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

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Proc Natl Acad Sci U S A ; 117(46): 28678-28683, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33127755

RESUMO

The abundance of media options is a central feature of today's information environment. Many accounts, often based on analysis of desktop-only news use, suggest that this increased choice leads to audience fragmentation, ideological segregation, and echo chambers with no cross-cutting exposure. Contrary to many of those claims, this paper uses observational multiplatform data capturing both desktop and mobile use to demonstrate that coexposure to diverse news is on the rise, and that ideological self-selection does not explain most of that coexposure. We show that mainstream media outlets offer the common ground where ideologically diverse audiences converge online, though our analysis also reveals that more than half of the US online population consumes no online news, underlining the risk of increased information inequality driven by self-selection along lines of interest. For this study, we use an unprecedented combination of observed data from the United States comprising a 5-y time window and involving tens of thousands of panelists. Our dataset traces news consumption across different devices and unveils important differences in news diets when multiplatform or desktop-only access is used. We discuss the implications of our findings for how we think about the current communication environment, exposure to news, and ongoing attempts to limit the effects of misinformation.

2.
IEEE Trans Neural Syst Rehabil Eng ; 25(8): 1287-1296, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-27654834

RESUMO

Ischemic stroke causes a series of complex pathophysiological events in the brain. Electrical stimulation of the brain has been considered as a novel neuroprotection intervention to save the penumbra. However, the effect on the cells' responsiveness and their ability to survive has yet to be established. The objective of the present study was to investigate the effects of low-frequency intracortical electrical stimulation (lf-ICES) applied to the ischemia-affected sensorimotor cortex immediately following ischemic stroke. Twenty male Sprague-Dawley rats were instrumented with an intracortical microelectrode array (IC MEA) and a cuff-electrode around the sciatic nerve. Photothrombosis intervention was performed within the sensorimotor cortex and the electrophysiological changes were assessed by analysis of the neural responses to stimulation of the sciatic nerve. Neuroprotection intervention consisted of eight 23 min lf-ICES blocks applied to the IC MEA during the initial 4 h following photothrombosis. Our results revealed that the area and magnitude of the sensorimotor cortex response significantly increased if ischemic stroke was allowed to progress uninterrupted, whereas this was not observed for the group of rats subjected to lf-ICES. Our findings indicate that low-frequency electrical stimulation is able to minimize hyperexcitability and may therefore be a candidate as neuroprotection intervention in the future.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical , Estimulação Encefálica Profunda/métodos , Rede Nervosa/fisiopatologia , Córtex Sensório-Motor/fisiopatologia , Acidente Vascular Cerebral/prevenção & controle , Acidente Vascular Cerebral/fisiopatologia , Doença Aguda , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento
3.
IEEE Trans Neural Syst Rehabil Eng ; 21(6): 1006-15, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24122563

RESUMO

The aim of the present study was to investigate the effects of ischemic stroke and onset of subsequent rehabilitation of gait function in rats. Nine male Sprague-Dawley rats were instrumented with a 16-channel intracortical (IC) electrode array. An ischemic stroke was induced within the hindlimb area of the left motor cortex. The rehabilitation consisted of a repetitive training paradigm over 28 days, initiated on day one ("Early-onset", 5 rats) and on day seven, ("Late-onset", 4 rats). Data were obtained from IC microstimulation tests, treadmill walking tests, and beam walking tests. Results revealed an expansion of the hindlimb representation within the motor cortex area and an increased amount of cortical firing rate modulation for the "Early-onset" group but not for the "Late-onset" group. Kinematic data revealed a significant change for both intervention groups. However, this difference was larger for the "Early-onset" group. Results from the beam walking test showed functional performance deficits following stroke which returned to pre-stroke level after the rehabilitative training. The results from the present study indicate the existence of a critical time period following stroke where onset of rehabilitative training may be more effective and related to a higher degree of true recovery.


Assuntos
Modelos Animais de Doenças , Transtornos Neurológicos da Marcha/fisiopatologia , Transtornos Neurológicos da Marcha/reabilitação , Marcha , Córtex Motor/fisiopatologia , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/fisiopatologia , Animais , Isquemia Encefálica/complicações , Isquemia Encefálica/fisiopatologia , Isquemia Encefálica/reabilitação , Terapia por Exercício/métodos , Transtornos Neurológicos da Marcha/etiologia , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/etiologia , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA