Project: Research project

Project Details


When subjects selectively attend to visual stimuli, the event-related
potentials (ERPs) elicited by attended stimuli exhibit early sensory-evoked
Pl (100 ms) and Nl (180 ms) peaks of enhanced amplitude. This pattern
suggests that the mechanism of spatial selective attention involves, in
part, an increase in information flow in the visual pathways via a 'gating'
or 'gain control, process. At present, however, only minimal information
is available regarding either the neural generators of these early
attention-sensitive ERP peaks or the relationship between ERP attention
effects and perceptual processing. Proposed are a series of ERP
experiments investigating the mechanisms of visual selective attention. First, in healthy subjects, the neural bases of spatial selection will
be investigated by analysis of (i) scalp voltage and current density
distributions and (ii) dipole models of the attention-sensitive Pl and Nl
peaks elicited by different classes of visual stimuli. Second, the
perceptual significance of the early, attention-related ERP enhancements
will be investigated in a series of experiments that seek to correlate
signal detection measures (d') with the magnitudes of ERP attention
effects. Third, experiments will investigate the spatial selectivity of
the early Pl and Nl attention effects. ERPs to letter stimuli will be
compared as functions of their (i) distance from the current spatial focus
of attention in two-dimensional space and their (ii) similarity to the
attended-location events in color. Lastly, related experiments in
commissurotomy patients will investigate (i) the contributions of
callosally mediated activity to the attention-sensitive ERPs and (ii) the
hemispheric specialization of color selection. Understanding the basic mechanisms of selective attention will aid in
identifying the physiological bases of cognitive and mental disorders such
as schizophrenia, attention deficit disorder, dementia and learning
Effective start/end date4/1/913/31/97


  • National Institutes of Health
  • National Institutes of Health: $90,831.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health


  • Medicine(all)


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