title: Lead-induced impairments in the neural processes related to working memory function.
abstract: BACKGROUND
  It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls.
  
  
  RESULTS
  Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex.
  
  
  CONCLUSIONS
  Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects.
authors.affiliation: Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Jeehye
authors.initials: J
authors.lastname: Seo
authors.affiliation: Korean Industrial Health Association, Seoul, Korea.
authors.forename: Byung-Kook
authors.initials: BK
authors.lastname: Lee
authors.affiliation: Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Seong-Uk
authors.initials: SU
authors.lastname: Jin
authors.affiliation: Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Jang Woo
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Psychiatry, School of Medicine, Keimyung University, Daegu, Korea.
authors.forename: Yang-Tae
authors.initials: YT
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Hun-Kyu
authors.initials: HK
authors.lastname: Ryeom
authors.affiliation: Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Jongmin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Radiology, College of Medicine, Dongguk University, Gyeongju, Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Suh
authors.affiliation: Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Suk Hwan
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Psychiatry, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Sin-Jae
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Occupational and Environmental Medicine, Dongguk University College of Medicine, Dongguk University Ilsan Hospital, Goyang, Korea.
authors.forename: Kyoung Sook
authors.initials: KS
authors.lastname: Jeong
authors.affiliation: Department of Occupational and Environmental Medicine, Soonchunhyan University Hospital, Cheonan, Korea.
authors.forename: Jung-O
authors.initials: JO
authors.lastname: Ham
authors.affiliation: Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Yangho
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Medical & Biological Engineering, Kyungpook National University, Dong-In dong, Jung-gu, Daegu, Korea; Department of Radiology, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea; Department of Molecular Medicine, Kyungpook National University College of Medicine, Dong-In dong, Jung-gu, Daegu, Korea.
authors.forename: Yongmin
authors.initials: Y
authors.lastname: Chang
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D007854:Lead / Q000097:blood; D007855:Lead Poisoning / Q000503:physiopathology / Q000523:psychology*; D008279:Magnetic Resonance Imaging; D008570:Memory, Short-Term / Q000187:drug effects*; D008875:Middle Aged; D009784:Occupational Diseases / Q000503:physiopathology / Q000523:psychology*
chemical_list: D007854:Lead