Correlation between Thalamocortical Tract and Default Mode Network with Consciousness Levels in Hypoxic-Ischemic...

Area of Science:

• Neuroscience
• Radiology
• Neurology

Background:

• The thalamocortical tract (TCT) is crucial for relaying sensory and motor information between the thalamus and cerebral cortex.
• The default mode network (DMN) involves interconnected brain regions critical for self-referential thought and consciousness.
• Disorders of consciousness (DOC) following hypoxic-ischemic brain injury (HI-BI) represent a significant clinical challenge.

Purpose of the Study:

• To investigate the relationship between structural integrity of the TCT and DMN and the level of consciousness in patients with HI-BI.
• To compare TCT and DMN metrics between patients with DOC, patients without DOC, and healthy controls.
• To explore correlations between neuroimaging findings and clinical assessments of consciousness.

Main Methods:

• Retrospective study involving 31 HI-BI patients (17 DOC, 14 non-DOC) and 17 healthy controls.
• Magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) were used to assess TCT and DMN.
• Fractional anisotropy (FA) values and tract volumes (TV) of the TCT and DMN were quantified.
• The Coma Recovery Scale-Revised (CRS-R) was administered to assess consciousness levels.

Main Results:

• Patients with DOC showed significantly lower FA values and TV for both TCT and DMN compared to non-DOC patients and controls.
• Non-DOC patients also exhibited significantly lower TCT and DMN TV compared to controls.
• The CRS-R scores strongly correlated with TCT TV, DMN FA, and DMN TV in the DOC group.

Conclusions:

• Structural integrity of the TCT and DMN is significantly impaired in patients with HI-BI and disorders of consciousness.
• These white matter networks are closely associated with the level of consciousness in DOC patients.
• DTI metrics of TCT and DMN may serve as valuable biomarkers for assessing consciousness in HI-BI.