Top-down enhancement and suppression of the magnitude and speed of neural activity.

Published

Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Gazzaley, A; Cooney, JW; McEvoy, K; Knight, RT; D'Esposito, M

Published Date

  • March 2005

Published In

Volume / Issue

  • 17 / 3

Start / End Page

  • 507 - 517

PubMed ID

  • 15814009

Pubmed Central ID

  • 15814009

Electronic International Standard Serial Number (EISSN)

  • 1530-8898

International Standard Serial Number (ISSN)

  • 0898-929X

Digital Object Identifier (DOI)

  • 10.1162/0898929053279522

Language

  • eng