title: BOLD responses to different temporospatial frequency stimuli in V1 and V2 visual cortex of anisometropic amblyopia.
abstract: OBJECTIVE
  Functional magnetic resonance imaging (fMRI) is the most advanced neuroimaging technique. The aim of this study was to investigate the blood oxygenation level-dependent (BOLD) of V1 and V2 visual cortex in anisometropic amblyopia with fMRI and explore the neural mechanism of amblyopia.
  
  
  METHODS
  fMRI was performed with a 3.0-T MRI scanner during reversal checkerboard visual stimulation with different spatial frequencies (SF) of 0.4, 2, and 8 cpd in 2 states of temporal frequencies (TF) of 6 Hz and 8 Hz in a group of patients with anisometropic amblyopia (n=5) and a group of normal observers (n=4). Data were processed by SPM software offline. Responses of different eyes were compared in different conditions.
  
  
  RESULTS
  The BOLD signal magnitude in V1 and V2 visual cortex of amblyopic eyes was significantly lower than the fellow eyes with anisometropic amblyopia at low SF (0.4-2 cpd) (p<0.05), but it was significantly higher than the fellow eyes at high SF (8 cpd) (p<0.05). The BOLD signal magnitude in V1 and V2 visual cortex of amblyopic eyes was significantly lower than the nondominant eyes in normal subjects in all conditions (p<0.001).
  
  
  CONCLUSIONS
  There are cortical deficits in V1 and V2 visual cortex of anisometropic amblyopia, which may be useful for selecting an optimum stimulus at proper temporospatial frequency.
authors.affiliation: Department of Ophthalmology, West China Hospital of Sichuan University, Sichuan, PR, China; Yongchuan Hospital, Chongqing Medical University, Chongqing, PR, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Xubo
authors.initials: X
authors.lastname: Yang
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.forename: Huafu
authors.initials: H
authors.lastname: Chen
authors.forename: Meng
authors.initials: M
authors.lastname: Liao
authors.forename: Longqian
authors.initials: L
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000550:Amblyopia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D010775:Photic Stimulation; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology; D014793:Visual Cortex / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D010100:Oxygen