1,720,969 research outputs found
The serotonin 5-HT7 receptor agonist LP-44 microinjected into the dorsal raphe nucleus suppresses REM sleep in the rat
No full textThe effects of LP-44, a selective 5-HT7 receptor agonist, and of SB-269970, a selective 5-HT7 receptor
antagonist, on spontaneous sleep were studied in adult rats implanted for chronic sleep recordings. The
5-HT7 receptor ligands were microinjected directly into the dorsal raphe nucleus (DRN) during the light
period of the 12-h light/12-h dark cycle. Infusion of LP-44 (1.25–5.0mM)into theDRNinduced a significant
reduction of rapid-eye-movement sleep (REMS) and of the number of REM periods. Similar effects were
observed after the direct administration into the DRN of SB-269970 (0.5–1.0 mM). Pretreatment with a
dose of SB-269970 (0.5mM) that significantly affects sleep variables antagonized the LP-44 (2.5mM)-
induced suppression of REMS and of the number of REM periods. It is proposed that the suppression of
REMS after microinjection of LP-44 into the DRN is related, at least in part, to the activation of GABAergic
neurons in the DRN that contribute to long projections that reach, among others, the laterodorsal and
pedunculopontine tegmental nuclei involved in the promotion of REMS
Systemic administration and local microinjection into the central nervous system of the 5-HT(7) receptor agonist LP-211 modify the sleep-wake cycle in the rat.
No full textMicroinjection of the 5-HT7 receptor antagonist SB-269970 into the rat brainstem and basal forebrain: Site-dependent effects on REM sleep
No full textThe effects of SB-269970, a selective 5-HT7 receptor antagonist, on spontaneous sleep were studied in adult
rats implanted for chronic sleep recordings. The 5-HT7 receptor ligand was microinjected into the horizontal
limb of the diagonal band of Broca (HDB) and the laterodorsal tegmental nucleus (LDT) during the light period
of the 12-h light/12-h dark cycle. For comparative purposes the compound was administered systemically
and, in addition, injected directly into the dorsal raphe nucleus (DRN). Microinjection of SB-269970 into
the HDB and the DRN induced a significant reduction of rapid-eye-movement sleep (REMS). Similar effects
were observed after systemic administration of the 5-HT7 receptor antagonist. On the other hand, local infusion
of the compound into the LDT provoked the opposite effect. It is proposed that the deactivation of
GABAergic cells located in the HDB, DRN and LDT is responsible for the changes induced by SB-269970 on
REM sleep values. It is suggested that the antidepressant effect of the 5-HT7 receptor antagonist could partly
depend on the involvement of neuronal systems located in the DRN and the HDB
Sleep and autonomic dysregulation in the elderly
No full textThe primary function of the autonomic nervous system (ANS) is maintenance of homeostasis controlling involuntary functions of the body such as circulation and heart rate, respiration, thermoregulation, neuroendocrine secretion, and gastrointestinal and genitourinary function..
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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