New insights on the role of the insular cortex and habenula in OSA.

PURPOSE: Abnormal structure or function in the central nervous system (CNS) can also affect obstructive sleep apnea (OSA). Because human afferent and motor pathways that regulate apnea are still poorly understood, it is not possible to modify the behavior of motor neurons to control airway function. The purpose of this article is to clear the central control mechanism of genioglossus (GG) and to discuss how altered activity in the limbic system and its related structures might affect OSA development, in order to provide help for the treatment of this disease.

METHODS: Functional magnetic resonance imaging (fMRI) data from previous studies on OSA-related brain damage in human beings plus the data from clinical and animal experiments are summarized. These articles are overviewed to discuss the roles of the limbic system-the insular cortex (Ic), the habenula (Hb), and CNS-in the pathogenesis and mechanisms of OSA.

RESULTS: The Ic, which relays signals through the Hb, may play a role in OSA because activating the Ic causes the Hb to suppress activity of the raphe nucleus (RN), resulting in lower levels of 5-hydroxytryptamine (5-HT) that decreases the muscle tone of the GG. This leads to airway collapse.

CONCLUSIONS: The Ic may be an important region in the development of OSA. Altered activity in the limbic system and its related structures could also be associated with OSA.