Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Más filtros

Banco de datos
Tipo del documento
Asunto de la revista
Intervalo de año de publicación
1.
Proc Natl Acad Sci U S A ; 109(8): 3131-6, 2012 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-22323591

RESUMEN

Resting-state functional magnetic resonance imaging has become a powerful tool for the study of functional networks in the brain. Even "at rest," the brain's different functional networks spontaneously fluctuate in their activity level; each network's spatial extent can therefore be mapped by finding temporal correlations between its different subregions. Current correlation-based approaches measure the average functional connectivity between regions, but this average is less meaningful for regions that are part of multiple networks; one ideally wants a network model that explicitly allows overlap, for example, allowing a region's activity pattern to reflect one network's activity some of the time, and another network's activity at other times. However, even those approaches that do allow overlap have often maximized mutual spatial independence, which may be suboptimal if distinct networks have significant overlap. In this work, we identify functionally distinct networks by virtue of their temporal independence, taking advantage of the additional temporal richness available via improvements in functional magnetic resonance imaging sampling rate. We identify multiple "temporal functional modes," including several that subdivide the default-mode network (and the regions anticorrelated with it) into several functionally distinct, spatially overlapping, networks, each with its own pattern of correlations and anticorrelations. These functionally distinct modes of spontaneous brain activity are, in general, quite different from resting-state networks previously reported, and may have greater biological interpretability.


Asunto(s)
Mapeo Encefálico , Encéfalo/fisiología , Adulto , Cognición/fisiología , Giro del Cíngulo/fisiología , Humanos , Imagen por Resonancia Magnética , Actividad Motora/fisiología , Red Nerviosa/fisiología , Reproducibilidad de los Resultados , Factores de Tiempo , Vías Visuales/fisiología
2.
Psychiatry Res Neuroimaging ; 247: 49-56, 2016 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-26674413

RESUMEN

Neuroimaging research has implicated abnormalities in cortico-striatal-thalamic-cortical (CSTC) circuitry in pediatric obsessive-compulsive disorder (OCD). In this study, resting-state functional magnetic resonance imaging (R-fMRI) was used to investigate functional connectivity in the CSTC circuitry in adolescents with OCD. Imaging was obtained with the Human Connectome Project (HCP) scanner using newly developed pulse sequences which allow for higher spatial and temporal resolution. Fifteen adolescents with OCD and 13 age- and gender-matched healthy controls (ages 12-19) underwent R-fMRI on the 3T HCP scanner. Twenty-four minutes of resting-state scans (two consecutive 12-min scans) were acquired. We investigated functional connectivity of the striatum using a seed-based, whole brain approach with anatomically-defined seeds placed in the bilateral caudate, putamen, and nucleus accumbens. Adolescents with OCD compared with controls exhibited significantly lower functional connectivity between the left putamen and a single cluster of right-sided cortical areas including parts of the orbitofrontal cortex, inferior frontal gyrus, insula, and operculum. Preliminary findings suggest that impaired striatal connectivity in adolescents with OCD in part falls within the predicted CSTC network, and also involves impaired connections between a key CSTC network region (i.e., putamen) and key regions in the salience network (i.e., insula/operculum). The relevance of impaired putamen-insula/operculum connectivity in OCD is discussed.


Asunto(s)
Mapeo Encefálico , Encéfalo/fisiopatología , Imagen por Resonancia Magnética/métodos , Vías Nerviosas/patología , Trastorno Obsesivo Compulsivo/fisiopatología , Corteza Prefrontal/fisiopatología , Tálamo/fisiopatología , Adolescente , Encéfalo/patología , Estudios de Casos y Controles , Corteza Cerebral/patología , Niño , Cuerpo Estriado/patología , Femenino , Humanos , Masculino , Núcleo Accumbens/fisiopatología , Trastorno Obsesivo Compulsivo/diagnóstico , Putamen/fisiopatología , Procesamiento de Señales Asistido por Computador , Tálamo/patología , Adulto Joven
3.
Artif Intell Med ; 25(1): 19-33, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12009261

RESUMEN

In this paper, Kohonen's self-organizing mapping (SOM) is used as a data-driven technique for analyzing functional magnetic resonance imaging (fMRI) data. Upon the completion of an SOM analysis, a cluster merging technique, based on examining the reproducibility of the fMRI data across epochs, is utilized to merge SOM nodes whose feature vectors are sufficiently similar to one another. The resulting 'super nodes' give time course templates of potential interest. These templates can be subsequently used in traditional template-based analysis methods, such as cross-correlation analysis, yielding statistical maps and activation patterns. This technique has been demonstrated on two fMRI datasets obtained from a visually-guided motor paradigm and a visual paradigm, respectively, showing satisfactory results.


Asunto(s)
Encéfalo/fisiología , Imagen por Resonancia Magnética , Algoritmos , Interpretación Estadística de Datos , Humanos , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA