Dorsolateral prefrontal cortex hyperactivity during inhibitory control in children with ADHD in the antisaccade task
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ORIGINAL RESEARCH
Dorsolateral prefrontal cortex hyperactivity during inhibitory control in children with ADHD in the antisaccade task Juan Fernandez-Ruiz 1 & Rebecca M. Hakvoort Schwerdtfeger 2 & Nadia Alahyane 2,3 & Donald C. Brien 2 & Brian C. Coe 2 & Douglas P. Munoz 2,4,5,6
# Springer Science+Business Media, LLC, part of Springer Nature 2019
Abstract Children with ADHD show significant deficits in response inhibition. A leading hypothesis suggests prefrontal hypoactivation as a possible cause, though, there is conflicting evidence. We tested the hypoactivation hypothesis by analyzing the response inhibition process within the oculomotor system. Twenty-two children diagnosed with ADHD and twenty control (CTRL) children performed the antisaccade task while undergoing an fMRI study with concurrent eye tracking. This task included a preparatory stage that cued a prosaccade (toward a stimuli) or an antisaccade (away from a stimuli) without an actual presentation of a peripheral target. This allowed testing inhibitory control without the confounding activation from an actual response. The ADHD group showed longer reaction times and more antisaccade direction errors. While both groups showed activations in saccade network areas, the ADHD showed significant hyperactivation in the dorsolateral prefrontal cortex during the preparatory stage. No other areas in the saccade network had significant activation differences between groups. Further ADHD group analysis OFF and ON stimulant medication did not show drug-related activation differences. However, they showed a significant correlation between the difference in OFF/ON preparatory activation in the precuneus, and a decrease in the number of antisaccade errors. These results do not support the hypoactivity hypothesis as an inhibitory control deficit general explanation, but instead suggest less efficiency during the inhibitory period of the antisaccade task in children. Our findings contrast with previous results in ADHD adults showing decreased preparatory antisaccade activity, suggesting a significant age-dependent maturation effect associated to the inhibitory response in the oculomotor system. Keywords ADHD . Antisaccades . Precuneus . Dorsolateral prefrontal cortex . Methylphenidate . Childhood
Introduction * Juan Fernandez-Ruiz [email protected] 1
Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Av. Universidad 3000, Coyoacán, 04510 Ciudad de México, Mexico
2
Centre for Neuroscience Studies, Queen’s University, Kingston, Ontario, Canada
3
Laboratoire Vision Action Cognition, Universite Paris Descartes, Paris, France
4
Department of Medicine, Queen’s University, Kingston, Ontario, Canada
5
Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
6
Psychology, Queen’s University, Kingston, Ontario, Canada
Attention-deficit/hyperactivity disorder (ADHD) is one of the most common childhood psychiatric disorders, with a 5% prevalence worldwide (Polanczyk et al. 2007). ADHD is characterized by in
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