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Reduction of GFAP induced by long dark rearing is not restricted to visual cortex
No full textA key component of the astrocyte cytoskeleton is the glial fibrillary acidic protein (GFAP), which plays an essential role in neuron/astrocyte interactions. Environmental conditioning, such as visual experience manipulation, can affect neuronal and/or glial plasticity in specific brain areas. Previous work from our laboratory showed that short light deprivation throughout the period of GFAP maturation does not influence the expression profile of GFAP in mouse visual cortex; however, it was strong enough to affect neuronal phenotype. It was suggested that visual experience controls the maturation of the neuronal circuitry in this brain area. Therefore, to see whether the modifications of neuronal activity induced by light deprivation affect the maintenance of normal astrocytic phenotype, the dark rearing protocol was extended until the adult life. GFAP-immunoreactive cells were dramatically affected, showing an 80% decrease in number. In addition, GFAP protein level exhibited a 50% reduction, while its mRNA remained unaffected. Besides the visual cortex, two other areas of the brain not directly involved in vision, the hippocampus and the motor cortex, were chosen as internal controls. Unexpectedly, also in these areas, astrocytes were affected by light deprivation. The present results show that lack of visual experience for long periods of time deeply affects glial phenotype not only in visual areas but also in brain regions not directly involved in sensory processing. (c) 2005 Elsevier B.V. All rights reserved
Postnatal development of astrocytes in mouse visual cortex: role of the visual experience
No full textPostnatal development of GFAP in mouse visual cortex is not affected by light deprivation
No full textMammalian visual cortex is immature at birth and develops gradually during defined postnatal temporal windows. In the present work, we studied the maturation of astrocytes in developing mouse visual cortex (VC). The cellular distribution and the level of glial fibrillary acidic protein (GFAP) were analyzed by immunohistochemistry and Western blotting. Experiments were performed at different postnatal ages: postnatal day 12 (P12), before eye opening; P24, corresponding roughly to the peak of the critical period for monocular deprivation, and P60, after the end of the critical period. At P12, GFAP immunoreactivity (IR) was distributed throughout all cortical layers. At P24, there was a prominent localization of GFAP IR in layers I, II, and VI, while cortical layers III, IV, and V contained no longer GFAP IR cells. No differences were found in GFAP IR between P24 and P60. Western blot analysis revealed a reduction of GFAP expression in the VC at P24 with respect to P12 and no significant difference between P60 and P24. These results show that GFAP expression is modulated during early postnatal development. To know whether visual experience influences the maturation pattern of GFAP expression, mice were dark-reared from P12 to P24. Dark rearing did not change the distribution and the expression of GFAP. Our results indicate that maturation of GFAP expression occurs early in postnatal development in mouse VC. In addition, we showed that GFAP development is not affected by visual deprivation
Postnatal development of GFAP in mouse visual cortex is not affected by light deprivation
No full textMammalian visual cortex is immature at birth and develops gradually during defined postnatal temporal windows. In the present work, we studied the maturation of astrocytes in developing mouse visual cortex (VC). The cellular distribution and the level of glial fibrillary acidic protein (GFAP) were analyzed by immunohistochemistry and Western blotting. Experiments were performed at different postnatal ages: postnatal day 12 (P12), before eye opening; P24, corresponding roughly to the peak of the critical period for monocular deprivation, and P60, after the end of the critical period. At P12, GFAP immunoreactivity (IR) was distributed throughout all cortical layers. At P24, there was a prominent localization of GFAP IR in layers I, II, and VI, while cortical layers III, IV, and V contained no longer GFAP IR cells. No differences were found in GFAP IR between P24 and P60. Western blot analysis revealed a reduction of GFAP expression in the VC at P24 with respect to P12 and no significant difference between P60 and P24. These results show that GFAP expression is modulated during early postnatal development. To know whether visual experience influences the maturation pattern of GFAP expression, mice were dark-reared from P12 to P24. Dark rearing did not change the distribution and the expression of GFAP. Our results indicate that maturation of GFAP expression occurs early in postnatal development in mouse VC. In addition, we showed that GFAP development is not affected by visual deprivation. (C) 2003 Wiley-Liss, Inc
DIFFERENTIAL MODULATION OF INTERLEUKIN-6 EXPRESSION BY INTERLEUKIN-1BETA IN NEURONAL AND GLIAL CULTURES
No full textThe sensitivity of basal forebrain cholinergic neurons to NGF deprivation depends on their previous exposure to NGF itself
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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