1,721,010 research outputs found
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
Lesion-induced and activity-dependent structural plasticity of Purkinje cell dendritic spines in cerebellar vermis and hemisphere
No full textNeuroplasticity allows the brain to encode experience and learn behaviors, and also to re-acquire lost functions after damage. The cerebellum is a suitable structure to address this topic because of its strong involvement in learning processes and compensation of lesion-induced deficits. This study was aimed to characterize the effects of a hemicerebellectomy (HCb) combined or not with the exposition to environmental enrichment (EE) on dendritic spine density and size in Purkinje cell proximal and distal compartments of cerebellar vermian and hemispherical regions. Male Wistar rats were housed in enriched or standard environments from the 21st post-natal day (pnd) onwards. At the 75th pnd, rats were submitted to HCb or sham lesion. Neurological symptoms and spatial performance in the Morris water maze were evaluated. At the end of testing, morphological analyses assessed dendritic spine density, area, length, and head diameter on vermian and hemispherical Purkinje cells. All hemicerebellectomized (HCbed) rats showed motor compensation, but standardreared HCbed animals exhibited cognitive impairment that was almost completely compensated in enriched HCbed rats. The standard-reared HCbed rats showed decreased density with augmented size of Purkinje cell spines in the vermis, and augmented both density and size in the hemisphere. Enriched HCbed rats almost completely maintained the spine density and size induced by EE. Both lesion-induced and activity-dependent cerebellar plastic changes may be interpreted as ‘‘beneficial’’ brain reactions, aimed to support behavioral performance rescuing
A Comprehensive Assessment of Bedtime Routines and Strategies to Aid Sleep Onset in College Students: A Web-Based Survey
Full text linkCollege students often experience sleep-wake alterations. Different factors can contribute to insomnia symptoms in this population. The present study aims at investigating pre-sleep behaviours and strategies used to aid sleep onset in young college students and their association with insomnia symptoms. A total of 548 Italian college students (mean age = 23.48 years, range = 19-30 years, 80.5% female) completed a web-based survey on pre-sleep behaviours and sleep-onset facilitators, insomnia symptoms and sleep hygiene, anxiety and depression, and coping strategies. The use of electronic devices at bedtime and as a sleep-onset facilitator was predominant. Students using specific behaviours as sleep-onset facilitators were characterised by more psychological difficulties and poorer sleep. In multivariable linear regression analysis, the frequency of using medications and melatonin, regardless of motivations, was associated with higher insomnia symptoms. The use of specific sleep-onset facilitators positively correlated with the severity of insomnia symptoms. Many students engage in behaviours that are considered sleep-interfering and that are often employed in an attempt to facilitate sleep onset without benefits. Overall, the motivational factors behind pre-sleep behaviours need to be addressed in preventive programs targeting young college students
Bihemispheric tDCS enhances language recovery but does not alter BDNF levels in chronic aphasic patients
No full textVariations 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
Bihemispheric tDCS enhances language recovery but does not alter BDNF levels in chronic aphasic patients
No full textSeveral studies have shown that transcranial direct current stimulation (tDCS) is a useful tool to enhance language recovery in aphasia. It has also been suggested that modulation of the neurotrophin brain-derived neurotrophic factor (BDNF) might be part of the mechanisms involved in tDCS effects on synaptic connectivity. However, all language studies have previously investigated the effects using unihemispheric stimulation. The purpose of the present study is to investigate the role of bihemispheric tDCS on language recovery and BDNF serum levels
Effects of chronic donepezil treatment and cholinergic deafferentation on parietal pyramidal neuron morphology.
No full textActivity-dependent structural plasticity of Purkinje cell spines in cerebellar vermis and hemisphere.
No full textThe environmental enrichment (EE) paradigm is widely used to study experience-dependent brain plasticity. In spite of a long history of research, the EE influence on neuronal morphology has not yet been described in relation to the different regions of the cerebellum. Thus, aim of the present study was to characterize the EE effects on density and size of dendritic spines of Purkinje cell proximal and distal compartments in cerebellar vermian and hemispherical regions. Male Wistar rats were housed in an enriched or standard environment for 3.5 months from the 21st post-natal day onwards. The morphological features of Purkinje cell spines were visualized on calbindin immunofluorescence-stained cerebellar vermian and hemispherical sections. Density, area, length and head diameter of spines were manually (ImageJ) or automatically (Imaris) quantified. Results demonstrated that the Purkinje cell spine density was higher in enriched rats than in controls on both proximal and distal dendrite compartments in the hemisphere, while it increased only on distal compartment in the vermis. As for spine size, a significant increase of area, length and head diameter was found in the distal dendrites in both vermis and hemisphere. Thus, the exposure to a complex environment enhances synapse formation and plasticity either in the vermis involved in balance and locomotion and in the hemisphere involved in complex motor adaptations and acquisition of new motor strategies. These data highlight the importance of cerebellar activity-dependent structural plasticity underling the EE-related high-level performances
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