title: Attentional guidance during visual search among patients with schizophrenia.
abstract: The current study investigated visual guidance and saccadic selectivity during visual search among patients with schizophrenia (SCZ). Data from a previous study (Elahipanah, A., Christensen, B.K., & Reingold, E.M., 2008. Visual selective attention among persons with schizophrenia: The distractor ratio effect. Schizophr. Res. 105, 61-67.) suggested that visual guidance for the less frequent distractors in a conjunction search display (i.e., the distractor ratio effect) is intact among SCZ patients. The current study investigated the distractor ratio effect among SCZ patients when: 1) search is more demanding, and 2) search involves motion perception. In addition, eye tracking was employed to directly study saccadic selectivity for the different types of distractors. Twenty-eight SCZ patients receiving a single antipsychotic medication and 26 healthy control participants performed two conjunction search tasks: a within-dimension (i.e., colour × colour) search task; and a cross-dimension (i.e., motion × colour) search task. In each task the relative frequency of distractors was manipulated across 5 levels. Despite slower search times, patients' eye movement data indicated unimpaired visual guidance in both tasks. However, in the motion × colour conjunction search task, patients displayed disproportionate difficulty detecting the moving target when the majority of distractors were also moving. Results demonstrate that bottom-up attentional guidance is unimpaired among patients with SCZ; however, patients' impairment in motion discrimination impedes their ability to detect a moving target against noisy backgrounds.
authors: University of Toronto, Ontario, Canada. ava.elahipanah@utoronto.ca
authors: Ava
authors: A
authors: Elahipanah
authors: Bruce K
authors: BK
authors: Christensen
authors: Eyal M
authors: EM
authors: Reingold
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000209:etiology*; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000150:complications*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult