Thalamic structural connectivity profiles in blepharospam/Meige's syndrome

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Blepharospasm is a focal dystonia causing involuntary eyelid spasms, sometimes with oromandibular involvement (Meige's syndrome).
• Functional neuroimaging suggests the thalamus plays a key role in the abnormal brain networks implicated in blepharospasm.

Purpose of the Study:

• To investigate abnormal cortico-thalamic structural connectivity (SC) patterns in blepharospasm.
• To identify co-occurring abnormalities in subcortico-thalamo-cortical projections using diffusion tractography.

Main Methods:

• Diffusion imaging was performed on 17 blepharospasm patients and 17 controls.
• Probabilistic tractography quantified SC between cortical regions and the thalamus.
• Voxel-level thalamic SC mapping and white matter integrity analysis were conducted.

Main Results:

• Patients showed reduced right (pre)motor- and left occipital-thalamic SC.
• A topographic shift in left occipital-thalamic SC distribution was observed in patients.
• Reduced fractional anisotropy was found in dentato-thalamic tracts connecting to motor and occipital cortices.

Conclusions:

• Abnormal motor and occipital SC supports thalamic dysfunction in visual and motor networks in blepharospasm.
• Impaired microstructural integrity in dentato-thalamic tracts suggests cerebellar involvement.