title: Extinction and anti-extinction: the "attentional waiting" hypothesis.
abstract: OBJECTIVE
  Patients with visual extinction have difficulty detecting a single contralesional stimulus when a second stimulus is simultaneously presented on the ipsilesional side. The rarely reported phenomenon of visual anti-extinction describes the opposite behavior, in which patients show greater difficulty in reporting a stimulus presented in isolation than they do in reporting 2 simultaneously presented stimuli. S. J. Goodrich and R. Ward (1997, Anti-extinction following unilateral parietal damage, Cognitive Neuropsychology, Vol. 14, pp. 595-612) suggested that visual anti-extinction is the result of a task-specific mechanism in which processing of the ipsilesional stimulus facilitates responses to the contralesional stimulus; in contrast, G. W. Humphreys, M. J. Riddoch, G. Nys, and D. Heinke (2002, Transient binding by time: Neuropsychological evidence from anti-extinction, Cognitive Neuropsychology, Vol. 19, pp. 361-380) suggested that temporal binding groups contralesional and ipsilesional stimuli together at brief exposure durations.
  
  
  METHODS
  We investigated extinction and anti-extinction phenomena in 3 brain-damaged patients using an extinction paradigm in which the stimulus exposure duration was systematically manipulated.
  
  
  RESULTS
  Two patients showed both extinction and anti-extinction depending on the exposure duration of stimuli. Data confirmed the crucial role of duration in modulating the effect of extinction and anti-extinction. However, contrary to Humphreys and colleagues' (2002) single case, our patients showed extinction for short and anti-extinction for long exposure durations, suggesting that different mechanisms might underlie our patients' pattern of data.
  
  
  CONCLUSIONS
  We discuss a novel "attentional waiting" hypothesis, which proposes that anti-extinction may be observed in patients showing extinction if the exposure duration of stimuli is increased.
authors.affiliation: Psychology Department, Goldsmiths, University of London, London, England. watlingr@regents.ac.uk
authors.forename: Rosamond
authors.initials: R
authors.lastname: Watling
authors.forename: James
authors.initials: J
authors.lastname: Danckert
authors.forename: Karina J
authors.initials: KJ
authors.lastname: Linnell
authors.forename: Gianna
authors.initials: G
authors.lastname: Cocchini
mesh_terms: D000368:Aged; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000209:etiology*; D001930:Brain Injuries / Q000150:complications*; D005108:Extinction, Psychological / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007859:Learning Disabilities / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011569:Psychiatric Status Rating Scales