1,355,473 research outputs found
Brain tissue properties differentiate between motor and limbic basal ganglia circuits
No full textDespite advances in understanding basic organizational principles of the human basal ganglia, accurate in vivo assessment of their anatomical properties is essential to improve early diagnosis in disorders with corticosubcortical pathology and optimize target planning in deep brain stimulation. Main goal of this study was the detailed topological characterization of limbic, associative, and motor subdivisions of the subthalamic nucleus (STN) in relation to corresponding corticosubcortical circuits. To this aim, we used magnetic resonance imaging and investigated independently anatomical connectivity via white matter tracts next to brain tissue properties. On the basis of probabilistic diffusion tractography we identified STN subregions with predominantly motor, associative, and limbic connectivity. We then computed for each of the nonoverlapping STN subregions the covariance between local brain tissue properties and the rest of the brain using high-resolution maps of magnetization transfer (MT) saturation and longitudinal (R1) and transverse relaxation rate (R2*). The demonstrated spatial distribution pattern of covariance between brain tissue properties linked to myelin (R1 and MT) and iron (R2*) content clearly segregates between motor and limbic basal ganglia circuits. We interpret the demonstrated covariance pattern as evidence for shared tissue properties within a functional circuit, which is closely linked to its function. Our findings open new possibilities for investigation of changes in the established covariance pattern aiming at accurate diagnosis of basal ganglia disorders and prediction of treatment outcom
Drops22
No full textNatalia Lutti Hummel apresenta a iniciativa Tendências em Serviços Ecossistêmicos (TeSE) e os métodos de valoração
Slide falado
No full textAo comentar este infográfico, a gestora da iniciativa Tendências em Serviços Ecossistêmicos (TeSE), Natalia Lutti Hummel, explica como se dá a relação entre os serviços prestados pelos ecossistemas e o bem-estar humano
I lutti della R. Casa di Savoia : 12. gennaio, 20. gennaio, 10. febbraio MDCCCLV.
No full textIncludes two loosely inserted items: a manuscript note signed by Salvator Revelli, and a single issue of "Il Fischietto" (Anno VIII, Torino, martedì, 23 gennaio 1855, Num. 10) containing a poem and an allegorical illustration lithographed by Giordana, Grand Didier e Salusso Cia.Includes: Nei solenni funerali di Sua Altezza Reale Ferdinando Maria di Savoia duca di Genoa, celebrati nella chiesa metropolitana di Torino il dì x di marzo MDCCCLV, orazione detta dal p. Lorenzo Isnardi...", 40 p.Includes: "Discours prononcé aux funérailles solennelles de la reine de Sardaigne Marie Adélaïde, célébrées dans l'église métropolitaine de Turin le III mars MDCCCLV par sa grandeur monseigneur André Charvaz, archevéque de Gênes", 40 p.Includes: "Nei solenni funerali di Maria Teresa di Toscana, archiduchessa d'Austria, regina-vedova di Sardegna, celebrati nella chiesa metropolitana di Torino il XXVII febbraio MDCCCLV, orazione detta dall'ill.mo e rev.mo monsignor Lorenzo Renaldi, vescovo di Pinerolo", 39 p.Illustrations: facade of the San Lorenzo church in Turin (original photograph), three lithograph floor-plans indicating funeral decorations at the San Lorenzo church in Turin, lithograph portrait of Maria Adelaide of Sardinia, and an original photograph of a monument of Maria Adelaide.A collection of booklets and documents: epigraphs, descriptions of the funeral ceremonies, invitations, plans, and photographs regarding the funeral of the two Queens Maria Teresa and Maria Adelaide of Sardinia, and for the funeral of the Duke of Genoa, Ferdinando Maria di Savoia, all three deceased in the space of a month.Cover title.Mode of access: Internet.Binding: original black morocco, arms of the Royal family of Savoy on front cover, arms of Carlo dal Pozzo di Mombello on back cover, two stamps of Mons. G. Conforti on front fly-leaf
Estudio sobre prefactibilidad en la instalación de micro central hidro-eléctrica en "Lutti", provincia de Córdoba
No full textPráctica Supervisada (IC)--FCEFN-UNC, 2013Estudia la factibilidad sobre la instalación de una micro central hidroeléctrica en la localidad cordobesa de Lutti. Dicho estudio comprendio la evaluación del potencial energético del arroyo Lutti y de los medios necesarios para llevar a cabo la explotación del recurs
Multiparametric brainstem segmentation using a modified multivariate mixture of Gaussians
No full textThe human brainstem is a densely packed, complex but highly organised structure. It not only serves as a conduit for long projecting axons conveying motor and sensory information, but also is the location of multiple primary nuclei that control or modulate a vast array of functions, including homeostasis, consciousness, locomotion, and reflexive and emotive behaviours. Despite its importance, both in understanding normal brain function as well as neurodegenerative processes, it remains a sparsely studied structure in the neuroimaging literature. In part, this is due to the difficulties in imaging the internal architecture of the brainstem in vivo in a reliable and repeatable fashion. A modified multivariate mixture of Gaussians (mmMoG) was applied to the problem of multichannel tissue segmentation. By using quantitative magnetisation transfer and proton density maps acquired at 3 T with 0.8 mm isotropic resolution, tissue probability maps for four distinct tissue classes within the human brainstem were created. These were compared against an ex vivo fixated human brain, imaged at 0.5 mm, with excellent anatomical correspondence. These probability maps were used within SPM8 to create accurate individual subject segmentations, which were then used for further quantitative analysis. As an example, brainstem asymmetries were assessed across 34 right-handed individuals using voxel based morphometry (VBM) and tensor based morphometry (TBM), demonstrating highly significant differences within localised regions that corresponded to motor and vocalisation networks. This method may have important implications for future research into MRI biomarkers of pre-clinical neurodegenerative diseases such as Parkinson's disease
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Optimization and validation of methods for mapping of the radiofrequency transmit field at 3T
No full textMRI techniques such as quantitative imaging and parallel transmit require precise knowledge of the radio-frequency transmit field (B(1) (+)). Three published methods were optimized for robust B(1) (+) mapping at 3T in the human brain: three-dimensional (3D) actual flip angle imaging (AFI), 3D echo-planar imaging (EPI), and two-dimensional (2D) stimulated echo acquisition mode (STEAM). We performed a comprehensive comparison of the methods, focusing on artifacts, reproducibility, and accuracy compared to a reference 2D double angle method. For the 3D AFI method, the addition of flow-compensated gradients for diffusion damping reduced the level of physiological artifacts and improved spoiling of transverse coherences. Correction of susceptibility-induced artifacts alleviated image distortions and improved the accuracy of the 3D EPI imaging method. For the 2D STEAM method, averaging over multiple acquisitions reduced the impact of physiological noise and a new calibration method enhanced the accuracy of the B(1) (+) maps. After optimization, all methods yielded low noise B(1) (+) maps (below 2 percentage units), of the nominal flip angle value (p.u.) with a systematic bias less than 5 p.u. units. Full brain coverage was obtained in less than 5 min. The 3D AFI method required minimal postprocessing and showed little sensitivity to off-resonance and physiological effects. The 3D EPI method showed the highest level of reproducibility. The 2D STEAM method was the most time-efficient technique
Variations on the Author
No full text“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
A general linear relaxometry model of R1 using imaging data
No full textThe longitudinal relaxation rate (R1 ) measured in vivo depends on the local microstructural properties of the tissue, such as macromolecular, iron, and water content. Here, we use whole brain multiparametric in vivo data and a general linear relaxometry model to describe the dependence of R1 on these components. We explore a) the validity of having a single fixed set of model coefficients for the whole brain and b) the stability of the model coefficients in a large cohort
- …
