Mapping brain structural differences and neuroreceptor correlates in Parkinson's disease visual hallucinations

Area of Science:

• Neuroimaging
• Neurology
• Psychiatry

Background:

• Parkinson's psychosis (PDP) encompasses symptoms like visual hallucinations (VH) in Parkinson's disease (PD).
• Previous neuroimaging studies on PDP neural correlates yielded inconsistent results due to study design and scale limitations.

Purpose of the Study:

• To identify cortical regions and networks associated with VH in PD using a large-scale mega-analysis of structural imaging data.
• To investigate the relationship between these structural changes and neurotransmitter receptor binding.

Main Methods:

• Empirical Bayes harmonisation was used to pool structural imaging data from multiple research groups.
• Cortical morphometrics and structural covariance analyses were performed.
• Associations with neurotransmitter receptor density maps were examined.

Main Results:

• A broader cortical involvement in VH was identified, including the primary visual cortex, surrounding regions, and the hippocampus, independent of cognitive decline.
• Structural covariance analyses indicated the involvement of attentional control networks in PD-VH.
• Neurotransmitter loss was suggested to be linked to observed cortical changes.

Conclusions:

• VH in Parkinson's disease are associated with widespread cortical structural alterations.
• Attentional networks and neurotransmitter deficits may play a significant role in the pathophysiology of PD-VH.