Preparatory activity in visual cortex indexes distractor suppression during covert spatial orienting

J Neurophysiol. 2004 Dec;92(6):3538-45. doi: 10.1152/jn.00435.2004. Epub 2004 Jul 14.


The deployment of spatial attention induces retinotopically specific increases in neural activity that occur even before a target stimulus is presented. Although this preparatory activity is thought to prime the attended regions, thereby improving perception and recognition, it is not yet clear whether this activity is a manifestation of signal enhancement at the attended locations or suppression of interference from distracting stimuli (or both). We investigated the functional role of these preparatory shifts by isolating a distractor suppression component of selection. Behavioral data have shown that manipulating the probability that visual distractors will appear modulates distractor suppression without concurrent changes in signal enhancement. In 2 experiments, functional magnetic resonance imaging revealed increased cue-evoked activity in retinotopically specific regions of visual cortex when increased distractor suppression was elicited by a high probability of distractors. This finding directly links cue-evoked preparatory activity in visual cortex with a distractor suppression component of visual selective attention.

Publication types

  • 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
  • Male
  • Orientation / physiology*
  • Photic Stimulation
  • Space Perception / physiology*
  • Visual Cortex / physiology*