1,720,987 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Probing the timeline for the acquisition of altered circuit function in the developing prefrontal cortex
Get PDFNeurodevelopmental disorders are characterised by cognitive and behavioural deficits, which are underpinned by a broad spectrum of neural deficiencies in brain regions critical for higher-order cognition - more specifically, the medial prefrontal cortex (mPFC). The mPFC is involved in learning, memory, and decision-making, and its appropriate functioning in adulthood depends on the correct balance between excitation and inhibition established during early neural development.
GABAergic interneurons are critical components of cortical circuits where they modulate the firing of neurons and thus control information flow both in adult and developing cortical networks. The early circuits of the mPFC exhibit characteristic discontinuous oscillatory patterns in the beta and gamma frequency ranges. The precise characteristics of these early beta and gamma oscillations are unknown as well as how they relate to the activity of single neurons.
Here, we (1) explored the early oscillatory activity in the developing mPFC, (2) we examined the activity of single neurons during development, and (3) we characterised the specific interactions between beta and gamma oscillations and single neurons - with a focus on PV+ and SST+ GABAergic interneurons.
We recorded extracellularly from anaesthetised and awake animals and found that anaesthesia affects beta but not gamma oscillations and that both beta and gamma oscillations change over development - with a possible critical period at postnatal day (P) 12. Single neurons were also found to change their features during development and in anaesthesia. Through optotagging, we identified putative SST+ and PV+ interneurons and found that they differentially contribute to beta and gamma activity, as do other single neurons - with a possible critical period also at P12.
These findings shed light on the early oscillatory and single neuron activity in the mPFC and inform further investigations on the origins of neurodevelopmental dysfunctions in brain regions critical to higher-order cognition
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
On the role of the primary somatosensory cortex in motor control
No full textSSVLaboratory of Sensory Processing, EPF
Motor Control in the Mouse Whisker System
No full textThe motor systems of the mammalian brain are a remarkable product of many millions of years of evolution. It is the motor systems that make us and other mammals mobile, that guide our actions in response to sensory information and conversely modulate the very nature of the sensory input that our brain receives. The mystacial vibrissae or whiskers present on the face of mice are important sensors that provide high resolution tactile information to the brain. Whereas the pathways that are involved in signaling and processing sensory information from the whiskers have been the subject of intense investigation for many years, we know relatively little about how whisker movements are controlled by the brain. In the first part of the thesis, I present evidence for two parallel pathways originating from the neocortex that control antagonistic movements of the whiskers. I first describe whisker movements elicited upon Channelrhodopsin-2 (ChR2) stimulation of whisker somatosensory cortex (wS1) and whisker motor cortex (wM1). At short latencies, optogenetic stimulation of wS1 drove whisker retraction while optogenetic stimulation of wM1 drove rhythmic whisker protraction. Next, using recent developments in Rabies virus retrograde tracing, I mapped the location of the motor neurons in the facial nucleus, finding two distinct neuron pools for the extrinsic (retractor) muscle Nasolabialis and the intrinsic (protractor) follicular muscle. These distinct motor neuron populations received premotor input from different sources in the brainstem. While the premotor neurons of the extrinsic muscle were located more densely in the spinal trigeminal nucleus (Sp5), the premotor neurons of the intrinsic muscle were located more densely in the reticular formation (Rt). Anterograde tracing from wS1 and wM1 cortex revealed a complementary distribution of axons in the brainstem. Whereas wS1 strongly innervated Sp5, wM1 innervated the Rt. These data therefore begin to unravel the circuitry from the neocortex to the whisker motor neurons. In the second part of the thesis, I investigated the subthreshold and spiking correlates of whisker movements using whole-cell current clamp recordings of individual excitatory neurons in wM1. Brief 1 ms optogenetic stimulation of wS1 elicited rhythmic whisking after long latencies which was abolished upon pharmacological inactivation of wM1. Whole-cell recordings in wM1 during wS1 stimulation showed that the long-range synaptic input from wS1 to wM1 is encoded as a bi-phasic membrane potential response with an early depolarizing post-synaptic potential (Dep. PSP), followed by a hyperpolarizing post-synaptic potential (Hyp. PSP) in individual wM1 neurons. Approximately 150 ms after the wS1 stimulus, the Vm showed a rebound depolarization, which, on most trials, was followed by late rhythmic whisking. Whole-cell recordings during self-generated whisker movements showed that upon whisking, wM1 undergoes a profound cortical state change, where the mean Vm is more depolarized, slow fluctuations of the Vm are reduced and spike rates in layer 5 increase. Aligning the membrane potential trajectories to the onset of whisker movement epochs revealed that changes in Vm occurred almost 100 ms before movement onset. Finally, an examination of the Vm dynamics during rhythmic whisking showed that the Vm of individual wM1 neurons is modulated by the phase of the whisk cycle. This modulation is stronger in layer 2/3 compared to layer 5.LSEN
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