Brain mechanisms involved in the control of vocalization

This article reviews recent experimental and clinical literature on the central neural mechanisms involved in vocalization. Various parts of the cerebral cortex, limbic system, basal ganglia, and extrapyramidal system have been shown in human and animal studies to be important in vocalization, but the exact function of these areas with regard to vocal control is unclear. The limbic system and diencephalon project to the midbrain periaqueductal gray (PAG), which may be important for coordination of various muscle groups involved in vocalization. The PAG neurons project to the reticular formation, nucleus retroambiguus, and nucleus ambiguus. Neurons in the nucleus retroambiguus seem to be involved in control of neurons related to the respiratory or laryngeal systems. Different types of motoneurons of the laryngeal muscles in the nucleus ambiguus are related to various functions such as vocalization, swallowing, and respiration.