Neuroimaging of Insomnia Disorder

Insomnia disorder characterised by persistent difficulty in initiating or maintaining sleep has been the focus of extensive neuroimaging research aiming to elucidate its neural substrates and guide therapeutic development. Modern magnetic resonance imaging approaches, including structural, diffusion‐weighted and resting‐state functional modalities, have revealed that insomnia is associated with both macrostructural and microstructural alterations, as well as aberrant functional interactions among distributed brain networks. Structural studies highlight regional grey‐matter volume changes, particularly in prefrontal and orbitofrontal cortices, while diffusion‐weighted imaging has identified altered white‐matter integrity across frontoparietal and limbic pathways. Concurrently, resting‐state functional MRI has consistently demonstrated dysregulated connectivity within key networks, such as the default mode, salience and frontostriatal circuits, supporting a hyperarousal model of insomnia, where heightened salience‐network activity disrupts normal sleep–wake regulation. Graph theoretical analyses further indicate that insomnia entails disrupted network topology, characterised by altered global efficiency and hub connectivity, which correlate with clinical severity and cognitive impairments. Together, these findings offer a neurobiological framework for subtyping insomnia, predicting treatment response and developing targeted interventions.

Research from Nature Portfolio

Graph theory‐driven analyses have begun to uncover neural risk factors by mapping the topology of whole‐brain functional networks in insomnia disorder. Recent studies using seed‐based and network metrics reveal that individuals with primary insomnia show altered connection properties in executive control, default mode and salience networks, as well as disrupted inter‐network interactions with language and emotion‐related regions. These complex network alterations correlate with insomnia severity and negative emotional states, suggesting potential neuroimaging markers to distinguish affected individuals and inform personalised therapeutic strategies. This work underscores the importance of network‐level approaches in characterising the pathophysiology of insomnia.

Neuroimaging of Insomnia Disorder publication trend

The graph below shows the total number of articles in neuroimaging of insomnia disorder across all publications each year (not limited to Nature Index journals).

Technical terms

Functional magnetic resonance imaging (fMRI): A neuroimaging technique that measures brain activity by detecting changes associated with blood oxygenation.

Fractional anisotropy (FA): A diffusion MRI metric indicating the directional coherence of water diffusion, used to assess white‐matter integrity.

Resting‐state functional connectivity: Assessment of spontaneous synchrony between brain regions when a subject is not engaged in a specific task, revealing intrinsic network organisation.

Default mode network (DMN): A set of interconnected brain regions active during rest and internal thought, often implicated in self‐referential processing.

Salience network: A brain network including anterior insula and anterior cingulate cortex that detects and filters salient stimuli to guide behaviour.

Graph theory: A mathematical framework for analysing complex networks by representing brain regions as nodes and their connections as edges, enabling quantification of network properties.

References

1. Insomnia Subtypes Have Differentiating Deviations in Brain Structural Connectivity. Biological Psychiatry (2024).
2. Altered functional connectivity of the default mode and frontal control networks in patients with insomnia. CNS Neuroscience & Therapeutics (2023).
3. Hyperarousal and Beyond: New Insights to the Pathophysiology of Insomnia Disorder through Functional Neuroimaging Studies. Brain Sciences (2017).
4. Orbitofrontal Gray Matter Relates to Early Morning Awakening: A Neural Correlate of Insomnia Complaints?. Frontiers in Neurology (2012).
5. Disrupted Topology of Frontostriatal Circuits Is Linked to the Severity of Insomnia. Frontiers in Neuroscience (2017).
6. Enhanced Network Efficiency of Functional Brain Networks in Primary Insomnia Patients. Frontiers in Psychiatry (2018).
7. Altered connection properties of important network hubs may be neural risk factors for individuals with primary insomnia. Scientific Reports (2018).