Lead exposure, peripheral neurotransmitter levels and cognitive control: A neurobehavioral study in children from Montevideo, Uruguay

Abstract

Introduction

Lead exposure has been linked to significant brain disruptions. However, research on the neural correlates of blood lead level (BLL) and cognitive control remains limited. To address this gap, we investigated event-related potentials (ERPs) during an inhibition task, in conjunction with measurements of serum neurotransmitter availability.

Method

38 children (58 % girls) aged 9–13 years were evaluated using a go/no-go task. Total hits, commission and omission errors were registered. During the task, ERPs were recorded using a 59-channel array. BLL was measured using atomic absorption via flame or graphite furnace ionization techniques. In an exploratory approach, serum level of neurochemical factors such as BDNF, dopamine, serotonin, and GABA in serum were assessed using enzyme-linked immunosorbent assays.

Results

Median BLL was 1.00 µg/dL (IQR = 0.7, 1.7). In generalized linear regression models with Poisson distribution, BLL was associated with a 23 % higher commission errors (IRR [95 % CI] = 1.23 [1.14, 1.34]) and 16 % (1.16 [1.08, 1.22]) total omission errors after adjustment for age, sex, maternal education and hemoglobin level. Two ERPs linked to conflict monitoring (N2) and response inhibition (P3) showed positive, although non-significant, modulation by BLL. Regarding the neurotransmitters, dopamine was correlated with BLL particularly when measured concurrently (Spearman's rho = 0.51, p < 0.005)

Conclusions

BLL are associated with deficits in the inhibition of prepotent responses during pre-adolescence. Such failures can hinder academic and social development and increase risky behaviors. This study is the first to examine peripheral neurotransmitter levels and brain activity associated with cognitive control in Pb-exposed children.