Top-down enhancement and suppression of the magnitude and speed of neural activity.
J Cogn Neurosci
; 17(3): 507-17, 2005 Mar.
Article
em En
| MEDLINE
| ID: mdl-15814009
ABSTRACT
Top-down modulation underlies our ability to selectively attend to relevant stimuli and to ignore irrelevant stimuli. Theories addressing neural mechanisms of top-down modulation are driven by studies that reveal increased magnitude of neural activity in response to directed attention, but are limited by a lack of data reporting modulation of neural processing speed, as well as comparisons with a perceptual (passive view) baseline necessary to evaluate the presence of enhancement and suppression. Utilizing functional MRI (fMRI) and event-related potential recordings (ERPs), we provide converging evidence that both the magnitude of neural activity and the speed of neural processing are modulated by top-down influences. Furthermore, both enhancement and suppression occur relative to a perceptual baseline depending on task instruction. These findings reveal the fine degree of influence that goal-directed attention exerts upon activity within the visual association cortex. We further document capacity limitations in top-down enhancement corresponding with working memory performance deficits.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tempo de Reação
/
Atenção
/
Ureia
/
Córtex Visual
/
Percepção Visual
/
Mapeamento Encefálico
/
Inibição Neural
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Cogn Neurosci
Ano de publicação:
2005
Tipo de documento:
Article