title: Amblyopic-related frontal changes in an orientation discrimination task: a research of P3a event-related potentials in anisometropic amblyopia.
abstract: BACKGROUND
  Amblyopic deficits in the primary and secondary visual cortex have been demonstrated broadly. However, the cognitive process at late stage originating in higher brain area in amblyopes hasn't been studied yet. The aim of this study was to investigate the late cognitive process at the frontal lobe in anisometropic amblyopes of a distinct degree, using visual event-related potential (ERP) techniques.
  
  
  METHODS
  Thirteen severe anisometropic amblyopes, 14 mild-to-moderate anisometropic amblyopes, and 13 control subjects participated in this study. Oddball paradigm (three stimuli: target, novel, and non-target stimuli) of low spatial frequency (1 cycle per degree, CPD) was used to elicit brain ERP waves. Reaction time, accuracy, latency, and amplitude of P3a waves evoked by novel stimuli at Fz electrode (the central electrode at frontal lobe), were analyzed statistically.
  
  
  RESULTS
  Neither accuracy nor reaction time showed significant difference among the three groups. The latency of N200 wave showed no significant difference. The latency of P3a wave was delayed in the amblyopes compared with healthy controls, but there was no significant difference between severe and mild-to-moderate amblyopes. P3a amplitude in mild-to-moderate amblyopes was significantly higher than in controls and severe amblyopes.
  
  
  CONCLUSIONS
  Our findings indicated that the cognitive process in anisometropic amblyopes was impaired, and the compensative effect of P3a amplitude was shown in mild-to-moderate amblyopes. P3a visual ERP could become a useful tool to investigate cognitive processing in amblyopes. Hippokratia 2016, 20(1): 60-66.
authors.affiliation: Department of Optometry and Visual Science, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Optometry and Visual Science, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: X B
authors.initials: XB
authors.lastname: Yang
authors.affiliation: Department of Optometry and Visual Science, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: J L
authors.initials: JL
authors.lastname: Wang
authors.affiliation: Department of Medical Engineering, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: S J
authors.initials: SJ
authors.lastname: Wang
authors.affiliation: Department of Optometry and Visual Science, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: R
authors.initials: R
authors.lastname: Gong
authors.affiliation: Neurobiological Laboratory Center, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Zheng
authors.affiliation: Department of Optometry and Visual Science, West China School of Medicine, Sichuan University, Chengdu, China.
authors.forename: L Q
authors.initials: LQ
authors.lastname: Liu
keywords: Anisometropic amblyopia; Gabor patches; P3a; amplitude; event-related potentials; latency