Functional Connectivity of Vim Nucleus in Tremor- and Akinetic-/Rigid-Dominant Parkinson's Disease

The aim of this study was to investigate the involvement of the ventral intermediate nucleus of thalamus (Vim) in the tremor- and akinetic-/rigid-related networks in Parkinson's disease (PD).

Tremor-dominant (TD) and akinetic-/rigid-dominant (ARD) PD patients were recruited and scanned by resting-state functional MRI. Functional connectivity from the Vim nucleus was analyzed.

In the TD patients, the Vim nucleus exhibited increased connectivity with the cerebellum/dentate nucleus, primary motor cortex (M1), supplementary motor area (SMA), premotor cortex, thalamus, globus pallidus, putamen, and parietal cortex compared with the controls, while the connections between the Vim nucleus and M1 and cerebellum/dentate nucleus had positive correlations with the tremor scores. In the ARD patients, the Vim nucleus only showed enhanced connectivity with the globus pallidus and limbic lobe compared with the controls, and no connectivity showed correlation against the akinetic-rigidity scores. TD patients had increased connectivity with the Vim nucleus in the cerebellum, M1, SMA, thalamus, globus pallidus, putamen, and parietal cortex compared with ARD patients.

This study demonstrates that the Vim nucleus has an important role in the tremor-related network, but not in the akinetic-/rigid-related network. Our finding is helpful to explain the selective effect of Vim deep brain stimulation in PD.