title: Hemispheric dominance during the mental rotation task in patients with schizophrenia.
abstract: BACKGROUND
  Mental rotation is a spatial representation conversion capability using an imagined object and either object or self-rotation. This capability is impaired in schizophrenia.
  
  
  OBJECTIVE
  To provide a more detailed assessment of impaired cognitive functioning in schizophrenia by comparing the electrophysiological profiles of patients with schizophrenia and controls while completing a mental rotation task using both normally-oriented images and mirror images.
  
  
  METHODS
  This electroencephalographic study compared error rates, reaction times and the topographic map of event-related potentials in 32 participants with schizophrenia and 29 healthy controls during mental rotation tasks involving both normal images and mirror images.
  
  
  RESULTS
  Among controls the mean error rate and the mean reaction time for normal images and mirror images were not significantly different but in the patient group the mean (sd) error rate was higher for mirror images than for normal images (42% [6%] vs. 32% [9%], t=2.64, p=0.031) and the mean reaction time was longer for mirror images than for normal images (587 [11] ms vs. 571 [18] ms, t=2.83, p=0.028). The amplitude of the P500 component at Pz (parietal area), Cz (central area), P3 (left parietal area) and P4 (right parietal area) were significantly lower in the patient group than in the control group for both normal images and mirror images. In both groups the P500 for both the normal and mirror images was significantly higher in the right parietal area (P4) compared with left parietal area (P3).
  
  
  CONCLUSIONS
  The mental rotation abilities of patients with schizophrenia for both normally-oriented images and mirror images are impaired. Patients with schizophrenia show a diminished left cerebral contribution to the mental rotation task, a more rapid response time, and a differential response to normal images versus mirror images not seen in healthy controls. Specific topographic characteristics of the EEG during mental rotation tasks are potential biomarkers for schizophrenia.
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Jiu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Laiqi
authors.initials: L
authors.lastname: Yang
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Li
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Guangxiong
authors.initials: G
authors.lastname: Liu
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Ma
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Xingqu
authors.initials: X
authors.lastname: Wu
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Zihe
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Center for Mental Disease Control and Prevention, Third Hospital of the People's Liberation Army, Baoji, Shaanxi Province, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Tuo