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Multiple Regions (multiple + regions)
Selected AbstractsOrigin of the earliest correlated neuronal activity in the chick embryo revealed by optical imaging with voltage-sensitive dyesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009Yoko Momose-Sato Abstract Spontaneous correlated neuronal activity during early development spreads like a wave by recruiting a large number of neurons, and is considered to play a fundamental role in neural development. One important and as yet unresolved question is where the activity originates, especially at the earliest stage of wave expression. In other words, which part of the brain differentiates first as a source of the correlated activity, and how does it change as development proceeds? We assessed this issue by examining the spatiotemporal patterns of the depolarization wave, the optically identified primordial correlated activity, using the optical imaging technique with voltage-sensitive dyes. We surveyed the region responsible for the induction of the evoked and spontaneous depolarization waves in chick embryos, and traced its developmental changes. The results showed that the wave initially originated in a restricted area near the obex and was generated by multiple regions at later stages. We suggest that the upper cervical cord/lower medulla near the obex is the kernel that differentiates first as the source of the correlated activity, and that regional and temporal differences in neuronal excitability might underlie the developmental profile of wave generation in early chick embryos. [source] Intra- and intermuscular variation in human quadriceps femoris architecture assessed in vivoJOURNAL OF ANATOMY, Issue 3 2006Anthony J. Blazevich Abstract Despite the functional importance of the human quadriceps femoris in movements such as running, jumping, lifting and climbing, and the known effects of muscle architecture on muscle function, no research has fully described the complex architecture of this muscle group. We used ultrasound imaging techniques to measure muscle thickness, fascicle angle and fascicle length at multiple regions of the four quadriceps muscles in vivo in 31 recreationally active, but non-strength-trained adult men and women. Our analyses revealed a reasonable similarity in the superficial quadriceps muscles, which is suggestive of functional similarity (at least during the uni-joint knee extension task) given that they act via a common tendon. The deep vastus intermedius (VI) is architecturally dissimilar and therefore probably serves a different function(s). Architecture varies significantly along the length of the superficial muscles, which has implications for the accuracy of models that assume a constant intramuscular architecture. It might also have consequences for the efficiency of intra- and intermuscular force transmission. Our results provide some evidence that subjects with a given architecture of one superficial muscle, relative to the rest of the subject sample, also have a similar architecture in other superficial muscles. However, this is not necessarily true for vastus lateralis (VL), and was not the case for VI. Therefore, the relative architecture of one muscle cannot confidently be used to estimate the relative architecture of another. To confirm this, we calculated a value of whole quadriceps architecture by four different methods. Regardless of the method used, we found that the absolute or relative architecture of one muscle could not be used as an indicator of whole quadriceps architecture, although vastus medialis, possibly in concert with VL and the anterior portion of VI, could be used to provide a useful snapshot. Importantly, our estimates of whole quadriceps architecture show a gender difference in whole quadriceps muscle thickness, and that muscle thickness is positively correlated with fascicle angle whereas fascicle length is negatively, although weakly, correlated with fascicle angle. These results are supportive of the validity of estimates of whole quadriceps architecture. These data are interpreted with respect to their implications for neural control strategies, region-specific adaptations in muscle size in response to training, and gender-dependent differences in the response to exercise training. [source] Absence of detectable measles virus genome sequence in blood of autistic children who have had their MMR vaccination during the routine childhood immunization schedule of UKJOURNAL OF MEDICAL VIROLOGY, Issue 5 2006M.A. Afzal Abstract Leukocyte preparations from children with documented evidence of MMR vaccination and confirmed diagnosis of autism were examined by several assays designed to target multiple regions of the measles virus genome sequence. No sample was found positive by any method. The assays applied were highly sensitive, specific and robust in nature, and were based on the amplification of measles virus RNA transcripts by real-time quantitative RT-PCR (QRT-PCR) as well as by conventional RT-PCR-nested PCR. The assays applied were potentially able to detect measles virus RNA down to single figure copy numbers per reaction. The amount of total nucleic acid extract of leukocytes subjected to various measles virus-specific investigations was several fold higher than minimally required of a sample where measles virus persistence is well documented. This study failed to substantiate reports of the persistence of measles virus in autistic children with development regression. J. Med. Virol. 78:623,630, 2006. © 2006 Wiley-Liss, Inc. [source] Regional and cellular distribution of mitochondrial ferritin in the mouse brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2010Amanda M. Snyder Abstract Iron and mitochondrial dysfunction are important in many neurodegenerative diseases. Several iron transport proteins have been identified that are associated with mitochondria, most recently mitochondrial ferritin. Here we describe the cellular distribution of mitochondrial ferritin in multiple regions of the brain in C57/BL6 mice. Mitochondrial ferritin was found in all regions of the brain, although staining intensity varied between regions. Mitochondrial ferritin was detected throughout the layers of cerebral cortex and in the cerebellum, hippocampus, striatum, choroid plexus, and ependymal cells. The cell type in the brain that stains most prominently for mitochondrial ferritin is neuronal, but oligodendrocytes also stain strongly in both gray matter and in white matter tracts. Mice deficient in H-ferritin do not differ in the mitochondrial ferritin staining pattern or intensity compared with C57/BL6 mice, suggesting that there is no compensatory expression of these proteins. In addition, by using inbred mouse strains with differing levels of iron content, we have shown that regional brain iron content does not affect expression of mitochondria ferritin. The expression of mitochondria ferritin appears to be more influenced by mitochondrial density. Indeed, at an intracellular level, mitochondrial ferritin immunoreaction product is strongest where mitochondrial density is high, as seen in the ependymal cells. Given the importance and relationship between iron and mitochondrial activity, understanding the role of mitochondrial ferritin can be expected to contribute to our knowledge of mitochondrial dysfunction and neurodegenerative disease. © 2010 Wiley-Liss, Inc. [source] Narrow-band CCD photometry of giant H ii regionsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2002Guillermo Bosch We have obtained accurate CCD narrow-band H, and H, photometry of giant H ii regions (GEHRs) in M33, NGC 6822 and M101. Comparison with previous determinations of emission-line fluxes shows large discrepancies; their probable origins are discussed. Combining our new photometric data with global velocity dispersion (,) derived from emission linewidths, we review the relation. A re-analysis of the properties of the GEHRs included in our sample shows that age spread and the superposition of components in multiple regions introduce a considerable spread in the regression. Combining the information available in the literature regarding ages of the associated clusters, evolutionary footprints on the interstellar medium, and kinematical properties of the knots that build up the multiple GEHRs, we find that a subsample , which we refer to as young and single GEHRs , do follow a tight relation in the plane. [source] The neuropathology of autism: where do we stand?NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 1 2008C. Schmitz The neurobiology and neuropathology of the autism spectrum disorders (ASD) remain poorly defined. Brain imaging studies suggest that the deficits in social cognition, language, communication and stereotypical patterns of behaviour that are manifest in individuals with ASD, are related to functional disturbance and ,disconnectivity', affecting multiple brain regions. These impairments are considered to arise as a consequence of abnormal pre- and postnatal development of a distributed neural network. Examination of the brain post mortem continues to provide fundamental information concerning the cellular and subcellular alterations that take place in the brain of autistic individuals. Neuropathological observations that have emerged over the past decade also point towards early pre- and postnatal developmental abnormalities that involve multiple regions of the brain, including the cerebral cortex, cortical white matter, amygdala, brainstem and cerebellum. However, the neuropathology of autism is yet to be clearly defined, and there are several areas that remain open to further investigation. In this respect, more concerted efforts are required to examine the various aspects of cellular pathology affecting the brain in autism. This paper briefly highlights four key areas that warrant further evaluation. [source] INTERNATIONAL AND INTRA-NATIONAL TRADE: A CONTINUUM APPROACH,THE JAPANESE ECONOMIC REVIEW, Issue 3 2009SUGATA MARJIT We build up a Ricardian trade model with multiple regions within a nation and examine how international trade determines interregional patterns of production and specialization. We show that the degree of interregional concentration of economic activities moves in different directions in two trading nations. The role of "absolute advantage" becomes crucial in dictating the course of income disparity across regions. We discuss cases with varying degrees of labour mobility and reconfirm the result on post-trade interregional concentration and dispersion. Later we explore the impact of "scale factor" in this model and show how principle of comparative advantage and economies of scale interact to determine the pattern of specialization and volume of trade. [source] | ||||||||||