Abnormal distraction and load-specific connectivity during working memory in cognitively normal Parkinson's disease

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neurology

Background:

• Visuospatial working memory deficits are prevalent in Parkinson's disease (PD).
• The neural underpinnings of these impairments remain largely unclear.
• Understanding functional connectivity in PD is crucial for identifying mechanisms of cognitive dysfunction.

Purpose of the Study:

• To investigate context-dependent functional connectivity abnormalities in working memory hubs in individuals with PD.
• To differentiate between distraction and load-modulated connectivity during working memory tasks.
• To explore the relationship between aberrant connectivity and cognitive performance in PD.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed in cognitively normal PD patients and controls.
• Participants performed a visuospatial working memory task.
• Connectivity patterns during encoding and retrieval phases were analyzed, disentangling distraction and load effects.

Main Results:

• Despite intact working memory performance, PD participants exhibited abnormal functional connectivity.
• Loss of striatal-prefrontal coupling during encoding (distraction/high load) was observed in PD.
• Upregulated long-range connectivity in PD during encoding and aberrant precuneus/prefrontal connectivity during retrieval were noted.
• Aberrant connectivity patterns correlated with both cognitive deficits and preserved visuospatial skills.

Conclusions:

• PD is associated with distinct patterns of aberrant cortico-cortical and corticostriatal functional connectivity during working memory tasks.
• These connectivity alterations may reflect both pathological and compensatory mechanisms.
• Findings offer insights into neural signatures that could predict future working memory decline in PD.