The Ventral Intermediate Nucleus Differently Modulates Subtype-Related Networks in Parkinson’s Disease

Abstract

Background: Posture instability gait difficulty-dominant (PIGD) and tremor-dominant (TD) are two subtypes of Parkinson’s disease (PD). The thalamus is involved in the neural circuits of both subtypes. However, which subregion of the thalamus has an influence on the PD subtypes remains unclear.Objective: To explore the core subregion of the thalamus showing a significant influence on the PD subtypes and its directional interaction between the PD subtypes.Methods: A total of 79 PD patients (43 TD and 36 PIGD) and 31 normal controls (NC) were enrolled, and the gray matter volume and perfusion characteristics in the thalamus were compared between the three groups. The subregion of the thalamus with significantly different perfusion and volume among three groups was used as the seed of a Granger causality analysis (GCA) to compare the causal connectivity between different subtypes.Results: Perfusion with an increased gradient among the three groups (TD > PIGD > NC) in the bilateral ventral intermediate nucleus (Vim) was observed, which was positively correlated with the clinical tremor scores. The GCA revealed that TD patients had enhanced causal connectivity from the bilateral Vim to the bilateral paracentral gyrus, M1 and the cerebellum compared with the NC group, while the PIGD subtype revealed an increased causal connectivity from the bilateral Vim to the bilateral premotor cortex (preM) and putamen. Additionally, there were positive correlations between the tremor scores and a causal connectivity from the Vim to the cerebellum. The connectivity from the right Vim to the right preM and the right putamen was positively correlated with the PIGD scores.Conclusion: This multilevel analysis showed that the Vim had a significant influence on the PD subtypes and that it differentially mediated the TD and PIGD-related causal connectivity pattern in PD.

Neuroimaging Detectable Differences between Parkinson's Disease Motor Subtypes: A Systematic Review

“…These results show that fMRI and rs‐fMRI are valuable imaging techniques to better understand functional differences in PD subtypes and further underline the importance of cerebellular and basal nuclei activity as well as the STC and CTC tracts in functional PD imaging, with 86 recently denoting the cerebellar‐receiving nucleus of the thalamus, the Vim, as a “key nodal point” in both PD subtypes. It seems that the dysfunction of the STC seen in bradykinesia and rigidity and the primary dysfunction of the CTC in TD are the key functional deficits between PD subtypes 79 .…”

“…In reference 17, the ability to functionally distinguish TD and nTD was influenced by the cerebellum, while in 15 TD showed increased global functional connectivity density (FCD) in the cerebellum anterior lobe relative to AR. In 86, TD showed to have greater connectivity between the bilateral ventral intermediate nucleus (Vim) and the bilateral cerebellum compared to PIGD while reference 87 showed TD to have increased FC between the left putamen and right cerebellum lobule VI and cerebellum crus I compared to PIGD. TD has also shown to have higher FC between the BG and calcarine region (occipital lobe) compared to PIGD 88 .…”

Cerebro-cerebellar motor networks in clinical subtypes of Parkinson’s disease

“…The study is not without limitations. First, the classification of PD motor subtypes in TD/indeterminate/PIGD put forward by Jankovic is inherently unstable 2 , as one subject can shift forward and back to one subtype to another along disease progression 4 , 12 . In addition, it is possible that the two motor subtypes do not represent fixed entities, but rather represent different stages of disease progression.…”

Current applications for magnetic resonance-guided focused ultrasound in the treatment of Parkinson's disease

“…Vim : The Vim is a key relay point of the striatal-thalamocortical and cerebello-thalamocortical circuits and is an important node that is affected in patients with tremor-predominant PD [28] . Therefore, tremor-predominant PD is a good indication for Vim-MRgFUS [Figure 2].…”

“…Vim : The Vim is a key relay point of the striatal-thalamocortical and cerebello-thalamocortical circuits and is an important node that is affected in patients with tremor-predominant PD. [ 28 ] Therefore, tremor-predominant PD is a good indication for Vim-MRgFUS [Figure 2 ]. [ 29 ] Bond et al [ 4 ] conducted a randomized, double-blind controlled study of 27 patients with tremor-predominant PD, of whom 20 patients received unilateral Vim-MRgFUS and seven patients received a sham procedure.…”