Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Brain Imaging Behav ; 9(3): 484-99, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25953056

RESUMO

To realize the potential value of tractography in traumatic brain injury (TBI), we must identify metrics that provide meaningful information about functional outcomes. The current study explores quantitative metrics describing the spatial properties of tractography from advanced diffusion imaging (High Definition Fiber Tracking, HDFT). In a small number of right-handed males from military TBI (N = 7) and civilian control (N = 6) samples, both tract homologue symmetry and tract spread (proportion of brain mask voxels contacted) differed for several tracts among civilian controls and extreme groups in the TBI sample (high scorers and low scorers) for verbal recall, serial reaction time, processing speed index, and trail-making. Notably, proportion of voxels contacted in the arcuate fasciculus distinguished high and low performers on the CVLT-II and PSI, potentially reflecting linguistic task demands, and GFA in the left corticospinal tract distinguished high and low performers in PSI and Trail Making Test Part A, potentially reflecting right hand motor response demands. The results suggest that, for advanced diffusion imaging, spatial properties of tractography may add analytic value to measures of tract anisotropy.


Assuntos
Lesões Encefálicas/patologia , Lesões Encefálicas/psicologia , Encéfalo/patologia , Imagem de Tensor de Difusão/métodos , Militares/psicologia , Testes Neuropsicológicos , Adolescente , Adulto , Idoso , Anisotropia , Doença Crônica , Imagem de Difusão por Ressonância Magnética/métodos , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Adulto Jovem
2.
Cereb Cortex ; 25(6): 1509-18, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24334917

RESUMO

Given the importance of gamma oscillations in normal and disturbed cognition, there has been growing interest in their developmental trajectory. In the current study, age-related changes in sensory cortical gamma were studied using the auditory steady-state response (ASSR), indexing cortical activity entrained to a periodic auditory stimulus. A large sample (n = 188) aged 8-22 years had electroencephalography recording of ASSR during 20-, 30-, and 40-Hz click trains, analyzed for evoked amplitude, phase-locking factor (PLF) and cross-frequency coupling (CFC) with lower frequency oscillations. Both 40-Hz evoked power and PLF increased monotonically from 8 through 16 years, and subsequently decreased toward ages 20-22 years. CFC followed a similar pattern, with strongest age-related modulation of 40-Hz amplitude by the phase of delta oscillations. In contrast, the evoked power, PLF and CFC for the 20- and 30-Hz stimulation were distinct from the 40-Hz condition, with flat or decreasing profiles from childhood to early adulthood. The inverted U-shaped developmental trajectory of gamma oscillations may be consistent with interacting maturational processes-such as increasing fast GABA inhibition that enhances gamma activity and synaptic pruning that decreases gamma activity-that may continue from childhood through to adulthood.


Assuntos
Vias Aferentes/fisiologia , Envelhecimento/fisiologia , Encéfalo/fisiologia , Ritmo Gama/fisiologia , Adolescente , Adulto , Fatores Etários , Análise de Variância , Criança , Eletroencefalografia , Feminino , Humanos , Masculino , Análise Espectral , Estatística como Assunto , Fatores de Tempo , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...