title: The effects of attention and conscious state on the detection of gaps in long duration auditory stimuli.
abstract: OBJECTIVE
  To determine the extent to which the detection of a gap occurring in a long duration stimulus is affected by attention and conscious state.
  
  
  METHODS
  The first experiment manipulated the extent to which active processing was required for the detection of a 20 ms gap in a 1.4 s duration pure tone stimulus. In a second experiment carried out during all-night sleep, a gap was presented in a 1.5 s noise segment having an intensity of 60 or 80 dB SPL.
  
  
  RESULTS
  The gap-elicited N1 did not significantly vary with the extent of active processing during wakefulness. N1 was not elicited by the gap during NREM sleep and was much reduced during REM sleep. A large P2 and later N350 was however observed, varying directly in amplitude with the intensity of the noise segment.
  
  
  CONCLUSIONS
  The operations required for the detection of a physical gap function early in processing, at a pre-conscious level.
  
  
  CONCLUSIONS
  Attention had relatively little effect on the detection of a gap as indexed by the amplitude of N1. Detection of a gap also appears to be made during sleep, as indexed by a large amplitude P2.
authors.affiliation: School of Psychology, University of Ottawa, Ottawa, ON, Canada K1N 6N5. kcampbel@uottawa.ca
authors.forename: Kenneth
authors.initials: K
authors.lastname: Campbell
authors.forename: Margaret
authors.initials: M
authors.lastname: Macdonald
mesh_terms: D000161:Acoustic Stimulation; D016477:Artifacts; D001288:Attention / Q000502:physiology*; D003243:Consciousness / Q000502:physiology*; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D004585:Electrooculography; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology; D012890:Sleep / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult