Journal Article
Response inhibition and error monitoring during a visual go/no-go task in Inuit children exposed to lead, polychlorinated biphenyls, and methylmercury
Boucher, O; Burden, MJ; Muckle, G; Saint-Amour, D; Ayotte, P; Dewailly, É; Nelson, CA; Jacobson, SW; Jacobson, JL
Environmental Health Perspectives
ISSN: 0091-6765
EISSN: 1552-9924
Background: Lead (Pb) and polychlorinated biphenyls (PCBs) are neurotoxic contaminants that have been related to impairment in response inhibition. Objectives: This study examined the neurophysiological correlates of the response inhibition deficits associated with these exposures, using event-related potentials (ERP) in a sample of school-aged 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 analysed 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, % Correct Go, % Correct No-go) and five ERPs (N2, P3, ERN, Pe, and 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 behavioural regulation required to adequately adapt to the changing demands of the environment, which results in reduced task efficiency.
event-related potentials; error monitoring; executive function; lead; methylmercury; neurotoxicity; polychlorinated biphenyls; response inhibition
