Abnormal whole-brain functional connectivity in patients with primary insomnia

Area of Science:

• Neuroscience
• Sleep Medicine
• Psychiatry

Background:

• Insomnia is a prevalent sleep disorder impacting millions globally.
• Understanding the neural mechanisms underlying insomnia is crucial for developing effective treatments.
• The hyperarousal hypothesis suggests that insomnia is characterized by an overactive brain state.

Purpose of the Study:

• To investigate whole-brain functional connectivity abnormalities in insomnia patients.
• To analyze the global distribution of these functional connectivity alterations.
• To explore the relationship between functional connectivity and insomnia severity.

Main Methods:

• Utilized functional magnetic resonance imaging (fMRI) data from 50 insomnia patients and 40 healthy controls.
• Divided the whole brain into 116 regions for connectivity analysis.
• Employed general linear model analyses to compare Pearson's correlation coefficients between groups, controlling for age, sex, and education.

Main Results:

• Insomnia patients displayed increased positive functional connectivity between regions associated with wakefulness, emotion, worry, attention, and sensory-motor functions.
• Decreased positive connectivity was observed between networks that typically inhibit each other, such as the salience and default mode networks.
• Increased functional connectivity correlated with higher scores on depression, insomnia severity, and sleep quality indices.

Conclusions:

• The observed pattern of increased and decreased functional connectivity supports the hyperarousal hypothesis of insomnia.
• Findings suggest that strengthened connectivity may represent function strengthening, while decreased connectivity may indicate function disinhibition.
• This study provides a whole-brain functional connectivity perspective on the neurobiological underpinnings of insomnia.