Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"brain size"”.
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From brains to bears. understanding brain size evolution: causes, costs and benefits
Developmental and energetic costs result in brains being expensive organs to grow and maintain, yet large brains have evolved in many mammalian species. The adaptive value of increased brain size has come under scrutiny over the past few decades and despite considerable research effort, much …
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Analysing the evolution of brain size in three clades of carnivora using model selection
The evolution of brain size is a contentious topic, spawning numerous hypotheses on what drives it. In this study, we analyse and take several of them, and apply those theories to be tested on. We used a dataset by combining two forms of secondary data, the first on the brain sizes of various …
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Using multivariate calibration to evaluate hominin brain/body size relationships
… are highly encephalized, having relatively large brains despite our already large bodies. The current assumption is that brains and bodies have both increased in size during the course of human evolution but the rate, timing, and evolutionary relationship of the two are still unclear. This study …
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The evolution of neuronal progenitor cell division in mammals: The role of the abnormal spindle-like microcephaly associated (Aspm) protein and epithelial cell polarity
… primates are exceptional for their large brain size relative to body size. Relative brain size, or encephalization, is particularly striking among humans and their direct ancestors. Since the human-chimp split 5 to 7 million years ago, brain size has tripled in the human lineage (Wood …
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Insight Into Human Brain Evolution Through Phylogenetic Analysis And Comparative Genomics
… among mammals, with respect to their large brain size and enhanced cognitive abilities. Humans are the most encephalized mammals, with a brain that is six times larger than expected relative to body mass. Presumably, it is this high degree of encephalization that underlies our advanced …
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Patterns of variation and allometry in sub-cortical structures of the human brain: an evaluation of sex differences and age
… questions concerning relationships between size, shape (static adult scaling relations) and multivariate patterns of variation in brains of adult modern humans using in vivo measurements from magnetic resonance imaging (MRI) scans. The main research questions consider if patterns of adult …
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Urban establishment success of corvids
… einen größeren Erfolg in Städten haben, weil die brain size-environmental change Hypothese besagt, dass sich große Gehirne evolviert haben, um auf eine neue Umwelt mit innovativen Verhalten reagieren zu können.
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Towards mapping spatial transcriptome of an entire vertebrate brain
Both the brain’s substantial complexity and technical challenges in monitoring and manipulating brains present challenges for understanding this essential organ. Zebrafish, for their modest brain size and transparency in the larval stage, serve as a model organism for whole-brain in vivo imaging …
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The Effects of Intracerebroventricular Leptin on Milk Availability in Lactating Rats
… to pup. Hypothalamic mRNA leptin levels and brain size in the offspring from leptin treated dams were significantly higher than the control. These findings support the involvement of leptin in reproduction and could lead to better understanding of leptin transfer from dam to offspring.</p>
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Endocranial volume and shape variation in early anthropoid evolution
<p>Fossil taxa are crucial to studies of brain evolution, as they allow us to identify evolutionary trends in relative brain size and brain shape that may not otherwise be identifiable in comparative studies using only extant taxa, owing to multiple events of parallel encephalization among primate …
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Hand Preference for Holding, Tapping, Probing and Digit-Feeding in Captive Adult Aye-ayes (<i>Daubentonia madagascariensis</i>)
… unique characteristics. They have the largest brain to body size ratio of any lemur and are the largest nocturnal primate. Insect larvae are a dietary staple. They use their elongated third digit to tap on structures such as tree bark and their large ears to listen for auditory changes caused …
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Perspectives from above: The role of altitude in bumblebee spatial orientation and navigation
… master these task despite their relatively small brain size. They acquire visual memories of their nest location, well hidden from predators, to return home after their forag- ing trips. With this thesis I contribute to the field of neuroethological research investigating the underlying mechanisms …
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A matter of evolutionary life and death: an ecological model of growth and development in Homo erectus
… and the energetic implications bf increasing brain size are addressed. A comparative study of two modern human populations supports the prediction that stability of environment translates into stability of growth, and these findings are applied to H. erectus. I demonstrate that H erectus …
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The role of cnd-1/NeuroD1 in C. elegans nervous system development
… mice is uncoordinated, has seizures and a reduce brain size (Miyata et al. 1999). In C. elegans, the ortholog gene is <em>cnd-1</em>. Hallam et al. 2000, showed that <em>cnd-1</em> has a role in cell fate determination of GABAergic, DD motor neurons, in addition to a role in axon morphology. …
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Investigating the role of ZEB2 in the establishment of neuroepithelial architecture and axon tract formation
… factor ZEB2 as a putative regulator of brain size. In this work we show that in both human brain organoids and mouse embryos ZEB2 is expressed in telencephalic neuroepithelial cells (NECs) before the switch to radial glia (RGCs). By establishing a human embryonic stem cell (hESC) model …
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Exploring Human Natures: and their variation in the Genus Homo
… when a concept does not preserve. Language, Art, Brain Size and Cranial Morphology have all been used as proxies for Human-Natures. Hunting and hunting sites are an important proxy explored here, as explained by (Underdown and Smith, 2019), the proxy offers insight into modern cognition. This …
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Evolutionary Relationship between Life History and Brain Growth in Anthropoid Primates
… rates are constant across species, and thus body size is determined by mortality rates.</p><p>This project posits that the intrinsic characteristics of species set the pace of life history. Among anthropoids, there is a great deal of variation in growth rates and the pace of life history relative …
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Effects of prolonged mitosis on neural stem cells in vivo during development
<p>Microcephaly patients are born with a brain size >3 standard deviations below normal and have mild to severe cognitive deficits. 12 microcephaly-linked genes identified in human genetics studies encode microtubule/centrosome-associated proteins and mutations in these genes are strongly tied to …
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Gene action involved with reproduction and growth of brain and muscle in weight-selected lines of chickens
… at all ages (Experiment 3). Reduced egg size of dwarf pullets did not reduce embryonic weights. Embryo length and weight and yolk sac weight were greater for line HH than LL. In Experiment 4, allometric growth and cellular content of brains were measured in normal and dwarf chickens from …
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What Makes Our Minds Human? Comparative Phylogenetic Perspectives on the Evolution of Cognition
… predicted by absolute (but not relative) brain size. Further, I show that two of the other leading hypotheses put forth to explain primate intelligence, namely sociality and diet, do not predict cognitive skills on these tasks. These data illustrate the power of the comparative method for …
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