Objective: To elucidate the effect of deep brain stimulation at globus pallidus interna (GPi-DBS) on the functional brain network of patients with Parkinson’s disease (PD).

Background: The classic pathophysiological model based on cortico-basal ganglia-cortical loops is now recognized as limited and incapable of providing explanations for many clinical observations such as the clinical effects of GPi inhibition. In the present study, we aimed at elucidating the influence of GPi-DBS on the functional brain network of PD patients.

Method: We acquired the resting-state functional magnetic resonance images from 14 PD patients with GPi-DBS (8 females, mean age of 63.1±2.0 years) in the conditions of DBS on and off(medication off), and 16 healthy control subjects ( 8 females, mean age of 60.3±1.9 years). Voxel-wise degree centrality was calculated as an indicator of functional connectivity strength. The relationship of the impact of DBS on GPi, estimated using the Lead-DBS software, and the alteration in functional connectivity (DBS-on versus DBS-off) were examined. Furthermore, the functional-connectivity similarity with that of the healthy controls was compared between the conditions of DBS-on and DBS-off in the patients. The difference between the whole-brain functional connectivity for DBS-on versus DBS-off was also examined.

Results: Our results first indicated that the impact of GPi-DBS could explain the global connectivity alterations in the motoric brain regions (e.g., supplementary motor area, r=0.59, p=0.017; precentral gyrus: r=0.43, p=0.056), confirming the influence of GPi-DBS on the motor network. Furthermore, the functional connectivity indices showed a trend of normalization when GPi-DBS was on compared with when GPi-DBS was off (t(13)=2.01, p=0.066). The GPi-DBS increases the degree centrality in the bilateral superior frontal gyri and right middle cingulate gyrus and decreases the degree centrality in the cerebellum (p<0.05, AlphaSim corrected).

Conclusion: Our preliminary results suggest a relationship between the GPi DBS and the alteration of functional connectivity in the motor areas. GPi-DBS has a trend of normalizing the functional brain network of PD patients towards that of healthy controls. The effect of GPi-DBS on the whole-brain functional connectivity is also found, its relationship to the clinical effects needs further exploration.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/effect-of-globus-pallidus-interna-deep-brain-stimulation-on-functional-connectivity-in-patients-with-parkinsons-disease/