title: Brain mediators of systemic oxidative stress on perceptual impairments in Parkinson's disease.
abstract: BACKGROUND
  Parkinson's disease (PD) is well documented to be associated with elevated systemic oxidative stress and perceptual impairments. Furthermore, the striatum and extrastriatal cortical areas, which are involved in the coordination of perceptual functions, are impaired at an early stage of the disease. However, the possible pathophysiology involved in perceptual impairments remains unclear. This raises the possibility that structural abnormalities might mediate the relationship between oxidative stress and perceptual impairments.
  
  
  METHODS
  We explored the differences between 27 patients with PD and 25 healthy controls in terms of serum oxidative stress, perceptual functions, and regional gray matter. A single-level three-variable mediation model was used to investigate the possible relationships between serum oxidative stress, regional gray matter volume, and different domains of perceptual functioning.
  
  
  RESULTS
  The results demonstrate that increased serum oxidative stress (as indicated by thiobarbituric acid reactive substances) was associated with declined perceptual functioning in PD patients. We further explored significant gray matter volume reductions in the bilateral temporal gyri (middle temporal gyrus and fusiform gyrus), bilateral frontal gyri, limbic lobe (hippocampus and uncus), left inferior parietal lobule, right caudate nucleus, and insula in PD. Further mediation analysis showed that gray matter volumes in the middle temporal gyrus, inferior parietal lobule, hippocampus, and insula served as brain mediators between elevated serum oxidative stress and perceptual impairments.
  
  
  CONCLUSIONS
  These results suggest that higher oxidative stress levels adversely impact perceptual functions by causing temporal and mesolimbic abnormalities.
authors.affiliation: Department of Diagnostic Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. u64lin@yahoo.com.tw.
authors.forename: Wei-Che
authors.initials: WC
authors.lastname: Lin
authors.affiliation: Brain Research Center, National Yang-Ming University, Taipei, Taiwan. dargonchow@gmail.com.
authors.forename: Kun-Hsien
authors.initials: KH
authors.lastname: Chou
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, Institute of Neuroscience, National Yang-Ming University, 155 Li-Nong St., Sec. 2, Peitou, Taipei, Taiwan. lynnlee0226@gmail.com.
authors.forename: Pei-Lin
authors.initials: PL
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. ychbibi@gmail.com.
authors.forename: Yung-Cheng
authors.initials: YC
authors.lastname: Huang
authors.affiliation: Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta Pei Road, Niao Sung, Kaohsiung, Taiwan. tsainw@yahoo.com.tw.
authors.forename: Nai-Wen
authors.initials: NW
authors.lastname: Tsai
authors.affiliation: Department of Diagnostic Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. suring.tw@gmail.com.|Department of Biomedical Imaging and Radiological Sciences, Institute of Neuroscience, National Yang-Ming University, 155 Li-Nong St., Sec. 2, Peitou, Taipei, Taiwan. suring.tw@gmail.com.
authors.forename: Hsiu-Ling
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta Pei Road, Niao Sung, Kaohsiung, Taiwan. 2221@adm.cgmh.org.tw.
authors.forename: Kuei-Yueh
authors.initials: KY
authors.lastname: Cheng
authors.affiliation: Department of Neurosurgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. m82whc@yahoo.com.tw.
authors.forename: Hung-Chen
authors.initials: HC
authors.lastname: Wang
authors.affiliation: Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta Pei Road, Niao Sung, Kaohsiung, Taiwan. tklin@adm.cgmh.org.tw.
authors.forename: Tsu-Kung
authors.initials: TK
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. lee0624@adm.cgmh.org.tw.
authors.forename: Shau-Hsuan
authors.initials: SH
authors.lastname: Li
authors.affiliation: Department of Diagnostic Radiology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. sperfect@msn.com.
authors.forename: Meng-Hsiang
authors.initials: MH
authors.lastname: Chen
authors.affiliation: Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, 123, Ta Pei Road, Niao Sung, Kaohsiung, Taiwan. chlu99@adm.cgmh.org.tw.
authors.forename: Cheng-Hsien
authors.initials: CH
authors.lastname: Lu
authors.affiliation: Brain Research Center, National Yang-Ming University, Taipei, Taiwan. cplin@ym.edu.tw.|Department of Biomedical Imaging and Radiological Sciences, Institute of Neuroscience, National Yang-Ming University, 155 Li-Nong St., Sec. 2, Peitou, Taipei, Taiwan. cplin@ym.edu.tw.
authors.forename: Ching-Po
authors.initials: CP
authors.lastname: Lin
mesh_terms: D000368:Aged; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D018384:Oxidative Stress; D010300:Parkinson Disease / Q000378:metabolism / Q000503:physiopathology*; D010465:Perception