Neurobiology of Neuronal Network Alteration in Intellectual Disability Related to Fetal Alcohol Spectrum Disorders

Abstract

The molecular and cellular mechanisms by which alcohol produces its deleterious effects on neuronal networks are only now beginning to be understood. This review focused on alcohol-induced neurobiological alterations on neuronal network components underlying information processing, for further understanding of intellectual disability related to FASD. Abnormal neurodevelopmental events related to alcohol-damaged fetal brain included neurogenesis inhibition, aberrant migration, impaired differentiation, exacerbated apoptosis, impaired axon outgrowth and branching altering synaptogenesis and synaptic plasticity, abnormal GABAergic interneurons triggering synaptic inhibitory/excitatory imbalance, reduced myelinogenesis causing injured white matter in prefrontal lobe and atrophied corpus callosum compromising interhemispheric information transfer, the whole compromising neuronal network scaffolding which may lead to biased information processing with deficits in executive function. What added to these abnormalities are smaller gray matter and reduced hippocampus, resulting in cognition and memory failures. As a whole, these developmental disorders may underlie intellectual disability related to FASD. In rodents, these neuronal network components matured mainly during the second and third trimesters equivalents of human gestation. Transferability of results from animal to human was also discussed. It was hoped that the understanding of alcohol-induced neuronal networks failure mechanisms during the developing brain may lay a foundation for prospective new treatments and interventions.