title: Local-global processing in early-onset schizophrenia: evidence for an impairment in shifting the spatial scale of attention.
abstract: In this study we report the results of two experiments on visual attention conducted with patients with early-onset schizophrenia. These experiments investigated the effect of irrelevant spatial-scale information upon the processing of relevant spatial-scale information, and the ability to shift the spatial scale of attention, across consecutive trials, between different levels of the hierarchical stimulus. Twelve patients with early-onset schizophrenia and matched controls performed local-global tasks under: (1) directed attention conditions with a consistency manipulation and (2) divided-attention conditions. In the directed-attention paradigm, the early-onset patients exhibited the normal patterns of global advantage and interference, and were not unduly affected by the consistency manipulation. Under divided-attention conditions, however, the early-onset patients exhibited a local-processing deficit. The source of this local processing deficit lay in the prolonged reaction time to local targets, when these had been preceded by a global target, but not when preceded by a local target. These findings suggest an impaired ability to shift the spatial scale of attention from a global to a local spatial scale in early-onset schizophrenia.
authors.affiliation: Department of Psychology, Monash University, Clayton, Vic, Australia. bellgrom@tcd.ie
authors.forename: Mark A
authors.initials: MA
authors.lastname: Bellgrove
authors.forename: Alasdair
authors.initials: A
authors.lastname: Vance
authors.forename: John L
authors.initials: JL
authors.lastname: Bradshaw
mesh_terms: D000293:Adolescent; D000339:Affect; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001288:Attention / Q000502:physiology*; D001569:Benzodiazepines; D003006:Clopenthixol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D003975:Diazepam / Q000627:therapeutic use; D005260:Female; D005475:Flupenthixol / Q000627:therapeutic use; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008297:Male; D000077152:Olanzapine; D010296:Parietal Lobe / Q000503:physiopathology; D010468:Perceptual Disorders / Q000209:etiology*; D010890:Pirenzepine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D011930:Reaction Time; D018967:Risperidone / Q000627:therapeutic use; D012559:Schizophrenia / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; C060342:clopenthixol acetate ester; D001569:Benzodiazepines; D010890:Pirenzepine; D003006:Clopenthixol; D005475:Flupenthixol; D018967:Risperidone; D000077152:Olanzapine; D003975:Diazepam