269 research outputs found

    Motor simulation without motor expertise: enhanced corticospinal excitability in visually experienced dance spectators

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    The human “mirror-system” is suggested to play a crucial role in action observation and execution, and is characterized by activity in the premotor and parietal cortices during the passive observation of movements. The previous motor experience of the observer has been shown to enhance the activity in this network. Yet visual experience could also have a determinant influence when watching more complex actions, as in dance performances. Here we tested the impact visual experience has on motor simulation when watching dance, by measuring changes in corticospinal excitability. We also tested the effects of empathic abilities. To fully match the participants' long-term visual experience with the present experimental setting, we used three live solo dance performances: ballet, Indian dance, and non-dance. Participants were either frequent dance spectators of ballet or Indian dance, or “novices” who never watched dance. None of the spectators had been physically trained in these dance styles. Transcranial magnetic stimulation was used to measure corticospinal excitability by means of motor-evoked potentials (MEPs) in both the hand and the arm, because the hand is specifically used in Indian dance and the arm is frequently engaged in ballet dance movements. We observed that frequent ballet spectators showed larger MEP amplitudes in the arm muscles when watching ballet compared to when they watched other performances. We also found that the higher Indian dance spectators scored on the fantasy subscale of the Interpersonal Reactivity Index, the larger their MEPs were in the arms when watching Indian dance. Our results show that even without physical training, corticospinal excitability can be enhanced as a function of either visual experience or the tendency to imaginatively transpose oneself into fictional characters. We suggest that spectators covertly simulate the movements for which they have acquired visual experience, and that empathic abilities heighten motor resonance during dance observation

    Redox-active metallodithiolene groups separated by insulating tetraphosphinobenzene spacers

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    Compounds of the type [(S2C2R2)M(μ-tpbz)M(S2C2R2)] (R = CN, Me, Ph, p-anisyl; M = Ni, Pd, Pt; tpbz = 1,2,4,5-tetrakis(diphenylphosphino)benzene) have been prepared by transmetalation with [(S2C2R2)SnR′2] reagents, by direct displacement of dithiolene ligand from [M(S2C2R2)2] with 0.5 equiv of tpbz, or by salt metathesis using Na2[S2C2(CN)2] in conjunction with X2M(μ-tpbz)MX2 (X = halide). X-ray crystallography reveals a range of topologies (undulating, chair, bowed) for the (S2C2)M(P2C6P2)M(S2C2) core. The [(S2C2R2)M(μ-tpbz)M(S2C2R2)] (R = Me, Ph, p-anisyl) compounds support reversible or quasireversible oxidations corresponding to concurrent oxidation of the dithiolene terminal ligands from ene-1,2-dithiolates to radical monoanions, forming [(−S•SC2R2)M(μ-tpbz)M(−S•SC2R2)]2+. The R = Ph and p-anisyl compounds support a second, reversible oxidation of the dithiolene ligands to their α-dithione form. In contrast, [(S2C2(CN)2)Ni(tpbz)Ni(S2C2(CN)2)] sustains only reversible, metal-centered reductions. Spectroscopic examination of [(−S•SC2(p-anisyl)2)Ni(μ-tpbz)Ni(−S•SC2(p-anisyl)2)]2+ by EPR reveals a near degenerate singlet–triplet ground state, with spectral simulation revealing a remarkably small dipolar coupling constant of 18 × 10–4 cm–1 that is representative of an interspin distance of 11.3 Å. This weak interaction is mediated by the rigid tpbz ligand, whose capacity to electronically insulate is an essential quality in the development of molecular-based spintronic devices

    Mechanisms of Post-Stroke Fatigue: A Follow-Up From the Third Stroke Recovery and Rehabilitation Roundtable

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    Background Post-stroke fatigue (PSF) is a significant and highly prevalent symptom, whose mechanisms are poorly understood. The third Stroke Recovery and Rehabilitation Roundtable paper on PSF focussed primarily on defining and measuring PSF while mechanisms were briefly discussed. This companion paper to the main paper is aimed at elaborating possible mechanisms of PSF. Methods This paper reviews the available evidence that potentially explains the pathophysiology of PSF and draws parallels from fatigue literature in other conditions. We start by proposing a case for phenotyping PSF based on structural, functional, and behavioral characteristics of PSF. This is followed by discussion of a potentially significant role of early inflammation in the development of fatigue, specifically the impact of low-grade inflammation and its long-term systemic effects resulting in PSF. Of the many neurotransmitter systems in the brain, the dopaminergic systems have the most evidence for a role in PSF, along with a role in sensorimotor processing. Sensorimotor neural network dynamics are compromised as highlighted by evidence from both neurostimulation and neuromodulation studies. The double-edged sword effect of exercise on PSF provides further insight into how PSF might emerge and the importance of carefully titrating interventional paradigms. Conclusion The paper concludes by synthesizing the presented evidence into a unifying model of fatigue which distinguishes between factors that pre-dispose, precipitate, and perpetuate PSF. This framework will help guide new research into the biological mechanisms of PSF which is a necessary prerequisite for developing treatments to mitigate the debilitating effects of post-stroke fatigue

    Hypertrophic Stimulation Increases β-actin Dynamics in Adult Feline Cardiomyocytes

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    The myocardium responds to hemodynamic stress through cellular growth and organ hypertrophy. The impact of cytoskeletal elements on this process, however, is not fully understood. While α-actin in cardiomyocytes governs muscle contraction in combination with the myosin motor, the exact role of β-actin has not been established. We hypothesized that in adult cardiomyocytes, as in non-myocytes, β-actin can facilitate cytoskeletal rearrangement within cytoskeletal structures such as Z-discs. Using a feline right ventricular pressure overload (RVPO) model, we measured the level and distribution of β-actin in normal and pressure overloaded myocardium. Resulting data demonstrated enriched levels of β-actin and enhanced translocation to the Triton-insoluble cytoskeletal and membrane skeletal complexes. In addition, RVPO in vivo and in vitro hypertrophic stimulation with endothelin (ET) or insulin in isolated adult cardiomyocytes enhanced the content of polymerized fraction (F-actin) of β-actin. To determine the localization and dynamics of β-actin, we adenovirally expressed GFP-tagged β-actin in isolated adult cardiomyocytes. The ectopically expressed β-actin-GFP localized to the Z-discs, costameres, and cell termini. Fluorescence recovery after photobleaching (FRAP) measurements of β-actin dynamics revealed that β-actin at the Z-discs is constantly being exchanged with β-actin from cytoplasmic pools and that this exchange is faster upon hypertrophic stimulation with ET or insulin. In addition, in electrically stimulated isolated adult cardiomyocytes, while β-actin overexpression improved cardiomyocyte contractility, immunoneutralization of β-actin resulted in a reduced contractility suggesting that β-actin could be important for the contractile function of adult cardiomyocytes. These studies demonstrate the presence and dynamics of β-actin in the adult cardiomyocyte and reinforce its usefulness in measuring cardiac cytoskeletal rearrangement during hypertrophic stimulation

    Open-ended metallodithiolene complexes with the 1,2,4,5-tetrakis(diphenylphosphino)benzene ligand: modular building elements for the synthesis of multimetal complexes

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    Open-ended, singly metalated dithiolene complexes with 1,2,4,5-tetrakis(diphenylphosphino)benzene (tpbz) are prepared either by ligand transfer to [Cl2M(tpbz)] from (R2C2S2)SnR′2 (R = CN, R′ = Me; R = Me, R′ = nBu) or by a direct reaction between tpbz and [M(S2C2R2)2] (M = Ni, Pd, Pt; R = Ph, p-anisyl) in a 1:1 ratio. The formation of dimetallic [(R2C2S2)M(tpbz)M(S2C2R2)] attends these syntheses in modest amounts, but the open-ended compounds are readily separated by silica chromatography. As affirmed by X-ray crystallographic characterization of numerous members of the set, the [(R2C2S2)M(tpbz)] compounds show dithiolene ligands in their fully reduced ene-1,2-dithiolate form conjoined with divalent Group 10 ions. Minor amounts of octahedral [(Ph2C2S2)2PtIV(tpbz)], a presumed intermediate, are isolated from the preparation of [(Ph2C2S2)PtII(tpbz)]. Heterodimetallic [(Ph2C2S2)Pt(tpbz)Ni(S2C2Me2)] is prepared from [(Ph2C2S2)PtII(tpbz)]; its cyclic voltammogram, upon anodic scanning, shows two pairs of closely spaced, but resolved, 1e– oxidations corresponding first to [R2C2S22–] – 1e– → [R2C2S•S–] and then to [R2C2S•S–] – 1e– → [R2(C═S)2]. The open diphosphine of [(R2C2S2)M(tpbz)] can be oxidized to afford open-ended [(R2C2S2)M(tpbzE2)] (E = O, S). Synthesis of the octahedral [(dppbO2)3Ni][I3]2 [dppbO2 = 1,2-bis(diphenylphosphoryl)benzene] suggests that the steric profile of [(R2C2S2)M(tpbzE2)] is moderated enough that three could be accommodated as ligands around a metal ion

    Structural studies of (rac)-BIPHEN organomagnesiates and intermediates in the halogen-metal exchange of 2-Bromopyridine

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    Four lithium magnesiate complexes (2−5) containing the dianionic (rac)-BIPHEN ligand have been prepared and characterized using X-ray crystallography and NMR spectroscopy. (THF)3·Li2Mg{(rac)-BIPHEN}nBu2, 2, (THF)3·Li2Mg{(rac)-BIPHEN}(CH2SiMe3)2, 3, and (THF)2·Li2Mg{(rac)-BIPHEN}neoPe2, 4, have been prepared by complexation of the appropriate dialkylmagnesium compound with in situ prepared Li(rac)-BIPHEN in a mixture of hydrocarbon/THF. For all structures, the Mg centers are four-coordinate (and retain the alkyl groups); however, in 2 and 3 the two Li centers have different coordination spheres (one binding to one THF molecule, the other to two). The solid-state structures of 2 and 3 are essentially isostructural with that of 4 except that both Li atoms in this molecule have equivalent coordination spheres. The solution behaviors of these three molecules have been studied by 1H, 13C, and DOSY NMR spectroscopy. During the synthesis of 2, it was discovered that a (rac)-BIPHEN-rich (or n-butyl-free) lithium magnesiate, (THF)4Li2Mg{(rac)-BIPHEN}fo2, 2b, could be isolated. The lithium precursor to 2−5, (THF)4·Li4{(rac)-BIPHEN)}2, 1, has also been isolated. Within the molecular structure of this tetranuclear complex, there are three different Li coordination environments. Finally, 2 has already shown promise as a reagent in a halogen−metal exchange reaction with 2-bromopyridine. The structural chemistry at play in this reaction was probed by X-ray crystallography and NMR spectroscopy. The organometallic intermediate pyridyl-magnesiated 5, (THF)2·Li2Mg{(rac)-BIPHEN}(2-pyridyl)2, was isolated in high yield

    Long-term psychological outcomes following stroke: the OX-CHRONIC study

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    This is the final version. Available on open access from BMC via the DOI in this recordAvailability of data and materials: The dataset supporting the conclusions of this article is available in the study-specific Open Science Framework repository: osf.io/y2mevBACKGROUND: Stroke survivors rate longer-term (> 2 years) psychological recovery as their top priority, but data on how frequently psychological consequences occur is lacking. Prevalence of cognitive impairment, depression/anxiety, fatigue, apathy and related psychological outcomes, and whether rates are stable in long-term stroke, is unknown. METHODS: N = 105 long-term stroke survivors (M [SD] age = 72.92 [13.01]; M [SD] acute NIH Stroke Severity Score = 7.39 [6.25]; 59.0% Male; M [SD] years post-stroke = 4.57 [2.12]) were recruited (potential N = 208). Participants completed 3 remote assessments, including a comprehensive set of standardized cognitive neuropsychological tests comprising domains of memory, attention, language, and executive function, and questionnaires on emotional distress, fatigue, apathy and other psychological outcomes. Ninety participants were re-assessed one year later. Stability of outcomes was assessed by Cohen's d effect size estimates and percent Minimal Clinically Important Difference changes between time points. RESULTS: On the Montreal Cognitive Assessment 65.3% scored  2 years post-event exhibited psychological difficulties including domains of cognition, mood, and fatigue, which impact long-term quality of life. Stroke is a chronic condition with highly prevalent psychological needs, which require monitoring and intervention development.Stroke AssociationNational Institute for Health and Care Research (NIHR

    Loss of full length CtBP1 expression enhances the invasive potential of human melanoma

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    BACKGROUND: The C-terminal binding protein 1 (CtBP1) is a known co-repressor of gene transcription. We recently revealed that CtBP1 expression is lost in melanoma cells and melanoma inhibitory activity (MIA) expression is subsequently increased. The present study was performed to evaluate a more general role of CtBP1 in human melanoma and identify further CtBP1-regulated target genes. METHODS: Sequence analysis and expression profile of CtBP1 in melanoma cell lines were done by PCR. Boyden Chamber assays and co-immunoprecipitation were performed to investigate the functional role of CtBP1. Gene expression analysis and micro array data were used to define target genes. RESULTS: Interestingly, we detected an alternative splice product of CtBP1 with unknown function whose expression is induced at reduction of full length CtBP1. Overexpression of full length CtBP1 in melanoma cells had no effect on cell proliferation but did influence cell migration and invasiveness. To understand the effect of CtBP1 we identified putative LEF/TCF target genes found to be strongly expressed in melanoma using DNA microarray analysis. We focused on fourteen genes not previously associated with melanoma. Detailed analysis revealed that most of these were known to be involved in tumor metastasis. Eleven genes had expression profiles associated with melanoma cell invasiveness. CONCLUSION: In summary, this study revealed that reduction of CtBP1 expression is correlated with migratory, invasive potential of melanoma cells

    Metabolic Syndrome: a challenging health Issue in highly urbanized Union Territory of north India

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    <p>Abstract</p> <p>Objectives</p> <p>1. To determine the prevalence of Metabolic Syndrome in adults aged 18 years and above in Chandigarh, India. 2. To determine the socio-demographic factors associated with MS. 3. To determine the agreement between IDF (International Diabetes federation definition) and ATP-III (National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults criteria).</p> <p>Methods</p> <p>In a community based cross-sectional study, total 605 subjects aged 18 yrs and above were studied using multistage random sampling.</p> <p>Results</p> <p>Prevalence of Metabolic Syndrome was estimated by using IDF and ATP-III criteria. By IDF, Metabolic Syndrome was found in 287 (47.4%) subjects and it was more prevalent among females 171 (59.6%) as compared to males 116 (40.4%). By applying ATP-III overall prevalence was less i.e. 233 (38.5%) but again its prevalence was more among females 141 (44.8%) than males 116 (39.5%). Higher socioeconomic status, sedentary occupation and high body mass index were significantly associated with Metabolic Syndrome.</p> <p>Conclusions</p> <p>Metabolic Syndrome is a major health problem in the region and proper emphasis should be given on its prevention and control.</p
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