Altered dynamic brain activity and functional connectivity in thyroid-associated ophthalmopathy.

Area of Science:

• Neuroimaging
• Neuroscience
• Ophthalmology

Background:

• Thyroid-associated ophthalmopathy (TAO) is linked to brain functional disturbances.
• Previous studies rarely focused on the dynamic characteristics of brain activity and functional connectivity (FC) in TAO.

Purpose of the Study:

• To investigate alterations in the temporal variability of brain activity and FC in TAO patients using resting-state functional magnetic resonance imaging (rs-fMRI).
• To explore the neurobiological mechanisms underlying TAO by examining dynamic brain function.

Main Methods:

• Utilized rs-fMRI on 47 TAO patients and 30 healthy controls (HCs).
• Calculated dynamic amplitude of low-frequency fluctuation (dALFF) to assess temporal brain activity variability.
• Performed seed-based dynamic functional connectivity (dFC) analysis to evaluate communication variability between brain regions.
• Analyzed correlations between dALFF, dFC, and clinical indicators.

Main Results:

• TAO patients exhibited decreased dALFF in the left superior occipital gyrus (SOG) and cuneus (CUN).
• Increased dALFF was observed in the left inferior frontal gyrus (IFGtriang, ORBinf), insula (INS), superior temporal gyrus (STG), and temporal pole (TPOsup).
• Reduced dFC was found between the left STG and right middle occipital gyrus (MOG), and between left TPOsup and right calcarine fissure (CAL)/MOG.
• Altered dALFF in SOG/CUN positively correlated with visual acuity and quality of life (QoL) for visual functioning.

Conclusions:

• TAO patients demonstrate abnormal temporal variability in brain activity across vision, emotion, and cognition-related areas.
• Reduced temporal variability in FC is associated with vision deficits in TAO.
• These findings enhance understanding of the neurobiological underpinnings of TAO.