Abnormal Neural Responses During Reflexive Blinking in Blepharospasm: An Event-Related Functional MRI Study

Area of Science:

• Neuroscience
• Movement Disorders
• Neuroimaging

Background:

• Blepharospasm is a disabling movement disorder characterized by involuntary eyelid spasms.
• The underlying neurophysiological disruptions remain poorly understood.

Purpose of the Study:

• To investigate the neural substrates of reflexive blinking in blepharospasm patients versus healthy controls.
• Utilizing simultaneous functional MRI and surface electromyography for comprehensive analysis.

Main Methods:

• Recruited 15 blepharospasm patients and 15 healthy controls.
• Induced reflexive eye blinks using air puffs during functional MRI scans.
• Monitored blink responses with surface electromyography and analyzed imaging data via an event-related design.

Main Results:

• Blepharospasm patients showed distinct brain activation patterns during reflexive blinking compared to controls.
• Increased activation was observed in the caudate nucleus, sensorimotor cortices (postcentral gyrus, precentral gyrus), and occipital cortex in patients.
• Disease duration correlated negatively with cerebellar activity during reflexive blinking.

Conclusions:

• Reflexive blinking in blepharospasm is linked to heightened activation in the caudate nucleus and sensorimotor cortices.
• This suggests a potential loss of inhibition within the sensorimotor corticobasal ganglia network.
• Decreasing cerebellar neural response with disease duration may indicate an adaptive role.