Functional connectivity and metabolic brain alterations in sleepwalkers

Area of Science:

• Neuroscience
• Sleep Medicine
• Neuroimaging

Background:

• Disorders of arousal (DoA) involve incomplete awakenings from sleep, with subtle neurophysiologic changes observed even during wakefulness.
• The posterior cingulate cortex (PCC) is crucial for cognitive and emotional processing, making it a key area to investigate in DoA.

Purpose of the Study:

• To investigate brain functional connectivity and the metabolic profile of the anterior and posterior cingulate cortex in patients with DoA.
• To explore potential neurobiological underpinnings of arousal dysfunction and associated symptoms in DoA.

Main Methods:

• Utilized multimodal brain MRI, including resting-state functional MRI (rs-fMRI) and 1H-MR spectroscopy.
• Analyzed functional connectivity (FC) using independent component analysis and seed-based analysis.
• Assessed 15 DoA patients and 15 age/sex-matched healthy controls, including sleep and psychological evaluations.

Main Results:

• DoA patients exhibited altered resting-state functional connectivity (FC) in the sensory-motor network, with increased connectivity in specific cortical and occipital regions.
• A decreased FC was observed between the posterior cingulate cortex (PCC) and other cerebral areas in DoA patients.
• Spectroscopic imaging revealed significantly reduced glutamine levels in the PCC of DoA patients compared to controls.

Conclusions:

• Increased sensory-motor network connectivity in DoA may facilitate motor circuit activation.
• Altered PCC connectivity and metabolism in DoA could be a trait feature contributing to arousal dysfunction and impaired awareness.
• These resting-state alterations may correlate with daytime impairments, suggesting a need for novel management strategies for DoA.