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Search Results: 1 - 10 of 19829 matches for " André Steinecke "
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GABA through the Ages: Regulation of Cortical Function and Plasticity by Inhibitory Interneurons
Konrad Lehmann,André Steinecke,Jürgen Bolz
Neural Plasticity , 2012, DOI: 10.1155/2012/892784
Abstract: Inhibitory interneurons comprise only about 20% of cortical neurons and thus constitute a clear minority compared to the vast number of excitatory projection neurons. They are, however, an influential minority with important roles in cortical maturation, function, and plasticity. In this paper, we will highlight the functional importance of cortical inhibition throughout brain development, starting with the embryonal formation of the cortex, proceeding by the regulation of sensory cortical plasticity in adulthood, and finishing with the GABA involvement in sensory information processing in old age. 1. Introduction The functioning of the cerebral cortex depends critically on the precise balance between excitatory and inhibitory neurotransmitter systems. Excitation is mediated via glutamate by pyramidal neurons, the projection neurons of the cortex, and by a special class of local neurons in cortical layer IV, the spiny stellate cells. Inhibition is mediated via γ-aminobutyric acid (GABA) by cortical interneurons, which regulate the degree of glutamatergic excitation, filtering the input and regulate the output of projection neurons. GABAergic interneurons, the “nonpyramidal cells” of the cerebral cortex, take many different forms of dendritic and axonal arborization, which have been used for their morphological classification ever since their first description by Ramon Cajal [1–5]. Moreover, interneurons also differ in their firing patterns, the neuropeptides they express, their calcium-binding protein content, and other molecular markers such as ion channels, receptors, and transporters. Based on the combination of structural, functional, and biochemical criteria, interneurons have been subdivided into many different subclasses and it is still a matter of hot debate among the experts of how many interneuron subtypes exist in the cortices of different species [6–8]. At the circuit level, interneurons control the flow of information and synchronization in the cerebral cortex. There are about five times more glutamatergic neurons than GABAergic neurons in the neocortex; this ratio is consistently observed across many mammalian species. This then suggests that the numerical balance of excitatory and inhibitory neurons may be important for normal brain function and behavior. Even though GABAergic interneurons comprise only a small fraction of the cells in the neocortex, disturbances in their development, and hence the delicate balance between excitation and inhibition, can lead to neurological or neuropsychiatric diseases such as epilepsy, autism, and
A dual role of EphB1/ephrin-B3 reverse signaling on migrating striatal and cortical neurons originating in the preoptic area: should I stay or go away ?
André Steinecke,Annika D?ding,Jürgen Bolz
Frontiers in Cellular Neuroscience , 2014, DOI: 10.3389/fncel.2014.00185
Abstract: During embryonic development the preoptic area (POA) gives rise to two populations of neurons which are generated at the same time, cortical interneurons and striatal cells. POA-derived cortical interneurons take a superficial path and avoid the developing striatum when they migrate to their target region. We found that EphB1, which is expressed in the striatal anlage, prevents cortical interneurons from entering the striatum via ephrin-B3 reverse signaling. In contrast, for striatal neurons which also express ephrin-B3, EphB1 acts as a stop signal. This dual role of EphB1 is due to differences in ephrin-B3 reverse signaling cascades. For striatal neurons, binding of EphB1 to ephrin-B3 reduces endogenously high levels of pSrc and pFAK, which then causes the cells to stop migration. In contrast, in cortical interneurons EphB1-ephrin-B3 reverse signaling leads to phosphorylation of Src and FAK which then mediates repulsion. Consistent with these in vitro findings, in an ephrin-B3 knockout mouse line, we discovered misrouted cortical interneurons in the striatum and an over-migration of striatal neurons in their target region. Thus, EphB1/ephrin-B3 reverse signaling has a different impact on two sets of neurons which are generated at the same time and place: it can act as a repulsive cue for migrating neurons or it can terminate neuronal migration, a novel role of the Eph/ephrin system.
Structural Brain Alterations in Patients with Lumbar Disc Herniation: A Preliminary Study
Michael Luchtmann, Yvonne Steinecke, Sebastian Baecke, Ralf Lützkendorf, Johannes Bernarding, Jana Kohl, Boris J?llenbeck, Claus Tempelmann, Patrick Ragert, Raimund Firsching
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090816
Abstract: Chronic pain is one of the most common health complaints in industrial nations. For example, chronic low back pain (cLBP) disables millions of people across the world and generates a tremendous economic burden. While previous studies provided evidence of widespread functional as well as structural brain alterations in chronic pain, little is known about cortical changes in patients suffering from lumbar disc herniation. We investigated morphometric alterations of the gray and white matter of the brain in patients suffering from LDH. The volumes of the gray and white matter of 12 LDH patients were determined in a prospective study and compared to the volumes of healthy controls to distinguish local differences. High-resolution MRI brain images of all participants were performed using a 3 Tesla MRI scanner. Voxel-based morphometry was used to investigate local differences in gray and white matter volume between patients suffering from LDH and healthy controls. LDH patients showed significantly reduced gray matter volume in the right anterolateral prefrontal cortex, the right temporal lobe, the left premotor cortex, the right caudate nucleus, and the right cerebellum as compared to healthy controls. Increased gray matter volume, however, was found in the right dorsal anterior cingulate cortex, the left precuneal cortex, the left fusiform gyrus, and the right brainstem. Additionally, small subcortical decreases of the white matter were found adjacent to the left prefrontal cortex, the right premotor cortex and in the anterior limb of the left internal capsule. We conclude that the lumbar disk herniation can lead to specific local alterations of the gray and white matter in the human brain. The investigation of LDH-induced brain alterations could provide further insight into the underlying nature of the chronification processes and could possibly identify prognostic factors that may improve the conservative as well as the operative treatment of the LDH.
Post-Formal Thought in Gerontagogy or Beyond Piaget  [PDF]
André Lemieux
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.23046
Abstract: Jean Piaget, one of the most influential theorists in developmental psychology, assumed that formal thought, characterized by the development of an individual’s logical capacities, was the last stage of adult thinking. In this article, we review how the brain evolved, describing its main structures, and examining each cerebral hemisphere’s specific functions. Evidence is also provided for the production of new neurons and new connections between them, forcing a revision of old theories about the decline of intellectual functions in the elderly. We then consider Jones’ theories X and Y, and the different definitions of intelligence (fluid vs. crystallized, and qualitative vs. quantitative), and how these perspectives have influenced the way we see intelligence. Evidence supporting the addition of another stage, named post-formal thought, is examined in the context of gerontagogy. Dialectical thought characterizes this stage, and developing wisdom is its main goal. We examine the two basic principles of dialectical thought, namely the principle of contradiction and the principle of relativity of everything. It is suggested that the learning of wisdom should be the focus of future university programs to educate the elderly.
The History of the Basal Ganglia: The Contribution of Karl Friedrich Burdach  [PDF]
André Parent
Neuroscience & Medicine (NM) , 2012, DOI: 10.4236/nm.2012.34046
Abstract:

It took many centuries for the basal ganglia (BG) to be recognized as specific brain entities involved in the control of psychomotor behavior. Andreas Vesalius (1514-1564) was the first to delineate this set of structures, but he did not name them nor payany attention to their functional significance. This was left to the English physician Thomas Willis (1621-1675), who used the term corpus striatum (striated or chamfered body) to designate the largest BG constituent, which he considered a major sensorimotor integration center. Willis’s pioneering description influenced markedly some 18th and 19th centuries scholars, particularly the German physician and anatomist Karl Friedrich Burdach (1776-1847). Burdach’s insightful studies of the human brain are summarized in a three-volume treatise entitled Vom Baue und Leben des Gehirns (1819-1826). This landmark opus provides a description of the BGwhose originality has largely been overlooked. Burdach’s careful investigation allowed him to differentiate the caudate nucleus from the putamen, which he respectively termed Streifenhügel (elongated hillock) and Schale (shell). He also called the putamen Linsenkern (lens-shaped nucleus), a term that he admittedly borrowed from his compatriot Johann Christian Reil (1759-1813). He further identified a paler structure (blasser Klumpen) within the inner portion of the lentiform nucleus that he called globus pallidus, and correctly identified its inner and outer segments (innern und ?ussern Theil). He aptly pointed out that the major BG nuclei are separated from one another by fibers fascicles that he termed inner and ?ussre Capsel (internal and external capsules). Burdach also referred to the substantia nigra (schwarzgraue Schicht or stratum nigrum) and claustrum (Vormauer), but gave full credit to the French anatomist Félix Vicq-d’Azyr (1748-1794) for their discovery. Although Burdach did not comment much on BG function, his anatomical description was sufficiently cogent to be still in use two centuries after its inception.

Louis Pierre Gratiolet (1815-1865) and His Contribution to the Study of Cerebral Convolutions in Primates  [PDF]
André Parent
Neuroscience & Medicine (NM) , 2014, DOI: 10.4236/nm.2014.51001
Abstract:

Louis Pierre Gratiolet (1815-1865) was one of the first modern anatomists to pay attention to cerebral convolutions. Born in Sainte-Foy-la-Grande (Gironde), he moved to Paris in 1834 to study medicine, as well as comparative anatomy under Henri de Blainville (1777-1850). In 1842, he accepted de Blainville’s offer to become his assistant at the Muséum dhistoire naturelle and progressively abandoned medicine for comparative anatomy. He undertook a detailed study of brains of human and nonhuman primates and soon realized that the organizational pattern of cerebral convolutions was so predictable that it could serve as a criterion to classify primate groups. He noted that only the deepest sulci exist in lower primate forms, while the complexity of cortical folding increases markedly in great apes and humans. Gratiolet provided the first cogent description of the lobular organization of primate cerebral hemispheres. He saw the insula as a central lobe around which revolved the frontal, parietal, temporal (temporo-sphenoidal) and occipital lobes. He correctly identified most gyri and sulci on all brain surfaces, introduced the term plis de passage for some interconnecting gyri, and provided the first description of the optic radiations. In the early 1860s, Gratiolet fought a highly publicized battle against Paul Broca (1824-1880) on the relationship between brain and intelligence. Gratiolet agreed that the brain was most likely the seat of intelligence, but he considered human cognition far too subtle to have any direct relationship with

Procedural Utility in the Work Place, Evidence from Mexico  [PDF]
André Vargas
Theoretical Economics Letters (TEL) , 2014, DOI: 10.4236/tel.2014.49104
Abstract: The concept of Utility usually refers to the satisfaction a person acquires by consuming, in general under circumstances bonded to income, and the price of goods. In a psychological vision of personal well-being, happiness and its components, consider the fact that people can value anything. This notion has led to the study of Procedural Utility, that means people not only value the outcome of something, but also values the process and conditions in which the outcome is achieved. Procedural Utility can be obtained from various economic procedures in which individuals are part of, e.g. Work and consumption among others. Evidence has been found that in the work place the fact of being attached to hierarchy generates negative Procedural Utility because it disrupts psychological precepts that determine happiness, well-being, or utility [1]. In other cases it has been found that the process on how a wage cut is done must be considered [2]. In the light of this phenomena, I’ll discuss the concept of Procedural Utility and analyze empirical evidence for the Mexican case with “Instituto Nacional de Estadistica y Geografía” INEGI’s self-reported well-being survey (BIARE), with the finality to give suggestions on possible applications of processes to improve the worker’s satisfaction.
The Hydrogen Atom Fundamental Resonance States  [PDF]
André Michaud
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.95067
Abstract: In the 1920’s, Louis de Broglie’s observation that the integer sequence that could be related to the interference patterns produced by the various electromagnetic energy quanta emitted by hydrogen atoms was identical to those of very well known classical resonance processes, made him conclude that electrons were captive in resonance states within atoms. This led Schr?dinger to propose a wave function to represent these resonance states that still have not been reconciled with the electromagnetic properties of electrons. This article is meant to identify and discuss the electromagnetic harmonic oscillation properties that the electron must possess as a resonator in order to explain the resonance volume described by the wave function, as well as the electromagnetic interactions between the elementary charged particles making up atomic structures that could explain electronic and nucleonic orbitals stability. An unexpected benefit of the expanded space geometry required to establish these properties and interactions is that the fundamental symmetry requirement is respected by structure for all aspects of the distribution of energy within electromagnetic quanta.
The Mechanics of Conceptual Thinking  [PDF]
André Michaud
Creative Education (CE) , 2019, DOI: 10.4236/ce.2019.102028
Abstract: Description of the mechanics of conceptual thinking?that?stems?from interaction sequences between the limbic system and the verbal areas of the neocortex. Description of the rise of the attention level to full active awareness when a feeling of uneasiness due to a verbal stimulus is triggered by the amygdala, followed by an active cogitation process involving the verbal areas of the neocortex, ending in the strengthening in the neocortex by the hippocampus of a synaptic network corresponding to a modified verbal sequence that removes or reduces the feeling of uneasiness that initiated the sequence. Description of the generalization abilitythat?emerges from the use of articulated languages, acquired by education, from which conceptual thinking andalso?the collectively intelligible mathematical language emerge that also develops to various degrees in some individuals by education. Description of the mathematical thinking mode, about?whose engrams have been located in the neocortex in areas that do not overlap the verbal areas.
Educational Boxing Is Worth Becoming a Template for Building up Concussion Prevention Means in Children and Adolescents Sports  [PDF]
André Mukala Nsengu Tshibangu
Advances in Physical Education (APE) , 2013, DOI: 10.4236/ape.2013.31008
Abstract: After comparing the means of concussion prevention used in educational boxing with similar means used in other sports practiced by children and adolescents, we noted that the exclusive use of light touches instead of blows in competitions of educational boxing is an original means of preventing concussion, acting on the direct cause rather than on the possible victim of concussion. We have then predicted that educational boxing is possibly the concussion-free form of competition boxing and that it is possibly chronic damage-free. If our predictions are fulfilled, educational boxing may serve as a template for building up concussion prevention means in all sports. Moreover, we would better go on popularizing the practice of educational boxing which is less likely to induce concussion than amateur and professional boxing; which has had more license owners than the two latter the 2004-2005, 2005-2006 and 2006-2007 boxing seasons in France; and which is practiced almost exclusively by children and adolescents in France. Despite the fact that light touches force of impact is sub-concussive, we need research work be undertaken in order to know whether light touches are harmless in educational boxers having had many fights and to know the occurrence frequency of unexpected concussions from light touches that turn to unintentional counter- punches.


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