title: Response inhibition and error monitoring during a visual go/no-go task in inuit children exposed to lead, polychlorinated biphenyls, and methylmercury.
abstract: BACKGROUND
  Lead (Pb) and polychlorinated biphenyls (PCBs) are neurotoxic contaminants that have been related to impairment in response inhibition.
  
  
  OBJECTIVE
  In this study we examined the neurophysiological correlates of the response inhibition deficits associated with these exposures, using event-related potentials (ERPs) in a sample of school-age Inuit children from Arctic Québec exposed through their traditional diet.
  
  
  METHODS
  In a prospective longitudinal study, we assessed 196 children (mean age, 11.3 years) on a visual go/no-go response inhibition paradigm. Pb, PCB, and mercury (Hg) concentrations were analyzed in cord and current blood samples. Hierarchical multiple regression analyses were conducted to examine the associations of contaminant levels to go/no-go performance (mean reaction time, percent correct go, percent correct no-go) and five ERPs [N2, P3, error-related negativity, error positivity (Pe), and correct response positivity (Pc)] after control for confounding variables.
  
  
  RESULTS
  Current blood Pb concentrations were associated with higher rates of false alarms and with decreased P3 amplitudes to go and no-go trials. Current plasma PCB-153 concentrations were associated with slower reaction times and with reduced amplitudes of the Pe and Pc response-related potentials. Hg concentrations were not related to any outcome on this task but showed significant interactions with other contaminants on certain outcomes.
  
  
  CONCLUSIONS
  These results suggest that Pb exposure during childhood impairs the child's ability to allocate the cognitive resources needed to correctly inhibit a prepotent response, resulting in increased impulsivity. By contrast, postnatal PCB exposure appears to affect processes associated with error monitoring, an aspect of behavioral regulation required to adequately adapt to the changing demands of the environment, which results in reduced task efficiency.
authors.affiliation: Centre de recherche du Centre Hospitalier Universitaire de Québec, Québec, Canada.
authors.forename: Olivier
authors.initials: O
authors.lastname: Boucher
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Burden
authors.forename: Gina
authors.initials: G
authors.lastname: Muckle
authors.forename: Dave
authors.initials: D
authors.lastname: Saint-Amour
authors.forename: Pierre
authors.initials: P
authors.lastname: Ayotte
authors.forename: Éric
authors.initials: É
authors.lastname: Dewailly
authors.forename: Charles A
authors.initials: CA
authors.lastname: Nelson
authors.forename: Sandra W
authors.initials: SW
authors.lastname: Jacobson
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Jacobson
mesh_terms: D000293:Adolescent; D002648:Child; D004569:Electroencephalography; D004785:Environmental Pollutants / Q000097:blood / Q000633:toxicity*; D005074:Evoked Potentials, Visual; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D007266:Inhibition, Psychological; D004930:Inuit; D007854:Lead / Q000097:blood / Q000633:toxicity*; D008137:Longitudinal Studies; D008767:Methylmercury Compounds / Q000097:blood / Q000633:toxicity*; D011078:Polychlorinated Biphenyls / Q000097:blood / Q000633:toxicity*; D011446:Prospective Studies; D011597:Psychomotor Performance; D011792:Quebec; D011930:Reaction Time; D013054:Spectrophotometry, Atomic
chemical_list: D004785:Environmental Pollutants; D008767:Methylmercury Compounds; D007854:Lead; D011078:Polychlorinated Biphenyls; C014024:2,4,5,2',4',5'-hexachlorobiphenyl