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It has been observed that every signature is distinctive, and that΄s why, the use of signatures as a biometric has been supported and implemented in various technologies. It is almost impossible for a person himself to repeat the same signature every time he signs. We proposed an intelligent system for off-line signature verification using chain-code. Dynamic features are not available, so, it becomes more difficult to achieve the goal. Chain-code is extracted locally and Feed Forward Back Propagation Neural Network used as a classifier. Chain-code is a simple directional feature, extracted from a thinned image of signature because contour based system acquires more memory. An intelligent network is proposed for training and classification. The results are compared with a very basic energy density method. Chain-code method is found very effective if number of samples available for training is limited, which is also practically feasible. [ABSTRACT FROM AUTHOR]

Transient receptor potential (TRP) channels represent a superfamily of cation channels found in all eukaryotes. The C. elegans genome encodes seventeen TRP channels covering all of the seven TRP subfamilies. Genetic analyses in C. elegans have implicated TRP channels in a wide spectrum of behavioral and physiological processes, ranging from sensory transduction (e.g. chemosensation, touch sensation, proprioception and osmosensation) to fertilization, drug dependence, organelle biogenesis, apoptosis, gene expression, and neurotransmitter/hormone release. Many C. elegans TRP channels share similar activation and regulatory mechanisms with their vertebrate counterparts. Studies in C. elegans have also revealed some previously unrecognized functions and regulatory mechanisms of TRP channels. C. elegans represents an excellent genetic model organism for the study of function and regulation of TRP channels in vivo. [ABSTRACT FROM AUTHOR]

In this, we study the bursting dynamics of the complex neural networks with chemical synapses. A quantitative characteristics, width factor, is introduced to describe the bursting dynamics of the neuron. Then we study the effects of the coupling schemes and the network topology on the rhythmic dynamics of the networks. It is concluded that the coupling scheme plays the key role in shaping the bursting types of the neurons. As for the network topology, more links can only change the bursting type of the long bursting neurons, and the short bursting neurons are robust to the link numbers. [ABSTRACT FROM AUTHOR]

We investigate phase synchronization of uncoupled bursting neurons, caused by spatially correlated noise. It is found that the degree of synchronization between non-identical neurons decreases monotonously when increasing partially correlated noise intensity, but undergoes a minimum with the common noise intensity increasing. [ABSTRACT FROM AUTHOR]

We hypothesize that the prefrontal cortex is involved in category inference. To test this hypothesis, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) of two monkeys performing a sequential paired-association task with an asymmetric reward schedule. We found that a group of LPFC neurons encoded reward value specific to a category of visual stimuli defined by relevant behavioral responses. And these neurons predicted the amount of reward based on new category members that had never been used in the asymmetric reward task, when a member from the same category was paired with a large (or small) amount of reward. The results suggest that LPFC neurons encode category-based reward information, and transfer this information to category members including new ones, which could be the neural basis of category inference. [ABSTRACT FROM AUTHOR]

The nervous system is especially vulnerable to reactive oxygen species (ROS)-mediated injury for the following reasons. (1) High oxygen consumption of the brain for high energy needs, that is, high O2 consumption, results in excessive ROS produced. (2) Neuronal membranes are rich in polyunsaturated fatty acids (PUFA), which are particularly vulnerable to free radical attack. (3) The ratio of membrane surface area to cytoplasmic volume is high. (4) Specialized neuronal conduction and synaptic transmission activity depend on efficient membrane function. (5) Extended axonal morphology is prone to peripheral injury. (6) Neuronal anatomic network is vulnerable to disruptions. (7) The excitotoxic glutamate is the major effector that causes oxidative stress (OS). (8) The high Ca2+ traffic across neuronal membranes and interference of ion transport increase intracellular Ca2+, often leading to OS. (9) Auto-oxidation of neurotransmitters can generate O2 and quinones that reduce glutathione. (10) Iron is formed throughout the brain, and brain damage readily releases iron ions capable of catalyzing free radical reactions. (11) Antioxidant defense mechanisms are modest, in particular, low levels of catalase, glutathione peroxidase, and vitamin E. (12) ROS directly downregulate proteins of tight junctions and indirectly activate matrix metalloproteinases (MMP) that contribute to open the blood–brain barrier (BBB). (13) Activated microglia produce ROS and cytokines in a perpetual process. (14) Cytochrome P450 produces ROS. (15) Loss of trophic support can activate NADPH oxidase, which increases ROS. (16) The presence of hemoglobin within the neural tissues secondary to spontaneous, iatrogenic, or traumatic causes is neurotoxic. Heme and iron are released and promote ROS. (17) Neuronal mitochondria generate O2. (18) The interaction of NO with superoxide can be implicated also in neuronal degeneration. (19) Neuronal cells are nonreplicating and thus are sensitive to ROS. In comparison with other organs, the neuronal network may be especially vulnerable to ROS-mediated injury because of the following anatomic, physiological, and biochemical properties of the brain. [ABSTRACT FROM AUTHOR]

This chapter is an introduction to the biology of reactive oxygen species (ROS) in the brain. In healthy aerobes, there is a balance between the production of various ROS and antioxidant defenses. Living organisms have not only adapted to coexistence with free radicals but have developed various mechanisms for the advantageous use of free radicals in various physiological functions. Infectious diseases were a powerful driver of natural selection in early human civilizations. Indeed, ROS participate directly in defense against infection. In a normal situation, microglia, which are resident macrophages of the brain, fight against infection by ROS. ROS are well recognized for playing a dual role, having both deleterious and beneficial effects, which in most cases depend on concentration. At high ROS concentrations there are harmful effects, and in a low–moderate concentration ROS are involved in physiological roles in cellular response to noxious stimuli. It was suggested that the main effects of ROS on cells are through their actions on signaling pathways rather than causing nonspecific damage. With aging, when these pathways deteriorate, accumulation of higher concentrations of ROS occurs in amounts beyond the capacity of antioxidants to cope. This deterioration results in the age-associated neurodegenerative disorders such as stroke and central nervous system (CNS) trauma as well as Parkinson΄s and Alzheimer΄s disease. Some of the CNS-evolved specific signaling pathways are described. [ABSTRACT FROM AUTHOR]

A method was described for the acute isolation of neurons suitable for patch-clamping study from the frontal cortex of 7-10-d-old Kunming mice by a combination of mechanical and enzymatic means. Using inverted microscope and whole-cell configuration of patch-clamp technique, the morphological and electrophysiological properties of cortical neurons were studied respectively. It was shown that the enzymatically isolated neurons had plump profile, smooth surface, strong aureole and long survival time, met the electrophysiological requirements, and exhibited the whole-cell transmembrane currents, voltage-gated sodium and potassium currents. The experiment proves that this method is simple, efficient, reliable and utility. The dissociated cortical neurons could be obtained and applied to patch-clamping study, which has reference value for studying the effects of physiology, pathology, pharmacology and physical factors on the ion channels of the cortical neurons of mice. [ABSTRACT FROM AUTHOR]

The morphology and structure of 3D dendritic backbones are the essential to understand the neuronal circuitry and behaviors in the neurodegenerative diseases. As a big challenge, the research of extraction of dendritic backbones using image processing and analysis technology has attracted many computational scientists. This paper proposes a reliable and robust approach for automatically extract dendritic backbones in 3D optical microscopy images. Our systematic scheme is a gradient vector field based skeletonization approach. We first use self-snake based nonlinear diffusion, adaptive segmentation to smooth noise and segment the neuron object. Then we propose a hierarchical skeleton points detection algorithm (HSPD) using the measurement criteria of low divergence and high iso-surface principle curvature. We further create a minimum spanning tree to represent and establish effective connections among skeleton points and prune small and spurious branches. To improve the robustness and reliability, the dendrite backbones are refined by B-Spline kernel based data fitting. Experimental results on different datasets demonstrate that our approach has high reliability, good robustness and requires less user interaction. [ABSTRACT FROM AUTHOR]

We describe a method to isolate and co-culture dissociated hippocampal neurons and cortical astrocytes from young mice (E17 and newborn, respectively). This protocol is useful to investigate the effects of astrocytes on the developmental biology of neurons. By independently isolating the astrocytes and neurons (with different genetic backgrounds) from different mice, an in vitro environment can be created where one cell type is deficient in a gene or protein of interest. For example, this method is well suited to examine the effect of a genetic mutation in astrocytes on the development of neuronal processes and synapses. [ABSTRACT FROM AUTHOR]

Future networks are becoming larger in scale, more dynamic and heterogeneous. In such environments, adaptation of algorithms in the current networking conditions is necessary in order to increase the efficiency and performance of the deployed mechanisms. Knowledge of network based parameters may facilitate the decision making processes in a dynamic environment. Self-awareness will help the network to diagnose faults and realize the current status and, thus, proceed to self-optimization actions. In this paper, a neighbour to neighbour gossiping mechanism is proposed for autonomic estimation of network based parameters. The described mechanism is evaluated in terms of message exchanges and convergence time until accurate parameters΄ estimation. [ABSTRACT FROM AUTHOR]

Stroke/brain ischemia, caused predominantly by an occlusion of cerebral blood flow to the brain tissue, is a leading cause of death and long-term disabilities in the developed countries. Unfortunately, there is no effective treatment for stroke patients other than the use of thrombolitic agents, which have limited therapeutic time window of less than 3 h and a potential side effect of intracranial hemorrhage. Therefore, searching for new cell injury mechanism(s) and effective therapeutic strategies has been a major challenge. It was recognized several decades ago that excessive intracellular Ca2+ accumulation and subsequent Ca2++ toxiCity is critical for neuronal injury associated with brain ischemia. However, the exact pathway(s) underlying toxic Ca2+ loading responsible for ischemic brain injury remained elusive. For many years, accumulation of glutamate in the extracellular space and overactivation of postsynaptic glutamate receptors have been the central focus for Ca2+ toxiCity in brain ischemia. However, the recent large-scale multicenter clinical trials using the antagonists of glutamate receptors as the neuroprotective agents have failed to demonstrate a satisfactory effect. Although multiple factors may have contributed to the failure of the trials, studies in the last 5 years have suggested that Ca2+ loading through several glutamate receptor-independent pathways, e.g., Ca2+-permeable acid-sensing ion channels and TRPM7 channels, may contribute equally to the pathological loading of Ca2+ in ischemic brain. This review focuses on the role of acid-sensing ion channels in glutamate receptor-independent neuronal injury. [ABSTRACT FROM AUTHOR]

Abstract: New fundamental results on stem cell biology have been obtained in the past 15 years. These results allow us to reinterpret the functioning of the cerebral tissue in health and disease. Proliferating stem cells have been found in the adult brain, which can be involved in postinjury repair and can replace dead cells under specific conditions. Numerous genomic mechanisms controlling stem cell proliferation and differentiation have been identified. The involvement of stem cells in the genesis of malignant tumors has been demonstrated. Neural stem cell tropism toward tumors has been shown. These findings suggest new lines of research on brain functioning and development. Stem cells can be used to develop radically new treatments of neurodegenerative and cancer diseases of the brain. [Copyright &y& Elsevier]

Neurobiology is the study and functional organization of the cells that make up the nervous system. The central nervous system (CNS) begins as a simple neural plate that folds to form a groove and then a tube. Then stem cells within the neural tube are directed toward glia and neurons under the influence of various neural developing signaling processes. It is these cells including, but not limited to, neurons, microglia, astrocytes, endothelial cells, their communication and circuitry, one with the other, that lead to our abilities to sense and respond to the environment, think, ambulate, and behave. Neurobiology is at the very interface of biology and neuroscience but is significantly different from each of the fields. Biology is that of all building blocks of cell organization and function regardless of tissue origin. It is broad and without limits. Neuroscience is by its very integration includes works in computation and cognition that are linked to the clinical disciplines of psychiatry and neurology. Each alone or together relate to cell and system analyses and disease. Nonetheless, the disciplines of neuroscience and biology overlap to generate the field of neurobiology. Here there is a central focus on the cell and its functional outcomes. This chapter seeks to describe the discipline of neurobiology starting from the cell and its function to system organization to function. Such processes underlie both nerve cell communication and function as well as the role glial cells can affect the process overall. [ABSTRACT FROM AUTHOR]

The major function of the nervous system is to rapidly transfer and integrate information with a view to organizing the diverse functions of multicellular organisms. Our present understanding as to how nerve cells communicate originates with studies in the nineteenth century on the anatomy of the nervous system. Work conducted by Camillo Golgi and Santiago Ramon y Cajal defined the fine structure of neurons for the first time. Golgi favored the idea that all the nerves in the nervous system existed as a sort of reticular net, rather than as separate entities. Cajal, in contrast, concluded that neurons were independent entities and that a minute gap existed between the ends of nerve fibers and other nerve cells or the muscles that they innervate. This gap was ultimately named a ˵synapse″ by the great neurologist Sir Charles Sherrington in 1897, from the Greek meaning ˵to clasp″. Cajal also argued that neurotransmission was basically a unidirectional process, information being received by dendrites and being transmitted unidirectionally along axons. The actual existence of the synapse as a structure was not confirmed until the development of the electron microscope in the 1950s. Around this time a fierce debate took place between two opposing sets of scientists (Valenstein, 2005). One set, primarily electrophysiologists, held the view that information was transmitted between nerves and between nerves and muscles by purely electrical processes. The other group, primarily pharmacologists, suggested that chemical messenger molecules were released by the presynaptic nerve and carried the information across the synapse. The nature of the chemicals that constitute neurotransmitters was gradually revealed by the work of several important investigators who characterized the effects of different substances that mimicked or blocked the actions of neurotransmitters on fast skeletal muscles and in the autonomic nervous system. This finally culminated in the demonstration by Otto Loewi in 1921 that the vagus nerve secreted a chemical (˵Vagusstoff″) that mediated the slowing effect of vagal stimulation on the heart. This substance turned out to be acetylcholine. [ABSTRACT FROM AUTHOR]

In this paper, a novel approach to Arabic letter recognition is proposed. The system is based on the classified vector quantization (CVQ) technique employing the minimum distance classifier. To prove the robustness of the CVQ system, its performance is compared to that of a standard artificial neural network (ANN)-based solution. In the CVQ system, each input letter is mapped to its class using the minimum Euclidean distance. Simulation results are provided and show that the CVQ system always produces a lower Mean Squared Error (MSE) and higher success rates than the current ANN solutions. [ABSTRACT FROM AUTHOR]

Numerous approaches have been proposed for Handwritten Signature Identification systems. Various successful domain specific applications using ANN (artificial neural networks) can be found, but not flexible enough for generalization. Besides all, one approach that has shown great promise is the use of ANN in the Handwritten Signature Identification. In this paper we have explored a new recognition technique; an ANN is trained to identify patterns among different supplied handwriting samples. Handwritten signature samples are considered input for our artificial neural network model and typically weights also supplied for recognition. [ABSTRACT FROM AUTHOR]

Chapter 4 of the book "Psychiatric Mental Health Nursing: Concepts of Care in Evidence-Based Practice" is presented. It explains the functions of cerebrum which comprises the largest part of the human brain. Neurotransmitters are chemicals which are responsible for sending information across synaptic clefts to adjacent target cells. It emphasizes the need for psychiatric nurses to incorporate knowledge of biological sciences to their practices to ensure quality care to mentally ill patients.

MEDICAL WISDOM When the medieval doctor looked into the past for the beginnings of his own profession, what he found was the figure of Hippocrates, the Father of Medicine in the medical tradition from the Middle Ages to the Enlightenment. Modern scholarship has not revealed much about the historical Hippocrates or which of the ‘Hippocratic’ works were written by him, but the medieval doctor felt more secure in his knowledge. The Hippocratic works gave him a number of things. There was technical advice in a practical subject, which told him what to do and what to expect. For instance, the corpus includes works that explain how to reduce dislocations and how to bandage wounds. The Hippocratic works were also valuable because they were Hippocratic, that is, ancient and authoritative in an age that revered antiquity. These first two chapters are not directly concerned with the first of these aspects of antiquity, the technical content of Greek medicine and philosophy. They are not, that is, a background to or an early history of a professional activity developed during the Middle Ages and beyond. Rather, they present an image of the medieval and later perception of antiquity, a construction (however false in our historical terms) within the Latin tradition and on which the later Western doctors based their actions. It is not a story of beginnings but of resources. [ABSTRACT FROM AUTHOR]