Involvement of striate and extrastriate visual cortical areas in spatial attention

Nat Neurosci. 1999 Apr;2(4):364-9. doi: 10.1038/7274.


We investigated the cortical mechanisms of visual-spatial attention while subjects discriminated patterned targets within distractor arrays. Functional magnetic resonance imaging (fMRI) was used to map the boundaries of retinotopic visual areas and to localize attention-related changes in neural activity within several of those areas, including primary visual (striate) cortex. Event-related potentials (ERPs) and modeling of their neural sources, however, indicated that the initial sensory input to striate cortex at 50-55 milliseconds after the stimulus was not modulated by attention. The earliest facilitation of attended signals was observed in extrastriate visual areas, at 70-75 milliseconds. We hypothesize that the striate cortex modulation found with fMRI may represent a delayed, re-entrant feedback from higher visual areas or a sustained biasing of striate cortical neurons during attention. ERP recordings provide critical temporal information for analyzing the functional neuroanatomy of visual attention.

Publication types

  • 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
  • Cerebrovascular Circulation
  • Discrimination, Psychological / physiology
  • Evoked Potentials, Visual
  • Feedback
  • Female
  • Geniculate Bodies / physiology
  • Humans
  • Magnetic Resonance Imaging*
  • Models, Neurological
  • Parietal Lobe / physiology
  • Pattern Recognition, Visual / physiology*
  • Space Perception / physiology*
  • Visual Cortex / physiology*
  • Visual Pathways / physiology