Increased functional connectivity within the salience network in patients with insomnia

Area of Science:

• Neuroscience
• Sleep Medicine
• Psychiatry

Background:

• Insomnia frequently co-occurs with emotional dysregulation, but the underlying neural mechanisms are unclear.
• The salience network (SN) is implicated in both sleep regulation and emotional processing.
• Understanding SN alterations in insomnia is vital for addressing comorbid emotional symptoms.

Purpose of the Study:

• To investigate functional connectivity (FC) changes within the salience network (SN) in individuals with insomnia disorder.
• To explore the relationship between SN FC alterations and clinical measures of sleep quality and emotional distress.

Main Methods:

• Resting-state functional magnetic resonance imaging (fMRI) was used in 30 insomnia patients and 30 healthy controls.
• Seed-based region-to-region connectivity analysis was performed to examine FC within the SN.
• Psychometric assessments included the Hamilton Depression Rating Scale (HAMD), Pittsburgh Sleep Quality Index (PSQI), and Hamilton Anxiety Rating Scale (HAMA).

Main Results:

• Insomnia patients displayed significantly increased FC within the SN compared to healthy controls.
• Key areas with altered FC included connections between the anterior cingulate cortex (ACC) and right superior frontal gyrus (SFG), and between the right insular (INS) and left supramarginal gyrus (SMG).
• Increased SN FC correlated significantly with higher scores on HAMD, PSQI, and HAMA, indicating a link with depression, anxiety, and poor sleep.

Conclusions:

• Elevated functional connectivity within the salience network is associated with insomnia and comorbid emotional dysregulation.
• These findings underscore the SN's critical role in the pathophysiology of insomnia, particularly when accompanied by emotional disturbances.
• Targeting the SN may offer novel therapeutic strategies for insomnia patients experiencing emotional difficulties.