1,720,987 research outputs found
Short interval intracortical facilitation correlates with the degree of disability in multiple sclerosis
No full textMori F, Kusayanagi H, Monteleone F, et al. Short interval intracortical facilitation correlates with the degree of disability in multiple sclerosis. Brain Stimulation. 2013;6(1):67-71
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
Cortical plasticity predicts recovery from relapse in multiple sclerosis
No full textBACKGROUND:
Relapsing-remitting multiple sclerosis (RRMS) is characterized by the occurrence of clinical relapses, followed by remitting phases of a neurological deficit. Clinical remission after a relapse can be complete, with a return to baseline function that was present before, but is sometimes only partial or absent. Remyelination and repair of the neuronal damage do contribute to recovery, but they are usually incomplete.
OBJECTIVE:
We tested the hypothesis that synaptic plasticity, namely long-term potentiation (LTP), may represent an additional substrate for compensating the clinical defect that results from the incomplete repair of neuronal damage.
METHODS:
We evaluated the correlation between a measure of LTP, named paired associative stimulation (PAS), at the time of relapse and symptom recovery, in a cohort of 22 newly-diagnosed MS patients.
RESULTS:
PAS-induced LTP was normal in patients with complete recovery, and reduced in patients showing incomplete or absent recovery, 12 weeks after the relapse onset. A multivariate regression model showed that PAS-induced LTP and age may contribute to predict null, partial or complete symptom recovery after a relapse.
CONCLUSION:
Synaptic plasticity may contribute to symptom recovery after a relapse in MS; and PAS, measured during a relapse, may be used as a predictor of recovery
Chronic psychoemotional stress impairs cannabinoid-receptor-mediated control of GABA transmission in the striatum
No full textExposure to stressful events has a myriad of consequences in animals and in humans, and triggers synaptic adaptations in many brain areas. Stress might also alter cannabinoid-receptor-mediated transmission in the brain, but no physiological study has addressed this issue so far. In the present study, we found that social defeat stress, induced in mice by exposure to aggression, altered cannabinoid CB(1)-receptor-mediated control of synaptic transmission in the striatum. In fact, the presynaptic inhibition of GABAergic IPSCs induced by the cannabinoid CB(1) receptor agonist HU210 [(6aR)-trans-3-(1,1-dimethylheptyl)-6a,7,10,10a-tetrahydro-1-hydroxy-6,6-dimethyl-6H-dibenzo[b,d]pyran-9-methanol] was reduced after a single stressful episode and fully abolished after 3 and 7 d of stress exposure. Repeated psychoemotional stress also impaired the sensitivity of GABA synapses to endocannabinoids mobilized by group I metabotropic glutamate receptor stimulation, whereas the cannabinoid CB(1)-mediated control of glutamate transmission was unaffected by repeated exposure to an aggressor. Corticosteroids released in response to the activation of the hypothalamic-pituitary-adrenal axis played a major role in the synaptic defects observed in stressed animals, because these alterations were fully prevented by pharmacological blockade of glucocorticoid receptors and were mimicked by corticosterone injections. The recovery of stress-induced synaptic defects was favored when stressed mice were given access to a running wheel or to sucrose consumption, which function as potent natural rewards. A similar rescuing effect was obtained by a single injection of cocaine, a psychostimulant with strong rewarding properties. Targeting cannabinoid CB(1) receptors or endocannabinoid metabolism might be a valuable option to treat stress-associated neuropsychiatric conditions
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
Differential patterns of interhemispheric functional disconnection in mild and advanced multiple sclerosis
No full textBackground: Patients with multiple sclerosis may present altered patterns of connectivity between the two brain
hemispheres. To date, only transcallosal connectivity between the two primary motor cortices (M1) has been investigated functionally in patients with multiple sclerosis.
Objectives: The aim of this study was to investigate whether connectivity between the dorsal premotor cortex and the
contralateral M1 was altered in patients with multiple sclerosis, and to see whether clinical progression is accompanied
by exacerbated dorsal premotor cortex–M1 disconnectivity.
Methods: A twin-coil transcranial magnetic stimulation approach was used to investigate both excitatory and inhibitory
interhemispheric connections between the left dorsal premotor cortex and the contralateral M1 in 18 multiple sclerosis
patients without disability, in 18 multiple sclerosis patients with advanced disease and in 12 age-matched healthy subjects. To
activate distinct inhibitory and facilitatory transcallosal pathways, the intensity of dorsal premotor cortex stimulation was
adjusted to be either suprathreshold (110% of resting motor threshold) or subthreshold (80% of active motor threshold).
Results: Our sample of patients with multiple sclerosis showed altered patterns of interhemispheric dorsal premotor
cortex–M1 functional connectivity even in the absence of clinical deficits. Facilitatory connections originating from dorsal
premotor cortex were reduced in multiple sclerosis patients with or without disability, while inhibitory dorsal premotor
cortex–M1 connections were altered only in disabled patients.
Conclusions: The current study demonstrates that functional excitatory connectivity originating from non-primary
motor areas is compromised in multiple sclerosis patients even in the absence of clinical disability. Clinical disease
progression leads to an impairment of both excitatory and inhibitory transcallosal connections.Background: Patients with multiple sclerosis may present altered patterns of connectivity between the two brain hemispheres. To date, only transcallosal connectivity between the two primary motor cortices (M1) has been investigated functionally in patients with multiple sclerosis. Objectives: The aim of this study was to investigate whether connectivity between the dorsal premotor cortex and the contralateral M1 was altered in patients with multiple sclerosis, and to see whether clinical progression is accompanied by exacerbated dorsal premotor cortex-M1 disconnectivity. Methods: A twin-coil transcranial magnetic stimulation approach was used to investigate both excitatory and inhibitory interhemispheric connections between the left dorsal premotor cortex and the contralateral M1 in 18 multiple sclerosis patients without disability, in 18 multiple sclerosis patients with advanced disease and in 12 age-matched healthy subjects. To activate distinct inhibitory and facilitatory transcallosal pathways, the intensity of dorsal premotor cortex stimulation was adjusted to be either suprathreshold (110% of resting motor threshold) or subthreshold (80% of active motor threshold). Results: Our sample of patients with multiple sclerosis showed altered patterns of interhemispheric dorsal premotor cortex-M1 functional connectivity even in the absence of clinical deficits. Facilitatory connections originating from dorsal premotor cortex were reduced in multiple sclerosis patients with or without disability, while inhibitory dorsal premotor cortex-M1 connections were altered only in disabled patients. Conclusions: The current study demonstrates that functional excitatory connectivity originating from non-primary motor areas is compromised in multiple sclerosis patients even in the absence of clinical disability. Clinical disease progression leads to an impairment of both excitatory and inhibitory transcallosal connections. © The Author(s) 2010
Effects of intermittent theta burst stimulation on spasticity in patients with multiple sclerosis
No full textBackground and purpose: Spasticity is a common disorder and a major cause of long-term disability in patients with multiple sclerosis (MS). Our aim was to evaluatewhether a recently developed repetitive transcranial magnetic stimulation protocol, theintermittent theta burst stimulation (iTBS) is effective in modulating lower limbspasticity in MS patients.Methods: Twenty MS patients were pseudorandomized to undergo a 2-week dailysessions of real or sham iTBS protocol. The H/M amplitude ratio of the Soleus Hreflex, a reliable neurophysiological index of spinal excitability and the ModifiedAshworth Scale (MAS) for spasticity were evaluated by blinded raters before and afterthe stimulation protocols.Results: Patients receiving real iTBS showed a significant reduction of H/M ampli-tude ratio and MAS scores 1 week after the stimulation and persisting up to 2 weeksafter the end of stimulation protocol. There were no significant effects for shamstimulation.Conclusions: These results show that iTBS, a safe, non-invasive, well-tolerated andfeasible protocol, is a promising tool for the treatment of spasticity in MS.Background and purpose: Spasticity is a common disorder and a major cause of long-term disability in patients with multiple sclerosis (MS). Our aim was to evaluate whether a recently developed repetitive transcranial magnetic stimulation protocol, the intermittent theta burst stimulation (iTBS) is effective in modulating lower limb spasticity in MS patients. Methods: Twenty MS patients were pseudorandomized to undergo a 2-week daily sessions of real or sham iTBS protocol. The H/M amplitude ratio of the Soleus H reflex, a reliable neurophysiological index of spinal excitability and the Modified Ashworth Scale (MAS) for spasticity were evaluated by blinded raters before and after the stimulation protocols. Results: Patients receiving real iTBS showed a significant reduction of H/M amplitude ratio and MAS scores 1 week after the stimulation and persisting up to 2 weeks after the end of stimulation protocol. There were no significant effects for sham stimulation. Conclusions: These results show that iTBS, a safe, non-invasive, well-tolerated and feasible protocol, is a promising tool for the treatment of spasticity in MS. © 2009 EFNS
CSF tau levels influence cortical plasticity in Alzheimer's disease patients
No full textAlzheimer's disease (AD) is a neurodegenerative process characterized by progressive neuronal degeneration, reduced levels of neurotransmitters, and altered forms of synaptic plasticity. In animal models of AD, amyloid-β (Aβ) and tau proteins are supposed to interfere with synaptic transmission. In the current study, we investigated the correlation between motor cortical plasticity, measured with 1 Hz repetitive transcranial magnetic stimulation (rTMS), and the levels of Aβ1-42, total tau (t-Tau), and phosphorylated tau (p-Tau) detected in cerebrospinal fluid (CSF) of AD patients
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