1,721,079 research outputs found
Deep brain stimulation of the pedunculopontine nucleus modulates subthalamic pathological oscillations
Full text linkLow frequency deep brain stimulation (DBS) of the pedunculopontine nucleus area (PPNa) has been proposed as a novel surgical target for gait dysfunction in the late stage of Parkinson's disease (PD). Since the mid-2000s, we have shown that intrasurgical delivery of stimulation in the pontine tegmentum affects the firing activity in the subthalamic nucleus (STN), but its effect on STN oscillatory rhythms has not been studied. Neuronal oscillations detected by local field potential (LFPs) have great importance, since they express complex movement-related behavior such as locomotion. Therefore, we examined the effect of three PPNa-DBS stimulation protocols (at 10, 25 and 80 Hz) on the STN oscillatory activity of PD patients. We focused on the anti-kinetic beta (beta, 15-30 Hz), the pro-kinetic gamma (gamma, 60-90 Hz) and "gait-related" alpha (alpha, 7-12 Hz) bands. We hypothesized that modulation of STN oscillations might have clinical relevance in the PPNa-mediated effects.PPNa stimulation at 25 and 80 Hz decreased the power of the STN beta band by 33.94 and 40.22%, respectively. PPNa-DBS did not affect the other two bands with a tendency to suppress alpha power, while gamma oscillation increased.Our results suggest that the anti-kinetic beta band is the oscillation most sensitive to PPNa-DBS despite the negligible clinical efficacy on bradykinesia. However, how these changes interact reciprocally with the cortex or are counterbalanced by lower brainstem/spinal pathways remain to be elucidated.Our observation might turn out to be helpful in new protocols designed with adaptive DBS supporting the addition of PPN implantation in PD patients experiencing declining efficacy of STN-DBS
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
Multi-target strategy for Parkinsonian patients: the role of deep brain stimulation in the centromedian-parafascicularis complex.
No full textBrain Res Bull. 2009 Feb 16;78(2-3):113-8. doi: 10.1016/j.brainresbull.2008.08.007. Epub 2008 Sep 21.
Multi-target strategy for Parkinsonian patients: the role of deep brain stimulation in the centromedian-parafascicularis complex.
Stefani A, Peppe A, Pierantozzi M, Galati S, Moschella V, Stanzione P, Mazzone P.
SourceIRCCS Fondazione S. Lucia, Roma, Italy. [email protected]
Abstract
The intra-laminar (IL) thalamic complex, composed of centromedian (CM) and parafascicular (Pf) nucleus, is a strategic crossroad for the activity of the basal ganglia and is recently regaining its position has a putative neurosurgical target for Parkinsonian syndromes. The multi-target approach we have encouraged since the late nineties has allowed the combined implantation of a standard target (the subthalamic nucleus-STN or the internal pallidus-GPi) plus an innovative one (CM/Pf) in well-identified Parkinson's disease (PD) patients; hence, it is possible to study, in the same PD patients, the specific target-mediated effects on different clinical signs. Here, we focus on the potential usefulness of implanting the CM/Pf complex when required in the management of contra-lateral tremor (resistant to standard deep brain stimulation-DBS - in STN - , n=2) and disabling involuntary movements, partially responsive to GPi-DBS (n=6). When considering global UPDRS scores, CM/Pf-DBS ameliorate extra-pyramidal symptoms but not as strongly as STN (or GPi) does. Yet, CM/Pf acts very powerfully on tremor and contributes to the long-term management of l-Dopa-induced involuntary movements. The lack of cognitive deficits and psychic impairment associated with the improvement of their quality of life, in our small cohort of CM/Pf implanted patients, reinforces the notion of CM/Pf as a safe and attractive area for surgical treatment of advanced PD, possibly affecting not only motor but also associative functions
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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