70 research outputs found

    Relationships between neuropsychological and antisaccade measures in multiple sclerosis patients

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    Background: The Stroop test is frequently used to assess deficits in inhibitory control in people with multiple sclerosis (MS). This test has limitations and antisaccade eye movements, that also measure inhibitory control, may be an alternative to Stroop.Objectives: The aim of this study was twofold: (i) to investigate if the performance in the antisaccade task is altered in patients with MS and (ii) to investigate the correlation between performances in neuropsychological tests, the Stroop test and the antisaccade task.Methods: We measured antisaccades (AS) parameters with an infrared eye tracker (SMIRED 250 Hz) using a standard AS paradigm. A total of 38 subjects diagnosed with MS and 38 age and gender matched controls participated in this study. Neuropsychological measures were obtained from the MS group.Results: Patients with MS have higher error rates and prolonged latency than controls in the antisaccade task. There was a consistent association between the Stroop performance and AS latency. Stroop performance but not AS latency was associated with other neuropsychological measures in which the MS group showed deficits.Conclusions: Our findings suggest that AS may be a selective and independent measure to investigate inhibitory control in patients with MS. More studies are necessary to confirm our results and to describe brain correlates associated with impaired performance in the antisaccade task in people diagnosed with MS.The Vision Rehabilitation Lab and Antonio Filipe Macedo receive or received funding from Shamir Optical Industry Lt, Portugal, from grants PTDC/DTP-EPI/0412/2012 (Prevalence and Costs of Visual Impairment in Portugal) and UID/FIS/04650/2013 (Framework of the Strategic Funding granted to Centre of Physics at Minho University). Multiple Sclerosis Association "Todos com a Esclerose Multiple" paid the salary of Marisa Borges Ferreira. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

    Planet Hunters TESS III: Two transiting planets around the bright G dwarf HD 152843

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    We report on the discovery and validation of a two-planet system around a bright (V = 8.85 mag) early G dwarf (1.43 R⊙R_{\odot}, 1.15 M⊙M_{\odot}, TOI 2319) using data from NASA's Transiting Exoplanet Survey Satellite (TESS). Three transit events from two planets were detected by citizen scientists in the month-long TESS light curve (sector 25), as part of the Planet Hunters TESS project. Modelling of the transits yields an orbital period of \Pb\ and radius of 3.41−0.12+0.143.41 _{ - 0.12 } ^ { + 0.14 } R⊕R_{\oplus} for the inner planet, and a period in the range 19.26-35 days and a radius of 5.83−0.14+0.145.83 _{ - 0.14 } ^ { + 0.14 } R⊕R_{\oplus} for the outer planet, which was only seen to transit once. Each signal was independently statistically validated, taking into consideration the TESS light curve as well as the ground-based spectroscopic follow-up observations. Radial velocities from HARPS-N and EXPRES yield a tentative detection of planet b, whose mass we estimate to be 11.56−6.14+6.5811.56 _{ - 6.14 } ^ { + 6.58 } M⊕M_{\oplus}, and allow us to place an upper limit of 27.527.5 M⊕M_{\oplus} (99 per cent confidence) on the mass of planet c. Due to the brightness of the host star and the strong likelihood of an extended H/He atmosphere on both planets, this system offers excellent prospects for atmospheric characterisation and comparative planetology

    Planet Hunters Tess I: TOI 813, a subgiant hosting a transiting Saturn-sized planet on an 84-day orbit

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    We report on the discovery and validation of TOI 813 b (TIC55525572b), a transiting exoplanet identified by citizen scientists in data from NASA's Transiting Exoplanet Survey Satellite (TESS) and the first planet discovered by the Planet Hunters TESS project. The host star is a bright (V = 10.3 mag) subgiant (R* = 1.94 R☉, M☉ = 1.32 M☉). It was observed almost continuously by TESS during its first year of operations, during which time four individual transit events were detected. The candidate passed all the standard light curve-based vetting checks, and ground-based follow-up spectroscopy and speckle imaging enabled us to place an upper limit of 2 MJup (99 per cent confidence) on the mass of the companion, and to statistically validate its planetary nature. Detailed modelling of the transits yields a period of 83.8911+0.0027-0.0031 d, a planet radius of 6.71 ± 0.38 R⊕ and a semimajor axis of 0.423+0031-0.037 AU. The planet's orbital period combined with the evolved nature of the host star places this object in a relatively underexplored region of parameter space. We estimate that TOI 813 b induces a reflex motion in its host star with a semi-amplitude of ∼6 m s−1, making this a promising system to measure the mass of a relatively long-period transiting planet

    Cardiac Phenylethanolamine N-methyltransferase: Localization and Regulation of Gene Expression in the Spontaneously Hypertensive Rat

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    Phenylethanolamine N-methyltransferase (PNMT) is the terminal enzyme in the catecholamine biosynthetic pathway responsible for adrenaline biosynthesis. Adrenaline is involved in the sympathetic control of blood pressure; it augments cardiac function by increasing stroke volume and cardiac output. Genetic mapping studies have linked the PNMT gene to hypertension. This study examined the expression of cardiac PNMT and changes in its transcriptional regulators in the spontaneously hypertensive (SHR) and wild type Wistar-Kyoto (WKY) rats. SHR exhibit elevated levels of corticosterone, and lower levels of the cytokine IL-1 β, revealing systemic differences between SHR and WKY. PNMT mRNA was significantly increased in all chambers of the heart in the SHR, with the greatest increase in the right atrium. Transcriptional regulators of the PNMT promoter show elevated expression of Egr-1, Sp1, AP-2 and GR mRNA in all chambers of the SHR heart, while protein levels of Sp1, Egr-1 and GR were elevated only in the RA. Interestingly, only AP-2 protein-DNA binding was increased, suggesting it may be a key regulator of cardiac PNMT in SHR. This study provides the first insights into the molecular mechanisms involved in the dysregulation of cardiac PNMT in a genetic model of hypertension.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

    Neural Correlates of Predictive Saccades.

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    Every day we generate motor responses that are timed with external cues. This phenomenon of sensorimotor synchronization has been simplified and studied extensively using finger tapping sequences that are executed in synchrony with auditory stimuli. The predictive saccade paradigm closely resembles the finger tapping task. In this paradigm, participants follow a visual target that steps between two fixed locations on a visual screen at predictable ISIs. Eventually, the time from target appearance to saccade initiation (i.e., saccadic RT) becomes predictive with values nearing 0 msec. Unlike the finger tapping literature, neural control of predictive behavior described within the eye movement literature has not been well established and is inconsistent, especially between neuroimaging and patient lesion studies. To resolve these discrepancies, we used fMRI to investigate the neural correlates of predictive saccades by contrasting brain areas involved with behavior generated from the predictive saccade task with behavior generated from a reactive saccade task (saccades are generated toward targets that are unpredictably timed). We observed striking differences in neural recruitment between reactive and predictive conditions: Reactive saccades recruited oculomotor structures, as predicted, whereas predictive saccades recruited brain structures that support timing in motor responses, such as the crus I of the cerebellum, and structures commonly associated with the default mode network. Therefore, our results were more consistent with those found in the finger tapping literature
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