Connectivity abnormalities observed on MRIs of insomnia patients
Functional magnetic resonance imaging can offer insight into brain connectivity abnormalities and how they correlate with cognitive impairments observed in patients with insomnia.
Experts compared two sets of patients who underwent both resting-state functional MRI (rs-fMRI) and three-dimensional arterial spin labeling (3D ASL) to examine the functional connectivity of the thalamus. Given that the thalamus plays a vital role in sleep and wakefulness, researchers hypothesized that the scans might identify abnormalities in functional connectivity patterns and perfusion in patients with disordered sleeping.
“Thalamic neurons modulate the generation of sleep spindles and regulate sleep/wakefulness,” corresponding author Lianping Zhao, of the Department of Radiology at Gansu Provincial Hospital in Gansu, China, and co-authors wrote. “Based on the previous literature, these findings demonstrate that the thalamus plays a crucial role in sleep-related physiological phenomena, and the dysfunction of thalamus might be associated with the neurobiological mechanisms of insomnia disorder.”
Experts with the Sleep Medicine Center and Department of Radiology at Gansu Provincial Hospital obtained rs-fMRI and 3D ASL scans on a group of 56 patients diagnosed with insomnia disorder and a cohort of 59 healthy control individuals. Whole brain connectivity was measured using rs-fMRI and cerebral blood-flow of the bilateral thalamus was assessed via 3D ASL technique.
The imaging identified a number of alterations in the group of patients with insomnia. Increased connectivity was observed in several areas of interest, including between the left thalamus and right precentral gyrus, and right thalamus and left middle frontal gyrus (MFG), right superior parietal lobule (SPL) and right superior frontal gyrus (SFG). During wakefulness, there were no significant differences noted in bilateral thalamus CBF.
The authors explained that the increased connectivity observed in those with insomnia could lead to hypersensitivity to external stimulation, which would result in a state of hyperarousal.
“There were several alterations in the resting-state functional connectivity in patients with insomnia disorder. One possibility is that resting-state functional connectivity may be more sensitive than cerebral blood perfusion in functional alteration in patients with insomnia disorder, thus further longitudinal studies were needed to confirm this speculation,” they wrote.
The full paper can be viewed in Clinical Imaging.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.