Neural fate of ignored stimuli: dissociable effects of perceptual and working memory load

Nat Neurosci. 2004 Sep;7(9):992-6. doi: 10.1038/nn1294. Epub 2004 Aug 1.


Observers commonly experience functional blindness to unattended visual events, and this problem has fuelled an intense debate concerning the fate of unattended visual information in neural processing. Here we used functional magnetic resonance imaging (fMRI) to demonstrate that the type of task that a human subject engages in determines the way in which ignored visual background stimuli are processed in parahippocampal cortex. Increasing the perceptual difficulty of a foveal target task attenuated processing of task-irrelevant background scenes, whereas increasing the number of objects held in working memory did not have this effect. These dissociable effects of perceptual and working memory load clarify how task-irrelevant, unattended stimuli are processed in category-selective areas in human ventral visual cortex.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Attention / physiology*
  • Brain Mapping
  • Female
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Memory, Short-Term / physiology*
  • Oxygen / blood
  • Parahippocampal Gyrus / blood supply
  • Parahippocampal Gyrus / physiology*
  • Photic Stimulation / methods
  • Visual Cortex / physiology*
  • Visual Perception / physiology*


  • Oxygen