Neuromodulation in chronic insomnia: Targeting the dorsal raphe nucleus.

Chronic insomnia is a prevalent disabling disorder that disrupts sleep patterns, mental health and cognitive processes. Although standard treatments, including cognitive-behavioral therapy for insomnia (CBT-I) and medications, treat the disorder in some patients, their use is curtailed by poor adherence or tolerance to adverse effects or only partial amelioration of symptoms. The modulatory site of the serotonergic system and its relationship to sleep-wake control have recently been studied in detail in neuroscience, with a focus on the dorsal raphe nuclei (DRN) as one of the central structures involved in both falling asleep and promoting being asleep. Our objective in the current article is to provide a conceptual model for the exploitation of neuromodulation approaches targeting the DRN as a novel treatment strategy for chronic insomnia. It reviews recent advances in the study of the neurobiology of the DRN, and presents current methodologies for neuromodulation approaches (including transcranial magnetic stimulation, focused ultrasound, and deep brain stimulation paradigms), and discusses how DRN-targeted interventions may offer personalized, biologically informed treatments for individuals with chronic insomnia.