Download or read book Mechanisms Underlying the Early Development and Function of the Xenopus Tadpole Retinotectal Circuit written by Zhenyu Liu and published by . This book was released on 2018 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proper neural circuit development across time and space is critical to give rise a well- functioning organism. The way that neurons self assemble into functional circuits is a fundamental question in neuroscience. To study how the molecular mechanism and activity regulates neural circuit development and function, we use Xenopus laevis as our model, specifically the retinotectal circuit – the major component of the amphibian visual system. It is comprised of the retinal ganglion cells (RGCs) in the eye, which project their axons to the optic tectum and form synapses onto the tectal neurons. The retinotectal circuit is a classic model to study important phases of neural development, from neurogenesis and neural differentiation, to axon guidance and synapse formation. My work utilized a recently developed brain preparation (horizontal brain slice preparation) to identify and characterize a population of gap junctionally coupled neurons residing in the superficial layer of the tectum that gate local recurrent network activity through their coupling. Further by using the same preparation, we discovered an NMDA-receptor dependent mechanism for subcellular segregation of sensory inputs in the tadpole optic tectum. Finally, to study the molecular mechanism underlying synapse formation and circuit development, we focused on the role of a single molecule, presenilin. Although studied and named in the context of Alzheimer’s disease, we are finding that normal function of presenilin is critical for proper retinotectal circuit synapse formation and development. These findings together contribute for better understanding of the mechanisms underlying proper development and function of the retinotectal circuit and thus give insights of how neural circuit develops, in general.

Download or read book Functional Development of the Xenopus Laevis Tadpole Visual System written by Ali Hamodi and published by . This book was released on 2016 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tectum is a multisensory integration center in amphibians. It is both functionally and structurally homologous to the superior colliculus in mammals. It is comprised of tectal neurons receiving direct visual input from the contralateral eye and non-visual input through the hindbrain, in addition to the microcircuitry formed by tectal-tectal connections within the tectum. The way tectal neurons process sensory information is dependent upon the connectivity of the circuit along with the function of individual tectal neurons. Therefore, to understand how sensory information is processed, it is crucial to study the mechanisms underlying the development of the function of individual tectal neurons and the formation of their connectivity. The function of individual neurons is shaped by a combination of their synaptic drive and voltage-gated intrinsic currents. Our whole-cell recordings from tectal neurons show that across the developmental rostrocaudal (RC) axis, peak Na+ and K+ currents increase in a graded manner, such that tectal neurons in the most caudal, immature portion of the tectum express relatively small peak currents, whereas more mature neurons at the most rostral end of the axis express the highest. This position-dependent increase in intrinsic currents is correlated with the ability of tectal neurons to fire action potentials in response to a sustained current injection. Furthermore, the amount of synaptic drive received by a given tectal neuron increases in the same direction. Finally, we found that chronic reduction of circuit activity to test the dependence of the gradient on activity induced upregulation of both Na+ and K+ currents only in neurons of the caudal portion of the tectum, suggesting a region-specific form of compensatory intrinsic plasticity. Although much work has been done to understand the development of tectal neuron function and connectivity, all physiological studies in the tadpole tectum have focused only on the deep-layer tectal neurons due to the inability to access superficial layers using traditional tadpole brain preparation. To remedy this, we developed a novel brain slice preparation that allows visualization and access of all tectal neuron layers and the tectal neuropil. Next, we use this preparation to study the functional pattern of multisensory inputs onto tectal neurons. As previously mentioned, tectal neurons receive visual input through retinal ganglion cells (RGCs), which send their axons to synapse onto the distal part of tectal neuron dendrites. At the same time, non-visual inputs arriving through the hindbrain (HB) send their axons to synapse onto the proximal part of the same tectal neuron dendrite. Segregation of different sets of axons along the same dendrite is seen in many other systems; however, the mechanism underling the formation of this pattern is unknown. Here, we directly tested this mechanism by surgically removing one eye at the stage when RGC axons have just exited the eyecup (stage 34). We found that in the tectum that doesn’t receive contralateral RGC input, HB axons invaded the region of the dendrite that is normally occupied by contralateral RGC axons. We detect this axon shifting using field potential recordings and fluorescent imaging of axonal dye fills. This suggested to us that this form of axon segregation is competition-dependent. Therefore, we next tested the role of NMDA receptor activation due to its previously shown role in competition-based establishment of topographic maps. We found that chronically rearing tadpoles in the NMDAR blocker, MK-801, starting at stage 39 (when RGC axons have just arrived to the tectum), but not stage 45 (when the circuit has already been established) disrupted the segregation of multisensory axons such that the two sets of axons are intermingled and spread out across the entire length of the laminar axis. These results suggest that formation, but not maintenance, of multisensory axon segregation along the laminar axis is based on NMDAR-dependent competition.

Download or read book Spontaneous Activity in the Sensory System written by Kazuo Imaizumi and published by Frontiers Media SA. This book was released on 2018-05-10 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spontaneous activity in the nervous system is defined as neural activity that is not driven by an external stimulus and is considered a problem for sensory processing and computation. However, spontaneous activity is not completely random and often has unique spatiotemporal patterns that instruct neural circuit development in the developing brain. Moreover, normal and aberrant patterns of spontaneous activity underlie behavioral states and diseased conditions in the adult brain. The recent technological development has shed light on these unique questions in spontaneous activity. This eBook provides both original and review articles in the propensity, mechanisms, and functions of spontaneous activity in the sensory system. Our goal is to define the state of knowledge in the field, the current challenges, and the future directions for research.

Download or read book Clinical Neuroembryology written by Hans J. ten Donkelaar and published by Springer Science & Business Media. This book was released on 2006-09-07 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress in developmental neurobiology and advances in (neuro) genetics have been spectacular. The high resolution of modern imaging techniques applicable to developmental disorders of the human brain and spinal cord have created a novel insight into the developmental history of the central nervous system (CNS). This book provides a comprehensive overview of the development of the human CNS in the context of its many developmental disorders. It provides a unique combination of data from human embryology, animal research and developmental neuropathology, and there are more than 400 figures in over a hundred separate illustrations.

Download or read book Frog Neurobiology written by R. Llinas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1056 pages. Available in PDF, EPUB and Kindle. Book excerpt: In review, the amount of information available on the morphological and func tional properties of the frog nervous system is very extensive indeed and in certain areas is the only available source of information in vertebrates. Further more, much of the now classical knowledge in neurobiology was originally ob tained and elaborated in depth in this vertebrate. To cite only a few examples, studies of nerve conduction, neuromuscular transmission, neuronal integration, sense organs, development, and locomotion have been developed with great detail in the frog and in conjunction provide the most complete holistic descrip tion of any nervous system. Added to the above considerations, the ease with which these animals may be maintained (both as adults and during development) and the advantage of their lower cost as compared with other vertebrate forms make the frog one of the most important laboratory animals in neurobiology. With these thoughts in mind, we decided to compile this volume. Our goal in doing so was to assemble as much as possible of the information available on frog neurobiology and to have the different topics covered by authorities in each of the fields represented. To keep the handbook restricted to one volume, we found it necessary to omit the large field of amphibian muscle neurobiology, which has already been summarized in various other publications.

Download or read book Retinal Development written by Evelyne Sernagor and published by Cambridge University Press. This book was released on 2012-11-29 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced text, first published in 2006, takes a developmental approach to the presentation of our understanding of how vertebrates construct a retina. Written by experts in the field, each of the seventeen chapters covers a specific step in the process, focusing on the underlying molecular, cellular, and physiological mechanisms. There is also a special section on emerging technologies, including genomics, zebrafish genetics, and stem cell biology that are starting to yield important insights into retinal development. Primarily aimed at professionals, both biologists and clinicians working with the retina, this book provides a concise view of vertebrate retinal development. Since the retina is 'an approachable part of the brain', this book will also be attractive to all neuroscientists interested in development, as processes required to build this exquisitely organized system are ultimately relevant to all other parts of the central nervous system.

Download or read book Cell Cycle and Cell Differentiation written by J. Reinert and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is instructive to compare the response of biologists to the two themes that comprise the title of this volume. The concept of the cell cycle-in contra distinction to cell division-is a relatively recent one. Nevertheless biologists of all persuasions appreciate and readily agree on the central problems in this area. Issues ranging from mechanisms that initiate and integrate the synthesis of chro mosomal proteins and DNA during S-phase of mitosis to the manner in which assembly of microtubules and their interactions lead to the segregation of metaphase chromosomes are readily followed by botanists and zoologists, as well as by cell and molecular biologists. These problems are crisp and well-defined. The current state of "cell differentiation" stands in sharp contrast. This, one of the oldest problems in experimental biology, almost defies definition today. The difficulties arise not only from a lack of pertinent information on the regulatory mechanisms, but also from conflicting basic concepts in this field. One of the ways in which this situation might be improved would be to find a broader experimental basis, including a better understanding of the relationship between the cell cycle and cell differentiation.

Download or read book The Cell Biology of Stem Cells written by Eran Meshorer and published by Springer Science & Business Media. This book was released on 2011-01-11 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem cells have been gaining a lot of attention in recent years. Their unique potential to self-renew and differentiate has turned them into an attractive model for the study of basic biological questions such as cell division, replication, transcription, cell fate decisions, and more. With embryonic stem (ES) cells that can generate each cell type in the mammalian body and adult stem cells that are able to give rise to the cells within a given lineage, basic questions at different developmental stages can be addressed. Importantly, both adult and embryonic stem cells provide an excellent tool for cell therapy, making stem cell research ever more pertinent to regenerative medicine. As the title The Cell Biology of Stem Cells suggests, our book deals with multiple aspects of stem cell biology, ranging from their basic molecular characteristics to the in vivo stem cell trafficking of adult stem cells and the adult stem-cell niche, and ends with a visit to regeneration and cell fate reprogramming. In the first chapter, “Early embryonic cell fate decisions in the mouse”, Amy Ralson and Yojiro Yamanaka describe the mechanisms that support early developmental decisions in the mouse pre-implantation embryo and the current understanding of the source of the most immature stem cell types, which includes ES cells, trophoblast stem (TS) cells and extraembryonic endoderm stem (XEN) cells.

Download or read book Behavioral Embryology written by Gilbert Gottlieb and published by Academic Press. This book was released on 2013-10-22 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Behavioral Embryology deals with the theoretical, philosophical, and empirical problems of behavioral embryology. The book is composed of studies on prenatal neural and behavioral development. The text discussed various topics on behavioral embryology such as the genetic aspects of neuro-embryology; prenatal ""organizing"" effect of gonadal hormones on the brain and later behavior; sensory, motor, or central neural function; overt embryonic or fetal sensitivity; and overt motility and actual behavior. Embryologists, anatomists, cell biologists, physiologists, physicians, and medical researchers will find the book invaluable.

Download or read book Embodied Mind Meaning and Reason written by Mark Johnson and published by University of Chicago Press. This book was released on 2017-11-20 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mark Johnson is one of the great thinkers of our time on how the body shapes the mind. This book brings together a selection of essays from the past two decades that build a powerful argument that any scientifically and philosophically satisfactory view of mind and thought must ultimately explain how bodily perception and action give rise to cognition, meaning, language, action, and values. A brief account of Johnson’s own intellectual journey, through which we track some of the most important discoveries in the field over the past forty years, sets the stage. Subsequent chapters set out Johnson’s important role in embodied cognition theory, including his cofounding (with George Lakoff) of conceptual metaphor theory and, later, their theory of bodily structures and processes that underlie all meaning, conceptualization, and reasoning. A detailed account of how meaning arises from our physical engagement with our environments provides the basis for a nondualistic, nonreductive view of mind that he sees as most congruous with the latest cognitive science. A concluding section explores the implications of our embodiment for our understanding of knowledge, reason, and truth. The resulting book will be essential for all philosophers dealing with mind, thought, and language.

Download or read book Handbook of the Cerebellum and Cerebellar Disorders written by Mario Manto and published by Springer. This book was released on 2012-08-04 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our knowledge of cerebellar functions and cerebellar disorders, called ataxias, is increasing considerably. Studies of the cerebellum are now a central focus in neuroscience. During the last four decades, many laboratories worldwide have dedicated their research activities to understanding the roles of the cerebellum in motor control, cognitive processes and biology of mental processes, behavioral symptoms, and emotion. It is now accepted that the cerebellum acts as a cognitive operator in learning, perception, and attention. Moreover, major improvements in our assessment of in vivo cerebellar architecture using imaging techniques have occurred. A typical example is the accurate description of cerebellar anatomy during fetal development with MRI, a progress which has direct impacts on patient care. These advances have been associated with discoveries of new clinical disorders, in particular in the field of genetic ataxias. More than 20 new genes have been identified these last 10 years. Only for dominant ataxias, more than 30 diseases have now been unravelled. The number of ataxic disorders will increase with aging, the cerebellum being the structure of the brain with the most important loss of neurons with age. More than 300 different cerebellar disorders are encountered during daily practice, but we are missing a single source of information explaining their pathogenesis. Despite the immense amount of knowledge acquired about the cerebellar circuitry these last years, a large book covering the neuroscience of the cerebellum is missing. The goal of this endeavour is to bring up to date information relevant for basic science and also for clinical activities. To reach this goal, the most renowned authors are gathered in a unique and in-depth book with a format of a handbook. We emphasize the connections between molecular findings, imaging features, behavioural/neuropsychological aspects, and clinical implications.

Download or read book Neural Circuit and Cognitive Development written by Bin Chen and published by Academic Press. This book was released on 2020-06-10 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neural Circuit and Cognitive Development, Second Edition, the latest release in the Comprehensive Developmental Neuroscience series, provides a much-needed update to underscore the latest research in this rapidly evolving field, with new section editors discussing the technological advances that are enabling the pursuit of new research on brain development. This volume is devoted mainly to anatomical and functional development of neural circuits and neural systems and cognitive development. Understanding the critical role these changes play in neurodevelopment provides the ability to explore and elucidate the underlying causes of neurodevelopmental disorders and their effect on cognition. This series is designed to fill the knowledge gap, offering the most thorough coverage of this field on the market today and addressing all aspects of how the nervous system and its components develop. Features leading experts in various subfields as section editors and article authors Presents articles that have been peer reviewed to ensure accuracy, thoroughness and scholarship Includes coverage of mechanisms that control the assembly of neural circuits in specific regions of the nervous system and multiple aspects of cognitive development

Download or read book Development and Reproduction in Humans and Animal Model Species written by Werner A. Mueller and published by Springer. This book was released on 2015-01-03 with total page 723 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes human development including sexual reproduction and stem cell research with the development of model organisms that are accessible to genetic and experimental analysis in readily understandable texts and 315 multi-colored graphics. The introductory account of model organisms selected from the entire animal kingdom presents general principles, which are then outlined in subsequent chapters devoted to, for example, sexual development; genes controlling development and their contemporary molecular-analysis methods; production of clones and transgenic animals; development of the nervous and circulatory systems; regenerative medicine and ageing. Finally the evolution of developmental toolkits and novelties is discussed including the genetic basis of the enlargement of the human forebrain. Separate boxes are devoted to controversial questions such as the benefits and problems of prenatal diagnostics or the construction of ancient body plans.

Download or read book The Visual System in Vertebrates written by F. Crescitelli and published by Springer Science & Business Media. This book was released on 2013-12-11 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vertebrate eye has been, and continues to be, an object of interest and of inquiry for biologists, physicists, chemists, psychologists, and others. Quite apart from its important role in the development of ophthalmology and related medical disciplines, the vertebrate eye is an exemplar of the ingenuity of living systems in adapting to the diverse and changing environments in which vertebrates have evolved. The wonder is not so much that the visual system, like other body systems, has been able to adapt in this way, but rather that these adaptations have taken such a variety of forms. In a previous volume in this series (VII/I) Eakin expressed admiration for the diversity of invertebrate photoreceptors. A comparable situation exists for the vertebrate eye as a whole and one object of this volume is to present to the reader the nature of this diversity. One result of this diversification of ocular structures and properties is that the experimental biologist has available a number of systems for study that are unique or especially favorable for the investigation of particular questions in visual science or neurobiology. This volume includes some examples of progress made by the use of such specially selected vertebrate systems. It is our hope that this comparative approach will continue to reveal new and useful preparations for the examination of important questions.

Download or read book Retinal Vascular Disease written by A.M. Joussen and published by Springer Science & Business Media. This book was released on 2010-03-29 with total page 807 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vascular diseases of the retina are a major cause of blindness among all age groups. Edited and written by internationally well-known experts, this state-of-the-art comprehensive overview of basic and clinical science will enhance the understanding of retinal vascular disease and help in the evaluation of current and future treatment approaches for the clinician. The well-structured and highly illustrated text is divided into three easy-to-follow sections. This unique textbook-atlas also includes topics which are not currently found in other retinal disease textbooks, such as case reports and clinical follow-ups.

Download or read book Reproductive and Developmental Strategies written by Kazuya Kobayashi and published by Springer. This book was released on 2018-06-01 with total page 783 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides new insights into the universality of biological systems in animal reproduction and development by a comparative study of a variety of mechanisms in animals ranging from basal invertebrates to vertebrates, including mammals. Animals accomplish genetic diversity through meiosis and fertilization, and during embryogenesis animals must produce specialized cell types, including germ cells, in accordance with their individual body plan. This series of phenomena is essential to the continuity of life in the animal kingdom, and animals show various reproductive and developmental strategies. This volume, comprising four parts, reviews animal kingdom diversity, including reproductive strategies and germ cell differentiation mechanisms (Part 1), sex determination and differentiation (Part2), the mechanisms of fertilization (Part 3), and body axis formation (Part 4). Readers will find descriptions of the reproduction or development of 180 species, 13 phyla, 35 classes, 74 orders, 117 families, and 151 genera in this book. Of particular interest is the diversity of molecules and mechanisms used to achieve the same biological purpose in different animals. Undergraduates, graduate students, and professional scientists who want a deeper understanding of animal reproductive and developmental mechanisms will find this book to be of great value.

Download or read book Developmental Neurobiology written by Mahendra S. Rao and published by Springer Science & Business Media. This book was released on 2006-04-04 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: This consistent and well-illustrated text is an up-to-date survey of cellular and molecular events contributing to the assembly of the vertebrate nervous system. Chapters include a mixture of historical content and descriptions from literature that best illustrate specific aspects of development.