolution from an isothermal (780 °C) pressure up to c. 24 kbar to decompression and cooling. Such a P-T trajectory is typically attained in a subduction zone setting where a gabbroic/ultramafic complex is subducted and later exhumed to the present crustal level during oceanic closure and final continental collision. The present results suggest that the presence of such deeply subducted rocks of the Andriamena complex is related to formation of the Betsimisaraka suture. LA-ICPMS U-Pb zircon dating of pelitic gneisses from the Betsimisaraka suture yields low Th/U ratios and protolith ages ranging from 2535 to 2625 Ma. A granitic gneiss from the Alaotra complex yields a zircon crystallization age of ca. 818 Ma and Th/U ratios vary from 1.08 to 2.09. K-Ar dating of muscovite and biotite from biotite-kyanite-sillimanite gneiss and garnet-biotite gneiss yields age of 486 ± 9 Ma and 459 ± 9 Ma respectively. We have estimated regional crustal thicknesses in NE Madagascar using a flexural inversion technique, which indicates the presence of an anomalously thick crust (c. 43 km) beneath the Antananarivo block. This result is consistent with the present concept that subduction beneath the Antananarivo block resulted in a more competent and thicker crust. The textural data, thermodynamic model, and geophysical evidence together provide a new insight to the subduction history, crustal thickening and evolution of the high-pressure Andriamena complex and its link to the terminal

  18. Evolution of genomic imprinting with biparental care: implications for Prader-Willi and Angelman syndromes.

    Directory of Open Access Journals (Sweden)

    Francisco Ubeda

    2008-08-01

    Full Text Available The term "imprinted gene" refers to genes whose expression is conditioned by their parental origin. Among theories to unravel the evolution of genomic imprinting, the kinship theory prevails as the most widely accepted, because it sheds light on many aspects of the biology of imprinted genes. While most assumptions underlying this theory have not escaped scrutiny, one remains overlooked: mothers are the only source of parental investment in mammals. But, is it reasonable to assume that fathers' contribution of resources is negligible? It is not in some key mammalian orders including humans. In this research, I generalize the kinship theory of genomic imprinting beyond maternal contribution only. In addition to deriving new conditions for the evolution of imprinting, I have found that the same gene may show the opposite pattern of expression when the investment of one parent relative to the investment of the other changes; the reversion, interestingly, does not require that fathers contribute more resources than mothers. This exciting outcome underscores the intimate connection between the kinship theory and the social structure of the organism considered. Finally, the insight gained from my model enabled me to explain the clinical phenotype of Prader-Willi syndrome. This syndrome is caused by the paternal inheritance of a deletion of the PWS/AS cluster of imprinted genes in human Chromosome 15. As such, children suffering from this syndrome exhibit a striking biphasic phenotype characterized by poor sucking and reduced weight before weaning but by voracious appetite and obesity after weaning. Interest in providing an evolutionary explanation to such phenotype is 2-fold. On the one hand, the kinship theory has been doubted as being able to explain the symptoms of patients with Prader-Willi. On the other hand, the post-weaning symptoms remain as one of the primary concern of pediatricians treating children with Prader-Willi. In this research, I

  19. Evolution of motion uncertainty in rectal cancer: implications for adaptive radiotherapy

    Science.gov (United States)

    Kleijnen, Jean-Paul J. E.; van Asselen, Bram; Burbach, Johannes P. M.; Intven, Martijn; Philippens, Marielle E. P.; Reerink, Onne; Lagendijk, Jan J. W.; Raaymakers, Bas W.

    2016-01-01

    Reduction of motion uncertainty by applying adaptive radiotherapy strategies depends largely on the temporal behavior of this motion. To fully optimize adaptive strategies, insight into target motion is needed. The purpose of this study was to analyze stability and evolution in time of motion uncertainty of both the gross tumor volume (GTV) and clinical target volume (CTV) for patients with rectal cancer. We scanned 16 patients daily during one week, on a 1.5 T MRI scanner in treatment position, prior to each radiotherapy fraction. Single slice sagittal cine MRIs were made at the beginning, middle, and end of each scan session, for one minute at 2 Hz temporal resolution. GTV and CTV motion were determined by registering a delineated reference frame to time-points later in time. The 95th percentile of observed motion (dist95%) was taken as a measure of motion. The stability of motion in time was evaluated within each cine-MRI separately. The evolution of motion was investigated between the reference frame and the cine-MRIs of a single scan session and between the reference frame and the cine-MRIs of several days later in the course of treatment. This observed motion was then converted into a PTV-margin estimate. Within a one minute cine-MRI scan, motion was found to be stable and small. Independent of the time-point within the scan session, the average dist95% remains below 3.6 mm and 2.3 mm for CTV and GTV, respectively 90% of the time. We found similar motion over time intervals from 18 min to 4 days. When reducing the time interval from 18 min to 1 min, a large reduction in motion uncertainty is observed. A reduction in motion uncertainty, and thus the PTV-margin estimate, of 71% and 75% for CTV and tumor was observed, respectively. Time intervals of 15 and 30 s yield no further reduction in motion uncertainty compared to a 1 min time interval.

  20. On the role of emerging voluntary control of vocalization in language evolution. Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael A. Arbib

    Science.gov (United States)

    Coudé, Gino

    2016-03-01

    This comment will be focused on the role of monkey vocal control in the evolution of language. I will essentially reiterate the observations expressed in a commentary [1] about the book "How the brain got language: the mirror system hypothesis", written by Arbib [2]. I will hopefully clarify our suggestion that non-human primates vocal communication, in conjunction with gestures, could have had an active role in the emergence of the first voluntary forms of utterances that will later shape protospeech. This suggestion is mainly rooted in neurophysiological data about vocal control in monkey. I will very briefly summarize how neurophysiological data allowed us to suggest a possible role for monkey vocalization in language evolution. We conducted a study [3] in which we recorded from ventral premotor cortex (PMv) of macaques trained to emit vocalizations (i.e. coo-calls). The results showed that the rostro-lateral part of PMv contains neurons that fire during conditioned vocalization. The involvement of PMv in vocalization production was further supported by electrical microstimulation of the cortical sector where some of the vocalization neurons were found. Microstimulation elicited in some cases a combination of jaw, tongue and larynx movements. To us, the evolutionary implications of those results were obvious: a partial voluntary vocal control was already taking place in the primate PMv cortex some 25 million years ago.

  1. Evolution of the vacuolar H sup + -ATPase: Implications for the origin of eukaryotes

    Energy Technology Data Exchange (ETDEWEB)

    Gogarten, J.P.; Kibak, H.; Dittrich, P.; Taiz, L.; Bowman, E.J.; Bowman, B.J. (Univ. of California, Santa Cruz (USA)); Manolson, M.F.; Poole, R.J. (McGill Univ., Montreal, Quebec (Canada)); Date, Takayasu (Kanazawa Medical School, Ishikawa (Japan)); Oshima, Tairo; Konishi, Jin; Denda, Kimitoshi; Yoshida, Masasuke (Tokyo Institute of Technology, Yokohama (Japan))

    1989-09-01

    Active transport across the vaculoar components of the eukaryotic endomembrane system is energized by a specific vacuolar H{sup +}-ATPase. The amino acid sequences of the 70- and 60-kDa subunits of the vacuolar H{sup +}-ATPase are {approx}25% identical to the {beta} and {alpha} subunits, respectively, of the eubacterial-type F{sub 0}F{sub 1}-ATPases. The authors now report that the same vacuolar H{sup +}-ATPase subunits are {approx}50% identical to the {alpha} and {beta} subunits, respectively, of the sulfur-metabolizing Sulfolobus acidocaldarius, an archaebacterium (Archaeobacterium). Moreover, the homologue of an 88-amino acid stretch near the amino-terminal end of the 70-kDa subunit is absent from the F{sub 0}F{sub 1}-ATPase {beta} subunit but is present in the {alpha} subunit of Sulfolobus. Since the two types of subunits are homologous to each other, they must have arisen by a gene duplication that occurred prior to the last common ancestor of the eubacteria, eukaryotes, and Sulfolobus. Thus, the phylogenetic tree of the subunits can be rooted at the site where the gene duplication occurred. The inferred evolutionary tree contains two main branches: a eubacterial branch and an eocyte branch that gave rise to Sulfolobus and the eukaryotic host cell. The implication is that the vacuolar H{sup +}-ATPase of eukaryotes arose by the internalization of the plasma membrane H{sup +}-ATPase of an archaebacterial-like ancestral cell.

  2. [From brain imaging to good teaching? implicating from neuroscience for research on learning and instruction].

    Science.gov (United States)

    Stubenrauch, Christa; Krinzinger, Helga; Konrad, Kerstin

    2014-07-01

    Psychiatric disorders in childhood and adolescence, in particular attention deficit disorder or specific learning disorders like developmental dyslexia and developmental dyscalculia, affect academic performance and learning at school. Recent advances in neuroscientific research have incited an intensive debate both in the general public and in the field of educational and instructional science as well as to whether and to what extent these new findings in the field of neuroscience might be of importance for school-related learning and instruction. In this review, we first summarize neuroscientific findings related to the development of attention, working memory and executive functions in typically developing children and then evaluate their relevance for school-related learning. We present an overview of neuroimaging studies of specific learning disabilities such as developmental dyslexia and developmental dyscalculia, and critically discuss their practical implications for educational and teaching practice, teacher training, early diagnosis as well as prevention and disorder-specific therapy. We conclude that the new interdisciplinary field of neuroeducation cannot be expected to provide direct innovative educational applications (e.g., teaching methods). Rather, the future potential of neuroscience lies in creating a deeper understanding of the underlying cognitive mechanisms and pathomechanisms of learning processes and learning disorders.

  3. Identification of Mushroom body miniature, a zinc-finger protein implicated in brain development of Drosophila

    Science.gov (United States)

    Raabe, Thomas; Clemens-Richter, Susanne; Twardzik, Thomas; Ebert, Anselm; Gramlich, Gertrud; Heisenberg, Martin

    2004-01-01

    The mushroom bodies are bilaterally arranged structures in the protocerebrum of Drosophila and most other insect species. Mutants with altered mushroom body structure have been instrumental not only in establishing their role in distinct behavioral functions but also in identifying the molecular pathways that control mushroom body development. The mushroom body miniature1 (mbm1) mutation results in grossly reduced mushroom bodies and odor learning deficits in females. With a survey of genomic rescue constructs, we have pinpointed mbm1 to a single transcription unit and identified a single nucleotide exchange in the 5′ untranslated region of the corresponding transcript resulting in a reduced expression of the protein. The most obvious feature of the Mbm protein is a pair of C2HC zinc fingers, implicating a function of the protein in binding nucleic acids. Immunohistochemical analysis shows that expression of the Mbm protein is not restricted to the mushroom bodies. BrdUrd labeling experiments indicate a function of Mbm in neuronal precursor cell proliferation. PMID:15375215

  4. Shared brain activity for aesthetic and moral judgments: implications for the Beauty-is-Good stereotype.

    Science.gov (United States)

    Tsukiura, Takashi; Cabeza, Roberto

    2011-01-01

    The Beauty-is-Good stereotype refers to the assumption that attractive people possess sociably desirable personalities and higher moral standards. The existence of this bias suggests that the neural mechanisms for judging facial attractiveness and moral goodness overlap. To investigate this idea, we scanned participants with functional magnetic resonance imaging while they made attractiveness judgments about faces and goodness judgments about hypothetical actions. Activity in the medial orbitofrontal cortex increased as a function of both attractiveness and goodness ratings, whereas activity in the insular cortex decreased with both attractiveness and goodness ratings. Within each of these regions, the activations elicited by attractiveness and goodness judgments were strongly correlated with each other, supporting the idea of similar contributions of each region to both judgments. Moreover, activations in orbitofrontal and insular cortices were negatively correlated with each other, suggesting an opposing relationship between these regions during attractiveness and goodness judgments. These findings have implications for understanding the neural mechanisms of the Beauty-is-Good stereotype.

  5. Shared brain activity for aesthetic and moral judgments: implications for the Beauty-is-Good stereotype

    Science.gov (United States)

    Cabeza, Roberto

    2011-01-01

    The Beauty-is-Good stereotype refers to the assumption that attractive people possess sociably desirable personalities and higher moral standards. The existence of this bias suggests that the neural mechanisms for judging facial attractiveness and moral goodness overlap. To investigate this idea, we scanned participants with functional magnetic resonance imaging while they made attractiveness judgments about faces and goodness judgments about hypothetical actions. Activity in the medial orbitofrontal cortex increased as a function of both attractiveness and goodness ratings, whereas activity in the insular cortex decreased with both attractiveness and goodness ratings. Within each of these regions, the activations elicited by attractiveness and goodness judgments were strongly correlated with each other, supporting the idea of similar contributions of each region to both judgments. Moreover, activations in orbitofrontal and insular cortices were negatively correlated with each other, suggesting an opposing relationship between these regions during attractiveness and goodness judgments. These findings have implications for understanding the neural mechanisms of the Beauty-is-Good stereotype. PMID:20231177

  6. Environmental and genetic sources of diversification in the timing of seed germination: implications for the evolution of bet hedging.

    Science.gov (United States)

    Simons, Andrew M; Johnston, Mark O

    2006-11-01

    .468) observed for a cohort's germination fraction over two seasons. We discuss implications of the results for the evolution of bet hedging and highlight the need for further empirical study of the causal components of diversification.

  7. Detrital Thermochronology of the Indus-Yarlung suture zone and implications for the tectonic and surface evolution of southern Tibet

    Science.gov (United States)

    Carrapa, B.; Hassim, F.; Kapp, P. A.

    2015-12-01

    Detrital thermochronology has the unique potential to resolve the timing of source cooling associated with magmatic, tectonic and surface processes. Correct interpretation of the detrital signature requires a multi-dating approach involving chronometers sensitive to different temperatures and processes. A multi-dating study of modern river sands from southern Tibet reveals distinct cooling signals that provide significant information about tectonic and erosional evolution of the Indus-Yarlung suture (IYS) after the India-Asia collision with implications for the Cenozoic topographic evolution of the Tibetan Plateau. Modern sands from tributaries of the Yarlung River provide an opportunity to broadly sample source rocks exposed within the suture zone, including the Gangdese batholith, Xigaze forearc, Cenozoic basins, and Tethyan Himalayan rocks, and to investigate their regional geochemical signatures. Samples from rivers along the IYS in southern Tibet, between Xigaze and Mt. Kailas, were analyzed for detrital geochronology and low-temperature thermochronology. Comparison between ages recorded in the source and the detrital signature indicates that both the ages and their proportions directly reflect the ages and relative areas of source rocks in the catchment basins. Apatite fission track ages show two main cooling signals at 22-18 Ma and 12 Ma, which are consistent with accelerated exhumation of the Gangdese batholith and Oligo-Miocene Kailas basin and indicate significant regional exhumation of the IYS during the Miocene. Regional exhumation recorded throughout the IYS is likely the combined product of active Miocene tectonics and erosion of a paleo-Yarlung River. Efficient incision and evacuation of material from the IYS zone by a paleo-Yarlung River during the Miocene suggests a significantly different paleoenvironment than that which exists today. Miocene capture of the Yarlung River by the Brahmaputra River may have enhanced erosion in the IYS zone.

  8. Adaptive Evolution of cry Genes in Bacillus thuringiensis:Implications for Their Specificity Determination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The cry gene family, produced during the late exponential phase of growth in Bacillus thuringiensis, is a large, still-growing family of homologous genes, in which each gene encodes a protein with strong specific activity against only one or a few insect species. Extensive studies are mostly focusing on the structural and functional relationships of Cry proteins, and have revealed several residues or domains that are important for the target recognition and receptor attachment. In this study,we have employed a maximum likelihood method to detect evidence of adaptive evolution in Cry proteins, and have identified 24 positively selected residues, which are all located in Domain Ⅱ or Ⅲ. Combined with known data from mutagenesis studies, the majority of these residues, at the molecular level, contribute much to the insect specificity determination. We postulate that the potential pressures driving the diversification of Cry proteins may be in an attempt to adapt for the "arm race" between δ-endotoxins and the targeted insects, or to enlarge their target spectra, hence result in the functional divergence. The sites identified to be under positive selection would provide targets for further structural and functional analyses on Cry proteins.

  9. Molecular Gas Content of HI Monsters and Implications to Cold Gas Content Evolution in Galaxies

    CERN Document Server

    Lee, Cheoljong; Yun, Min S; Cybulski, Ryan; Narayanan, G; Erickson, N

    2014-01-01

    We present 12CO (J=1-0) observations of a sample of local galaxies (0.043e10Msun from the ALFALFA survey and 8 LSBs with a comparable M(HI) (>1.5e10Msun). Our sample selection is purely based on the amount of neutral hydrogen, thereby providing a chance to study how atomic and molecular gas relate to each other in these HI-massive systems. We have detected CO in 15 out of 20 ALFALFA selected galaxies and 4 out of 8 LSBs with molecular gas mass M(H2) of (1-11)e9Msun. Their total cold gas masses of (2-7e10Msun make them some of the most gas-massive galaxies identified to date in the Local Universe. Observed trends associated with HI, H2, and stellar properties of the HI massive galaxies and the field comparison sample are analyzed in the context of theoretical models of galaxy cold gas content and evolution, and the importance of total gas content and improved recipes for handling spatially differentiated behaviors of disk and halo gas are identified as potential areas of improvement for the modeling.

  10. The Dearth of UV-Bright Stars in M32: Implications for Stellar Evolution Theory

    CERN Document Server

    Brown, Thomas M; Ferguson, Henry C; Sweigart, Allen V; Kimble, Randy A; Bowers, Charles W

    2008-01-01

    Using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, we have obtained deep far-ultraviolet images of the compact elliptical galaxy M32. When combined with earlier near-ultraviolet images of the same field, these data enable the construction of an ultraviolet color-magnitude diagram of the hot horizontal branch (HB) population and other hot stars in late phases of stellar evolution. We find few post-asymptotic giant branch (PAGB) stars in the galaxy, implying that these stars either cross the HR diagram more rapidly than expected, and/or that they spend a significant fraction of their time enshrouded in circumstellar material. The predicted luminosity gap between the hot HB and its AGB-Manque (AGBM) progeny is less pronounced than expected, especially when compared to evolutionary tracks with enhanced helium abundances, implying that the presence of hot HB stars in this metal-rich population is not due to (Delta Y)/(Delta Z) > 4. Only a small fraction (~2%) of the HB population is hot ...

  11. Millisecond Pulsar Ages: Implications of Binary Evolution and a Maximum Spin Frequency

    CERN Document Server

    Kiziltan, Bulent

    2009-01-01

    In the absence of constraints from the binary companion or supernova remnant, the standard method for estimating pulsar ages is to infer an age from the rate of spin-down. While the generic spin-down age may give realistic estimates for normal pulsars, it can fail for pulsars with very short periods. Details of the spin-up process during the low mass X-ray binary phase pose additional constraints on the period (P) and spin-down rates (Pdot) that may consequently affect the age estimate. Here, we propose a new recipe to estimate millisecond pulsar (MSP) ages that parametrically incorporates constraints arising from binary evolution and limiting physics. We show that the standard method can be improved by this approach to achieve age estimates closer to the true age whilst the standard spin-down age may over- or under-estimate the age of the pulsar by more than a factor of ~10 in the millisecond regime. We use this approach to analyze the population on a broader scale. For instance, in order to understand the d...

  12. The Composition of the Sagittarius Dwarf Spheroidal Galaxy and Implications for Nucleosynthesis and Chemical Evolution

    CERN Document Server

    McWilliam, A; William, Andrew Mc; Smecker-Hane, Tammy A.

    2004-01-01

    We outline the results of a study of the chemical composition of 14 stars in the Sagittarius dwarf spheroidal galaxy (Sgr dSph). For the Sgr dSph stars with [Fe/H]>-1 the abundances are highly unusual, showing a striking enhancement in heavy s-process elements, increasing with [Fe/H], deficiencies of the alpha- elements (O, Si, Ca, and Ti), deficiencies of Al and Na, and deficiencies of the iron-peak elements Mn and Cu. Our abundances suggest that the composition of the metal-rich Sgr dSph stars is dominated by the ejecta of an old, metal-poor population, including products of AGB stars and type Ia supernovae (SN). We suggest two scenarios to explain the observations: Prolonged chemical evolution in a galaxy experiencing significant mass-loss, and chemical enrichment with episodic bursts of star formation. The Galactic globular cluster Omega Cen, and the Fornax dwarf galaxy show similar abundance patterns, which suggests that those systems evolved similar to the Sgr dSph.

  13. Geomorphological evolution of badlands based on the dynamics of palaeo-channels and their implications

    Indian Academy of Sciences (India)

    V Ranga; S N Mohapatra; P Pani

    2015-07-01

    The badlands along the lower Chambal valley represent the worst case of water erosion in India. These badlands are believed to have developed due to neo-tectonic activities and, probably, strengthening of southwest monsoon in late Pleistocene–Holocene. Due to neo-tectonic activities, the Chambal River has undergone many changes before reaching to its present planform. This study reports palaeo-channels on the Chambal River’s right flank along its lower reaches. Salient features of the palaeo-channels and their relation to present spatial pattern of badlands are studied. These palaeo-channels have significantly influenced the development of badlands along the lower Chambal River and have given them distinct and conspicuous spatial patterns. In the light of the evidences, a modified schematic geomorphic evolution of badlands development is also proposed starting from a pre-incision scenario till the present day situation. A major modification in the proposed model is the multi-channel planform of the Chambal River before its incision.

  14. Organics Produced by Irradiation of Frozen and Liquid HCN Solutions: Implications for Chemical Evolution Studies

    Science.gov (United States)

    Colín-García, M.; Negrón-Mendoza, A.; Ramos-Bernal, S.

    2009-04-01

    Hydrogen cyanide (HCN), an important precursor of organic compounds, is widely present in extraterrestrial environments. HCN is also readily synthesized in prebiotic simulation experiments. To gain insight into the radiation chemistry of one of the most important and highly versatile constituents of cometary ices, we examined the behavior of over-irradiated frozen and liquid HCN solutions under ionizing radiation. The samples were exposed to gamma radiation at a dose range from 0 up to 419 kGy. Ultraviolet spectroscopy and gas chromatography were used to follow the process. The analyses confirmed that gamma-ray irradiation of liquid HCN solutions generates several organic products. Many of them are essential to life; we verified the presence of carboxylic acids (some of them members of the Krebs cycle) as well as free amino acids and urea. These are the first studies to reveal the presence of these compounds in experiments performed at low temperatures and bulk irradiation. Organic material was produced even at low temperatures and low radiation doses. This work strongly supports the presumption that, as a parent molecule, HCN played a central essential role in the process of chemical evolution on early Earth, comets, and other extraterrestrial environments.

  15. Following The Cosmic Evolution Of Pristine Gas I: Implications For Milky Way Halo Stars

    CERN Document Server

    Sarmento, Richard; Pan, Liubin

    2016-01-01

    We make use of new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova ejecta, and the impact on the chemical composition of the Galactic Halo. Using the cosmological adaptive mesh refinement code RAMSES, we implement a model for the pollution of pristine gas as described in Pan et al. (2013). Tracking the metallicity of Pop III stars with metallicities below a critical value allows us to account for the fraction of Z < Zcrit stars formed even in regions in which the gas' average metallicity is well above Zcrit. We demonstrate that such partially-mixed regions account for 0.5 to 0.7 of all Pop III stars formed up to z = 5. Additionally, we track the creation and transport of "primordial metals" generated by Pop III supernovae (SNe). These metals are taken up by second-generation stars and likely lead to unique abundance signatures characteristic of carbon enhanced, metal poor (CEMP) stars. As an illustrative example, we associa...

  16. Snežna jama (Slovenia): Interdisciplinary dating of cave sediments and implication for landscape evolution

    Science.gov (United States)

    Häuselmann, Philipp; Mihevc, Andrej; Pruner, Petr; Horáček, Ivan; Čermák, Stanislav; Hercman, Helena; Sahy, Diana; Fiebig, Markus; Hajna, Nadja Zupan; Bosák, Pavel

    2015-10-01

    Caves are important markers of surface evolution, since they are, as a general rule, linked with ancient valley bottoms by their springs. However, caves can only be dated indirectly by means of the sediments they contain. If the sediment is older than common dating methods, one has to use multiple dating approaches in order to get meaningful results. U/Th dating, palaeomagnetic analysis of flowstone and sediment profiles, cosmogenic dating of quartz pebbles, and mammalian dating allowed a robust estimate of speleogenesis, sediment deposition, climatic change at the surface, and uplift history on the Periadriatic fault line during the Plio-Pleistocene. Our dates indicate that Snežna jama was formed in the (Upper) Miocene, received its sedimentary deposits during the Pliocene in a rather low-lying, hilly landscape, and became inactive due to uplift along the Periadriatic and Sava faults and climatic changes at the beginning of the Quaternary. Although it is only a single cave, the information contained within it makes it an important site of the Southern Alps.

  17. Seismic Interpretation of the Nam Con Son Basin and its Implication for the Tectonic Evolution

    Directory of Open Access Journals (Sweden)

    Nguyen Quang Tuan

    2016-08-01

    Full Text Available The Nam Con Son Basin covering an area of circa 110,000 km2 is characterized by complex tectonic settings of the basin which has not fully been understood. Multiple faults allowed favourable migration passageways for hydrocarbons to go in and out of traps. Despite a large amount of newly acquired seismic and well data there is no significant update on the tectonic evolution and history of the basin development. In this study, the vast amount of seismic and well data were integrated and reinterpreted to define the key structural events in the Nam Con Son Basin. The results show that the basin has undergone two extentional phases. The first N - S extensional phase terminated at around 30 M.a. forming E - W trending grabens which are complicated by multiple half grabens filled by Lower Oligocene sediments. These grabens were reactivated during the second NW - SE extension (Middle Miocene, that resulted from the progressive propagation of NE-SW listric fault from the middle part of the grabens to the margins, and the large scale building up of roll-over structure. Further to the SW, the faults of the second extentional phase turn to NNE-SSW and ultimately N - S in the SW edge of the basin. Most of the fault systems were inactive by Upper Miocene except for the N - S fault system which is still active until recent time.

  18. Evolution of massive black hole binaries in rotating galactic nuclei: implications for gravitational wave detection

    Science.gov (United States)

    Rasskazov, Alexander; Merritt, David

    2017-01-01

    The subject of our study is a binary supermassive black hole (BSBH) in the center of a galactic nucleus. We model the evolution of its orbit due to interactions with the stars of the galaxy by means of 3-body scattering experiments. Our model includes a new degree of freedom - the orientation of the BSBH’s orbital plane - which is allowed to change due to interaction with the stars in a rotating nucleus. The binary’s eccentricity also evolves in an orientation-dependent manner. We find that the dynamics are qualitatively different compared with non-rotating nuclei: 1) The BSBH's orbital plane evolves toward alignment with the plane of rotation of the nucleus; 2) The BSBH’s eccentricity decreases for aligned BSBHs and increases for counter-aligned ones.We then apply our model to calculate the effects of stellar environment on the gravitational wave background spectrum produced by BSBHs. Using the results of recent N-body/Monte-Carlo simulations we account for different rates of stellar interaction in spherical, axisymmetric and triaxial galaxies. We also consider the possibility that SBH masses are systematically lower than usually assumed. The net result of the new physical mechanisms included here is a spectrum for the stochastic gravitational wave background that has a significantly lower amplitude than in previous treatments, which could explain the discrepancy that currently exists between the models and the upper limits set by pulsar timing array observations.

  19. Observations of dwarfs in nearby voids: implications for galaxy formation and evolution

    CERN Document Server

    Pustilnik, Simon A

    2014-01-01

    The intermediate results of the ongoing study of deep samples of ~200 galaxies residing in nearby voids, are presented. Their properties are probed via optical spectroscopy, ugri surface photometry, and HI 21-cm line measurements, with emphasis on their evolutionary status. We derive directly the hydrogen mass M(HI), the ratio M(HI)/L_B and the evolutionary parameter gas-phase O/H. Their luminosities and integrated colours are used to derive stellar mass M(*) and the second evolutionary parameter -- gas mass-fraction f_g. The colours of the outer parts, typically representative of the galaxy oldest stellar population, are used to estimate the upper limits on time since the beginning of the main SF episode. We compare properties of void galaxies with those of the similar late-type galaxies in denser environments. Most of void galaxies show smaller O/H for their luminosity, in average by ~30%, indicating slower evolution. Besides, the fraction of ~10% of the whole void sample or ~30% of the least luminous void ...

  20. Organics produced by irradiation of frozen and liquid HCN solutions: implications for chemical evolution studies.

    Science.gov (United States)

    Colín-García, M; Negrón-Mendoza, A; Ramos-Bernal, S

    2009-04-01

    Hydrogen cyanide (HCN), an important precursor of organic compounds, is widely present in extraterrestrial environments. HCN is also readily synthesized in prebiotic simulation experiments. To gain insight into the radiation chemistry of one of the most important and highly versatile constituents of cometary ices, we examined the behavior of over-irradiated frozen and liquid HCN solutions under ionizing radiation. The samples were exposed to gamma radiation at a dose range from 0 up to 419 kGy. Ultraviolet spectroscopy and gas chromatography were used to follow the process. The analyses confirmed that gamma-ray irradiation of liquid HCN solutions generates several organic products. Many of them are essential to life; we verified the presence of carboxylic acids (some of them members of the Krebs cycle) as well as free amino acids and urea. These are the first studies to reveal the presence of these compounds in experiments performed at low temperatures and bulk irradiation. Organic material was produced even at low temperatures and low radiation doses. This work strongly supports the presumption that, as a parent molecule, HCN played a central essential role in the process of chemical evolution on early Earth, comets, and other extraterrestrial environments.

  1. Evolution of feline immunodeficiency virus in Felidae: implications for human health and wildlife ecology.

    Science.gov (United States)

    Pecon-Slattery, Jill; Troyer, Jennifer L; Johnson, Warren E; O'Brien, Stephen J

    2008-05-15

    Genetic analyses of feline immunodeficiency viruses provide significant insights on the worldwide distribution and evolutionary history of this emerging pathogen. Large-scale screening of over 3000 samples from all species of Felidae indicates that at least some individuals from most species possess antibodies that cross react to FIV. Phylogenetic analyses of genetic variation in the pol-RT gene demonstrate that FIV lineages are species-specific and suggest that there has been a prolonged period of viral-host co-evolution. The clinical effects of FIV specific to species other than domestic cat are controversial. Comparative genomic analyses of all full-length FIV genomes confirmed that FIV is host specific. Recently sequenced lion subtype E is marginally more similar to Pallas cat FIV though env is more similar to that of domestic cat FIV, indicating a possible recombination between two divergent strains in the wild. Here we review global patterns of FIV seroprevalence and endemnicity, assess genetic differences within and between species-specific FIV strains, and interpret these with patterns of felid speciation to propose an ancestral origin of FIV in Africa followed by interspecies transmission and global dissemination to Eurasia and the Americas. Continued comparative genomic analyses of full-length FIV from all seropositive animals, along with whole genome sequence of host species, will greatly advance our understanding of the role of recombination, selection and adaptation in retroviral emergence.

  2. Evolution Of Massive Black Hole Binaries In Rotating Stellar Nuclei: Implications For Gravitational Wave Detection

    CERN Document Server

    Rasskazov, Alexander

    2016-01-01

    We compute the isotropic gravitational wave (GW) background produced by binary supermassive black holes (SBHs) in galactic nuclei. In our model, massive binaries evolve at early times via gravitational-slingshot interaction with nearby stars, and at later times by the emission of GWs. Our expressions for the rate of binary hardening in the "stellar" regime are taken from the recent work of Vasiliev et al., who show that in the non-axisymmetric galaxies expected to form via mergers, stars are supplied to the center at high enough rates to ensure binary coalescence on Gyr timescales. We also include, for the first time, the extra degrees of freedom associated with evolution of the binary's orbital plane; in rotating nuclei, interaction with stars causes the orientation and the eccentricity of a massive binary to change in tandem, leading in some cases to very high eccentricities (e>0.9) before the binary enters the GW-dominated regime. We argue that previous studies have over-estimated the mean ratio of SBH mas...

  3. Revisiting the origin of modern humans in China and its implications for global human evolution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The debates over the origin of modern humans have long been centered on two competing theories:the "Out-of-Africa"(single-place origin) theory and the "Multi-regional Evolution" theory.China is an extremely important region where many ancient human fossils were collected along with numerous associated faunal remains and artefacts.These cultural remains,unearthed from different areas in the country and covering a long time span,will help clarify the controversy.The study of cultural materials in China is expected to shed important light on biological evolutionary patterns and social and technical developments of those early humans as well as their environmental conditions.Based on the analysis of Chinese fossils and associated materials,in conjunction with some genetic studies,this paper aims at evaluating each of the two theories in order to stimulate more discussions.Our study suggests that the evolutionary model of "Continuity with Hybridization" is most relevant in reflecting the current understanding of human evolutionary history in China.Furthermore,we propose that the concept of regional diversity of evolutionary models should be seriously considered to illustrate different evolutionary modes applied to different parts of the world.

  4. Whole genome comparative studies between chicken and turkey and their implications for avian genome evolution

    Directory of Open Access Journals (Sweden)

    Carré Wilfrid

    2008-04-01

    Full Text Available Abstract Background Comparative genomics is a powerful means of establishing inter-specific relationships between gene function/location and allows insight into genomic rearrangements, conservation and evolutionary phylogeny. The availability of the complete sequence of the chicken genome has initiated the development of detailed genomic information in other birds including turkey, an agriculturally important species where mapping has hitherto focused on linkage with limited physical information. No molecular study has yet examined conservation of avian microchromosomes, nor differences in copy number variants (CNVs between birds. Results We present a detailed comparative cytogenetic map between chicken and turkey based on reciprocal chromosome painting and mapping of 338 chicken BACs to turkey metaphases. Two inter-chromosomal changes (both involving centromeres and three pericentric inversions have been identified between chicken and turkey; and array CGH identified 16 inter-specific CNVs. Conclusion This is the first study to combine the modalities of zoo-FISH and array CGH between different avian species. The first insight into the conservation of microchromosomes, the first comparative cytogenetic map of any bird and the first appraisal of CNVs between birds is provided. Results suggest that avian genomes have remained relatively stable during evolution compared to mammalian equivalents.

  5. Snežna jama (Slovenia): Interdisciplinary dating of cave sediments and implication for landscape evolution

    Science.gov (United States)

    Häuselmann, Philipp; Mihevc, Andrej; Pruner, Petr; Horáček, Ivan; Čermák, Stanislav; Hercman, Helena; Sahy, Diana; Fiebig, Markus; Hajna, Nadja Zupan; Bosák, Pavel

    2015-01-01

    Caves are important markers of surface evolution, since they are, as a general rule, linked with ancient valley bottoms by their springs. However, caves can only be dated indirectly by means of the sediments they contain. If the sediment is older than common dating methods, one has to use multiple dating approaches in order to get meaningful results. U/Th dating, palaeomagnetic analysis of flowstone and sediment profiles, cosmogenic dating of quartz pebbles, and mammalian dating allowed a robust estimate of speleogenesis, sediment deposition, climatic change at the surface, and uplift history on the Periadriatic fault line during the Plio-Pleistocene. Our dates indicate that Snežna jama was formed in the (Upper) Miocene, received its sedimentary deposits during the Pliocene in a rather low-lying, hilly landscape, and became inactive due to uplift along the Periadriatic and Sava faults and climatic changes at the beginning of the Quaternary. Although it is only a single cave, the information contained within it makes it an important site of the Southern Alps. PMID:26516294

  6. Tumor histology and location predict deep nuclei toxicity: Implications for late effects from focal brain irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Plaga, Alexis; Shields, Lisa B.E. [Norton Neuroscience Institute, Louisville, KY (United States); Sun, David A.; Vitaz, Todd W. [Norton Neuroscience Institute, Louisville, KY (United States); Brain Tumor Center, Norton Healthcare, Louisville, KY (United States); Spalding, Aaron C., E-mail: acspalding1@gmail.com [Brain Tumor Center, Norton Healthcare, Louisville, KY (United States); Norton Cancer Institute, Radiation Center, Kosair Children' s Hospital, Louisville, KY (United States)

    2012-10-01

    Normal tissue toxicity resulting from both disease and treatment is an adverse side effect in the management of patients with central nervous system malignancies. We tested the hypothesis that despite these improvements, certain tumors place patients at risk for neurocognitive, neuroendocrine, and neurosensory late effects. Defining patient groups at risk for these effects could allow for development of preventive strategies. Fifty patients with primary brain tumors underwent radiation planning with magnetic resonance imaging scan and computed tomography datasets. Organs at risk (OAR) responsible for neurocognitive, neuroendocrine, and neurosensory function were defined. Inverse-planned intensity-modulated radiation therapy was optimized with priority given to target coverage while penalties were assigned to exceeding normal tissue tolerances. Tumor laterality, location, and histology were compared with OAR doses, and analysis of variance was performed to determine the significance of any observed correlation. The ipsilateral hippocampus exceeded dose limits in frontal (74%), temporal (94%), and parietal (100%) lobe tumor locations. The contralateral hippocampus was at risk in the following tumor locations: frontal (53%), temporal (83%), or parietal (50%) lobe. Patients with high-grade glioma were at risk for ipsilateral (88%) and contralateral (73%) hippocampal damage (P <0.05 compared with other histologies). The pituitary gland and hypothalamus exceeded dose tolerances in patients with pituitary tumors (both 100%) and high-grade gliomas (50% and 75%, P <0.05 compared with other histologies), respectively. Despite application of modern radiation therapy, certain tumor locations and histologies continue to place patients at risk for morbidity. Patients with high-grade gliomas or tumors located in the frontal, temporal, or parietal lobes are at risk for neurocognitive decline, likely because of larger target volumes and higher radiation doses. Data from this study

  7. Brain response to a humanoid robot in areas implicated in the perception of human emotional gestures.

    Directory of Open Access Journals (Sweden)

    Thierry Chaminade

    Full Text Available BACKGROUND: The humanoid robot WE4-RII was designed to express human emotions in order to improve human-robot interaction. We can read the emotions depicted in its gestures, yet might utilize different neural processes than those used for reading the emotions in human agents. METHODOLOGY: Here, fMRI was used to assess how brain areas activated by the perception of human basic emotions (facial expression of Anger, Joy, Disgust and silent speech respond to a humanoid robot impersonating the same emotions, while participants were instructed to attend either to the emotion or to the motion depicted. PRINCIPAL FINDINGS: Increased responses to robot compared to human stimuli in the occipital and posterior temporal cortices suggest additional visual processing when perceiving a mechanical anthropomorphic agent. In contrast, activity in cortical areas endowed with mirror properties, like left Broca's area for the perception of speech, and in the processing of emotions like the left anterior insula for the perception of disgust and the orbitofrontal cortex for the perception of anger, is reduced for robot stimuli, suggesting lesser resonance with the mechanical agent. Finally, instructions to explicitly attend to the emotion significantly increased response to robot, but not human facial expressions in the anterior part of the left inferior frontal gyrus, a neural marker of motor resonance. CONCLUSIONS: Motor resonance towards a humanoid robot, but not a human, display of facial emotion is increased when attention is directed towards judging emotions. SIGNIFICANCE: Artificial agents can be used to assess how factors like anthropomorphism affect neural response to the perception of human actions.

  8. Brain circuits implicated in psychogenic paralysis in conversion disorders and hypnosis.

    Science.gov (United States)

    Vuilleumier, P

    2014-10-01

    Conversion disorders are defined as neurological symptoms arising without organic damage to the nervous system, presumably in relation to various emotional stress factors, but the exact neural substrates of these symptoms and the mechanisms responsible for their production remain poorly understood. In the past 15 years, novel insights have been gained with the advent of functional neuroimaging studies in patients suffering from conversion disorders in both motor and non-motor (e.g. somatosensory, visual) domains. Several studies have also compared brain activation patterns in conversion to those observed during hypnosis, where similar functional losses can be evoked by suggestion. The current review summarizes these recent results and the main neurobiological hypotheses proposed to account for conversion symptoms, in particular motor deficits. An emerging model points to an important role of ventromedial prefrontal cortex (VMPFC), precuneus, and perhaps other limbic structures (including amygdala), all frequently found to be hyperactivated in conversion disorders in parallel to impaired recruitment of primary motor and/or sensory pathways at the cortical or subcortical (basal ganglia) level. These findings are only partly shared with hypnosis, where increases in precuneus predominate, together with activation of attentional control systems, but without any activation of VMPFC. Both VMPFC and precuneus are key regions for access to internal representations about the self, integrating information from memory and imagery with affective relevance (in VMPFC) and sensory or agency representations (in precuneus). It is therefore postulated that conversion deficits might result from an alteration of conscious sensorimotor functions and self-awareness under the influence of affective and sensory representations generated in these regions, which might promote certain patterns of behaviors in response to self-relevant emotional states.

  9. Low temperature thermochronology in the Eastern Alps: Implications for structural and topographic evolution

    Science.gov (United States)

    Wölfler, Andreas; Stüwe, Kurt; Danišík, Martin; Evans, Noreen J.

    2012-01-01

    According to new apatite fission track, zircon- and apatite (U–Th)/He data, we constrain the near-surface history of the southeastern Tauern Window and adjacent Austrolapine units. The multi-system thermochronological data demonstrate that age-elevation correlations may lead to false implications about exhumation and cooling in the upper crust. We suggest that isothermal warping in the Penninic units that are in the position of a footwall, is due to uplift, erosion and the buildup of topography. Additionally we propose that exhumation rates in the Penninic units did not increase during the Middle Miocene, thus during the time of lateral extrusion. In contrast, exhumation rates of the Austroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this unit were not warped. The new zircon (U–Th)/He ages as well as zircon fission track ages from the literature document a Middle Miocene exhumation pulse which correlates with a period of enhanced sediment accumulation during that time. However, enhanced sedimentation- and exhumation rates at the Miocene/Pliocene boundary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for surface uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvious to explain surface uplift in the Eastern Alps. In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the Möll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik–Möll valley- and Mur–Mürz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg–Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc. PMID:27065501

  10. Effectiveness of a neuropsychological treatment for confabulations after brain injury: A clinical trial with theoretical implications

    Science.gov (United States)

    Triviño, Mónica; Ródenas, Estrella; Lupiáñez, Juan; Arnedo, Marisa

    2017-01-01

    Confabulators consistently generate false memories without intention to deceive and with great feelings of rightness. However, to our knowledge, there is currently no known effective treatment for them. In order to fill this gap, our aim was to design a neuropsychological treatment based on current theoretical models and test it experimentally in 20 confabulators sequentially allocated to two groups: an experimental and a control group. The experimental group received nine sessions of treatment for three weeks (three sessions per week). The sessions consisted of some brief material that participants had to learn and recall at both immediate and delayed time points. After this, patients were given feedback about their performance (errors and correct responses). Pre- and post-treatment measurements were recorded. Confabulators in the control group were included in a waiting list for three weeks, performed the pre- and post- measurements without treatment, and only then received the treatment, after which a post-treatment measurement was recorded. This applied to only half of the participants; the other half quit the study prematurely. Results showed a significant decrease in confabulations and a significant increase in correct responses in the experimental group; by contrast, patients in the control group did not improve during the waiting list period. Only control group patients who subsequently received the treatment after serving as controls improved. The effects of the treatment were generalized to patients’ everyday lives, as reported by relatives, and persisted over time. This treatment seems to be effective and easy to implement and consequently of clinical interest. Moreover, it also has theoretical implications regarding the processes related to the genesis and/or maintenance of confabulations. In particular, results point to a deficit in early stages of memory retrieval with the preservation of later strategic monitoring processes. Specifically, some of

  11. Authigenic iron oxide proxies for marine zinc over geological time and implications for eukaryotic metallome evolution.

    Science.gov (United States)

    Robbins, L J; Lalonde, S V; Saito, M A; Planavsky, N J; Mloszewska, A M; Pecoits, E; Scott, C; Dupont, C L; Kappler, A; Konhauser, K O

    2013-07-01

    Here, we explore enrichments in paleomarine Zn as recorded by authigenic iron oxides including Precambrian iron formations, ironstones, and Phanerozoic hydrothermal exhalites. This compilation of new and literature-based iron formation analyses track dissolved Zn abundances and constrain the magnitude of the marine reservoir over geological time. Overall, the iron formation record is characterized by a fairly static range in Zn/Fe ratios throughout the Precambrian, consistent with the shale record (Scott et al., 2013, Nature Geoscience, 6, 125-128). When hypothetical partitioning scenarios are applied to this record, paleomarine Zn concentrations within about an order of magnitude of modern are indicated. We couple this examination with new chemical speciation models to interpret the iron formation record. We present two scenarios: first, under all but the most sulfidic conditions and with Zn-binding organic ligand concentrations similar to modern oceans, the amount of bioavailable Zn remained relatively unchanged through time. Late proliferation of Zn in eukaryotic metallomes has previously been linked to marine Zn biolimitation, but under this scenario the expansion in eukaryotic Zn metallomes may be better linked to biologically intrinsic evolutionary factors. In this case, zinc's geochemical and biological evolution may be decoupled and viewed as a function of increasing need for genome regulation and diversification of Zn-binding transcription factors. In the second scenario, we consider Archean organic ligand complexation in such excess that it may render Zn bioavailability low. However, this is dependent on Zn-organic ligand complexes not being bioavailable, which remains unclear. In this case, although bioavailability may be low, sphalerite precipitation is prevented, thereby maintaining a constant Zn inventory throughout both ferruginous and euxinic conditions. These results provide new perspectives and constraints on potential couplings between the

  12. Molecular evolution of a-kinase anchoring protein (AKAP-7: implications in comparative PKA compartmentalization

    Directory of Open Access Journals (Sweden)

    Johnson Keven R

    2012-07-01

    Full Text Available Abstract Background A-Kinase Anchoring Proteins (AKAPs are molecular scaffolding proteins mediating the assembly of multi-protein complexes containing cAMP-dependent protein kinase A (PKA, directing the kinase in discrete subcellular locations. Splice variants from the AKAP7 gene (AKAP15/18 are vital components of neuronal and cardiac phosphatase complexes, ion channels, cardiac Ca2+ handling and renal water transport. Results Shown in evolutionary analyses, the formation of the AKAP7-RI/RII binding domain (required for AKAP/PKA-R interaction corresponds to vertebrate-specific gene duplication events in the PKA-RI/RII subunits. Species analyses of AKAP7 splice variants shows the ancestral AKAP7 splice variant is AKAP7α, while the ancestral long form AKAP7 splice variant is AKAP7γ. Multi-species AKAP7 gene alignments, show the recent formation of AKAP7δ occurs with the loss of native AKAP7γ in rats and basal primates. AKAP7 gene alignments and two dimensional Western analyses indicate that AKAP7γ is produced from an internal translation-start site that is present in the AKAP7δ cDNA of mice and humans but absent in rats. Immunofluorescence analysis of AKAP7 protein localization in both rat and mouse heart suggests AKAP7γ replaces AKAP7δ at the cardiac sarcoplasmic reticulum in species other than rat. DNA sequencing identified Human AKAP7δ insertion-deletions (indels that promote the production of AKAP7γ instead of AKAP7δ. Conclusions This AKAP7 molecular evolution study shows that these vital scaffolding proteins developed in ancestral vertebrates and that independent mutations in the AKAP7 genes of rodents and early primates has resulted in the recent formation of AKAP7δ, a splice variant of likely lesser importance in humans than currently described.

  13. Hormones and phenotypic plasticity: Implications for the evolution of integrated adaptive phenotypes

    Institute of Scientific and Technical Information of China (English)

    Sean C.LEMA; Jun KITANO

    2013-01-01

    It is generally accepted that taxa exhibit genetic variation in phenotypic plasticity,but many questions remain unanswered about how divergent plastic responses evolve under dissimilar ecological conditions.Hormones are signaling molecules that act as proximate mediators of phenotype expression by regulating a variety of cellular,physiological,and behavioral responses.Hormones not only change cellular and physiological states but also influence gene expression directly or indirectly,thereby linking environmental conditions to phenotypic development.Studying how hormonal pathways respond to environmental variation and how those responses differ between individuals,populations,and species can expand our understanding of the evolution of phenotypic plasticity.Here,we explore the ways that the study of hormone signaling is providing new insights into the underlying proximate bases for individual,population or species variation in plasticity.Using several studies as exemplars,we examine how a 'norm of reaction' approach can be used in investigations of hormone-mediated plasticity to inform the following:1) how environmental cues affect the component hormones,receptors and enzymes that comprise any endocrine signaling pathway,2) how genetic and epigenetic variation in endocrine-associated genes can generate variation in plasticity among these diverse components,and 3) how phenotypes mediated by the same hormone can be coupled and decoupled via independent plastic responses of signaling components across target tissues.Future studies that apply approaches such as reaction norms and network modeling to questions concerning how hormones link environmental stimuli to ecologically-relevant phenotypic responses should help unravel how phenotypic plasticity evolves.

  14. Bedrock gorges in the central mainland Kachchh: Implications for landscape evolution

    Indian Academy of Sciences (India)

    M G Thakkar; B Goyal; A K Patidar; D M Maurya; L S Chamyal

    2006-04-01

    Kachchh possesses a fault-controlled first-order topography and several geomorphic features indicative of active tectonics.Though coseismic neotectonic activity is believed to be the major factor in the evolution of the landscape,detailed documentation and analysis of vital landscape features like drainage characteristics,bedrock gorges and terraces are lacking.The present study is a site-speci fic documentation of gorges developed in the central part of the mainland Kachchh.We analyzed and interpreted four gorges occurring on either side of Katrol Hill Fault (KHF).The Khari river gorge is endowed with six levels of bedrock terraces,some of which are studded with large potholes and flutings.Since no active development of potholes is observed along the rivers in the present day hyper-arid conditions,we infer an obvious linkage of gorges to the humid phases,which provided high energy runoff for the formation of gorges and distinct bedrock terraces and associated erosional features.Development of gorges within the miliolites and incision in the fluvial deposits to the south of the KHF indicates that the gorges were formed during Early Holocene.However,ubi-quitous occurrence of gorges along the streams to the south of KHF,the uniformly N40°E trend of the gorges,their close association with transverse faults and the short length of the exceptionally well developed Khari river gorge in the low-relief rocky plain to the north of KHF suggests an important role of neotectonic movements.

  15. Fish Ecology and Evolution in the World's Oxygen Minimum Zones and Implications of Ocean Deoxygenation.

    Science.gov (United States)

    Gallo, N D; Levin, L A

    Oxygen minimum zones (OMZs) and oxygen limited zones (OLZs) are important oceanographic features in the Pacific, Atlantic, and Indian Ocean, and are characterized by hypoxic conditions that are physiologically challenging for demersal fish. Thickness, depth of the upper boundary, minimum oxygen levels, local temperatures, and diurnal, seasonal, and interannual oxycline variability differ regionally, with the thickest and shallowest OMZs occurring in the subtropics and tropics. Although most fish are not hypoxia-tolerant, at least 77 demersal fish species from 16 orders have evolved physiological, behavioural, and morphological adaptations that allow them to live under the severely hypoxic, hypercapnic, and at times sulphidic conditions found in OMZs. Tolerance to OMZ conditions has evolved multiple times in multiple groups with no single fish family or genus exploiting all OMZs globally. Severely hypoxic conditions in OMZs lead to decreased demersal fish diversity, but fish density trends are variable and dependent on region-specific thresholds. Some OMZ-adapted fish species are more hypoxia-tolerant than most megafaunal invertebrates and are present even when most invertebrates are excluded. Expansions and contractions of OMZs in the past have affected fish evolution and diversity. Current patterns of ocean warming are leading to ocean deoxygenation, causing the expansion and shoaling of OMZs, which is expected to decrease demersal fish diversity and alter trophic pathways on affected margins. Habitat compression is expected for hypoxia-intolerant species, causing increased susceptibility to overfishing for fisheries species. Demersal fisheries are likely to be negatively impacted overall by the expansion of OMZs in a warming world.

  16. Following the Cosmic Evolution of Pristine Gas. I. Implications for Milky Way Halo Stars

    Science.gov (United States)

    Sarmento, Richard; Scannapieco, Evan; Pan, Liubin

    2017-01-01

    We make use of a new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova (SN) ejecta, and the impact on the chemical composition of the Galactic Halo. Using the cosmological adaptive mesh refinement code ramses, we implement a model for the pollution of pristine gas as described in Pan et al. Tracking the metallicity of Pop III stars with metallicities below a critical value allows us to account for the fraction of Zmixed regions account for 0.5 to 0.7 of all Pop III stars formed up to z = 5. Additionally, we track the creation and transport of “primordial metals” (PM) generated by Pop III SNe. These neutron-capture deficient metals are taken up by second-generation stars and likely lead to unique abundance signatures characteristic of carbon-enhanced, metal-poor (CEMP-no) stars. As an illustrative example, we associate primordial metals with abundance ratios used by Keller et al. to explain the source of metals in the star SMSS J031300.36-670839.3, finding good agreement with the observed [Fe/H], [C/H], [O/H], and [Mg/Ca] ratios in CEMP-no Milky Way halo stars. Similar future simulations will aid in further constraining the properties of Pop III stars using CEMP observations, as well as improve predictions of the spatial distribution of Pop III stars, as will be explored by the next generation of ground- and space-based telescopes.

  17. Evolution of Migmatitic Granulite Complexes: implications from Lapland Granulite Belt, Part II: isotopic dating

    Directory of Open Access Journals (Sweden)

    Pekka Tuisku

    2006-01-01

    Full Text Available The migmatitic metapelites of the Lapland granulite belt (LGB in the NE part of the Fennoscandian Shield represent an arc-related greywacke basin metamorphosed in the granulite facies. Detrital zircons from migmatitic metapelites are derived from 1.94 - 2.9 Ga old acid source rocks (U-Pb SIMS ages. The clustering of detrital zircon ages between 1.97 and 2.2 Ga is problematic, because abundant felsic crust of this age is absent in the shield. The metasediments are characterized by Sm-Nd model ages of ca. 2.3 Ga. A younger, 1905-1880 Ma population of homogeneous zircons was formed during regional metamorphism. The peak high-grade metamorphism took place at ~1900 Ma and the latest chronological record from subsequent decompression and cooling phase is from ca. 1870 Ma. The norite-enderbite series of the LGB represents arc-magmas, which were intruded into the metasediments at ~1920-1905 Ma ago according to zircon U-Pb ages and were probably an important heat source for metamorphism. Older, zoned zircon grains in a quartz norite vein, initial εNd values of 0 to +1 and the continuous spectrum of LILE enrichment in the enderbite-series probably reflect assimilation of metasediments by magmas. Monazite U-Pb ages of migmatitic metasediments in the range 1906-1910±3 Ma overlap the late stage of enderbite intrusion and growth of early metamorphic zircons. Garnet-whole rock Sm-Nd ages from leucosomes in the range 1880-1886±7 Ma are concurrent with the growth of the youngest metamorphic zircons and probably indicate the crystallization of leucosomes of the influence of a fluid liberated from them. Isotopic and petrologic data reveal that the evolution of Lapland Granulite belt from the erosion of source rocks to the generation of a sedimentary basin, its burial, metamorphism and exhumation took place within ca. 60 Ma.

  18. Cretaceous to miocene palaeogegraphic evolution of Turkey: implications for hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Gorur, N. [Tubitak Mam, Gebze (Turkey)

    2001-04-01

    The Cretaceous to Miocene palaeogeographic development of Turkey in general reflects the evolution of the various oceanic branches of Neo-Tethys together with interactions between the Laurasian and Gondwanan margins. At the beginning of the Cretaceous, the first-order palacotectonic units which make up present-day Turkey either formed parts of these supercontinents or were isolated continental blocks within the Neo-Tethys. In Aptian to Albian times, north-dipping subduction commenced along the southern margins of these units and resulted in the development of magmatic arcs and arc-related sedimentary basins. Coeval with the start of subduction, large-scale ophiolite abduction occurred on the units' passive margins. Terminal closure of the oceans' branches took place between the latest Cretaceous and the Miocene, forming the Anatolian orogenic collage whose outline defines present-day Turkey. Post-collisional intra-continental convergence continued until the late Miocene and resulted in north-south shortening of the collage. This shortening led to internal imbrication, thrusting and crustal thickening. It forced the Anatolian landmass westwards, away from east Anatolia where there has been continuous north-south compression since the Miocene between Laurasia and the Arabian Platform. Both the continental and the oceanic palaeotectonic units pose significant problems regarding their original geometry, size, depth, extent, contact relations, motion paths, subduction polarity, stratigraphy and timing of formation. Clarification of these issues is essential if the units' original paleogeographic relationships with respect to Neo-Tethys are to be reconstructed. This paper reviews some of these problems with the aid of a number of palinspastic and non-palinspastic maps. These maps are intended to provide a basis for evaluating the hydrocarbon potential of Turkey. (author)

  19. Delimitation and phylogeny of Aletris (Nartheciaceae) with implications for perianth evolution

    Institute of Scientific and Technical Information of China (English)

    Yi-Min ZHAO; Wei WANG; Shu-Ren ZHANG

    2012-01-01

    Aletris,containing approximately 21 species,is the largest genus in Nartheciaceae,and is disjunctively distributed in eastern Asia and eastern North America.Its delimitation has been controversial because it is uncertain whether Metanarthecium should be included in the genus.Although there are a few molecular phylogenetic studies on Aletris,the interspecific relationships within the genus have never been evaluated in a phylogenetic context.Here we used two cpDNA loci,matK and trnL-F,to delimitate A letris and discuss the phylogeny within the genus.Phylogenetic analyses showed Metanarthecium might be distantly related to Aletris.This is also supported by morphological,palynological,cytological,and phytochemical data.Therefore,Metanarthecium should be excluded from Aletris.Within Aletris,there are two major clades:A.farinosa and A.lutea of eastern North America and A.glabra of eastern Asia form clade A; and the remaining Asian species form clade B.The Asian clade includes three subclades:subclade Ⅰ (two varieties ofA.pauciflora,and A.glandulifera and A.megalantha),subclade Ⅱ (three samples of A.laxiflora),and subclade Ⅲ (all other sampled Asian species).Based on phylogenetic relationships,A.pauciflora var.khasiana deserves a specific status,and A.gracilipes,formerly a synonym ofA.laxiflora,should be reinstated.The reconstruction of the perianth evolution indicates that perianth connate halfway and glabrous on abaxial surface are plesiomorphic for Aletris and Nartheciaceae.Farinose-glutinous perianth is a diagnostic character for clade A.

  20. Hormones and phenotypic plasticity: Implications for the evolution of integrated adaptive phenotypes

    Directory of Open Access Journals (Sweden)

    Sean C. LEMA, Jun KITANO

    2013-08-01

    Full Text Available It is generally accepted that taxa exhibit genetic variation in phenotypic plasticity, but many questions remain unanswered about how divergent plastic responses evolve under dissimilar ecological conditions. Hormones are signaling molecules that act as proximate mediators of phenotype expression by regulating a variety of cellular, physiological, and behavioral responses. Hormones not only change cellular and physiological states but also influence gene expression directly or indirectly, thereby linking environmental conditions to phenotypic development. Studying how hormonal pathways respond to environmental variation and how those responses differ between individuals, populations, and species can expand our understanding of the evolution of phenotypic plasticity. Here, we explore the ways that the study of hormone signaling is providing new insights into the underlying proximate bases for individual, population or species variation in plasticity. Using several studies as exemplars, we examine how a ‘norm of reaction’ approach can be used in investigations of hormone-mediated plasticity to inform the following: 1 how environmental cues affect the component hormones, receptors and enzymes that comprise any endocrine signaling pathway, 2 how genetic and epigenetic variation in endocrine-associated genes can generate variation in plasticity among these diverse components, and 3 how phenotypes mediated by the same hormone can be coupled and decoupled via independent plastic responses of signaling components across target tissues. Future studies that apply approaches such as reaction norms and network modeling to questions concerning how hormones link environmental stimuli to ecologically-relevant phenotypic responses should help unravel how phenotypic plasticity evolves [Current Zoology 59 (4: 506–525, 2013].

  1. Post-Gondwana geomorphic evolution of southwestern Africa: Implications for hte controls on landscape development from observations and numerical experiments

    Science.gov (United States)

    Gilchrist, Alan R.; Kooi, Henk; Beaumont, Christopher

    1994-06-01

    The relationship between morphology and surficial geology is used to quantify the denudation that has occurred across southwestern Africa sicne the fragmentation of Gondwana during the Early Mesozoic. Two main points emerge. Signficant denudation, of the order of kilometers, is widespread except in the Kalahari region of the continental interior. The denudation is systematically distributed so that the continental exterior catchment, draining directly to the Cape basin, is denuded to a greater depth than the interior catchment inland of the Great Escarpment. The analysis also implies tha the majority of the denudation occurred before the beginning of the Cenozoic for both teh exerior and interior catchments. Existing models of landscape development are reviewed, and implications of the denudation chronology are incorporated into a revised conceptual model. This revision implies tha thte primary effect of rifting on the subsequent landscape evolution is that it generates two distinct drainage regimes. A marginal upwarp, or rift flank uplift, separates rejuvenated rivers that drain into the subsiding rift from rivers in the continetal interior that are deflected but not rejuvenated. The two catchments evolve independently unless they are integrated by breaching of hte marginal upwarp. If this occurs, the exterior baselevel is communicated to the interior catchment that is denuded accordingly. Denudation rates generally decrease as the margin evolves, and this decrease is reinforced by the exposure of substrate that is resistant to denudation and/or a change to a more arid climate. The observations do not reveal a particular style of smaller-scale landscape evolution, sucha s escarpment retreat, that is responsible for the differential denudation across the region. It is proposed that numerical model experiments, which reflect the observational insights at the large scale, may identify the smaller-scale controls on escarpment development if the model and natural

  2. Si- and alkali-rich melt inclusions in minerals of mantle peridotites from eastern China: Implication for lithospheric evolution

    Institute of Scientific and Technical Information of China (English)

    FAN; Qicheng; SUI; Jianli; XU; Ping; LI; Ni; SUN; Qian; WANG; Tuanhua

    2006-01-01

    Minerals of spinel- and garnet-facies mantle xenoliths entrained in Cenozoic basalts from eastern China (North China, Northeastern China and Southeastern China coastal area) contains lots of melt inclusions. Studies on these melt inclusions show that the glass inclusions are rich in SiO2 (60%―68%) and alkalis (K2O+Na2O=5%―11%, especially for K2O) as well as volatiles such as H2O and CO2 (2%―7%), which belong to dacites and andesites of the high-K calcic alkali series rocks with few shoshonites. High Al and Ca diopside in melt inclusion is the product of melt crystallization at high temperature and pressure, rather than the product of devitrification. Results show that these K-rich (in general K2O>3%) intermediate-acidic silicate melt inclusions have characteristics of continent without a genetical link to host basalts and their phenocrystic minerals. Thus, these trapped melt inclusions represent melts of Mesozoic lithospheric mantle-crust interaction and imply that the continental lithospheric mantle beneath eastern China had undergone fragmentation and recreation processes during the Mesozoic and Cenozoic periods. This result undoubtly provides important implication for the evolution of sub-continental lithosphere beneath eastern China. We propose that these Si- and alkalis-rich melts should be responsible for the mantle chemical heterogeneity underneath eastern China.

  3. The cultural evolution of language and brain: Comment on "Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain" by Michael A. Arbib

    Science.gov (United States)

    Colagè, Ivan

    2016-03-01

    Michael A. Arbib's Mirror System Hypothesis (MSH) [1,2] is among the most elaborate attempts at disentangling the issue of language origin. I will focus on the role that cultural evolution, as distinct from biological (genetic) evolution, may have played in the emergence of "modern" human language (as contrasted with forms of proto-languages).

  4. Patterns and Implications of Gene Gain and Loss in the Evolution of Prochlorococcus

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, Alla; Kettler, Gregory C.; Martiny, Adam C.; Huang, Katherine; Zucker, Jeremy; Coleman, Maureen L.; Rodrigue, Sebastien; Chen, Feng; Lapidus, Alla; Ferriera, Steven; Johnson, Justin; Steglich, Claudia; Church, George M.; Richardson, Paul; Chisholm, Sallie W.

    2007-07-30

    Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolatesfrom diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL)-adapted clade, or a more divergent low-light (LL)-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ by at most 3percent, and the four initially published genomes revealed patterns of genetic differentiation that help explain physiological differences among the isolates. Here we describe the genomes of eight newly sequenced isolates and combine them with the first four genomes for a comprehensive analysis of the core (shared by all isolates) and flexible genes of the Prochlorococcus group, and the patterns of loss and gain of the flexible genes over the course of evolution. There are 1,273 genes that represent the core shared by all 12 genomes. They are apparently sufficient, according to metabolic reconstruction, to encode a functional cell. We describe a phylogeny for all 12 isolates by subjecting their complete proteomes to three different phylogenetic analyses. For each non-core gene, we used a maximum parsimony method to estimate which ancestor likely first acquired or lost each gene. Many of the genetic differences among isolates, especially for genes involved in outer membrane synthesis and nutrient transport, are found within the same clade. Nevertheless, we identified some genes defining HL and LL ecotypes, and clades within these broad ecotypes, helping to demonstrate the basis of HL and LL adaptations in Prochlorococcus. Furthermore, our estimates of gene gain events allow us to identify highly variable genomic islands that are not apparent through simple pairwise comparisons. These results emphasize the functional roles, especially those connected to outer

  5. Patterns and implications of gene gain and loss in the evolution of Prochlorococcus.

    Directory of Open Access Journals (Sweden)

    Gregory C Kettler

    2007-12-01

    Full Text Available Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolates from diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL-adapted clade, or a more divergent low-light (LL-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ by at most 3%, and the four initially published genomes revealed patterns of genetic differentiation that help explain physiological differences among the isolates. Here we describe the genomes of eight newly sequenced isolates and combine them with the first four genomes for a comprehensive analysis of the core (shared by all isolates and flexible genes of the Prochlorococcus group, and the patterns of loss and gain of the flexible genes over the course of evolution. There are 1,273 genes that represent the core shared by all 12 genomes. They are apparently sufficient, according to metabolic reconstruction, to encode a functional cell. We describe a phylogeny for all 12 isolates by subjecting their complete proteomes to three different phylogenetic analyses. For each non-core gene, we used a maximum parsimony method to estimate which ancestor likely first acquired or lost each gene. Many of the genetic differences among isolates, especially for genes involved in outer membrane synthesis and nutrient transport, are found within the same clade. Nevertheless, we identified some genes defining HL and LL ecotypes, and clades within these broad ecotypes, helping to demonstrate the basis of HL and LL adaptations in Prochlorococcus. Furthermore, our estimates of gene gain events allow us to identify highly variable genomic islands that are not apparent through simple pairwise comparisons. These results emphasize the functional roles, especially those connected to

  6. Rodinian granulites from southern Qiangtang terrane: Implications for tectonic evolution of the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Tingyuan Yuan

    2017-03-01

    Full Text Available Bordered by the Longmu Co-Shuang Hu-Lancangjiang suture zone in the north and east, as well as the Bangong Nujiang suture zone in the south and west, the southern Qiangtang terrane is one of the least-studied blocks in the Tibetan region. The early tectonic evolution of the southern Qiangtang terrane has remained a controversy for a long time. Here we report granulites from the Tongka high-grade metamorphic complexes in the southern Qiangtang terrane. The mafic granulites occur as small lenses in the felsic granulites and leucogranites with peak mineral assemblage including garnet (core + diopside + low An plagioclase + quartz. The retrograde assemblage is represented by garnet (rim + pargasite + high An plagioclase + quartz. The fine-grained aggregates of feldspar + garnet + aluminosilicates + rutile around reddish-brown biotite relics in the felsic granulites are interpreted as products of partial melting of biotites. Thermobarometric estimates for the peak assemblages of the mafic rocks are P = 17.5 kbar and T = 811 °C, whereas the retrograde assemblages of the mafic rocks experienced decompression to P = 10.4 kbar, at T = 674 °C. Zircon texture and SIMS U-Pb data reveal that the felsic granulites were derived from Achaean to Proterozoic sedimentary rocks that underwent high-temperature metamorphism and transformation to paragneisses or granitoids at 1100 to 1000 Ma. During 950–900 Ma, the crystalline rocks were further buried deeply to be transformed into the felsic granulites. We therefore interpret the Tongka high-grade metamorphic complexes to be a portion of the Rodinian continental collision belt. Evidently some domains of the Rodinian continental crust were thickened during the Grenville events, similar to the more recent processes in the Himalaya and Tibetan plateau. The Tongka high-grade metamorphic complexes which form the basement of the southern Qiangtang terrane was subsequently disrupted and

  7. Phylogeny of North American fireflies (Coleoptera: Lampyridae): implications for the evolution of light signals.

    Science.gov (United States)

    Stanger-Hall, Kathrin F; Lloyd, James E; Hillis, David M

    2007-10-01

    Representatives of the beetle family Lampyridae ("fireflies", "lightningbugs") are well known for their use of light signals for species recognition during mate search. However, not all species in this family use light for mate attraction, but use chemical signals instead. The lampyrids have a worldwide distribution with more than 2000 described species, but very little is known about their phylogenetic relationships. Within North America, some lampyrids use pheromones as the major mating signal whereas others use visual signals such as extended glows or short light flashes. Here, we use a phylogenetic approach to illuminate the relationships of North American lampyrids and the evolution of their mating signals. Specifically, to establish the first phylogeny of all North American lampyrid genera, we sequenced nuclear (18S) and mitochondrial (16S and COI) genes to investigate the phylogenetic relationships of 26 species from 16 North American (NA) genera and one species from the genus Pterotus that was removed recently from the Lampyridae. To test the monophyly of the NA firefly fauna we sequenced the same genes from three European lampyrids and three Asian lampyrids, and included all available Genbank data (27 additional Asian lampyrids and a former lampyrid from Asia, Rhagophthalmus). Our results show that the North American lampyrids are not monophyletic. Different subgroups are closely related to species from Europe, Asia and tropical America, respectively. The present classification of fireflies into subfamilies and tribes is not, for the most part, supported by our phylogenetic analysis. Two former lampyrid genera, Pterotus and Rhagophthalmus, which have recently been removed from this family, are in fact nested within the Lampyridae. Further, we found that the use of light as a sexual signal may have originated one or four times among lampyrids, followed by nine or four losses, respectively. Short flashes originated at least twice and possibly three times

  8. Suspended sediment transport in distributary channel networks and its implication on the evolution of delta

    Science.gov (United States)

    Suying, Ou; hao, Yang

    2016-04-01

    Suspended sediment (SS) transport in distributary channels play an important role on the evolution of deltas and estuaries. Under the interactions between river discharge, tide, and bathymetry of Pearl River delta (PRD) in south China, the spatial and temporal characteristics of suspended sediment transport are investigated by using the field data of July 16 to 25, 1999 and February 7 to 15, 2001. The PRD, as one of the most complex tributary system in the world and composed of 324 transversal and longitudinal tributaries, with eight outlets to the three sub-estuaries, has higher suspended sediment load in middle delta including six outlets than in right and left tidal dominant channels of PRD, that is Humen channel and Yamen channel system. Under large river discharge of one flood in summer, the tidal averaged SS transport from channel to the estuaries, the SS concentration of middle delta is 10~20 times and the transport rate is 100~500 times of dry season. But the transport rate changes little between flood season and dry season in the upper channel system of Yamen and Humen, and in dry season the tidal averaged transport change direction from estuary to these channel systems. About 70~85% of total Pearl River SS load transport along the main channel of West River, then transport about 45~55% into the lower West river delta, about 30% of total SS load flushed into the Modaomen outlets. Under the bathymetry of branched channels, SS load which advected from the Pearl River and resuspended from bed, redistributed 4~8 times in the PRD and then cause the different changes of channels. It found that in flood season, the suspended sediment load from Pearl River including East, West, North River and Tanjiang, Liuxi River into the PRD is less than that discharged into the estuaries through eight outlets, which indicated the erosion in the channels of PRD especially in the lower part of PRD. Suspended sediment budget in dry season during neap-spring cycle indicated that

  9. Young child with severe brain volume loss easily passes the word memory test and medical symptom validity test: implications for mild TBI.

    Science.gov (United States)

    Carone, Dominic A

    2014-01-01

    The Word Memory Test (WMT) and Medical Symptom Validity Test (MSVT) are two commonly used free-standing measures of test-taking effort. The use of any test as a measure of effort is enhanced when evidence shows that it can be easily passed by patients with severe neurological conditions. The opportunity arose to administer the WMT and MSVT to a 9-year-old girl (referred to as CJ) with severe congenital bilateral brain tissue loss (shown via a compelling brain MRI image), chronic epilepsy, an extremely low Full Scale IQ, extremely low adaptive functioning, developmental delays, numerous severe cognitive impairments, and treatment with multiple high-dose benzodiazepines. She received extensive early intervention services and numerous academic accommodations. Despite this set of problems, CJ passed the WMT and MSVT at perfect to near perfect levels. Implications for failure on these tests among patients with known or alleged mild traumatic brain injury are discussed.

  10. Temporal evolution of wildfire ash and its implications for water pollution

    Science.gov (United States)

    Santin, Cristina; Doerr, Stefan H.; Otero, Xose L.; Chafer, Chris J.

    2015-04-01

    soluble major and trace elements. 'Aged ash' was richer in soil-derived elements (Al, Si and Fe) and exhibited higher bulk density and a lower rainfall storage capacity. We will discuss the similarities and differences between 'fresh' and 'aged' ash properties and identify the potential main threats to water quality derived from each of them. The water contamination potential from wildfire ash varies depending, among other factors, on the time between the production and transport of the ash into the hydrological system. Therefore, to evaluate the threat of wildfire ash to water quality, not only its intrinsic characteristics, but also its temporal evolution in conjunction with the probability of ash erosion to occur at a given time, need to be evaluated. These additional parameters highlight the complexity of the interaction of many different factors in the post-fire landscape.

  11. New geological framework for Western Amazonia (Brazil) and implications for biogeography and evolution

    Science.gov (United States)

    de Fátima Rossetti, Dilce; Mann de Toledo, Peter; Góes, Ana Maria

    2005-01-01

    Although many of the current hypotheses to explain the origin and distribution of the Amazon biodiversity has been based directly or indirectly on geological data, the reconstruction of the geological history of the Amazon region is still inadequate to analyze its relationship with the biodiversity. This work has the main goal to characterize the sedimentary successions formed in the Brazilian Amazon in the Neogene-Quaternary discussing the evolution of the depositional systems through time and analyzing their main controlling mechanisms in order to fill up this gap. Radar image interpretation, sedimentological studies, and radiocarbon dating allowed the mapping of Plio-Pleistocene to Holocene units along the Solimões-Amazonas River, Brazil. This integrated work led to the characterization of five sedimentary successions overlying Miocene deposits of the Solimões/Pebas Formation, which include the following: Içá Formation (Plio-Pleistocene), deposits Q1 (37,400-43,700 14C yr B.P.), deposits Q2 (27,200 14C yr B.P.), deposits Q3 (6730-2480 14C yr B.P.), and deposits Q4 (280-130 14C yr B.P.). These deposits occur mostly to the west of Manaus, forming NW-SE elongated belts that are progressively younger from SW to NE, indicating a subsiding basin with a depocenter that migrated to the NE. The reconstruction of the depositional history is consistent with significant changes in the landscapes. Hence, the closure of a large lake system at the end of the Miocene gave rise to the development of a Plio-Pleistocene fluvial system. This was yet very distinct from the modern drainage, with shallow, energetic, highly migrating, braided to anastomosed channels having an overall northeast outlet. This fluvial system formed probably under climatic conditions relatively drier than today's. During the early Pleistocene, there was pronounced erosion, followed by a renewed depositional phase ca. 40,000 14C yr B.P., with the development of prograding lobes and/or crevasse splays

  12. The Oral Iron Chelator, Deferasirox, Reverses the Age-Dependent Alterations in Iron and Amyloid-β Homeostasis in Rat Brain: Implications in the Therapy of Alzheimer's Disease.

    Science.gov (United States)

    Banerjee, Priyanjalee; Sahoo, Arghyadip; Anand, Shruti; Bir, Aritri; Chakrabarti, Sasanka

    2016-01-01

    The altered metabolism of iron impacts the brain function in multiple deleterious ways during normal aging as well as in Alzheimer's disease. We have shown in this study that chelatable iron accumulates in the aged rat brain along with overexpression of transferrin receptor 1 (TfR1) and ferritin, accompanied by significant alterations in amyloid-β (Aβ) peptide homeostasis in the aging brain, such as an increased production of the amyloid-β protein precursor, a decreased level of neprilysin, and increased accumulation of Aβ42. When aged rats are given daily the iron chelator, deferasirox, over a period of more than 4 months starting from the 18th month, the age-related accumulation of iron and overexpression of TfR1 and ferritin in the brain are significantly prevented. More interestingly, the chelator treatment also considerably reverses the altered Aβ peptide metabolism in the aging brain implying a significant role of iron in the latter phenomenon. Further, other results indicate that iron accumulation results in oxidative stress and the activation of NF-κB in the aged rat brain, which are also reversed by the deferasirox treatment. The analysis of the results together suggests that iron accumulation and oxidative stress interact at multiple levels that include transcriptional and post-transcriptional mechanisms to bring about changes in the expression levels of TfR1 and ferritin and also alterations in Aβ peptide metabolism in the aging rat brain. The efficacy of deferasirox in preventing age-related changes in iron and Aβ peptide metabolism in the aging brain, as shown here, has obvious therapeutic implications for Alzheimer's disease.

  13. Lsamp is implicated in the regulation of emotional and social behavior by use of alternative promoters in the brain.

    Science.gov (United States)

    Philips, Mari-Anne; Lilleväli, Kersti; Heinla, Indrek; Luuk, Hendrik; Hundahl, Christian Ansgar; Kongi, Karina; Vanaveski, Taavi; Tekko, Triin; Innos, Jürgen; Vasar, Eero

    2015-01-01

    Limbic system-associated membrane protein (LSAMP) is a neural cell adhesion molecule involved in neurite formation and outgrowth. The purpose of the present study was to characterize the distribution of alternatively transcribed Lsamp isoforms in the mouse brain and its implications on the regulation of behavior. Limbic system-associated membrane protein 1b transcript was visualized by using a mouse strain expressing beta-galactosidase under the control of Lsamp 1b promoter. The distribution of Lsamp 1a transcript and summarized expression of the Lsamp transcripts was investigated by non-radioactive in situ RNA hybridization analysis. Cross-validation was performed by using radioactive in situ hybridization with oligonucleotide probes. Quantitative RT-PCR was used to study correlations between the expression of Lsamp isoforms and behavioral parameters. The expression pattern of two promoters differs remarkably from the developmental initiation at embryonic day 12.5. Limbic system-associated membrane protein 1a promoter is active in "classic" limbic structures where the hippocampus and amygdaloid area display the highest expression. Promoter 1b is mostly active in the thalamic sensory nuclei and cortical sensory areas, but also in areas that regulate stress and arousal. Higher levels of Lsamp 1a transcript had significant correlations with all of the measures indicating higher trait anxiety in the elevated plus-maze test. Limbic system-associated membrane protein transcript levels in the hippocampus and ventral striatum correlated with behavioral parameters in the social interaction test. The data are in line with decreased anxiety and alterations in social behavior in Lsamp-deficient mice. We propose that Lsamp is involved in emotional and social operating systems by complex regulation of two alternative promoters.

  14. Whole Planet Coupling from Climate to Core: Implications for the Evolution of Rocky Planets and their Prospects for Habitability

    Science.gov (United States)

    Foley, B. J.; Driscoll, P. E.

    2015-12-01

    for preserving hydrogen, and therefore water, on the surface. Thus whole planet coupling between the magnetic field, atmosphere, mantle, and core is possible. We lay out the basic physics governing whole planet coupling, and discuss the implications this coupling has for the evolution of rocky planets and their prospects for hosting life.

  15. Mechanism of noradrenaline-induced stimulation of Na-K ATPase activity in the rat brain: implications on REM sleep deprivation-induced increase in brain excitability.

    Science.gov (United States)

    Mallick, Birendra Nath; Singh, Sudhuman; Singh, Abhishek

    2010-03-01

    Rapid eye movement (REM) sleep is a unique phenomenon expressed in all higher forms of animals. Its quantity varies in different species and with ageing; it is also affected in several psycho-somatic disorders. Several lines of studies showed that after REM sleep loss, the levels of noradrenaline (NA) increase in the brain. The NA in the brain modulates neuronal Na-K ATPase activity, which helps maintaining the brain excitability status. The detailed mechanism of increase in NA level after REM sleep loss and the effect of NA on stimulation of Na-K ATPase in the neurons have been discussed. The findings have been reviewed and discussed with an aim to understand the role of REM sleep in maintaining brain excitability status.

  16. Firn densification in a Late Noachian “icy highlands” Mars: Implications for ice sheet evolution and thermal response

    Science.gov (United States)

    Cassanelli, James P.; Head, James W.

    2015-06-01

    Recent modeling of a thicker early CO2 martian atmosphere and Late Noachian climate predicts that for pressures beyond a fraction of a bar, atmosphere-surface thermal coupling occurs, resulting in adiabatic cooling of high areas across Mars. This promotes the transport of water ice from relatively warmer low-lying areas to the highlands, where deposition and accumulation of water ice result in an "icy highlands" Late Noachian Mars. Deposits will remain stable in the highlands under nominal Late Noachian conditions, but the potential exists for punctuated heating by both top-down (e.g. impacts, volcanism) and bottom-up (e.g. elevated geothermal heat flux) processes. Important in understanding melt generation from these processes is the state of the accumulated snow and ice. Through modeling of the firn densification process in the "icy highlands" framework we assess: (1) the nature of snow accumulation and the physical growth and evolution of the predicted ice deposits, and (2) the implications for the thermal properties of the ice sheets and the response to heating events. Analysis of the firn densification process in the "icy highlands" context indicates that: (1) the upper layers of the ice sheet will be more vulnerable to melting from top-down heating processes because they are comprised of the least dense and least thermally conductive ice, and (2) even with a low thermal conductivity firn layer, basal melting is only likely to occur through a combination of top-down and bottom-up heating. This is because at the nominal mean annual surface temperatures and estimated effective thermal conductivities, the predicted ice sheet thicknesses do not produce enough basal warming to initiate melting for plausible geothermal heat fluxes. Variations in spin-axis/orbital parameters alone are not predicted to cause widespread ablation (melting and sublimation) of the icy highlands ice sheets.

  17. Matrix metaloproteinases activity during the evolution of hypoxic-ischemic brain damage in the immature rat. The effect of 1-methylnicotinamide (MNA).

    Science.gov (United States)

    Dragun, P; Makarewicz, D; Wójcik, L; Ziemka-Nałecz, M; Słomka, M; Zalewska, T

    2008-09-01

    Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade the extracellular matrix and carry out key functions during brain development. Apart from a physiological role, excessive activation of MMPs in brain tissue has been postulated to represent a pathway for cell death arising from ischemia. To evaluate the possible involvement of MMPs in the perinatal brain asphyxia, we exposed 7-day-old rats to hypoxia-ischemia (HI). Unilateral HI was administered by ligation of the common carotid artery followed by hypoxia (7.4% O2/92.6% N2) for 65 minutes. This insult is known to produce brain damage confined to the cerebral hemisphere ipsilateral to the arterial occlusion in > 90% of animals. HI resulted in a significant elevation of MMP-2 and MMP-9 activity in the ipsilateral forebrain. The maximum activation was found at 48 hours and 7-14 days after the insult. These results suggest that early and late induction of MMPs may play a role in neuronal death as well as in repair processes. The treatment of animals subjected to HI with 1-methylnicotinamide (MNA), the anti-inflammatory agent, led to the inhibition of MMP-9 in an acute phase of ischemic damage and to the activation of MMP-2 in the later stages after injury. The timing of MMPs modulation by MNA may indicate its possible therapeutic implications.

  18. Neural network models of protein domain evolution

    OpenAIRE

    Sylvia Nagl

    2000-01-01

    Protein domains are complex adaptive systems, and here a novel procedure is presented that models the evolution of new functional sites within stable domain folds using neural networks. Neural networks, which were originally developed in cognitive science for the modeling of brain functions, can provide a fruitful methodology for the study of complex systems in general. Ethical implications of developing complex systems models of biomolecules are discussed, with particular reference to molecu...

  19. Brain cancer spreads.

    Science.gov (United States)

    Perryman, Lara; Erler, Janine T

    2014-07-30

    The discovery that ~20% of patients with brain cancer have circulating tumor cells breaks the dogma that these cells are confined to the brain and has important clinical implications (Müller et al., this issue).

  20. Non-local quantum evolution of entangled ensemble states in neural nets and its significance for brain function and a theory of consciousness

    CERN Document Server

    Bieberich, E

    1999-01-01

    Current quantum theories of consciousness suggest a configuration space of an entangled ensemble state as global work space for conscious experience. This study will describe a procedure for adjustment of the singlet evolution of a quantum computation to a classical signal input by action potentials. The computational output of an entangled state in a single neuron will be selected in a network environment by "survival of the fittest" coupling with other neurons. Darwinian evolution of this coupling will result in a binding of action potentials to a convoluted orbit of phase-locked oscillations with harmonic, m-adic, or fractal periodicity. Progressive integration of signal inputs will evolve a present memory space independent from the history of construction. Implications for mental processes, e.g., associative memory, creativity, and consciousness will be discussed. A model for the generation of quantum coherence in a single neuron will be suggested.

  1. The role of docosahexaenoic and the marine food web as determinants of evolution and hominid brain development: the challenge for human sustainability.

    Science.gov (United States)

    Crawford, Michael A; Broadhurst, C Leigh

    2012-01-01

    Life originated on this planet about 3 billion years ago. For the first 2.5 billion years of life there was ample opportunity for DNA modification. Yet there is no evidence of significant change in life forms during that time. It was not until about 600 million years ago, when the oxygen tension rose to a point where air-breathing life forms became thermodynamically possible, that a major change can be abruptly seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record was also associated with the appearance of intracellular detail not seen in previous life forms. That detail was provided by cell membranes made with lipids (membrane fats) as structural essentials. Lipids thus played a major, as yet unrecognised, role as determinants in evolution. The compartmentalisation of intracellular, specialist functions as in the nucleus, mitochondria, reticulo-endothelial system and plasma membrane led to cellular specialisation and then speciation. Thus, not only oxygen but also the marine lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA) (all-cis-docosa-4,7,10,13,16,19-hexaenoic acid, C22:6ω3 or C22:6, n-3, DHA) is a major feature of marine lipids. It requires six oxygen atoms to insert its six double bonds, so it would not have been abundant before oxidative metabolism became plentiful. DHA provided the membrane backbone for the emergence of new photoreceptors that converted photons into electricity, laying the foundation for the evolution of other signalling systems, the nervous system and the brain. Hence, the ω3 DHA from the marine food web must have played a critical role in human evolution. There is also clear evidence from molecular biology that DHA is a determinant of neuronal migration, neurogenesis and the expression of several genes involved in brain growth and function. That same process was essential to the ultimate cerebral expansion in human evolution. There is now incontrovertible support of this

  2. Human Development XIII: The Connection Between the Structure of the Overtone System and the Tone Language of Music. Some Implications for Our Understanding of the Human Brain

    Directory of Open Access Journals (Sweden)

    Søren Ventegodt

    2008-01-01

    Full Text Available The functioning brain behaves like one highly-structured, coherent, informational field. It can be popularly described as a “coherent ball of energy”, making the idea of a local highly-structured quantum field that carries the consciousness very appealing. If that is so, the structure of the experience of music might be a quite unique window into a hidden quantum reality of the brain, and even of life itself. The structure of music is then a mirror of a much more complex, but similar, structure of the energetic field of the working brain. This paper discusses how the perception of music is organized in the human brain with respect to the known tone scales of major and minor. The patterns used by the brain seem to be similar to the overtones of vibrating matter, giving a positive experience of harmonies in major. However, we also like the minor scale, which can explain brain patterns as fractal-like, giving a symmetric “downward reflection” of the major scale into the minor scale. We analyze the implication of beautiful and ugly tones and harmonies for the model. We conclude that when it comes to simple perception of harmonies, the most simple is the most beautiful and the most complex is the most ugly, but in music, even the most disharmonic harmony can be beautiful, if experienced as a part of a dynamic release of musical tension. This can be taken as a general metaphor of painful, yet meaningful, and developing experiences in human life.

  3. A Systems Approach Implicates a Brain Mitochondrial Oxidative Homeostasis Co-expression Network in Genetic Vulnerability to Alcohol Withdrawal

    Science.gov (United States)

    Walter, Nicole A. R.; Denmark, DeAunne L.; Kozell, Laura B.; Buck, Kari J.

    2017-01-01

    Genetic factors significantly affect vulnerability to alcohol dependence (alcoholism). We previously identified quantitative trait loci on distal mouse chromosome 1 with large effects on predisposition to alcohol physiological dependence and associated withdrawal following both chronic and acute alcohol exposure in mice (Alcdp1 and Alcw1, respectively). We fine-mapped these loci to a 1.1–1.7 Mb interval syntenic with human 1q23.2-23.3. Alcw1/Alcdp1 interval genes show remarkable genetic variation among mice derived from the C57BL/6J and DBA/2J strains, the two most widely studied genetic animal models for alcohol-related traits. Here, we report the creation of a novel recombinant Alcw1/Alcdp1 congenic model (R2) in which the Alcw1/Alcdp1 interval from a donor C57BL/6J strain is introgressed onto a uniform, inbred DBA/2J genetic background. As expected, R2 mice demonstrate significantly less severe alcohol withdrawal compared to wild-type littermates. Additionally, comparing R2 and background strain animals, as well as reciprocal congenic (R8) and appropriate background strain animals, we assessed Alcw1/Alcdp1 dependent brain gene expression using microarray and quantitative PCR analyses. To our knowledge this includes the first Weighted Gene Co-expression Network Analysis using reciprocal congenic models. Importantly, this allows detection of co-expression patterns limited to one or common to both genetic backgrounds with high or low predisposition to alcohol withdrawal severity. The gene expression patterns (modules) in common contain genes related to oxidative phosphorylation, building upon human and animal model studies that implicate involvement of oxidative phosphorylation in alcohol use disorders (AUDs). Finally, we demonstrate that administration of N-acetylcysteine, an FDA-approved antioxidant, significantly reduces symptoms of alcohol withdrawal (convulsions) in mice, thus validating a phenotypic role for this network. Taken together, these studies

  4. Spatiotemporal 16p11.2 protein network implicates cortical late mid-fetal brain development and KCTD13-Cul3-RhoA pathway in psychiatric diseases.

    Science.gov (United States)

    Lin, Guan Ning; Corominas, Roser; Lemmens, Irma; Yang, Xinping; Tavernier, Jan; Hill, David E; Vidal, Marc; Sebat, Jonathan; Iakoucheva, Lilia M

    2015-02-18

    The psychiatric disorders autism and schizophrenia have a strong genetic component, and copy number variants (CNVs) are firmly implicated. Recurrent deletions and duplications of chromosome 16p11.2 confer a high risk for both diseases, but the pathways disrupted by this CNV are poorly defined. Here we investigate the dynamics of the 16p11.2 network by integrating physical interactions of 16p11.2 proteins with spatiotemporal gene expression from the developing human brain. We observe profound changes in protein interaction networks throughout different stages of brain development and/or in different brain regions. We identify the late mid-fetal period of cortical development as most critical for establishing the connectivity of 16p11.2 proteins with their co-expressed partners. Furthermore, our results suggest that the regulation of the KCTD13-Cul3-RhoA pathway in layer 4 of the inner cortical plate is crucial for controlling brain size and connectivity and that its dysregulation by de novo mutations may be a potential determinant of 16p11.2 CNV deletion and duplication phenotypes.

  5. Brain cancer spreads

    DEFF Research Database (Denmark)

    Perryman, Lara; Erler, Janine Terra

    2014-01-01

    The discovery that ~20% of patients with brain cancer have circulating tumor cells breaks the dogma that these cells are confined to the brain and has important clinical implications (Müller et al., this issue).......The discovery that ~20% of patients with brain cancer have circulating tumor cells breaks the dogma that these cells are confined to the brain and has important clinical implications (Müller et al., this issue)....

  6. Variations in size, shape and asymmetries of the third frontal convolution in hominids: paleoneurological implications for hominin evolution and the origin of language.

    Science.gov (United States)

    Balzeau, Antoine; Gilissen, Emmanuel; Holloway, Ralph L; Prima, Sylvain; Grimaud-Hervé, Dominique

    2014-11-01

    The study of brain structural asymmetries as anatomical substrates of functional asymmetries in extant humans, great apes, and fossil hominins is of major importance in understanding the structural basis of modern human cognition. We propose methods to quantify the variation in size, shape and bilateral asymmetries of the third frontal convolution (or posterior inferior frontal gyrus) among recent modern humans, bonobos and chimpanzees, and fossil hominins using actual and virtual endocasts. These methodological improvements are necessary to extend previous qualitative studies of these features. We demonstrate both an absolute and relative bilateral increase in the size of the third frontal convolution in width and length between Pan species, as well as in hominins. We also observed a global bilateral increase in the size of the third frontal convolution across all species during hominin evolution, but also non-allometric intra-group variations independent of brain size within the fossil samples. Finally, our results show that the commonly accepted leftward asymmetry of Broca's cap is biased by qualitative observation of individual specimens. The trend during hominin evolution seems to be a reduction in size on the left compared with the right side, and also a clearer definition of the area. The third frontal convolution considered as a whole projects more laterally and antero-posteriorly in the right hemisphere. As a result, the left 'Broca's cap' looks more globular and better defined. Our results also suggest that the pattern of brain asymmetries is similar between Pan paniscus and hominins, leaving the gradient of the degree of asymmetry as the only relevant structural parameter. As the anatomical substrate related to brain asymmetry has been present since the appearance of the hominin lineage, it is not possible to prove a direct relationship between the extent of variations in the size, shape, and asymmetries of the third frontal convolution and the origin of

  7. What can volumes reveal about human brain evolution? A framework for bridging behavioral, histometric and volumetric perspectives

    Directory of Open Access Journals (Sweden)

    Alexandra A de Sousa

    2014-06-01

    Full Text Available An overall relationship between brain size and cognitive ability exists across primates. Can more specific information about neural function be gleaned from cortical area volumes? Numerous studies have found significant relationships between brain structures and behaviors. However, few studies have speculated about brain structure-function relationships from the microanatomical to the macroanatomical level. Here we address this problem in comparative neuroanatomy, where the functional relevance of overall brain size and the sizes of cortical regions have been poorly understood, by considering comparative psychology, with measures of visual acuity and the perception of visual illusions. We outline a model where the macroscopic size (volume or surface area of a cortical region (such as the primary visual cortex, V1 is related to the microstructure of discrete brain regions. The hypothesis developed here is that a larger absolute V1 can process more information with greater fidelity due to having more neurons to represent a field of space. This is the first time that the necessary comparative neuroanatomical research at the microstructural level has been brought to bear on the issue. The evidence suggests that as the size of V1 increases: the number of neurons increases, the neuron density decreases, and the density of neuronal connections increases. Thus, we describe how information about gross neuromorphology, using V1 as a model for the study of other cortical areas, may permit interpretations of cortical function.

  8. What can volumes reveal about human brain evolution? A framework for bridging behavioral, histometric, and volumetric perspectives.

    Science.gov (United States)

    de Sousa, Alexandra A; Proulx, Michael J

    2014-01-01

    An overall relationship between brain size and cognitive ability exists across primates. Can more specific information about neural function be gleaned from cortical area volumes? Numerous studies have found significant relationships between brain structures and behaviors. However, few studies have speculated about brain structure-function relationships from the microanatomical to the macroanatomical level. Here we address this problem in comparative neuroanatomy, where the functional relevance of overall brain size and the sizes of cortical regions have been poorly understood, by considering comparative psychology, with measures of visual acuity and the perception of visual illusions. We outline a model where the macroscopic size (volume or surface area) of a cortical region (such as the primary visual cortex, V1) is related to the microstructure of discrete brain regions. The hypothesis developed here is that an absolutely larger V1 can process more information with greater fidelity due to having more neurons to represent a field of space. This is the first time that the necessary comparative neuroanatomical research at the microstructural level has been brought to bear on the issue. The evidence suggests that as the size of V1 increases: the number of neurons increases, the neuron density decreases, and the density of neuronal connections increases. Thus, we describe how information about gross neuromorphology, using V1 as a model for the study of other cortical areas, may permit interpretations of cortical function.

  9. Implications of the Dependence of Neuronal Activity on Neural Network States for the Design of Brain-Machine Interfaces

    OpenAIRE

    Panzeri, Stefano; Safaai, Houman; De Feo, Vito; Vato, Alessandro

    2016-01-01

    Brain-machine interfaces (BMIs) can improve the quality of life of patients with sensory and motor disabilities by both decoding motor intentions expressed by neural activity, and by encoding artificially sensed information into patterns of neural activity elicited by causal interventions on the neural tissue. Yet, current BMIs can exchange relatively small amounts of information with the brain. This problem has proved difficult to overcome by simply increasing the number of recording or stim...

  10. Mars volatile evolution: Implications of the recent measurement of O-17 in water from the SNC meteorites

    Science.gov (United States)

    Jakosky, Bruce M.

    1992-01-01

    Oxygen, carbon, and hydrocarbon isotopes in water and carbon dioxide in the Martian environment can fractionate due to processes involving escape to space, exchange between atmospheric and non-atmospheric species, and exchange of atoms between different molecules. As a result, the ratios of O-18/O-17/O-16, C-13/C-12 and D/H in atmospheric and surface species are sensitive indicators of the integrated effects of outgassing and volatile evolution over geologic time. Previously, I summarized all of the available observations of isotopic abundances and compared them with models of fractionation in order to see which scenarios of volatile evolution were most plausible. Presently, I have included in the models the possible evolution of O-17 due to loss to space in order to see whether these measurements are consistent with various scenarios for atmospheric evolution.

  11. Opiates Upregulate Adhesion Molecule Expression in Brain MicroVascular Endothelial Cells (BMVEC: Implications for Altered Blood Brain Barrier (BBB Permeability

    Directory of Open Access Journals (Sweden)

    Madhavan P.N. Nair

    2006-01-01

    Full Text Available The blood-brain barrier (BBB is an intricate cellular system composed of vascular endothelial cells and perivascular astrocytes that restrict the passage of immunocompetent cells into the central nervous system (CNS. Expression of the adhesion molecules, intercellular adhesion molecule 1 (ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1 on brain microvascular endothelial cells (BMVEC and their interaction with human immunodeficiency virus (HIV-1 viral proteins may help enhance viral adhesion and virus-cell fusion resulting in increased infectivity. Additionally, transmigration through the BBB is facilitated by both endothelial and monocyte/macrophage-derived nitric oxide (NO. Dysregulated production of NO by BMVEC due to opiates and HIV-1 viral protein interactions play a pivotal role in brain endothelial injury, resulting in the irreversible loss of BBB integrity, which may lead to enhanced infiltration of virus-carrying cells across the BBB. Opioids act as co-factors in the neuropathogenesis of HIV-1 by facilitating BBB dysfunction however, no studies have been done to investigate the role of opiates alone or in combination with HIV-1 viral proteins on adhesion molecule expression in BMVEC. We hypothesize that opiates such as heroin and morphine in conjunction with the HIV-1 viral protein gp120 increase the expression of adhesion molecules ICAM-1 and VCAM-1 and these effects are mediated via the modulation of NO. Results show that opiates alone and in synergy with gp120 increase both the genotypic and phenotypic expression of ICAM-1 and VCAM-1 by BMVEC, additionally, these opiate induced effects may be the result of increased NO production. These studies will provide a better understanding of how opiate abuse in conjunction with HIV-1 infection facilitates the breakdown of the BBB and exacerbates the neuropathogenesis of HIV-1. Elucidation of the mechanisms of BBB modulation will provide new therapeutic approaches to maintain BBB integrity