1,720,989 research outputs found
Spplementary_figure – Supplemental material for Interleukin-6 Disrupts Synaptic Plasticity and Impairs Tissue Damage Compensation in Multiple Sclerosis
No full textSupplemental material, Spplementary_figure for Interleukin-6 Disrupts Synaptic Plasticity and Impairs Tissue Damage Compensation in Multiple Sclerosis by Mario Stampanoni Bassi, Ennio Iezzi, Francesco Mori, Ilaria Simonelli, Luana Gilio, Fabio Buttari, Francesco Sica, Nicla De Paolis, Georgia Mandolesi, Alessandra Musella, Francesca De Vito, Ettore Dolcetti, Antonio Bruno, Roberto Furlan, Annamaria Finardi, Girolama A. Marfia, Diego Centonze and Francesca Romana Rizzo in Neurorehabilitation and Neural Repair</p
Theta-burst stimulation over primary motor cortex degrades early motor learning
No full textTheta-burst stimulation (TBS) is currently used for inducing long-lasting changes in primary motor cortex (M1) excitability. More information is needed on how M1 is involved in early motor learning (practice-related improvement in motor performance, motor retention and motor consolidation). We investigated whether inhibitory continuous TBS (cTBS) is an effective experimental approach for modulating early motor learning of a simple finger movement in healthy humans. In a short task, 11 subjects practised 160 movements, and in a longer task also testing motor consolidation ten subjects practised 600 movements. During both experiments subjects randomly received real or sham cTBS over the left M1. Motor evoked potentials were tested at baseline and 7 min after cTBS. In the 160-movement experiment to test motor retention, 20 movements were repeated 30 min after motor practice ended. In the 600-movement experiment motor retention was assessed 15 and 30 min after motor practice ended, motor consolidation was tested by performing 20 movements 24 h after motor practice ended. Kinematic variables - movement amplitude, peak velocity and peak acceleration - were measured. cTBS significantly reduced the practice-related improvement in motor performance of finger movements in the experiment involving 160 movements and in the first part of the experiment involving 600 movements. After cTBS, peak velocity and peak acceleration of the 20 movements testing motor retention decreased whereas those testing motor consolidation remained unchanged. cTBS over M1 degrades practice-related improvement in motor performance and motor retention, but not motor consolidation of a voluntary finger movement
Ipsilateral sequential arm movements after unilateral subthalamic deep-brain stimulation in patients with Parkinson's disease
No full textUnilateral STN-DBS significantly improves the performance of contralateral sequential arm movements. Whether unilateral STN-DBS also improves ipsilateral sequential movement is unclear. In this Study in unmedicated parkinsonian patients. we tested the effect of unilateral STN-DBS on the performance of ipsilateral sequential movements and compared it with the performance of contralateral sequential movements. Three-dimensional movements were recorded with the ELITE system and three kinematic variables were considered: total movement time (TMT), total inter-onset latency (IOL), and spatial accuracy. Unilateral STN-DBS significantly decreased TMT in the contralateral arm and only tended to do so also in the ipsilateral arm, whereas it significantly decreased IOL and worsened spatial accuracy only on the contralateral side. Before unilateral STN-DBS a positive correlation was present between the clinical impairment and the TMTs in the contralateral and ipsilateral sides. After unilateral STN-DBS the UPDRS scores improved in the contralateral and to a lesser extent also in the ipsilateral side. Correlation analysis between clinical and kinematic data showed no differences between the contralateral and ipsilateral sides. Our kinematic findings show that after STN-DBS parkinsonian patients' performance of a sequential motor task improves significantly on the contralateral but only tended to do so on the ipsilateral side. Ipsilateral changes can be explained by the observation that the output structures of the basal ganglia send large ipsilateral and less dense contralateral projections to the thalamus. (C) 2008 Movement Disorder Society
Effects of attention on inhibitory and facilitatory phenomena elicited by paired-pulse transcranial magnetic stimulation in healthy subjects
No full textWe investigated whether human attentional processes influence the activity of intracortical inhibitory and excitatory circuits-short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI), and the intracortical facilitation (ICF)-elicited by paired-pulse transcranial magnetic stimulation (TMS) in healthy subjects. In eight healthy subjects we tested SICI, LICI and ICF under different attention-demanding conditions: "relaxed", "target hand" and "non-target hand". To compare the effects of attentional levels on SICI, LICI and ICF with those produced on the MEPs elicited by repetitive TMS (rTMS), in the same subjects we also delivered supra-threshold 5-Hz rTMS under the same three experimental conditions. To disclose whether attentional processes act selectively on circuits engaged by TMS delivered at 5 Hz frequency and at an interstimulus interval (ISI) of 200 ms, we also investigated the effects of different attention levels on paired-pulse TMS delivered at the 200 ms ISI and on the MEP size during 1-Hz rTMS. Attentional levels had no influence on SICI, ICF and LICI activated by paired-pulse TMS, but increased the MEP facilitation elicited by 5-Hz rTMS. Varying the attention level left the findings from 1-Hz rTMS unchanged. The finding that attention leaves the activity of intracortical inhibitory and excitatory circuits elicited by paired-pulse TMS unchanged but influences the MEP facilitation elicited by 5-Hz rTMS suggests that attention operates only when the stimulation entrains neural circuits made up of a large number of cortical cells with plasticity properties
Attention influences the excitability of cortical motor areas in healthy humans
No full textWe investigated whether human attentional processes influence the size of the motor evoked potentials (MEP) facilitation and the duration of the cortical silent period (CSP) elicited by high-frequency repetitive transcranial magnetic stimulation (rTMS). In healthy subjects we assessed the effects of 5 Hz-rTMS, delivered in trains of 10 stimuli at suprathreshold intensity over the hand motor area, on the MEP size and CSP duration in different attention-demanding conditions: "relaxed," "target hand," and "non-target hand" condition. We also investigated the inhibitory effects of 1 Hz-rTMS conditioning to the premotor cortex on the 5 Hz-rTMS induced MEP facilitation. F-waves evoked by ulnar nerve stimulation were also recorded. rTMS trains elicited a larger MEP size facilitation when the subjects looked at the target hand whereas the increase in CSP duration during rTMS remained unchanged during the three attention-demanding conditions. The conditioning inhibitory stimulation delivered to the premotor cortex decreased the MEP facilitation during the "target hand" condition, leaving the MEP facilitation during the other conditions unchanged. None of the attentional conditions elicited changes in the F wave. In healthy subjects attentional processes influence the size of the MEP facilitation elicited by high-frequency rTMS and do so through premotor-to-motor connections. © 2007 Springer-Verlag
Effects of intermittent theta-burst stimulation on practice-related changes in fast finger movements in healthy subjects
No full textIn this paper we investigated the effects of intermittent theta-burst stimulation (iTBS) applied to the primary motor cortex on practice-related changes in motor performance. Seventeen healthy subjects underwent two experimental sessions, one testing real iTBS and the other testing sham iTBS. Before and after both iTBS sessions, the subjects practiced fast right index-finger abductions for a few minutes. As measures of cortical excitability we calculated resting motor threshold and motor-evoked potential amplitude. As measures of practice-related changes we evaluated the mean movement amplitude, peak velocity and peak acceleration values for each block. When subjects practiced the movement task, the three variables measuring practice-related changes improved to a similar extent during real and sham iTBS whereas cortical excitability increased only during real iTBS. In a further group of five healthy subjects we investigated the effect of real and sham iTBS on changes in motor performance after a longer task practice and found no significant changes in motor performance and retention after real and sham iTBS. From our results overall we conclude that in healthy subjects iTBS applied to the primary motor cortex leaves practice-related changes in an index finger abduction task unaffected. We suggest that iTBS delivered over the primary motor cortex is insufficient to alter motor performance because early motor learning probably engages a wide cortical and subcortical network
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
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