Graves' disease-associated dopaminergic system dysfunction and its effects on striatocortical functional connectivity...

Area of Science:

• Neuroscience
• Radiology
• Psychiatry

Background:

• Cognitive deficits in psychiatric disorders are often linked to reduced striatal dopaminergic tone and impaired striatocortical functional connectivity (FC).
• Graves' disease (GD), a hyperthyroidism condition, is associated with decreased striatal dopaminergic tone, potentially causing cognitive impairments.
• This study explores the relationship between striatal dopamine transporter (DAT) availability, striatocortical FC, and cognitive function (IQ) in GD patients.

Purpose of the Study:

• To investigate striatal dopamine transporter (DAT) availability in Graves' disease (GD) patients.
• To examine the impact of DAT availability on striatocortical functional connectivity (FC).
• To assess the relationship between DAT availability, FC, and global cognitive function (IQ) in GD.

Main Methods:

• Recruited 34 GD patients and 24 healthy controls (HCs).
• Measured DAT availability using single-photon emission tomography (SPET).
• Assessed functional connectivity (FC) using resting-state functional MRI (rs-fMRI) and Full-Scale IQ (FIQ).

Main Results:

• GD patients exhibited significantly lower left and right striatal DAT availability compared to HCs.
• Lower DAT availability was strongly associated with altered FC between striatal regions and cortical areas, including the insula and parietal gyrus.
• Significantly lower Full-Scale IQ (FIQ) scores in GD patients were weakly associated with disrupted FC in specific fronto-parietal and temporo-striatal pathways.

Conclusions:

• Cognitive deficits in Graves' disease may stem from a dysfunctional striatal dopaminergic system and altered striatocortical FC.
• Disrupted parieto-striatal connectivity, associated with dopamine function, appears to play a role in compromising IQ in GD patients.
• These findings highlight the importance of the dopamine system and associated brain networks in cognitive function within the context of GD.